5G Radio Access Network Architecture: The Dark Side of 5G
5G Radio Access Network Architecture: The Dark Side of 5G explores foundational and advanced topics in Radio Access Network (RAN) architecture and why a re-thinking of that architecture is necessary to support new 5G requirements. The distinguished engineer and editor Sasha Sirotkin has included numerous works written by industry insiders with state of the art research at their disposal. The book explains the relevant standards and technologies from an academic perspective, but also explains why particular standards decisions were made and how a variety of NG-RAN architecture options could be deployed in real-life networks.
All major standards and technologies associated with the NG-RAN architecture are discussed in this book, including 3GPP, O-RAN, Small Cell Forum, IEEE, and IETF. Readers will learn about how a re-design of the RAN architecture would ensure that 5G networks can deliver their promised throughput and low latency KPIs consistently and sustainably.
- An overview of the market drivers of the NG-RAN architecture, like spectrum models, 5G-relevant regulatory considerations, and 5G radio interface technical requirements
- An overview of the 5G System, from the core network, to the RAN, to the radio interface protocols and physical layer, with emphasis on how these are different compared to 4G
- Release-15 RAN architectures defined in 3GPP, O-RAN, and Small Cell Forum
- RAN architecture evolution in Release-16 and Release-17
- Enabling technologies, like virtualization, open source technologies, multi-access edge (MEC) computing, and operations, administration, and management (OAM)
- NG-RAN deployment considerations, objectives, and challenges, like costs, spectrum and radio propagation considerations, and coverage
Perfect for network designers and operators who require a solid understanding of the NG-RAN architecture, 5G Radio Access Network Architecture also belongs on the bookshelves of network engineers who aim to increase their understanding of the standards and technologies relevant to the NG-RAN architecture.
Forensic entomology : an introduction
This invaluable text provides a concise introduction to entomology in a forensic context and is also a practical guide to collecting entomological samples at the crime scene. Forensic Entomology: An Introduction: Assumes no prior knowledge of either entomology or biology Provides background information about the procedures carried out by the professional forensic entomologist in order to determine key information about post-mortem interval presented by insect evidence Includes practical tasks and further reading to enhance understanding of the subject and to enable the reader to gain key laboratory skills and a clear understanding of insect life cycles, the identification features of insects, and aspects of their ecology Glossary, photographs, the style of presentation and numerous illustrations have been designed to assist in the identification of insects associated with the corpse. Keys are included to help students make this identification. - Publisher
Includes bibliographical references (pages 205-219) and index
List of figures -- List of tables -- Preface -- Acknowledgements -- 1. The breadth of forensic entomology -- 1.1. History of forensic entomology -- 1.2. Indicators of time of death -- 1.3. Stages of decomposition of a body -- 1.4. Indicators of physical abuse -- 1.5. Insect larvae : a resource for investigating drug consumption -- 1.6. Insect contamination of food -- 1.7. Further reading -- 2. Identifying flies that are important in forensic entomology -- 2.1. What is a fly and how do I spot one? -- 2.2. Forensically important families of flies -- 2.3. DNA identification of forensically important fly species -- 2.4. Further reading -- 3. Identifying beetles that are important in forensic entomology -- 3.1. What do beetles look like? -- 3.2. Features used in identifying forensically important beetle families -- 3.3. Identification of beetle families using DNA -- 3.4. Further reading -- 4. The life cycles of flies and beetles -- 4.1. The life stages of the fly -- 4.2. The life stages of the beetle -- 4.3. The influence of the environment on specific insect species -- 4.4. Succession of insect species on the corpse and its role in post mortem estimation -- 4.5. Review technique : preparing slides of larval spiracles or mouthparts--preparation of whole slide mounts -- 4.6. Further reading
5. Sampling at the crime scene -- 5.1. Entomological equipment needed to sample from a corpse -- 5.2. The sampling strategy for eggs -- 5.3. Catching adult flying insects at the crime scene -- 5.4. Catching adult crawling insects at the crime scene -- 5.5. Obtaining meteorological data at the crime scene -- 5.6. Review technique : investigating the influence of larval location -- 5.7. Further reading -- 6. Breeding entomological specimens from the crime scene -- 6.1. Returning to the laboratory with the entomological evidence -- 6.2. Fly-rearing conditions in the laboratory -- 6.3. Conditions for successful rearing to the adult (imago) fly stage -- 6.4. Beetle rearing in the laboratory -- 6.5. Dietary requirements of insects reared in the laboratory -- 6.6. Review technique : preserving and mounting insect specimens -- 6.7. Further reading
7. Calculating the post mortem interval -- 7.1. Working out the base temperature -- 7.2. Accumulated degree data -- 7.3. Calculation of accumulated degree hours (or days) from crime scene data -- 7.4. Sources of error -- 7.5. Use of larval growth in length to determine post mortem interval (isomegalen and isomorphen diagrams) -- 7.6. Calculating post mortem interval using succession -- 7.7. Review technique : interpretation of data from a crime scene case study -- 7.8. Further reading -- 8. Ecology of forensically important flies -- 8.1. Ecological features of bluebottles (Calliphoridae) -- 8.2. Greenbottles--Lucilia spp. -- 8.3. Ecological associations with living organisms -- 8.4. Further reading -- 9. Ecology of selected forensically important beetles -- 9.1. Categories of feeding relationship on a corpse -- 9.2. Ecology of carrion beetles (Silphidae) -- 9.3. Ecology of skin, hide and larder beetles (Dermestidae) -- 9.4. Ecology of clown beetles (Histeridae) -- 9.5. Ecology of checkered or bone beetles (Cleridae) -- 9.6. Ecology of rove beetles (Staphylinidae) -- 9.7. Ecology of dung beetles (Scarabaeidae) -- 9.8. Ecology of trogid beetles (Trogidae) -- 9.9. Ecology of ground beetles (Carabidae) -- 9.10. Review technique : determination of succession and PMI -- 9.11. Further reading
10. The forensic entomologist in court -- 10.1. The Statement of Witness -- 10.2. Council for the Registration of Forensic Practitioners -- 10.3. Communicating entomological facts in court -- 10.4. Physical evidence : its continuity and integrity -- 10.5. Review technique : writing a Statement of Witness using the post mortem calculations determined from details given in Chapter 7 -- 10.6. Further reading -- 11. The role of professional associations for forensic entomologists -- 11.1. Professional organizations -- 11.2. Forensic entomology protocols -- 11.3. Areas for future research -- 11.4. Further reading -- Appendices -- Appendix 1. Form for forensic entomology questions to be asked at the crime scene -- Appendix 2. Answers to the calculation of the post mortem interval for the body at the Pleasure Gardens, Wingsea -- Appendix 3. UK list of Calliphoridae (2006) -- Appendix 4. UK checklists for Coleoptera -- Appendix 5. List of relevant UK legal acts and orders -- Appendix 6. Selected sources of entomological equipment -- Appendix 7. Legal information relevant to giving testimony as a forensic entomologist in the USA -- Glossary -- References -- Index
The term conservation biology and its conception as a new field originated with the convening of "The First International Conference on Research in Conservation Biology" held at the University of California, San Diego in La Jolla, California in 1978 led by American biologists Bruce A. Wilcox and Michael E. Soulé with a group of leading university and zoo researchers and conservationists including Kurt Benirschke, Sir Otto Frankel, Thomas Lovejoy, and Jared Diamond. The meeting was prompted by the concern over tropical deforestation, disappearing species, eroding genetic diversity within species.  The conference and proceedings that resulted  sought to initiate the bridging of a gap between theory in ecology and evolutionary genetics on the one hand and conservation policy and practice on the other.  Conservation biology and the concept of biological diversity (biodiversity) emerged together, helping crystallize the modern era of conservation science and policy. The inherent multidisciplinary basis for conservation biology has led to new subdisciplines including conservation social science, conservation behavior and conservation physiology.  It stimulated further development of conservation genetics which Otto Frankel had originated first but is now often considered a subdiscipline as well.
The rapid decline of established biological systems around the world means that conservation biology is often referred to as a "Discipline with a deadline".  Conservation biology is tied closely to ecology in researching the population ecology (dispersal, migration, demographics, effective population size, inbreeding depression, and minimum population viability) of rare or endangered species.   Conservation biology is concerned with phenomena that affect the maintenance, loss, and restoration of biodiversity and the science of sustaining evolutionary processes that engender genetic, population, species, and ecosystem diversity.     The concern stems from estimates suggesting that up to 50% of all species on the planet will disappear within the next 50 years,  which has contributed to poverty, starvation, and will reset the course of evolution on this planet.  
Conservation biologists research and educate on the trends and process of biodiversity loss, species extinctions, and the negative effect these are having on our capabilities to sustain the well-being of human society. Conservation biologists work in the field and office, in government, universities, non-profit organizations and industry. The topics of their research are diverse, because this is an interdisciplinary network with professional alliances in the biological as well as social sciences. Those dedicated to the cause and profession advocate for a global response to the current biodiversity crisis based on morals, ethics, and scientific reason. Organizations and citizens are responding to the biodiversity crisis through conservation action plans that direct research, monitoring, and education programs that engage concerns at local through global scales.    
