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Are there species which is debatable if they should be classified as animals or plants?

Are there species which is debatable if they should be classified as animals or plants?


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I'm watching a sci fi series and a character who is a biologist claims "even on Earth there are species which is debatable if they should be classified as animals or plants". I looked for examples of this and I couldnt find any. Is this true? Are there species which is debatable if they should be classified as animals or plants?


No, there are no such debates. Plants and animals diverged over a billion years ago. Animals are defined by the unique molecules that are secreted by the cells, and fill the intercellular matrix, like collagen. Plants have unique cell walls, chlorophylls a and b, and plastids. The unique characteristics of plants are given here: http://www.bio.miami.edu/dana/160/160S10_10.html Although there may be animals like sponges that don't seem to move around a lot, or corals that have symbiotic relationships with algae, simply "behaving like a plant" does not make them plants. Similarly, there are plants that move and trap insects. But taxonomists would never confuse them with animals.


Taxonomy and Classification

Classification is in our nature. It can be argued that humans have been categorizing the natural world since before the advent of speech. The ability to discriminate aspects of our world is inherently necessary for our survival. In 1758, Swedish biologist Carl Linnaeus accomplished the amazing feat of classifying nearly all known organisms, published in his magnum opus Systema Naturae , categorizing all living organisms as either plants or animals (Fig 1). Systema Naturae marked the beginning of modern classification, and we still use many of the customs he developed .

For example, Carl Linnaeus developed a hierarchical system for organizing living organisms (Fig. 2 & 3) . The highest rank (most inclusive) was given to kingdom, followed subsequently by phylum, class, order, family, genus, and species. Species was Linnaeus’s least inclusive level of classification and includes all organisms of similar morphologies that can interbreed and produce viable offspring.

Given the vast scope of his work, Linnaeus completely ignored classifying single-celled organisms. Antonie van Leeuwenhoek was a pioneer of microscopy and the first person to identify single –celled organisms in 1674. He called these cells animalcules , which is Latin for “little animals.” Prior to this, the presence of single-celled organisms was completely unknown and his work was met with great skepticism. His first discoveries were of relatively large microorganisms we now call protists, unicellular organisms with a nucleus. Van Leeuwenhoek never stopped perfecting his microscope, and in 1676 he was the first person to identify and describe a bacterium, a very small microorganism lacking a nucleus and true organelles. Realizing Linnaeus’s oversight , his predecessors classified these microorganisms either as plants (if they were green) or animals. I n 1866, microorganisms got a major upgrade when Ernst Haeckel proposed that unicellular organisms should be in their own kingdom: Protista. All multicellular organisms were still classified either as plants or animals (Fig. 4).

When microscope technology was enhanced during the 19 th century, it became clear that microorganisms were actually two separate groups, based on their internal makeup. In 1925, Édouard Chatton argued that certain microorganisms are more closely related to plants and animals than they were to other microorganisms. He argued that organisms with the presence of nucleus should all be placed in a large group (collectively known as Superkingdom Eukaryota ), whether they are unicellular or multicellular. He suggested that all other microorganisms that lack a nucleus were in a separate kingdom: Monera (Fig. 5) . This theory was not well received by Chatton’s contemporaries, who argued that unicellular organisms are more closely related to each other than to any multicellular organisms (regardless of the internal makeup of the cells). Chatton’s realizations were not truly appreciated and widely accepted until the 1960s.

In 1969, Robert Whittaker recognized an additional kingdom: Fungi (Fig. 6). Prior to Whittaker’s classification, fungi were hypothesized to be in the Kingdom Plantae, due to the growth form of mushrooms coming up from the ground, similar to plants. He argued that fungi were most similar to animals because both groups are heterotrophic (they can not produce their own food) whereas plants are autotrophic (they can produce their own food). Further research has supported this hypothesis.

Also during the 1960s, Carl Woese and his colleagues began to compare RNA sequences from a wide variety of prokaryotic and eukaryotic organisms. What they found shocked the scientific community (Fig. 7) . Their work suggested that certain groups of prokaryotes are actually more evolutionarily distant than the groups of eukaryotic organisms, such as plants and animals, are to each other. Their evidence suggested that all eukaryotic organisms belong in one major monophyletic group (Eukarya), while prokaryotes had to be split into two monophyletic groups (Bacteria and Archaea). They inferred that all living organisms should be placed in three domains (a newly invented level of hierarchy above Kingdom): Bacteria, Archaea, and Eukarya . These results were highly controversial, and acceptance of Woese’s findings was slow. However, they were nearly universally accepted by the 1980s.

Analysis of Woese’s phylogeny provides an interesting twist. Bacteria and Archaea are prokaryotes, which all lack a true nucleus and membrane-bound organelles whereas all members of Eukarya have a nucleus encasing linear DNA and many membrane-bound organelles. While Bacteria and Archaea are more similar morphologically, Woese’s research suggests Archaea is genetically more closely aligned with Eukarya. This suggests that Archaea is actually more evolutionarily similar to Eukarya than it is to Bacteria, even though Archaea is more morphologically similar to Bacteria.

In the 21 st century, many scientists have accepted Woese’s three-domain system as the highest order of classification of life on Earth. However, the classification of members within Eukarya has been dramatically altered based on analyses of DNA since Whittaker (Fig. 8). Protists (single-celled eukaryotic organisms) are no longer thought to be a monophyletic group. In other words, not all protists form a single, cohesive group. Evidence also suggests that multicellular organisms (plants, animals, and fungi) are a part of different eukaryotic groups that also include single-celled organisms. This indicates that multicellularity originated more than once in Eukarya.