Natural resource conservation Edit
Conscious efforts to conserve and protect global biodiversity are a recent phenomenon.   Natural resource conservation, however, has a history that extends prior to the age of conservation. Resource ethics grew out of necessity through direct relations with nature. Regulation or communal restraint became necessary to prevent selfish motives from taking more than could be locally sustained, therefore compromising the long-term supply for the rest of the community.  This social dilemma with respect to natural resource management is often called the "Tragedy of the Commons".  
From this principle, conservation biologists can trace communal resource based ethics throughout cultures as a solution to communal resource conflict.  For example, the Alaskan Tlingit peoples and the Haida of the Pacific Northwest had resource boundaries, rules, and restrictions among clans with respect to the fishing of sockeye salmon. These rules were guided by clan elders who knew lifelong details of each river and stream they managed.   There are numerous examples in history where cultures have followed rules, rituals, and organized practice with respect to communal natural resource management.  
The Mauryan emperor Ashoka around 250 B.C. issued edicts restricting the slaughter of animals and certain kinds of birds, as well as opened veterinary clinics.
Conservation ethics are also found in early religious and philosophical writings. There are examples in the Tao, Shinto, Hindu, Islamic and Buddhist traditions.   In Greek philosophy, Plato lamented about pasture land degradation: "What is left now is, so to say, the skeleton of a body wasted by disease the rich, soft soil has been carried off and only the bare framework of the district left."  In the bible, through Moses, God commanded to let the land rest from cultivation every seventh year.   Before the 18th century, however, much of European culture considered it a pagan view to admire nature. Wilderness was denigrated while agricultural development was praised.  However, as early as AD 680 a wildlife sanctuary was founded on the Farne Islands by St Cuthbert in response to his religious beliefs. 
Early naturalists Edit
Natural history was a major preoccupation in the 18th century, with grand expeditions and the opening of popular public displays in Europe and North America. By 1900 there were 150 natural history museums in Germany, 250 in Great Britain, 250 in the United States, and 300 in France.  Preservationist or conservationist sentiments are a development of the late 18th to early 20th centuries.
Before Charles Darwin set sail on HMS Beagle, most people in the world, including Darwin, believed in special creation and that all species were unchanged.  George-Louis Leclerc was one of the first naturalist that questioned this belief. He proposed in his 44 volume natural history book that species evolve due to environmental influences.  Erasmus Darwin was also a naturalist who also suggested that species evolved. Erasmus Darwin noted that some species have vestigial structures which are anatomical structures that have no apparent function in the species currently but would have been useful for the species' ancestors.  The thinking of these early 18th century naturalists helped to change the mindset and thinking of the early 19th century naturalists.
By the early 19th century biogeography was ignited through the efforts of Alexander von Humboldt, Charles Lyell and Charles Darwin.  The 19th-century fascination with natural history engendered a fervor to be the first to collect rare specimens with the goal of doing so before they became extinct by other such collectors.   Although the work of many 18th and 19th century naturalists were to inspire nature enthusiasts and conservation organizations, their writings, by modern standards, showed insensitivity towards conservation as they would kill hundreds of specimens for their collections. 
Conservation movement Edit
The modern roots of conservation biology can be found in the late 18th-century Enlightenment period particularly in England and Scotland.   A number of thinkers, among them notably Lord Monboddo,  described the importance of "preserving nature" much of this early emphasis had its origins in Christian theology.
Scientific conservation principles were first practically applied to the forests of British India. The conservation ethic that began to evolve included three core principles: that human activity damaged the environment, that there was a civic duty to maintain the environment for future generations, and that scientific, empirically based methods should be applied to ensure this duty was carried out. Sir James Ranald Martin was prominent in promoting this ideology, publishing many medico-topographical reports that demonstrated the scale of damage wrought through large-scale deforestation and desiccation, and lobbying extensively for the institutionalization of forest conservation activities in British India through the establishment of Forest Departments. 
The Madras Board of Revenue started local conservation efforts in 1842, headed by Alexander Gibson, a professional botanist who systematically adopted a forest conservation program based on scientific principles. This was the first case of state conservation management of forests in the world.  Governor-General Lord Dalhousie introduced the first permanent and large-scale forest conservation program in the world in 1855, a model that soon spread to other colonies, as well the United States,    where Yellowstone National Park was opened in 1872 as the world's first national park. 
The term conservation came into widespread use in the late 19th century and referred to the management, mainly for economic reasons, of such natural resources as timber, fish, game, topsoil, pastureland, and minerals. In addition it referred to the preservation of forests (forestry), wildlife (wildlife refuge), parkland, wilderness, and watersheds. This period also saw the passage of the first conservation legislation and the establishment of the first nature conservation societies. The Sea Birds Preservation Act of 1869 was passed in Britain as the first nature protection law in the world  after extensive lobbying from the Association for the Protection of Seabirds  and the respected ornithologist Alfred Newton.  Newton was also instrumental in the passage of the first Game laws from 1872, which protected animals during their breeding season so as to prevent the stock from being brought close to extinction. 
One of the first conservation societies was the Royal Society for the Protection of Birds, founded in 1889 in Manchester  as a protest group campaigning against the use of great crested grebe and kittiwake skins and feathers in fur clothing. Originally known as "the Plumage League",  the group gained popularity and eventually amalgamated with the Fur and Feather League in Croydon, and formed the RSPB.  The National Trust formed in 1895 with the manifesto to ". promote the permanent preservation, for the benefit of the nation, of lands, . to preserve (so far practicable) their natural aspect." In May 1912, a month after the Titanic sank, banker and expert naturalist Charles Rothschild held a meeting at the Natural History Museum in London to discuss his idea for a new organisation to save the best places for wildlife in the British Isles. This meeting led to the formation of the Society for the Promotion of Nature Reserves, which later became the Wildlife Trusts.
In the United States, the Forest Reserve Act of 1891 gave the President power to set aside forest reserves from the land in the public domain. John Muir founded the Sierra Club in 1892, and the New York Zoological Society was set up in 1895. A series of national forests and preserves were established by Theodore Roosevelt from 1901 to 1909.   The 1916 National Parks Act, included a 'use without impairment' clause, sought by John Muir, which eventually resulted in the removal of a proposal to build a dam in Dinosaur National Monument in 1959. 
In the 20th century, Canadian civil servants, including Charles Gordon Hewitt  and James Harkin spearheaded the movement toward wildlife conservation. 
In the 21st century professional conservation officiers begun to collaborate with indigenous communities for protecting wildlife in Canada. 
Global conservation efforts Edit
In the mid-20th century, efforts arose to target individual species for conservation, notably efforts in big cat conservation in South America led by the New York Zoological Society.  In the early 20th century the New York Zoological Society was instrumental in developing concepts of establishing preserves for particular species and conducting the necessary conservation studies to determine the suitability of locations that are most appropriate as conservation priorities the work of Henry Fairfield Osborn Jr., Carl E. Akeley, Archie Carr and his son Archie Carr III is notable in this era.   [ citation needed ] Akeley for example, having led expeditions to the Virunga Mountains and observed the mountain gorilla in the wild, became convinced that the species and the area were conservation priorities. He was instrumental in persuading Albert I of Belgium to act in defense of the mountain gorilla and establish Albert National Park (since renamed Virunga National Park) in what is now Democratic Republic of Congo. 
By the 1970s, led primarily by work in the United States under the Endangered Species Act  along with the Species at Risk Act (SARA) of Canada, Biodiversity Action Plans developed in Australia, Sweden, the United Kingdom, hundreds of species specific protection plans ensued. Notably the United Nations acted to conserve sites of outstanding cultural or natural importance to the common heritage of mankind. The programme was adopted by the General Conference of UNESCO in 1972. As of 2006, a total of 830 sites are listed: 644 cultural, 162 natural. The first country to pursue aggressive biological conservation through national legislation was the United States, which passed back to back legislation in the Endangered Species Act  (1966) and National Environmental Policy Act (1970),  which together injected major funding and protection measures to large-scale habitat protection and threatened species research. Other conservation developments, however, have taken hold throughout the world. India, for example, passed the Wildlife Protection Act of 1972. 
In 1980, a significant development was the emergence of the urban conservation movement. A local organization was established in Birmingham, UK, a development followed in rapid succession in cities across the UK, then overseas. Although perceived as a grassroots movement, its early development was driven by academic research into urban wildlife. Initially perceived as radical, the movement's view of conservation being inextricably linked with other human activity has now become mainstream in conservation thought. Considerable research effort is now directed at urban conservation biology. The Society for Conservation Biology originated in 1985.  : 2
By 1992, most of the countries of the world had become committed to the principles of conservation of biological diversity with the Convention on Biological Diversity  subsequently many countries began programmes of Biodiversity Action Plans to identify and conserve threatened species within their borders, as well as protect associated habitats. The late 1990s saw increasing professionalism in the sector, with the maturing of organisations such as the Institute of Ecology and Environmental Management and the Society for the Environment.
Since 2000, the concept of landscape scale conservation has risen to prominence, with less emphasis being given to single-species or even single-habitat focused actions. Instead an ecosystem approach is advocated by most mainstream conservationists, although concerns have been expressed by those working to protect some high-profile species.