In 2005, the International Society of Protistologists divided Eukarya into six “supergroups” based on genetic analyses (Fig. 8) . Animals and fungi were included into the supergroup, Opisthokonta, alongside their suspected unicellular ( and sometimes colonial) cousin the choanoflagellate. Amoebozoid protists fall into two supergroups. Traditional amoebas with lobose pseudopodia form the Amoebozoa , while amoeboids with either filose or reticulose pseudopodia form Rhizaria .

Plants were grouped with the supergroup, Archaeaplastida , which included other photosynthetic organisms, green algae and red algae, which have unicellular , colonial, and multicellular growth forms. Photosynthetic organisms are also found in two other supergroups. Excavata are flagellated protists, some of which are photosynthetic (i.e. Euglena ). Diatoms are unicellular organisms that serve as the ocean’s primary source of energy via photosynthesis. Diatoms and many other unicellular photosynthetic organisms, along with multicellular brown algae, form the group Chromoalveolata . This group is widely variable, and the validity of this grouping is currently under serious scrutiny.


Dissecting Behavior

The question of whether dogs and wolves are members of the same or different species is a controversial one. To begin with, species classification is a convention used to help aid in our ability to organize nature and it is anything but definitively objective. This should not decrease the importance of classifying species, but before we begin to try and understand the question, we will benefit from understanding that the nature of the question is very philosophical. Always keep in the back of your mind that the personal preference of an individual will always be influential in subjective conclusions. Therefore, to try and be objective about the conversation I would like to discuss the big picture, and in biology, the big picture is always evolution.

Evolution is often described as cumulative processes so slow that they take between thousands and millions of decades to complete (e.g. Dawkins, 1986). This is only part of the picture. We certainly have an in-depth archeological fossil record that shows gradual changes in species over millennia (such as the development of feathers in dinosaurs or the eye-migration of flatfish), however biological changes can also happen in the wink of an eye—at least compared to traditionally conceptualized evolutionary timescales. Most simply, evolution can be defined as change over time. But what kind of change? Does any change constitute evolution? Does any duration sufficiently qualify for “time?” These are important considerations because whatever definition is chosen will create a first premise assumption from which any arguments will flow from—like the way the lens of a camera manipulates light before entering the camera body and forming an image, so too can a first premise assumption influence our perceptions so that our observations fit a desirable theory instead of the natural phenomenon.

Some evolution happens very slowly (such as the previously mentioned examples of feathers in dinosaurs and the eye-migration of flatfish) however, these changes arose most probably due to mutation and sexual selection, not because these changes condoned a functional advantage in evading hazards or finding food. Most examples of evolution are due to a change in the characteristics of a group that enable it to survive, thus evolution can be viewed in this light as a response to changes in the environment. Typically, environments change very slowly and significant changes often ride on the back of natural disasters. The evolution of dinosaurs into birds was due to a two-fold catastrophe. Approximately 200 million years ago, atmospheric oxygen declined nearly 20% causing one of the largest extinction periods in Earth’s history (Berner et al., 2006). This killed off an unprecedented amount of land dwelling animals and threatened aquatic living organisms as well. For example, some species of fish such as tuna evolved ram-air induction (whereby swimming at high velocity forced water across the gills at a higher speed to ensure maximum oxygen diffusion from water). As if global suffocation wasn’t bad enough, to add insult to injury, an asteroid the size of Manhattan slammed into Mexico just a few millennia later. These two factors meant that the only dinosaurs which survived were small and could fly—what we call birds. Predominantly, it is important to remember that changes to the environment are what drive these kinds of selection processes, especially when these changes create significant mortality rates—a concept I will return to later.

The controversy over the classification of dogs and wolves can be seen on numerous levels, but one that stands out for me is the way in which many wolf-dog hybrid enthusiasts are very passionate that the correct term is not “hybrid” but “wolf dog”—since both the dog (Canis lupus familiaris) and the wolf (Canis lupus lupus) are according to some scientists taxonomically sub-species of Canis lupus. While this is a relatively recent distinction (originally, Carl von Line classified the dog as Canis familiaris, a different species than the wolf) the taxonomic nomenclature does not determine whether the mating of two animals qualifies as a hybrid. Hybridization is the interbreeding of individuals from genetically distinct populations, regardless of their taxonomic status (Stronen & Paquet, 2013). Wolves and dogs may be amazingly similar in their genetics, however they are clearly genetically distinct populations (e.g. vanHoldt et al., 2011).

Principal component analysis of all wolf-like canids for the 48K SNP data set: PC1 represents a wild versus domestic canid axis, whereas PC2 separates wolves (n=198) and dogs (n=912) from coyotes (n=57) and red wolves (n=10). Result shows dogs and gray wolves are genetically distinct (Fst=0.165). PC2 in this analysis of the data demonstrate a geographically based population hierarchy within gray wolves and coyotes (vanHoldt et al., 2011)

Plots show ancestry blocks and their assignments for representative individuals of canid populations with average size of blocks, percent ancestry, and number of generations since most recent admixture (t) indicated. Two-ancestor (coyote, A gray wolf, B) analyses are presented for a Great Lakes wolf from Minnesota (C), a captive red wolf (D), and an Algonquin wolf (E). Three-ancestor analyses (coyote, A gray wolf, B dog, F) are presented for a Northeastern coyote from Vermont (G), a Southern coyote from Louisiana (H), and a Midwestern coyote from Ohio (I) – (vanHoldt et al., 2011)

The supposedly infallible “fact” that dogs are descended from wolves took the world by fire with research into mitochondrial DNA and a publication which appeared in Science titled “Multiple and Ancient Origins of the Domestic Dog” (Vila et al., 1997). In this paper, the authors concluded that dogs were 135,000 years old—a conclusion which is sheer nonsense (Larson, 2011 Larson et al., 2012). Over the last decade, geneticists have published paper after paper pointing at different dates and different locations for domestication with very little consensus but most supporting the conclusion that dogs are direct descendants of the wolf. One important reason for this is because the methodology behind examining mitochondrial DNA (mtDNA) has a very debilitating first premise assumption: that the rate of mtDNA mutation is constant in dogs and wolves despite a massive wolf population bottleneck and an exploding dog population. This is a problem because both of these population effects cause genetic drift. Imagine if you take a population and reduce it to a mere handful. How do you tell whether you are looking at the first members of a new species or the surviving members after a population endangerment? Likewise, imagine taking two dogs and deciding you will start your own breed. If your new breed goes through a population explosion, then their DNA will make up a unrepresentative sample of the historical population (this is called the “founder effect”).

Genetic research is awesome, don’t get me wrong, and it cannot be underappreciated that innovations in genetics have opened up wildly exciting new scientific avenues of investigation into organisms. However, genetic analysis is relatively new to the question of speciation in the animal kingdom and some insight to the Canis lupus dilemma can be gained by looking at the overall ecology of dogs and wolves instead of just their sequence of nucleic acids. Research that examines genotypes, high-density single nucleotide polymorphisms, epigenetic methylations, mitochondrial DNA, etc., is literally a whole new world, but it is not the whole picture. The expression of a plant or animal’s DNA is what creates its phenotype (from morphology to behavior), and it is the phenotype that is thus selected for in the environment and we can learn lots by simply examining the phenotype in and of itself.

As previously mentioned, when two genetically distinct species reproduce the offspring is called a hybrid. However in animals, hybridization is a pretty big deal. When sperm meets egg, a zygote is formed, thus ecologists look at both prezygotic (before reproduction) and postzygotic (after reproduction) barriers that make hybridization difficult. Examples of prezygotic barriers include: habitat isolation (where two species are geographically isolated, sometimes living in the same area but rarely meet), behavioral isolation (where two species do not recognize the signals/mating cues of each other or employ different foraging strategies), temporal isolation (where one species might breed in the spring while another breeds in the fall), mechanical isolation (where the “wedding tackle” of one species doesn’t fit in the “hoo-ha” of another species), and genetic isolation (where the sperm and egg of two species are unable to form a zygote). Postzygotic barriers include reduced hybrid viability (where hybrids fail to develop or reach sexual maturity), reduced hybrid fertility (e.g. mules are hybrids of horses and donkeys and are all sterile), and hybrid breakdown (where the offspring of hybrids have further reduced viability and/or fertility).

The behavioral isolation of dogs and wolves is astronomical because behaviorally there are almost no commonalities between them. In fact, leaving dogs aside for a moment, very important behavioral distinctions exist just between different groups of wolves that affect their offspring viability (postzygotic barriers). For example, one of the most important criteria for mate preference in wolves comes down to hunting strategies: wolves with similar hunting and foraging strategies are more likely to mate and teach these strategies to their offspring. Foraging behavior is a phenotypical characteristic that plays a major role in determining the ecological niche of a species—so much so that wolves who employ different foraging strategies also display different types of social relationships.

Very few dogs hunt for food. Even in societies which still use dogs for hunting (such as the indigenous Mayagna people of Nicaragua), dogs rarely make the kill. Their role in the hunt is to bring an animal to ground and make a loud ruckus until the humans can find it and make the killing blow with their machete. In this capacity, dogs are pound for pound as efficient as a rifle in bringing in meat for the indigenous people of Nicaragua, and the dogs benefit by being given leftovers (Koster, 2008). It is certainly true that some dogs (some) opportunistically take down and on occasion eat small animals such as rats, possums, cats, etc. However, dogs like other scavengers fill an important role in the grand ecological picture regarding the flow of biomass (Wikenros et al., 2013).

Hunting in the wild is simply not an available strategy for dogs to survive. One important reason for this is that the energy dogs would expend to take down and eat small prey animals would be much greater than the energy gained by hunting them. This is illustrated with African wild dogs (Lycaon pictus), who pound for pound hunt, kill, and consume more meat than any other predator in Africa—this is not because they are greedy, this is because of their metabolic needs. When you look at African wild dogs, small prey like African hares make up only an average profitability of 0.6kg per hunt (4.8kg per kilometer chased), whereas Wildebeest weighing approximately 100kg make a profitability of 35.2kg per hunt (51kg per kilometer chased). African Wild dogs not only make significantly more meat off of larger prey animals, but they also have a higher success catching them than they do small animals like African hares (38% success versus 31%) (see Creel & Creel, 1995 for Lycaon pictus data). If humans were to go extinct tomorrow, dogs could never fill the role of these kinds of predators. Simply put, dogs are more likely to try and play with a deer than to try and kill it.

Trophic diagram of organisms in relation to predators since reintroduction (Freeman et al., 2013)

As if there is very little difference, dogs are frequently labeled carnivores like their wolf cousins (implying a predatory nature) however ecological foraging models are much more nuanced than simply whether or not the food consumed is animal or plant-based. Dogs are detritivores (i.e. scavengers—animals which live off of dead food sources). Whether it is the kibble we drop in the bowl, the dump which feral dogs scavenge at, or even raw meat or table scraps being tossed from the table, dogs do not kill their food. Whether feral or companion pet, the dog’s niche relies on their ability to live in close proximity to humans—a quality which is typically severely impacted by interbreeding with wolves. Dogs utilize a very different and elongated socialization period that enables them to develop interspecies social bonds much easier (Lord, 2013), and thus the viability of hybrid offspring between dogs and wolves is severely impacted through both prezygotic and postzygotic barriers. Quite simply, just because two animals are capable of interbreeding, claiming they are the same species does not make sense in light of almost all aspects of their phenotype outside of morphology (and even then, calling a Chihuahua a wolf is simply absurd).