Ecology has clarified the workings of the biosphere i.e., the complex interrelationships among humans, other species, and the physical environment. The burgeoning human population and associated agriculture, industry, and the ensuing pollution, have demonstrated how easily ecological relationships can be disrupted. 
The last word in ignorance is the man who says of an animal or plant: "What good is it?" If the land mechanism as a whole is good, then every part is good, whether we understand it or not. If the biota, in the course of aeons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering.
Measuring extinction rates Edit
Extinction rates are measured in a variety of ways. Conservation biologists measure and apply statistical measures of fossil records,   rates of habitat loss, and a multitude of other variables such as loss of biodiversity as a function of the rate of habitat loss and site occupancy  to obtain such estimates.  The Theory of Island Biogeography  is possibly the most significant contribution toward the scientific understanding of both the process and how to measure the rate of species extinction. The current background extinction rate is estimated to be one species every few years.  Actual extinction rates are estimated to be orders of magnitudes higher. 
The measure of ongoing species loss is made more complex by the fact that most of the Earth's species have not been described or evaluated. Estimates vary greatly on how many species actually exist (estimated range: 3,600,000-111,700,000)  to how many have received a species binomial (estimated range: 1.5-8 million).  Less than 1% of all species that have been described beyond simply noting its existence.  From these figures, the IUCN reports that 23% of vertebrates, 5% of invertebrates and 70% of plants that have been evaluated are designated as endangered or threatened.   Better knowledge is being constructed by The Plant List for actual numbers of species.
Systematic conservation planning Edit
Systematic conservation planning is an effective way to seek and identify efficient and effective types of reserve design to capture or sustain the highest priority biodiversity values and to work with communities in support of local ecosystems. Margules and Pressey identify six interlinked stages in the systematic planning approach: 
- Compile data on the biodiversity of the planning region
- Identify conservation goals for the planning region
- Review existing conservation areas
- Select additional conservation areas
- Implement conservation actions
- Maintain the required values of conservation areas
Conservation biologists regularly prepare detailed conservation plans for grant proposals or to effectively coordinate their plan of action and to identify best management practices (e.g.  ). Systematic strategies generally employ the services of Geographic Information Systems to assist in the decision making process. The SLOSS debate is often considered in planning.
Conservation physiology: a mechanistic approach to conservation Edit
Conservation physiology was defined by Steven J. Cooke and colleagues as: 'An integrative scientific discipline applying physiological concepts, tools, and knowledge to characterizing biological diversity and its ecological implications understanding and predicting how organisms, populations, and ecosystems respond to environmental change and stressors and solving conservation problems across the broad range of taxa (i.e. including microbes, plants, and animals). Physiology is considered in the broadest possible terms to include functional and mechanistic responses at all scales, and conservation includes the development and refinement of strategies to rebuild populations, restore ecosystems, inform conservation policy, generate decision-support tools, and manage natural resources.'  Conservation physiology is particularly relevant to practitioners in that it has the potential to generate cause-and-effect relationships and reveal the factors that contribute to population declines.
Conservation biology as a profession Edit
The Society for Conservation Biology is a global community of conservation professionals dedicated to advancing the science and practice of conserving biodiversity. Conservation biology as a discipline reaches beyond biology, into subjects such as philosophy, law, economics, humanities, arts, anthropology, and education.   Within biology, conservation genetics and evolution are immense fields unto themselves, but these disciplines are of prime importance to the practice and profession of conservation biology.
Conservationists introduce bias when they support policies using qualitative description, such as habitat degradation, or healthy ecosystems. Conservation biologists advocate for reasoned and sensible management of natural resources and do so with a disclosed combination of science, reason, logic, and values in their conservation management plans.  This sort of advocacy is similar to the medical profession advocating for healthy lifestyle options, both are beneficial to human well-being yet remain scientific in their approach.
There is a movement in conservation biology suggesting a new form of leadership is needed to mobilize conservation biology into a more effective discipline that is able to communicate the full scope of the problem to society at large.  The movement proposes an adaptive leadership approach that parallels an adaptive management approach. The concept is based on a new philosophy or leadership theory steering away from historical notions of power, authority, and dominance. Adaptive conservation leadership is reflective and more equitable as it applies to any member of society who can mobilize others toward meaningful change using communication techniques that are inspiring, purposeful, and collegial. Adaptive conservation leadership and mentoring programs are being implemented by conservation biologists through organizations such as the Aldo Leopold Leadership Program. 
Conservation may be classified as either in-situ conservation, which is protecting an endangered species in its natural habitat, or ex-situ conservation, which occurs outside the natural habitat.  In-situ conservation involves protecting or restoring the habitat. Ex-situ conservation, on the other hand, involves protection outside of an organism's natural habitat, such as on reservations or in gene banks, in circumstances where viable populations may not be present in the natural habitat. 
Also, non-interference may be used, which is termed a preservationist method. Preservationists advocate for giving areas of nature and species a protected existence that halts interference from the humans.  In this regard, conservationists differ from preservationists in the social dimension, as conservation biology engages society and seeks equitable solutions for both society and ecosystems. Some preservationists emphasize the potential of biodiversity in a world without humans.
Ethics and values Edit
Conservation biologists are interdisciplinary researchers that practice ethics in the biological and social sciences. Chan states  that conservationists must advocate for biodiversity and can do so in a scientifically ethical manner by not promoting simultaneous advocacy against other competing values.
A conservationist may be inspired by the resource conservation ethic,  : 15 which seeks to identify what measures will deliver "the greatest good for the greatest number of people for the longest time."  : 13 In contrast, some conservation biologists argue that nature has an intrinsic value that is independent of anthropocentric usefulness or utilitarianism.  : 3,12,16–17 Intrinsic value advocates that a gene, or species, be valued because they have a utility for the ecosystems they sustain. Aldo Leopold was a classical thinker and writer on such conservation ethics whose philosophy, ethics and writings are still valued and revisited by modern conservation biologists.  : 16–17
Conservation priorities Edit
The International Union for the Conservation of Nature (IUCN) International Union for Conservation of Nature has organized a global assortment of scientists and research stations across the planet to monitor the changing state of nature in an effort to tackle the extinction crisis. The IUCN provides annual updates on the status of species conservation through its Red List.  The IUCN Red List serves as an international conservation tool to identify those species most in need of conservation attention and by providing a global index on the status of biodiversity.  More than the dramatic rates of species loss, however, conservation scientists note that the sixth mass extinction is a biodiversity crisis requiring far more action than a priority focus on rare, endemic or endangered species. Concerns for biodiversity loss covers a broader conservation mandate that looks at ecological processes, such as migration, and a holistic examination of biodiversity at levels beyond the species, including genetic, population and ecosystem diversity.  Extensive, systematic, and rapid rates of biodiversity loss threatens the sustained well-being of humanity by limiting supply of ecosystem services that are otherwise regenerated by the complex and evolving holistic network of genetic and ecosystem diversity. While the conservation status of species is employed extensively in conservation management,  some scientists highlight that it is the common species that are the primary source of exploitation and habitat alteration by humanity. Moreover, common species are often undervalued despite their role as the primary source of ecosystem services.  
While most in the community of conservation science "stress the importance" of sustaining biodiversity,  there is debate on how to prioritize genes, species, or ecosystems, which are all components of biodiversity (e.g. Bowen, 1999). While the predominant approach to date has been to focus efforts on endangered species by conserving biodiversity hotspots, some scientists (e.g)  and conservation organizations, such as the Nature Conservancy, argue that it is more cost-effective, logical, and socially relevant to invest in biodiversity coldspots.  The costs of discovering, naming, and mapping out the distribution of every species, they argue, is an ill-advised conservation venture. They reason it is better to understand the significance of the ecological roles of species. 
Biodiversity hotspots and coldspots are a way of recognizing that the spatial concentration of genes, species, and ecosystems is not uniformly distributed on the Earth's surface. For example, "[. ] 44% of all species of vascular plants and 35% of all species in four vertebrate groups are confined to 25 hotspots comprising only 1.4% of the land surface of the Earth." 
Those arguing in favor of setting priorities for coldspots point out that there are other measures to consider beyond biodiversity. They point out that emphasizing hotspots downplays the importance of the social and ecological connections to vast areas of the Earth's ecosystems where biomass, not biodiversity, reigns supreme.  It is estimated that 36% of the Earth's surface, encompassing 38.9% of the worlds vertebrates, lacks the endemic species to qualify as biodiversity hotspot.  Moreover, measures show that maximizing protections for biodiversity does not capture ecosystem services any better than targeting randomly chosen regions.  Population level biodiversity (mostly in coldspots) are disappearing at a rate that is ten times that at the species level.   The level of importance in addressing biomass versus endemism as a concern for conservation biology is highlighted in literature measuring the level of threat to global ecosystem carbon stocks that do not necessarily reside in areas of endemism.   A hotspot priority approach  would not invest so heavily in places such as steppes, the Serengeti, the Arctic, or taiga. These areas contribute a great abundance of population (not species) level biodiversity  and ecosystem services, including cultural value and planetary nutrient cycling. 