Thinking about the foraging strategy of the dog as more closely related to fungi, archaea, worms, and dung beetles as opposed to the apex predator wolf might seem rather unglamorous, however in truth it highlights their ecological and evolutionary success. All life is built on the need for energy and nutrients. Energy needed for life comes from the sun, regardless of the species. Plants use the energy from photons to produce sugar, which is natures way of storing energy from the sun. For this reason, plants are termed “producers” because they create available energy and nutrients for other organisms (such as hydrogen, carbon, nitrogen, oxygen and phosphorus—among other nutrients). Through nutrients, organisms manipulate the stored energy and use it to produce proteins that enable the organism to survive and reproduce. The availability of these resources on a large scale is quantified in ecology as Net Primary Productivity (NPP).

Data: NASA
Image: Freeman et al., 2013

NPP is essentially a quantification of the available resources organisms need to survive. If you look on the map above, you will see that NPP is highest in the tropics and lowest in the tundra. The niche of the wolf, compared to the tropics, is in regions of the world where NPP is strikingly low—emphasizing their need to hunt and kill large prey. Humans appropriate 24% of the NPP of the entire planet. Think about that for a moment… nearly one-quarter of all available energy on the planet, yet we are just one of thousands if not millions of species cohabitating this blue ball in our corner of the solar system. We can appreciate that with the laws of the conservation of energy, large consumption leads to large waste, waste that is still rich with hydrogen, carbon, nitrogen, sulfur and phosphorus. While dogs most certainly share a common ancestor with the wolf, their emergence as a species is due to the tremendous advantage of having proximity to the largest appropriation of nutrients on the planet. Coppinger has long emphasized the difference between “domestic” (living amongst humans) and “domesticated” (made to live amongst humans). With no evidence that humans were ever sophisticated enough to establish breeding programs to artificially select for tame qualities like the silver fox experiment, it is not logical to believe that dogs could have emerged through careful pup selection. Even today, it is extremely difficult to create human-socialized wolves (who still behave nothing like dogs) and inbreeding is an enormous issue within current populations—how would humans have overcome these issues when we still hadn’t become sophisticated enough to harness agriculture?

Data: Vince, 2011
Image: Freeman et al., 2013

It is hard to imagine that sometimes we forget just how much we have changed this planet. If the consumption of nearly 25% of the planet’s NPP doesn’t make you think for a moment, then consider that 90% of all mammalian biomass on the planet consists of humans and domesticated animals. 10,000 years ago, this number was approximately 0.1%. While rambling around since approximately 200,000 years ago, human population did not reach one billion until 1804. By 1927, human population reached two billion. 1960: three billion. 1974: four billion. 1987: five billion. 1999: six billion. By the year 2011, human population reached seven billion (population data and biomass percentages taken from Vince, 2011). In parallel with increasing human population, it is estimated that there are approximately one billion dogs around the world now, whereas wolves are on the brink of extinction. At this rate, it is only a matter of time before human population will exceed the appropriable NPP of the planet and very few undomesticated species will exist outside of detritivores feeding on human waste as the human population crashes into unsustainability.

The story is very romantic: man and wolf, hunting and foraging together. Unfortunately there is simply no evidence and if I’m being charitable, the probability that dogs evolved directly from grey wolves is extremely unlikely. While many similarities are perceived to exist between dog and wolf, upon closer examination, the similarities are almost impossible to find.

Berner, R. A., VandenBrooks, J. M., & Ward, P. D. (2007). Oxygen and Evolution. Science, 316(5824), 557–558. doi:10.1126/science.1142654

Brucker, R. M., & Bordenstein, S. R. (2012). Speciation by symbiosis. Trends in Ecology & Evolution, 27(8), 443–451. doi:10.1016/j.tree.2012.03.011

Creel, S., & Creel, N. M. (1995). Communal hunting and pack size in African wild dogs, Lycaon pictus. Animal Behaviour, 50(5), 1325–1339.

Freeman, S., Quiliin, K., & Allison, L. (2013). Biological Science (5th edition.). Benjamin Cummings.

Koster, J. M. (2008). Hunting with Dogs in Nicaragua: An Optimal Foraging Approach. Current Anthropology, 49(5), 935–944. doi:10.1086/595655

Larson, G. (2011). Genetics and Domestication: Important Questions for New Answers. Current Anthropology, 52(S4), S485–S495. doi:10.1086/658401

Larson, G., Karlsson, E. K., Perri, A., Webster, M. T., Ho, S. Y. W., Peters, J., … Lindblad-Toh, K. (2012). Rethinking dog domestication by integrating genetics, archeology, and biogeography. Proceedings of the National Academy of Sciences, 109(23), 8878–8883. doi:10.1073/pnas.1203005109

Lord, K. (2013). A Comparison of the Sensory Development of Wolves (Canis lupus lupus) and Dogs (Canis lupus familiaris). Ethology, 119(2), 110–120. doi:10.1111/eth.12044

Rousset, F., & Solignac, M. (1995). Evolution of single and double Wolbachia symbioses during speciation in the Drosophila simulans complex. Proceedings of the National Academy of Sciences, 92(14), 6389–6393.

Stronen, A. V., & Paquet, P. C. (2013). Perspectives on the conservation of wild hybrids. Biological Conservation, 167, 390–395. doi:10.1016/j.biocon.2013.09.004

Vince, G. (2011). An Epoch Debate. Science, 334(6052), 32–37. doi:10.1126/science.334.6052.32

vonHoldt, B. M., Pollinger, J. P., Earl, D. A., Knowles, J. C., Boyko, A. R., Parker, H., … Wayne, R. K. (2011). A genome-wide perspective on the evolutionary history of enigmatic wolf-like canids. Genome Research, 21(8), 1294–1305. doi:10.1101/gr.116301.110


Are there species which is debatable if they should be classified as animals or plants? - Biology

NSTA supports the decision of science teachers and their school or school district to integrate live animals and dissection in the K–12 classroom. Student interaction with organisms is one of the most effective methods of achieving many of the goals outlined in the National Science Education Standards (NSES). To this end, NSTA encourages educators and school officials to make informed decisions about the integration of animals in the science curriculum. NSTA opposes regulations or legislation that would eliminate an educator's decision-making role regarding dissection or would deny students the opportunity to learn through actual animal dissection.

NSTA encourages districts to ensure that animals are properly cared for and treated humanely, responsibly, and ethically. Ultimately, decisions to incorporate organisms in the classroom should balance the ethical and responsible care of animals with their educational value.

While this position statement is primarily focused on vertebrate animals, NSTA recognizes the importance of following similar ethical practices for all living organisms.

Including Live Animals in the Classroom

NSTA supports including live animals as part of instruction in the K-12 science classroom because observing and working with animals firsthand can spark students' interest in science as well as a general respect for life while reinforcing key concepts as outlined in the NSES.

NSTA recommends that teachers

  • Educate themselves about the safe and responsible use of animals in the classroom. Teachers should seek information from reputable sources and familiarize themselves with laws and regulations in their state.
  • Become knowledgeable about the acquisition and care of animals appropriate to the species under study so that both students and the animals stay safe and healthy during all activities.
  • Follow local, state, and national laws, policies, and regulations when live organisms, particularly native species, are included in the classroom.
  • Integrate live animals into the science program based on sound curriculum and pedagogical decisions.
  • Develop activities that promote observation and comparison skills that instill in students an appreciation for the value of life and the importance of caring for animals responsibly.
  • Instruct students on safety precautions for handling live organisms and establish a plan for addressing such issues as allergies and fear of animals.
  • Develop and implement a plan for future care or disposition of animals at the conclusion of the study as well as during school breaks and summer vacations.
  • Espouse the importance of not conducting experimental procedures on animals if such procedures are likely to cause pain, induce nutritional deficiencies, or expose animals to parasites, hazardous/toxic chemicals, or radiation.
  • Shelter animals when the classroom is being cleaned with chemical cleaners, sprayed with pesticides, and during other times when potentially harmful chemicals are being used.
  • Refrain from releasing animals into a non-indigenous environment.

Dissection

NSTA supports each teacher's decision to use animal dissection activities that help students

  1. develop skills of observation and comparison,
  2. discover the shared and unique structures and processes of specific organisms, and
  3. develop a greater appreciation for the complexity of life.

It is essential that teachers establish specific and clear learning goals that enable them to appropriately plan and supervise the activities.

NSTA recognizes science educators as professionals. As such, they are in the best position to determine when to use—or not use—dissection activities. NSTA encourages teachers to be sensitive to students’ views regarding dissection, and to be aware of students’ beliefs and their right to make an informed decision about their participation. Teachers, especially those at the primary level, should be especially cognizant of students’ ages and maturity levels when deciding whether to use animal dissection. Should a teacher feel that an alternative to dissection would be a better option for a student or group of students, it is important that the teacher select a meaningful alternative. NSTA is aware of the continuing development and improvement of these alternatives.

Finally, NSTA calls for more research to determine the effectiveness of animal dissection activities and alternatives and the extent to which these activities should be integrated into the science curriculum.

Regarding the use of dissection activities in school classrooms, NSTA recommends that science teachers

  • Be prepared to present an alternative to dissection to students whose views or beliefs make this activity uncomfortable and difficult for them.
  • Conduct laboratory and dissection activities with consideration and appreciation for the organism.
  • Plan laboratory and dissection activities that are appropriate to the maturity level of the students.
  • Use prepared specimens purchased from a reputable and reliable scientific supply company. An acceptable alternative source for fresh specimens (i.e., squid, chicken wings) would be an FDA-inspected facility such as a butcher shop, fish market, or supermarket. The use of salvaged specimens does not reflect safe practice.
  • Conduct laboratory and dissection activities in a clean and organized work space with care and laboratory precision.
  • Conduct dissections in an appropriate physical environment with the proper ventilation, lighting, furniture, and equipment, including hot water and soap for cleanup.
  • Use personal safety protective equipment, such as gloves, chemical splash goggles, and aprons, all of which should be available and used by students, teachers, and visitors to the classroom.
  • Address such issues as allergies and squeamishness about dealing with animal specimens.
  • Ensure that the specimens are handled and disposed of properly.
  • Ensure that sharp instruments, such as scissors, scalpels, and other tools, are used safely and appropriately.
  • Base laboratory and dissection activities on carefully planned curriculum objectives.

Adopted by the NSTA Board of Directors, June 2005
Revised: March 2008

References

National Research Council. (1996). National science education standards. Washington, DC: National Academy Press.