Summary of 2006 IUCN Red List categories
Those in favor of the hotspot approach point out that species are irreplaceable components of the global ecosystem, they are concentrated in places that are most threatened, and should therefore receive maximal strategic protections.  The IUCN Red List categories, which appear on Wikipedia species articles, is an example of the hotspot conservation approach in action species that are not rare or endemic are listed the least concern and their Wikipedia articles tend to be ranked low on the importance scale. [ dubious – discuss ] This is a hotspot approach because the priority is set to target species level concerns over population level or biomass.  [ failed verification ] Species richness and genetic biodiversity contributes to and engenders ecosystem stability, ecosystem processes, evolutionary adaptability, and biomass.  Both sides agree, however, that conserving biodiversity is necessary to reduce the extinction rate and identify an inherent value in nature the debate hinges on how to prioritize limited conservation resources in the most cost-effective way.
Economic values and natural capital Edit
Conservation biologists have started to collaborate with leading global economists to determine how to measure the wealth and services of nature and to make these values apparent in global market transactions.  This system of accounting is called natural capital and would, for example, register the value of an ecosystem before it is cleared to make way for development.  The WWF publishes its Living Planet Report and provides a global index of biodiversity by monitoring approximately 5,000 populations in 1,686 species of vertebrate (mammals, birds, fish, reptiles, and amphibians) and report on the trends in much the same way that the stock market is tracked. 
This method of measuring the global economic benefit of nature has been endorsed by the G8+5 leaders and the European Commission.  Nature sustains many ecosystem services  that benefit humanity.  Many of the Earth's ecosystem services are public goods without a market and therefore no price or value.  When the stock market registers a financial crisis, traders on Wall Street are not in the business of trading stocks for much of the planet's living natural capital stored in ecosystems. There is no natural stock market with investment portfolios into sea horses, amphibians, insects, and other creatures that provide a sustainable supply of ecosystem services that are valuable to society.  The ecological footprint of society has exceeded the bio-regenerative capacity limits of the planet's ecosystems by about 30 percent, which is the same percentage of vertebrate populations that have registered decline from 1970 through 2005. 
The inherent natural economy plays an essential role in sustaining humanity,  including the regulation of global atmospheric chemistry, pollinating crops, pest control,  cycling soil nutrients, purifying our water supply,  supplying medicines and health benefits,  and unquantifiable quality of life improvements. There is a relationship, a correlation, between markets and natural capital, and social income inequity and biodiversity loss. This means that there are greater rates of biodiversity loss in places where the inequity of wealth is greatest 
Although a direct market comparison of natural capital is likely insufficient in terms of human value, one measure of ecosystem services suggests the contribution amounts to trillions of dollars yearly.     For example, one segment of North American forests has been assigned an annual value of 250 billion dollars  as another example, honey-bee pollination is estimated to provide between 10 and 18 billion dollars of value yearly.  The value of ecosystem services on one New Zealand island has been imputed to be as great as the GDP of that region.  This planetary wealth is being lost at an incredible rate as the demands of human society is exceeding the bio-regenerative capacity of the Earth. While biodiversity and ecosystems are resilient, the danger of losing them is that humans cannot recreate many ecosystem functions through technological innovation.
Strategic species concepts Edit
Keystone species Edit
Some species, called a keystone species form a central supporting hub unique to their ecosystem.  The loss of such a species results in a collapse in ecosystem function, as well as the loss of coexisting species.  Keystone species are usually predators due to their ability to control the population of prey in their ecosystem.  The importance of a keystone species was shown by the extinction of the Steller's sea cow (Hydrodamalis gigas) through its interaction with sea otters, sea urchins, and kelp. Kelp beds grow and form nurseries in shallow waters to shelter creatures that support the food chain. Sea urchins feed on kelp, while sea otters feed on sea urchins. With the rapid decline of sea otters due to overhunting, sea urchin populations grazed unrestricted on the kelp beds and the ecosystem collapsed. Left unchecked, the urchins destroyed the shallow water kelp communities that supported the Steller's sea cow's diet and hastened their demise.  The sea otter was thought to be a keystone species because the coexistence of many ecological associates in the kelp beds relied upon otters for their survival. However this was later questioned by Turvey and Risley,  who showed that hunting alone would have driven the Steller's sea cow extinct.
Indicator species Edit
An indicator species has a narrow set of ecological requirements, therefore they become useful targets for observing the health of an ecosystem. Some animals, such as amphibians with their semi-permeable skin and linkages to wetlands, have an acute sensitivity to environmental harm and thus may serve as a miner's canary. Indicator species are monitored in an effort to capture environmental degradation through pollution or some other link to proximate human activities.  Monitoring an indicator species is a measure to determine if there is a significant environmental impact that can serve to advise or modify practice, such as through different forest silviculture treatments and management scenarios, or to measure the degree of harm that a pesticide may impart on the health of an ecosystem.
Government regulators, consultants, or NGOs regularly monitor indicator species, however, there are limitations coupled with many practical considerations that must be followed for the approach to be effective.  It is generally recommended that multiple indicators (genes, populations, species, communities, and landscape) be monitored for effective conservation measurement that prevents harm to the complex, and often unpredictable, response from ecosystem dynamics (Noss, 1997  : 88–89 ).
Umbrella and flagship species Edit
An example of an umbrella species is the monarch butterfly, because of its lengthy migrations and aesthetic value. The monarch migrates across North America, covering multiple ecosystems and so requires a large area to exist. Any protections afforded to the monarch butterfly will at the same time umbrella many other species and habitats. An umbrella species is often used as flagship species, which are species, such as the giant panda, the blue whale, the tiger, the mountain gorilla and the monarch butterfly, that capture the public's attention and attract support for conservation measures.  Paradoxically, however, conservation bias towards flagship species sometimes threatens other species of chief concern. 
Conservation biologists study trends and process from the paleontological past to the ecological present as they gain an understanding of the context related to species extinction.  It is generally accepted that there have been five major global mass extinctions that register in Earth's history. These include: the Ordovician (440 mya), Devonian (370 mya), Permian–Triassic (245 mya), Triassic–Jurassic (200 mya), and Cretaceous–Paleogene extinction event (66 mya) extinction spasms. Within the last 10,000 years, human influence over the Earth's ecosystems has been so extensive that scientists have difficulty estimating the number of species lost  that is to say the rates of deforestation, reef destruction, wetland draining and other human acts are proceeding much faster than human assessment of species. The latest Living Planet Report by the World Wide Fund for Nature estimates that we have exceeded the bio-regenerative capacity of the planet, requiring 1.6 Earths to support the demands placed on our natural resources. 
Holocene extinction Edit
Conservation biologists are dealing with and have published evidence from all corners of the planet indicating that humanity may be causing the sixth and fastest planetary extinction event.    It has been suggested that an unprecedented number of species is becoming extinct in what is known as the Holocene extinction event.  The global extinction rate may be approximately 1,000 times higher than the natural background extinction rate.  It is estimated that two-thirds of all mammal genera and one-half of all mammal species weighing at least 44 kilograms (97 lb) have gone extinct in the last 50,000 years.     The Global Amphibian Assessment  reports that amphibians are declining on a global scale faster than any other vertebrate group, with over 32% of all surviving species being threatened with extinction. The surviving populations are in continual decline in 43% of those that are threatened. Since the mid-1980s the actual rates of extinction have exceeded 211 times rates measured from the fossil record.  However, "The current amphibian extinction rate may range from 25,039 to 45,474 times the background extinction rate for amphibians."  The global extinction trend occurs in every major vertebrate group that is being monitored. For example, 23% of all mammals and 12% of all birds are Red Listed by the International Union for Conservation of Nature (IUCN), meaning they too are threatened with extinction. Even though extinction is natural, the decline in species is happening at such an incredible rate that evolution can simply not match, therefore, leading to the greatest continual mass extinction on Earth.  Humans have dominated the planet and our high consumption of resources, along with the pollution generated is affecting the environments in which other species live.   There are a wide variety of species that humans are working to protect such as the Hawaiian Crow and the Whooping Crane of Texas.  People can also take action on preserving species by advocating and voting for global and national policies that improve climate, under the concepts of climate mitigation and climate restoration. The Earth's oceans demand particular attention as climate change continues to alter pH levels, making it uninhabitable for organisms with shells which dissolve as a result. 
Status of oceans and reefs Edit
Global assessments of coral reefs of the world continue to report drastic and rapid rates of decline. By 2000, 27% of the world's coral reef ecosystems had effectively collapsed. The largest period of decline occurred in a dramatic "bleaching" event in 1998, where approximately 16% of all the coral reefs in the world disappeared in less than a year. Coral bleaching is caused by a mixture of environmental stresses, including increases in ocean temperatures and acidity, causing both the release of symbiotic algae and death of corals.  Decline and extinction risk in coral reef biodiversity has risen dramatically in the past ten years. The loss of coral reefs, which are predicted to go extinct in the next century, threatens the balance of global biodiversity, will have huge economic impacts, and endangers food security for hundreds of millions of people.  Conservation biology plays an important role in international agreements covering the world's oceans  (and other issues pertaining to biodiversity  ).