Additional Resources

Cross, Tina R. 2004. Scalpel or mouse: A statistical comparison of real and virtual frog dissections. The American Biology Teacher, 66(6): 408-411.

Institute of Laboratory Animal Resources, Commission on Life Sciences, National Research Council, National Academy of Sciences, National Academy of Engineering. 1989. Principles and Guidelines for the Use of Animals in Precollege Education. dels.nas.edu/ilar/prin_guide.asp.

Kinzie, M. B., R. Strauss, and J. Foss. 1993. The effects of an interactive dissection simulation on the performance and achievement of high school students. Journal of Research in Science Teaching 30(8): 989-1000.

Kwan, T., and J. Texley. National Science Teachers Association. 2002. Exploring safely A guide for elementary teachers. Arlington, VA: NSTA Press.

Kwan, T., and J. Texley. National Science Teachers Association. 2003. Inquiring safely A guide for middle school teachers. Arlington, VA: NSTA Press.

Madrazo, G. 2002. The debate over dissection: Dissecting a classroom dilemma. The Science Educator (NSELA). EJ64162.

National Science Teachers Association. 2000. Safety and School Science Instruction, an NSTA Position Statement. www.nsta.org/nstas-official-positions/safety-and-school-science-instruction.

Texley, J., T. Kwan, and J. Summers. National Science Teachers Association. 2004. Investigating safely A guide for high school teachers. Arlington, VA: NSTA Press.


Vocabulary

vascular: plants that use roots and stems to take in water and nutrients (refer to lesson 1 in Unit 3)

non-vascular: plants that don’t use roots and stems

angiosperms: also known as flowering plants all have seeds that are protected by an ovule (think of an apple or other fruit).

gymnosperms: a term meaning “naked seed” refers to plants with seeds that aren’t protected by an ovule . Examples are conifers, which have pinecones.

grasses: plants that have slender leaves and reproduce by sending out underground stems called rhizomes that usually grow horizontally

herbaceous plants: those with leaves and stems that die at the end of the growing season

woody shrubs: plants that have stems that are covered by a layer of bark

trees: woody shrubs that have a main trunk and many branches


Why The Eastern Coyote Should Be A Separate Species: The “Coywolf"

There is considerable debate and disagreement among scientists over what to call a canid inhabiting the northeastern United States. In the course of this creature’s less than 100-year history, it has been variously called coyote, eastern coyote, coydog, Tweed wolf, brush wolf, new wolf, northeastern coyote and now coywolf, with nature documentaries highlighting recent genetic findings.

Recently, Roland Kays penned an interesting article in The Conversation concluding that 𠇌oywolf is not a thing,” and that it should not be considered for species status. Interestingly, and perhaps ironically, the beautiful light orangey-red canid in the cover picture of that article looks nothing like a western coyote and has striking observable characteristics of both coyotes and wolves, as well as dogs.

Soon after, my colleague William Lynn (Marsh Institute, Clark University) and I published a meta-analysis in the scientific journal Canid Biology & Conservation that summarized recent studies on this creature and confirmed that what we call 𠇌oyotes” in northeastern North America formed from hybridization (the mating of two or more species) between coyotes and wolves in southern Ontario around the turn of the 20th century.

In the paper, we suggest that coywolf is the most accurate term for this animal and that they warrant new species status, Canis oriens, which literally means eastern canid in Latin. We based this on the fact that they are physically and genetically distinct from their parental species of mainly western coyotes (Canis latrans) and eastern wolves (Canis lycaon). They also have smaller amounts of gray wolf (Canis lupus) and domestic dog (Canis familiaris) genes.

The eastern coyote/coywolf in a nutshell

Before I describe why the coywolf is unique, let’s get a quick snapshot of the animal we are discussing.

What we are calling Canis oriens colonized northeastern North America 50-75 years ago and has been described in detail in Gerry Parker’s 1995 book, �stern Coyote: The Story of Its Success,” and my 2007 paperback, “Suburban Howls.” This animal averages 13.6-18.2 kg (30-40 lbs), with individual weights exceeding 22.7-25 kg (50-55 lbs).

The emerging picture of the coywolf is that they have a larger home range than most western coyotes but smaller than wolves, at about 30 square kilometers (about 11 square miles). They also travel long distances daily (10-15 miles), eat a variety of food including white-tailed deer, medium-sized prey such as rabbits and woodchucks, and small prey such as voles and mice. They are social, often living in families of three to five members.

Eastern coyotes hunt a wide range of animals, including small rodents but also deer. Two eastern coyotes took down this deer in eastern Canada, according to the photographer. rvewong/flickr, CC BY-SA

In short, the coywolf has ecological and physical characteristics that can be seen on a continuum of coyote-like to wolf-like predators, but occupies an ecological niche that is closer to coyotes than wolves.

So why is coywolf a more accurate name?

Some argue that if the coywolf is predominantly coyote, then they should be called coyotes. Let’s analyze this claim.

I have previously found coywolves to be significantly different in body size from both western coyotes and eastern wolves. However, they are closer to coyotes whereby eastern wolves are 61-71 percent heavier than the same-sex coywolf, while coywolves are 35-37 percent heavier than western coyotes.

Bill Lynn and I concluded that they are statistically different – both genetically and physically – from their parental species since the coywolf is about 60 percent coyote, 30 percent wolf, and 10 percent dog thus, nearly 40 percent of this animal is not coyote. That, essentially, is why we recommend that they be classified as a new species, Canis oriens.

Kays’ article stated that 𠇌oyotes” in the Northeast are mostly (60-84 percent) coyote, with lesser amounts of wolf (%-25 percent) and dog (8-11 percent). However, the values of 84 percent coyote and only 8 percent wolf used a study (by vonHoldt et al. 2011) that has since mostly been discounted by subsequent papers since eastern wolves were not adequately sampled in their analysis.

Thus, based on our analysis, the claim that coywolves are predominantly coyote is untrue. While they may be numerically closer in size and genetics to coyotes than wolves, they are clearly statistically divergent from both coyotes and wolves. Taken from a wolf-centric viewpoint, I can see that they seem more coyote-like than wolf-like, but it is important to realize that a large part of their background is not from coyotes.

Eastern coyotes, or coywolves, have ecological and physical characteristics that can fit on a continuum between coyote and wolf. Jonathan Way, Author provided

The term coywolf uses the portmanteau method (i.e., a word formed by combining two other words) of naming, whereby the first word (coyote) of the combined two (coyote-wolf) is the more dominant or robust descriptor of that term. It does not suggest that this animal is equally or more wolf than coyote as has been suggested.

Furthermore, I believe that the terms coyote, eastern coyote and northeastern coyote undervalue the importance of the eastern wolf – the animals that interbred with western coyotes in Canada in the early 20th century to produce the coywolf – in the ancestry of this canid. This naming effectively discounts that, for example, one-third of the population’s mitochondrial DNA (C1 haplotype) is derived from the eastern wolf and another one-third (C9 haplotype) is not found in most nonhybridized western coyote populations but is found in eastern wolves.

Research has confirmed that all canids in the genus Canis can and do mate with other species (or canid types). This includes gray wolves mating with eastern wolves around the Great Lakes area, eastern wolves with gray wolves and western coyotes north and south/west of Algonquin Park in Ontario, respectively. Also, western coyotes mix with eastern wolves and coywolves, especially at the edge of their respective ranges.

Given that the most up-to-date studies have discovered relatively small amounts of dog (

8-10 percent) in the coywolf’s genome, and dogs are closely related to wolves, it seems reasonable to keep 𠆌oywolf’ rather than 𠆌oywolfdog’ as this creature’s descriptor.

Benefits of hybridization

Hybridization is a natural process that can be greatly accelerated by human modifications to the environment, like hunting and habitat destruction – two key ingredients that paved the way for the creation of the coywolf.

Education efforts could actually use the hybrid coywolf as a model for science education and a flagship species for dynamic, urbanized ecosystems. While protecting natural habitat is vitally important to maintaining wild wolf populations, this isn’t possible anymore in many regions, such as much of southern New England. In these areas, any canid on the landscape is important – especially a hybrid one with genes from multiple species adapted to its environment.

Coyotes from the Plains intermixed with wolves in Canada about 100 years ago and their descendants have colonized the eastern U.S. Way (2013) from Canadian Field Naturalist, Author provided

In one word, coywolf quite accurately summarizes the main components of this animal’s background. Other species have far more names. For instance, cougars (Puma concolor) are also called mountain lions, pumas, catamounts and panthers, among dozens of other local names. To use the terms �stern coyote” (or northeastern coyote) and 𠇌oywolf” as synonyms seems highly valid to me.

Is eastern coyote even an accurate term?

It’s worth noting that coyote populations in eastern North America continue to change. Indeed, we recently questioned if the generic term �stern coyote” is even accurate or appropriate considering that colonizing 𠇌oyotes” in eastern North America are considerably different from each other.

Southeastern coyotes are more coyote-like compared to northeastern coyotes/coywolves, and coyotes in the mid-Atlantic region have medium amounts of wolf intermixing, or introgression, compared with more typical western coyotes in the southeast that have little wolf but some domestic dog admixture. Comparatively, coywolves in the northeast are more wolf-like.

There is also the possibility that coywolves in the northeast will eventually become genetically swamped by western coyote genes from the south and west. Eastern coyotes from the mid-Atlantic area, which are more coyote-like and less wolf-like, have recently contacted the coywolf in the west part of its range, which could affect the makeup of the populations in the eastern U.S.

Thus, it remains to be seen whether this entity will remain distinct, which could influence future discussions of its taxonomy.

Why does it all matter anyway?

In the long run, does it really matter what we call this animal?

Science, at its best, is self-correcting, and new science often leads one in new directions. As biologists, we are charged with accurately describing natural systems, and for this reason alone it is important that we accurately characterize (and even debate about) the systems that we are studying. The more I investigate the coywolf, the more I realize it is different than other canids, including western coyotes.

Perhaps the most important finding from our recent paper is that new species status, Canis oriens, is warranted for this cool creature. While there may be continued controversy over the simple naming scheme of this canid, the premises in this paper better explain why coywolf is an appropriate term to use moving forward.

This article was originally published on The Conversation. Read the original article.


About the Endangered Species Act

Conservation efforts to save species of plants and animals from extinction began in the early 1900s. A species of plant or animal is considered extinct when there are no living members of that group found alive anywhere on Earth in other words, all members of that group have died. Human activities have caused the extinction of many species.

Additional species are still faced with the possibility of extinction. In December 1973 the United States Congress signed the Endangered Species Act of 1973, to protect and preserve threatened and endangered plants and animals from extinction. The Endangered Species Act of 1973 replaced two previous laws, the Endangered Species Preservation Act of 1966 and the Endangered Species Conservation Act of 1969.