The oceans are threatened by acidification due to an increase in CO2 levels. This is a most serious threat to societies relying heavily upon oceanic natural resources. A concern is that the majority of all marine species will not be able to evolve or acclimate in response to the changes in the ocean chemistry. 
The prospects of averting mass extinction seems unlikely when "[. ] 90% of all of the large (average approximately ≥50 kg), open ocean tuna, billfishes, and sharks in the ocean"  are reportedly gone. Given the scientific review of current trends, the ocean is predicted to have few surviving multi-cellular organisms with only microbes left to dominate marine ecosystems. 
Groups other than vertebrates Edit
Serious concerns also being raised about taxonomic groups that do not receive the same degree of social attention or attract funds as the vertebrates. These include fungal (including lichen-forming species),  invertebrate (particularly insect    ) and plant communities where the vast majority of biodiversity is represented. Conservation of fungi and conservation of insects, in particular, are both of pivotal importance for conservation biology. As mycorrhizal symbionts, and as decomposers and recyclers, fungi are essential for sustainability of forests.  The value of insects in the biosphere is enormous because they outnumber all other living groups in measure of species richness. The greatest bulk of biomass on land is found in plants, which is sustained by insect relations. This great ecological value of insects is countered by a society that often reacts negatively toward these aesthetically 'unpleasant' creatures.  
One area of concern in the insect world that has caught the public eye is the mysterious case of missing honey bees (Apis mellifera). Honey bees provide an indispensable ecological services through their acts of pollination supporting a huge variety of agriculture crops. The use of honey and wax have become vastly used throughout the world.  The sudden disappearance of bees leaving empty hives or colony collapse disorder (CCD) is not uncommon. However, in 16-month period from 2006 through 2007, 29% of 577 beekeepers across the United States reported CCD losses in up to 76% of their colonies. This sudden demographic loss in bee numbers is placing a strain on the agricultural sector. The cause behind the massive declines is puzzling scientists. Pests, pesticides, and global warming are all being considered as possible causes.  
Another highlight that links conservation biology to insects, forests, and climate change is the mountain pine beetle (Dendroctonus ponderosae) epidemic of British Columbia, Canada, which has infested 470,000 km 2 (180,000 sq mi) of forested land since 1999.  An action plan has been prepared by the Government of British Columbia to address this problem.  
This impact [pine beetle epidemic] converted the forest from a small net carbon sink to a large net carbon source both during and immediately after the outbreak. In the worst year, the impacts resulting from the beetle outbreak in British Columbia were equivalent to 75% of the average annual direct forest fire emissions from all of Canada during 1959–1999.
Conservation biology of parasites Edit
A large proportion of parasite species are threatened by extinction. A few of them are being eradicated as pests of humans or domestic animals, however, most of them are harmless. Threats include the decline or fragmentation of host populations, or the extinction of host species.
Threats to biodiversity Edit
Today, many threats to Biodiversity exist. An acronym that can be used to express the top threats of present-day H.I.P.P.O stands for Habitat Loss, Invasive Species, Pollution, Human Population, and Overharvesting.  The primary threats to biodiversity are habitat destruction (such as deforestation, agricultural expansion, urban development), and overexploitation (such as wildlife trade).       Habitat fragmentation also poses challenges, because the global network of protected areas only covers 11.5% of the Earth's surface.  A significant consequence of fragmentation and lack of linked protected areas is the reduction of animal migration on a global scale. Considering that billions of tonnes of biomass are responsible for nutrient cycling across the earth, the reduction of migration is a serious matter for conservation biology.  
However, human activities need not necessarily cause irreparable harm to the biosphere. With conservation management and planning for biodiversity at all levels, from genes to ecosystems, there are examples where humans mutually coexist in a sustainable way with nature.  Even with the current threats to biodiversity there are ways we can improve the current condition and start anew.
A matter of life and death for caspase 8
Cells can control their own death as part of normal development or in response to pathogens and toxins. Although apoptosis allows the non-inflammatory clearance of cells from the body, other forms of programmed cell death, including necroptosis and pyroptosis, induce an inflammatory response to intracellular pathogens.
Programmed cell death is mediated by caspase cysteine proteases such as caspase 8, which can mediate extrinsic apoptosis and suppress necroptosis by inhibiting the kinases RIPK1/RIPK3 and the pseudokinase MLKL.
Now, studies by Fritsch et al. and Newton et al., both published in Nature, describe an additional role for caspase 8 in mediating pyroptosis when apoptosis and necroptosis are inhibited.
Both groups found that expression of a catalytically inactive caspase 8 was lethal to mice at embryonic day (E)11.5 and used different models to look for the cause of embryonic lethality. Fritsch et al. expressed caspase 8 with a point mutation in its substrate binding pocket (Casp8 C362S/fl ) in epidermal keratinocytes and in intestinal epithelial cells (using Krt14 cre and Villin cre drivers, respectively). These mice were viable but experienced necroptosis in these tissues. Suppression of necroptosis through deletion of Mlkl rescued the skin phenotype but worsened the inflammatory destruction of the intestine, leading to premature death of Casp8 C362S/fl Villin cre mice at 4 weeks of age. Moreover, Casp8 C362S/362S mice deficient in the necroptosis mediator RIPK3, while not showing embryonic lethality, were dramatically stunted, suggesting a necroptosis-independent role for inactive caspase 8. The authors examined soluble proteins in the ileum of Casp8 C362S/fl Villin cre Mlk −/− mice and found high levels of IL-1β and the active cleaved version of the executioner caspase caspase 1. Cleavage of caspase 1 and IL-1β are signs of pyroptotic cell death, suggesting pyroptosis of ileal epithelial cells in the absence of necroptosis.
In a concurrent study, Newton et al. showed that knockout of Mlkl in mice with a catalytically inactive caspase 8 (Casp8 C362A/C362A ) reversed embryonic death, but caused death during the perinatal period. Early embryos of Casp8 362A/362A Mlkl −/− mice expressed higher levels of inflammatory cytokines in the gut than Casp8 −/− Mlk −/− embryos. Using multiple knockout models to investigate the role of caspase 1, caspase 11 and the necroptosis protein RIPK3 in the Casp8 C362A/C362A Mlkl −/− phenotype, the authors found caspase 1 to be a major driver for perinatal lethality in Casp8 C362A/C362A Mlkl −/− mice, with caspase 11 contributing to death around weaning. These data suggest that pyroptosis mediates perinatal death. Although caspase 1 was driving lethality, knockout of the pyroptosis pore-forming protein and caspase 1 substrate gasdermin D did not rescue Casp8 C362A/C362A Mlkl −/− mice from dying shortly after birth, suggesting that cleavage of other caspase 1 substrates, such as caspase 3 or caspase 7, may drive perinatal lethality.
Both studies found that the expression of inactive caspase 8 or pan-caspase inhibition induced the formation of apoptosis-associated speck-like protein containing a CARD (ASC) specks and subsequent caspase 1 activation. Each group also showed that deletion of ASC or caspase 1 rescued perinatal lethality in caspase 8 activity-deficient Mlkl −/− mice, suggesting that an ASC inflammasome-driven mechanism causes lethality in the absence of active caspase 8.
“These studies… describe a previously unknown mechanism for catalytically inactive caspase 8 in triggering the pyroptosis cell death pathway in the absence of apoptosis and necroptosis”
These studies therefore describe a previously unknown mechanism for catalytically inactive caspase 8 in triggering the pyroptosis cell death pathway in the absence of apoptosis and necroptosis. This mechanism could act as a defence against viruses that have evolved strategies to inhibit caspase 8 catalytic activity and parts of the necroptosis machinery.
4. Natural Selection Accounts
Many philosophers of biology believe that functional explanation is uniquely appropriate to biology, turning to Darwin&rsquos theory of descent with modification to ground the practice of attributing functions. Like Wright, Hempel, and Nagel, natural-selection teleonaturalists take the primary target of explanation to be the presence of various traits in organisms.
Here we distinguish between two ways of using natural selection to ground biological teleology.
- Indirect approaches treat the adaptive, self-organizing nature of living cells and organisms as the natural basis for teleological properties of their traits, but give background credit to the power of natural selection to produce such self-organizational complexity as is found in living systems.
- Direct approaches invoke natural selection explicitly when explicating functional claims, either in an etiological sense based on the history of selection or in a dispositional sense based on the fitness of organisms possessing the traits.
The primary motivation for the earliest indirect, cybernetic accounts of biological teleology were to explain the apparent purposiveness of biological organisms, for instance, the maintenance of constant body temperature in endotherms. These accounts aimed to provide a naturalized explanation for the goal-directed behavior of biological systems through reference to their organization. In an influential early paper, Norbert Wiener and colleagues sought to explain the goal-directed behavior of biological organisms and machines as arising from their utilization of negative feedback mechanisms (Rosenblueth et al. 1943 for further development see also Braithwaite (1953), Sommerhoff (1950) and Nagel (1953)). Attributions of teleological, or goal-directed, behavior to animals or machines, they argued, meant nothing more than &ldquopurpose controlled by feed-back&rdquo (Rosenblueth et al. 1943, 23).
This cybernetic account of teleology inspired biologist Colin Pittendrigh to introduce the term &lsquoteleonomy&rsquo into the literature (Pittendrigh 1958). With this neologism, Pittendrigh hoped to purge biology of any vestiges of Aristotelian final causes whilst providing biology with an acceptable term to describe adapted, goal-directed systems. This term was taken up in the 1960s by evolutionary biologists such as Ernst Mayr (1974) and George Williams (1966), as well as by scientists studying cell metabolism and regulation, who were just beginning to elucidate the structural and molecular basis for cellular feedback mechanisms (Monod & Jacob 1961 Davis 1961). According to proponents, adopting a cybernetic account of goal-directed behavior in biological systems splits the explanatory problem in two. On the one hand, teleological activity in the biological world could be explained by the presence of teleonomic systems with negative feedback mechanisms, whereas the very presence of those teleonomic systems in living organisms, on the other hand, could be explained by the action of natural selection (Monod 1970 ).
Although explicit cybernetic accounts of biological teleology have fallen out of favor, other organizational approaches to biological function have had a recent resurgence in the function literature. These organizational, or systems-theoretic, approaches often build upon early cybernetic accounts or aim to extend Maturana and Varela&rsquos (1980) influential notion of autopoiesis, which refers to the self-organizing, self-maintaining characteristic of living systems (see the entry on Embodied Cognition for further description). These accounts identify the function of a biological trait through an analysis of the role the trait plays within an organized system in contributing to both its own persistence and the persistence of the system as a whole (Schlosser 1998 McLaughlin 2001 Mossio et al. 2009 Saborido et al. 2011 Moreno & Mossio 2015). Although they differ in their details, organizational approaches to biological function generally agree that a trait token T has a function F when the performance of F by T contributes to the maintenance of the complex organization of the system, which in turn results in T&rsquos continued existence. For example, the heart has the function to pump blood, according to these accounts, because it contributes to the maintenance of the entire organism by causing the blood to circulate, which facilitates the circulation of oxygen and nutrients. At the same time, this circulation is also responsible in part for the persistence of the heart itself, since the heart also benefits directly from this function (i.e., the cardiac cells receive the oxygen and nutrients necessary for their survival).
Similar to direct natural selection accounts, organizational accounts can be forward or backward-looking: the function of a trait may identify its dispositional contribution to the complex organization of the system which results in its own persistence or reproduction in the future (forward-looking Schlosser 1998), or a functional attribution may identify a trait&rsquos past contribution (etiological, or backward-looking McLaughlin 2001). Alvaro Moreno&rsquos group adopts a third position. They claim their organizational account of function unifies these two perspectives (Mossio et al 2009 cf. Artiga & Martinez 2016). All these organizational accounts differ from direct natural selection accounts, however, in that they make no appeal to the selection history of the trait. Instead, the function of a trait can be inferred from the present or past role of the trait in maintaining itself within the complex, organized system without further holding that the trait was selected for that role. On this view, functional attributions in biology are explanatory not because of selection, but rather because of the causal role traits play in contributing to the maintenance of the organization of a system, which in turn enables the traits themselves to persist.
4.2 Direct Natural Selection Approaches
Accounts of biological function which refer to natural selection typically have the form that a trait's functions causally explain the existence or maintenance of that trait in a given population via the mechanism of natural selection. William Wimsatt (1972), Ruth Millikan (1984), and Karen Neander (1991a), all treat the past history of natural selection as the selection process that legitimizes the notion of a biological function. Within such approaches there is a dispute about the exact role of natural selection, whether as a source of variation (sometimes referred to as the &ldquocreative&rdquo role of natural selection, e.g., Neander 1988 see also Ayala 1970, 1977), or only as a filter on variations that arise independently (Sober 1984).
Positions which ground functional claims in natural selection have much in common with Wright&rsquos etiological account. However, because the grounding is specific to biology, they may avoid the kinds of counterexamples to Wright&rsquos account introduced by critics such as Christopher Boorse, predicated on the idea that Wright&rsquos account is intended to provide a more general conceptual analysis. A related challenge stems from the claim that pre-Darwinian thinkers such as Harvey correctly identified functional properties of biological organs, and that natural selection cannot therefore be a requirement for the proper conceptual analysis of function. Defenders of direct natural selection accounts of function have responded in different ways. One way, exemplified by Millikan (1989), is to argue that conceptual analysis has no role to play in articulating what is essentially a theoretical term within modern evolutionary biology. Another way, exemplified by Neander (1991b), is to say that the task of conceptual analysis is appropriate but restricted to the concepts of the relevant scientific community.
Paul Davies (2001) and Arno Wouters (2005) argue that both Millikan and Neander are incorrect to treat malfunction as an important theoretical or conceptual aspect of the practice of attributing functions by biologists. Wouters declares the wish that the study of biological function should be liberated &ldquofrom the yoke of the philosophy of mind&rdquo (2005: 148). However, Ema Sullivan-Bissett (2017) argues that while the task of explicating biological practice by philosophers of biology is usefully distinguished from the broader goals of philosophers pursuing naturalistic accounts of mind and language (see the entry on teleological theories of mental content), the latter serves legitimate goals. She regards an account of malfunction to be integral to the latter project even if not to the former. Davies (2001) argues that the natural selection accounts are unable to provide an account of malfunction insofar as they individuate traits functionally, entailing that a putatively malfunctioning trait is not an instance of the functionally-defined kind. Sullivan-Bissett addresses Davies&rsquo objection by incorporating a structural condition on the individuation of traits. (See also Garson 2016: 48&ndash49, for additional discussion and critique of Davies&rsquo view.)
Returning to the kinds of traits studied by biologists, some theorists make a distinction between the initial spread of a new phenotypic trait in a population and the more recent maintenance of traits in populations. Take a trait such as feathers, arising in a population by whatever means. Initially this trait may have spread because of a role in mating displays. Later, feathers may have contributed to improved thermoregulation. And still later, the trait may have become more widely distributed because feathers make good flight control surfaces. If display or thermoregulatory functions of feathers become less important in some niches, the trait may nonetheless be maintained in a population due to selection for its flight-control function. The shifting functional profile may also be correlated with differentiation in form, such as between downy feathers and flight feathers.
Some biologists used the term pre-adaptation to capture the idea that a trait selected for one function may turn out to be very useful for something else. However, Gould and Vrba (1982) introduced the term &lsquoexaptation&rsquo to capture such transitions, and avoid what they saw as the overly teleological implications of pre-adaptation, as well as to recognize that non-selected traits of organisms could also be co-opted to serve a function, increasing fitness without having any further modification by natural selection (Lloyd & Gould 2017). Critics of the etiological natural selection approaches sometimes argue that backward-looking approaches are too vague with respect to questions about the point at which traits acquire or lose functions, and that they are consequently untestable empirically (Amundson & Lauder 1994). Godfrey-Smith (1994) independently proposed a &ldquomodern history&rdquo theory of functions to address these problems. Similarly, Griffiths (1993: 417) invokes a notion of the &ldquolast evolutionarily significant time period&rdquo to handle these issues, but many critics remain unconvinced (e.g., Wouters 1999 Davies 2001).
Another issue confronting direct natural selection accounts is the evident utility of attributing functions to novel traits of organisms developed within a single lifetime such as the capacity of brains to acquire new concepts of kinds of things not previously experienced in the evolutionary lineage, or of the immune system to develop antibodies to new infectious agents. Previously, Millikan (1984) had suggested a notion of &ldquoderived proper function&rdquo to capture this kind of example. More recently, Bouchard (2013) and Garson (2017) have developed more detailed accounts of derived function, respectively using &ldquodifferential persistence&rdquo and &ldquodifferential retention&rdquo within an organism&rsquos lifespan to play the role that differential reproduction plays in direct natural selection accounts.
Some biologists and philosophers of biology have been motivated by problems with the backward-looking etiological approach, or by seeing examples from biology that seek to identify the present functions of a trait. To deal with these issues they propose a dispositional or forward-looking approach that analyzes function in terms of those effects it is disposed to produce that tend to contribute to the present or future maintenance of the trait in a population of organisms. Various ways of spelling this out include Hinde&rsquos (1975) account of strong function, Boorse&rsquos (1976, 2002) biostatistical theory, Bigelow and Pargetter&rsquos (1987) propensity theory, and Walsh&rsquos (1996) relational theory (see also and Walsh & Ariew 1996).
The fourth edition of Media and Entertainment Law has been fully updated, analysing some of the most recent judgments in media law from across the United Kingdom, such as Cliff Richard v the BBC , Max Schrems v Facebook and the Irish Information Commissioner , developments on the ‘right to be forgotten’ (NT1 and NT2) and ABC v Daily Telegraph (Sir Philip Green).
The book’s two main themes are freedom of expression and an individual’s right to privacy. Regulation of the communication industries is covered extensively, including discussion of the print press and its online editions following Leveson, traditional broadcasting regulations for terrestrial TV and radio as well as media activities on converged devices, such as tablets, iPads, mobile phone devices and ‘on demand’ services. Intellectual property law (specifically copyright) in the music and entertainment industries is also explored in the book’s later chapters.
Also new to this edition are sections on:
The fourth edition also features a variety of pedagogical features to encourage critical analysis of case law and one’s own beliefs.
In animals [ edit ]
Arthropods [ edit ]
Arthropods are known to regenerate appendages following loss or autotomy. ⎣] Regeneration among arthropods is restricted by molting such that hemimetabolous insects are capable of regeneration only until their final molt whereas most crustaceans can regenerate throughout their lifetimes. ⎤] Molting cycles are hormonally regulated in arthropods, ⎥] although premature molting can be induced by autotomy. ⎣] Mechanisms underlying appendage regeneration in hemimetabolous insects and crustaceans is highly conserved. ⎦] During limb regeneration species in both taxa form a blastema ⎧] following autotomy with regeneration of the excised limb occurring during proecdysis. ⎥] Limb regeneration is also present in insects that undergo metamorphosis, such as beetles, although the cost of said regeneration is a delayed pupal stage. ⎨] Arachnids, including scorpions, are known to regenerate their venom, although the content of the regenerated venom is different than the original venom during its regeneration, as the venom volume is replaced before the active proteins are all replenished. ⎩]
Annelids [ edit ]
Many annelids (segmented worms) are capable of regeneration. ⎪] For example, Chaetopterus variopedatus and Branchiomma nigromaculata can regenerate both anterior and posterior body parts after latitudinal bisection. ⎫] The relationship between somatic and germline stem cell regeneration has been studied at the molecular level in the annelid Capitella teleta. ⎬] Leeches, however, appear incapable of segmental regeneration. ⎭] Furthermore, their close relatives, the branchiobdellids, are also incapable of segmental regeneration. ⎭] ⎪] However, certain individuals, like the lumbriculids, can regenerate from only a few segments. ⎭] Segmental regeneration in these animals is epimorphic and occurs through blastema formation. ⎭] Segmental regeneration has been gained and lost during annelid evolution, as seen in oligochaetes, where head regeneration has been lost three separate times. ⎭]
Along with epimorphosis, some polychaetes like Sabella pavonina experience morphallactic regeneration. ⎭] ⎮] Morphallaxis involves the de-differentiation, transformation, and re-differentation of cells to regenerate tissues. How prominent morphallactic regeneration is in oligochaetes is currently not well understood. Although relatively under-reported, it is possible that morphallaxis is a common mode of inter-segment regeneration in annelids. Following regeneration in L. variegatus, past posterior segments sometimes become anterior in the new body orientation, consistent with morphallaxis.
Following amputation, most annelids are capable of sealing their body via rapid muscular contraction. Constriction of body muscle can lead to infection prevention. In certain species, such as Limnodrilus, autolysis can be seen within hours after amputation in the ectoderm and mesoderm. Amputation is also thought to cause a large migration of cells to the injury site, and these form a wound plug.
Echinoderms [ edit ]
Tissue regeneration is widespread among echinoderms and has been well documented in starfish (Asteroidea), sea cucumbers (Holothuroidea), and sea urchins (Echinoidea). Appendage regeneration in echinoderms has been studied since at least the 19th century. ⎯] In addition to appendages, some species can regenerate internal organs and parts of their central nervous system. ⎰] In response to injury starfish can autotomize damaged appendages. Autotomy is the self-amputation of a body part, usually an appendage. Depending on severity, starfish will then go through a four-week process where the appendage will be regenerated. ⎱] Some species must retain mouth cells to regenerate an appendage, due to the need for energy. ⎲] The first organs to regenerate, in all species documented to date, are associated with the digestive tract. Thus, most knowledge about visceral regeneration in holothurians concerns this system. ⎳]
Planaria (Platyhelminthes) [ edit ]
Regeneration research using Planarians began in the late 1800s and was popularized by T.H. Morgan at the beginning of the 20th century. ⎲] Alejandro Sanchez-Alvarado and Philip Newmark transformed planarians into a model genetic organism in the beginning of the 20th century to study the molecular mechanisms underlying regeneration in these animals. ⎴] Planarians exhibit an extraordinary ability to regenerate lost body parts. For example, a planarian split lengthwise or crosswise will regenerate into two separate individuals. In one experiment, T.H. Morgan found that a piece corresponding to 1/279th of a planarian ⎲] or a fragment with as few as 10,000 cells can successfully regenerate into a new worm within one to two weeks. ⎵] After amputation, stump cells form a blastema formed from neoblasts, pluripotent cells found throughout the planarian body. ⎶] New tissue grows from neoblasts with neoblasts comprising between 20 and 30% of all planarian cells. ⎵] Recent work has confirmed that neoblasts are totipotent since one single neoblast can regenerate an entire irradiated animal that has been rendered incapable of regeneration. ⎷] In order to prevent starvation a planarian will use their own cells for energy, this phenomenon is known as de-growth. ⎖]
Amphibians [ edit ]
Limb regeneration in the axolotl and newt has been extensively studied and researched. Urodele amphibians, such as salamanders and newts, display the highest regenerative ability among tetrapods. ⎸] As such, they can fully regenerate their limbs, tail, jaws, and retina via epimorphic regeneration leading to functional replacement with new tissue. ⎹] Salamander limb regeneration occurs in two main steps. First, the local cells dedifferentiate at the wound site into progenitor to form a blastema. ⎺] Second, the blastemal cells will undergo cell proliferation, patterning, cell differentiation and tissue growth using similar genetic mechanisms that deployed during embryonic development. ⎻] Ultimately, blastemal cells will generate all the cells for the new structure. ⎸]
After amputation, the epidermis migrates to cover the stump in 1–2 hours, forming a structure called the wound epithelium (WE). ⎼] Epidermal cells continue to migrate over the WE, resulting in a thickened, specialized signaling center called the apical epithelial cap (AEC). ⎽] Over the next several days there are changes in the underlying stump tissues that result in the formation of a blastema (a mass of dedifferentiated proliferating cells). As the blastema forms, pattern formation genes – such as HoxA and HoxD – are activated as they were when the limb was formed in the embryo. ⎾] ⎿] The positional identity of the distal tip of the limb (i.e. the autopod, which is the hand or foot) is formed first in the blastema. Intermediate positional identities between the stump and the distal tip are then filled in through a process called intercalation. ⎾] Motor neurons, muscle, and blood vessels grow with the regenerated limb, and reestablish the connections that were present prior to amputation. The time that this entire process takes varies according to the age of the animal, ranging from about a month to around three months in the adult and then the limb becomes fully functional. Researchers at Australian Regenerative Medicine Institute at Monash University have published that when macrophages, which eat up material debris, ⏀] were removed, salamanders lost their ability to regenerate and formed scarred tissue instead. ⏁]
In spite of the historically few researchers studying limb regeneration, remarkable progress has been made recently in establishing the neotenous amphibian the axolotl (Ambystoma mexicanum) as a model genetic organism. This progress has been facilitated by advances in genomics, bioinformatics, and somatic cell transgenesis in other fields, that have created the opportunity to investigate the mechanisms of important biological properties, such as limb regeneration, in the axolotl. ⎻] The Ambystoma Genetic Stock Center (AGSC) is a self-sustaining, breeding colony of the axolotl supported by the National Science Foundation as a Living Stock Collection. Located at the University of Kentucky, the AGSC is dedicated to supplying genetically well-characterized axolotl embryos, larvae, and adults to laboratories throughout the United States and abroad. An NIH-funded NCRR grant has led to the establishment of the Ambystoma EST database, the Salamander Genome Project (SGP) that has led to the creation of the first amphibian gene map and several annotated molecular data bases, and the creation of the research community web portal. ⏂]
Anurans can only regenerate their limbs during embryonic development. ⏃] Once the limb skeleton has developed regeneration does not occur (Xenopus can grow a cartilaginous spike after amputation). ⏃] Reactive oxygen species (ROS) appear to be required for a regeneration response in the anuran larvae. ⏄] ROS production is essential to activate the Wnt signaling pathway, which has been associated with regeneration in other systems. ⏄] Limb regeneration in salamanders occurs in two major steps. First, adult cells de-differentiate into progenitor cells which will replace the tissues they are derived from. ⏅] ⏆] Second, these progenitor cells then proliferate and differentiate until they have completely replaced the missing structure. ⏇]
Hydra [ edit ]
Hydra is a genus of freshwater polyp in the phylum Cnidaria with highly proliferative stem cells that gives them the ability to regenerate their entire body. ⏈] Any fragment larger than a few hundred epithelial cells that is isolated from the body has the ability to regenerate into a smaller version of itself. ⏈] The high proportion of stem cells in the hydra supports its efficient regenerative ability. ⏉]
Regeneration among hydra occurs as foot regeneration arising from the basal part of the body, and head regeneration, arising from the apical region. ⏈] Regeneration tissues that are cut from the gastric region contain polarity, which allows them to distinguish between regenerating a head in the apical end and a foot in the basal end so that both regions are present in the newly regenerated organism. ⏈] Head regeneration requires complex reconstruction of the area, while foot regeneration is much simpler, similar to tissue repair. ⏊] In both foot and head regeneration, however, there are two distinct molecular cascades that occur once the tissue is wounded: early injury response and a subsequent, signal-driven pathway of the regenerating tissue that leads to cellular differentiation. ⏉] This early-injury response includes epithelial cell stretching for wound closure, the migration of interstitial progenitors towards the wound, cell death, phagocytosis of cell debris, and reconstruction of the extracellular matrix. ⏉]
Regeneration in hydra has been defined as morphallaxis, the process where regeneration results from remodeling of existing material without cellular proliferation. ⏋] ⏌] If a hydra is cut into two pieces, the remaining severed sections form two fully functional and independent hydra, approximately the same size as the two smaller severed sections. ⏈] This occurs through the exchange and rearrangement of soft tissues without the formation of new material. ⏉]
Aves (birds) [ edit ]
Owing to a limited literature on the subject, birds are believed to have very limited regenerative abilities as adults. Some studies ⏍] on roosters have suggested that birds can adequately regenerate some parts of the limbs and depending on the conditions in which regeneration takes place, such as age of the animal, the inter-relationship of the injured tissue with other muscles, and the type of operation, can involve complete regeneration of some musculoskeletal structure. Werber and Goldschmidt (1909) found that the goose and duck were capable of regenerating their beaks after partial amputation ⏍] and Sidorova (1962) observed liver regeneration via hypertrophy in roosters. ⏎] Birds are also capable of regenerating the hair cells in their cochlea following noise damage or ototoxic drug damage. ⏏] Despite this evidence, contemporary studies suggest reparative regeneration in avian species is limited to periods during embryonic development. An array of molecular biology techniques have been successful in manipulating cellular pathways known to contribute to spontaneous regeneration in chick embryos. ⏐] For instance, removing a portion of the elbow joint in a chick embryo via window excision or slice excision and comparing joint tissue specific markers and cartilage markers showed that window excision allowed 10 out of 20 limbs to regenerate and expressed joint genes similarly to a developing embryo. In contrast, slice excision did not allow the joint to regenerate due to the fusion of the skeletal elements seen by an expression of cartilage markers. ⏑]
Similar to the physiological regeneration of hair in mammals, birds can regenerate their feathers in order to repair damaged feathers or to attract mates with their plumage. Typically, seasonal changes that are associated with breeding seasons will prompt a hormonal signal for birds to begin regenerating feathers. This has been experimentally induced using thyroid hormones in the Rhode Island Red Fowls. ⏒]
Mammals [ edit ]
Mammals are capable of cellular and physiological regeneration, but have generally poor reparative regenerative ability across the group. Ώ] ⎤] Examples of physiological regeneration in mammals include epithelial renewal (e.g., skin and intestinal tract), red blood cell replacement, antler regeneration and hair cycling. ⏓] ⏔] Male deer lose their antlers annually during the months of January to April then through regeneration are able to regrow them as an example of physiological regeneration. A deer antler is the only appendage of a mammal that can be regrown every year. ⏕] While reparative regeneration is a rare phenomenon in mammals, it does occur. A well-documented example is regeneration of the digit tip distal to the nail bed. ⏖] Reparative regeneration has also been observed in rabbits, pikas and African spiny mice. In 2012, researchers discovered that two species of African Spiny Mice, Acomys kempi and Acomys percivali, were capable of completely regenerating the autotomically released or otherwise damaged tissue. These species can regrow hair follicles, skin, sweat glands, fur and cartilage. ⏗] In addition to these two species, subsequent studies demonstrated that Acomys cahirinus could regenerate skin and excised tissue in the ear pinna. ⏘] ⏙]
Despite these examples, it is generally accepted that adult mammals have limited regenerative capacity compared to most vertebrate embryos/larvae, adult salamanders and fish. ⏚] But the regeneration therapy approach of Robert O. Becker, using electrical stimulation, has shown promising results for rats ⏛] and mammals in general. ⏜]
Some researchers have also claimed that the MRL mouse strain exhibits enhanced regenerative abilities. Work comparing the differential gene expression of scarless healing MRL mice and a poorly-healing C57BL/6 mouse strain, identified 36 genes differentiating the healing process between MRL mice and other mice. ⏝] ⏞] Study of the regenerative process in these animals is aimed at discovering how to duplicate them in humans, such as deactivation of the p21 gene. ⏟] ⏠] However, recent work has shown that MRL mice actually close small ear holes with scar tissue, rather than regeneration as originally claimed. ⏘]
MRL mice are not protected against myocardial infarction heart regeneration in adult mammals (neocardiogenesis) is limited, because heart muscle cells are nearly all terminally differentiated. MRL mice show the same amount of cardiac injury and scar formation as normal mice after a heart attack. ⏡] However, recent studies provide evidence that this may not always be the case, and that MRL mice can regenerate after heart damage. ⏢]
Humans [ edit ]
The regrowth of lost tissues or organs in the human body is being researched. Some tissues such as skin regrow quite readily others have been thought to have little or no capacity for regeneration, but ongoing research suggests that there is some hope for a variety of tissues and organs. Ώ] ⏣] Human organs that have been regenerated include the bladder, vagina and the penis. ⏤]
As are all metazoans, humans are capable of physiological regeneration (i.e. the replacement of cells during homeostatic maintenance that does not necessitate injury). For example, the regeneration of red blood cells via erythropoiesis occurs through the maturation of erythrocytes from hematopoietic stem cells in the bone marrow, their subsequent circulation for around 90 days in the blood stream, and their eventual cell-death in the spleen. ⏥] Another example of physiological regeneration is the sloughing and rebuilding of a functional endometrium during each menstrual cycle in females in response to varying levels of circulating estrogen and progesterone. ⏦]
However, humans are limited in their capacity for reparative regeneration, which occurs in response to injury. One of the most studied regenerative responses in humans is the hypertrophy of the liver following liver injury. ⏧] ⏨] For example, the original mass of the liver is re-established in direct proportion to the amount of liver removed following partial hepatectomy, ⏩] which indicates that signals from the body regulate liver mass precisely, both positively and negatively, until the desired mass is reached. This response is considered cellular regeneration (a form of compensatory hypertrophy) where the function and mass of the liver is regenerated through the proliferation of existing mature hepatic cells (mainly hepatocytes), but the exact morphology of the liver is not regained. ⏨] This process is driven by growth factor and cytokine regulated pathways. ⏧] The normal sequence of inflammation and regeneration does not function accurately in cancer. Specifically, cytokine stimulation of cells leads to expression of genes that change cellular functions and suppress the immune response. ⏪]
Adult neurogenesis is also a form of cellular regeneration. For example, hippocampal neuron renewal occurs in normal adult humans at an annual turnover rate of 1.75% of neurons. ⏫] Cardiac myocyte renewal has been found to occur in normal adult humans, ⏬] and at a higher rate in adults following acute heart injury such as infarction. ⏭] Even in adult myocardium following infarction, proliferation is only found in around 1% of myocytes around the area of injury, which is not enough to restore function of cardiac muscle. However, this may be an important target for regenerative medicine as it implies that regeneration of cardiomyocytes, and consequently of myocardium, can be induced.
Another example of reparative regeneration in humans is fingertip regeneration, which occurs after phalange amputation distal to the nail bed (especially in children) ⏮] ⏯] and rib regeneration, which occurs following osteotomy for scoliosis treatment (though usually regeneration is only partial and may take up to 1 year). ]
Yet another example of regeneration in humans is vas deferens regeneration, which occurs after a vasectomy and which results in vasectomy failure. ]
Reptiles [ edit ]
The ability and degree of regeneration in reptiles differs among the various species, but the most notable and well-studied occurrence is tail-regeneration in lizards. ] ] ] In addition to lizards, regeneration has been observed in the tails and maxillary bone of crocodiles and adult neurogenesis has also been noted. ] ] ] Tail regeneration has never been observed in snakes. ] Lizards possess the highest regenerative capacity as a group. ] ] ] ] Following autotomous tail loss, epimorphic regeneration of a new tail proceeds through a blastema-mediated process that results in a functionally and morphologically similar structure. ] ]
Chondrichthyes [ edit ]
Studies have shown that some chondrichthyans can regenerate rhodopsin by cellular regeneration, ] micro RNA organ regeneration, ] teeth physiological teeth regeneration, ⏍] and reparative skin regeneration. ] Rhodopsin regeneration has been studied in skates and rays. ] After complete photo-bleaching, rhodopsin can completely regenerate within 2 hours in the retina. ] White bamboo sharks can regenerate at least two-thirds of their liver and this has been linked to three micro RNAs, xtr-miR-125b, fru-miR-204, and has-miR-142-3p_R-. ] In one study two thirds of the liver was removed and within 24 hours more than half of the liver had undergone hypertrophy. ] Leopard sharks routinely replace their teeth every 9–12 days ⏍] and this is an example of physiological regeneration. This can occur because shark teeth are not attached to a bone, but instead are developed within a bony cavity. ⏍] It has been estimated that the average shark loses about 30,000 to 40,000 teeth in a lifetime. ⏍] Some sharks can regenerate scales and even skin following damage. ] Within two weeks of skin wounding the mucus is secreted into the wound and this initiates the healing process. ] One study showed that the majority of the wounded area was regenerated within 4 months, but the regenerated area also showed a high degree of variability. ]