Extinction (“X-tink-shun”): the act of becoming extinct, a species is extinct when no living members exist

The Endangered Species Preservation Act of 1966 required a list to be made of endangered species and money from the Land and Conservation Funds to be used to purchase habitat for the protection of the species listed. This Act also required the Fish and Wildlife Service, a government agency devoted to the management of fish and wildlife, to spend money on the management of the listed endangered animals. There was one big problem with the Act of 1966. There were no regulations that protected the killing and trading of those listed endangered animals. Therefore animals faced with the possibility of going extinct were listed under the Act of 1966 as needing help and protection, but there were no rules or guidelines developed by Congress to help protect them.

The Endangered Species Conservation Act of 1969 continued to add to the protection of endangered and threatened animals by establishing 2 lists, one for foreign species (species living anywhere outside the United States of America) and the other for native species (species living in the United States). The Act of 1969 did not allow animals that were listed on the foreign species list to be brought into the United States. The Act also did not allow the purchase or sale of any animal taken (killed) illegally.

The Endangered Species Act of 1973 took further steps to recognize that endangered and threatened species needed worldwide protection through development of international treaties and conventions. The Endangered Species Act of 1973 also noted that endangered and threatened species were recognized as valuable educational, scientific, recreational, historical and esthetical purposes. Congress therefore wanted this act to protect not only the listed species but also the ecosystem within which these species live and need to survive.

Two categories were established to help classify and aid in setting up conservation programs for species faced with the possibility of extinction. The ENDANGERED category applies to any species considered to be in danger of becoming extinct throughout all or a significant portion of its range. THREATENED refers to any species that is likely to become an endangered species throughout all or a significant portion of its range within the near future.

The administration of the Endangered Species Act is a shared responsibility between two United States governmental agencies: The Fish and Wildlife Service and the National Marine Fisheries Service. The Fish and Wildlife Service is responsible for terrestrial (land) and freshwater species and migratory birds. The National Marine Fisheries Service is responsible for those species that live in marine environments. The Animal and Plant Health Inspection Service is also involved in enforcing the Endangered Species Act, by overseeing the incoming (importation) and outgoing (exportation) of listed terrestrial plants in the United States.

How does a species get listed as an endangered or threatened species?

There is a strict process that must be followed before a species is listed as endangered or threatened.

  1. A species is proposed for addition to the lists by the public, the Fish and Wildlife Service, other governmental agencies, and biologists.
  2. The public is offered the opportunity to comment about the proposal, and the rule is finalized (or withdrawn).
  3. Species to be listed are selected by the Fish and Wildlife Service from a list of candidates and are recognized using a priority system.

What happens if you hurt, touch, capture, or disrupt an endangered species?

Under the Endangered Species Act, all of those would be violations of the guidelines set down for the protection of the species. Violating the ESA involves most forms of interfering with the recovery of an endangered species, including trafficking, killing, harming, wounding, or simply harassing the animal or contributing to the devastation of its environment. The only way to be allowed to interact with a species classified as endangered is through a license or permit issued by a Federal Agency that permits research or trade, although it can be taken away or modified at any time.

Thus, the penalties for violating the Endangered Species Act and illegally interacting with a member of a protected species are very severe. Violators can face imprisonment or steep fines if their actions come to the attention of the Fish and Willife Service. The size of the penalty increases with the number of violations- either the size of the fine or the length of time spent in prison, with a maximum fine of $50,000 and a maximum imprisonment of one year, or a combination of the two. Violators may also incur civil penalties of up to $25,000 per violation, with the highest penalties reserved for unlawful trafficking in a protected species, or what the act refers to as consciously “taking” (which covers capturing and killing.) Simply harassing an endangered animal can carry a fine of $10,500.

Those species facing the greatest threat are given the highest priority.

In order for a species to be listed there must be enough information to support the proposed listing of that species. A species is listed based on its biological status and on the severity of the threat placed on its existence. Therefore, species can only be determined as endangered or threatened by one or more of the factors listed below.

  1. If there is present or threatened destruction and alteration of its habitat.
  2. If there is an over-utilization for commercial, educational, and/or scientific purposes.
  3. If there is a presence of disease or predation.
  4. If there are not enough regulatory mechanisms existing today to protect the species or
  5. If there are any other natural or man-made factors that may be or currently affecting its continued existence.

Sometimes there is not enough biological information on a species for the Fish and Wildlife Service to issue a classification of endangered and threatened. In this case the species is referred to as a “candidate species.”

Some facts about Endangered and Threatened Species

  • As of today in the United States there are 92 listed endangered species (357 animals and 567 plants).
  • There is a total of 256 listed threatened species in the United States (121 animals and 135 plants).
  • The total number of listed species is 1,180 (478 animals and 702 plants), this includes both the United States and foreign species.
  • Of the 924 endangered species in the United States, 70 are endangered and 40 are threatened species of fish.
  • Plants represent the largest group, followed by birds, fishes, mammals, and clams/mussels.

Why should we want to save endangered species?

If we protect endangered species we can maintain a healthy environment.

  • If wild creatures are able to have a healthy environment to live in, then people will also have a healthy environment surrounding them.
  • Many plants and wildlife help us by being important sources of medicines and food. By protecting endangered species and biodiversity we are able to protect animals and plants that may become important sources of new medicine and/or food for us in the future.
  • Endangered species can also provide an early warning or cue to us about any increases in pollution and changes in the environment. Increases in pollution and decreases in environmental quality can have large impacts on human health and safety in the future.

Biodiversity (“by-oh-die-verse-city”): is a term used to describe the variety of life (called biota) on Earth. This includes the millions of species of plants, birds, reptiles, mammals, fish, shellfish, amphibians, insects, spiders, microorganisms (such as bacteria), etc. Oh! And don’t forget yourself. All living species interact with each other in complex ways and occupy a variety of different habitats throughout the world.

  • One important job we have as American citizens is our duty to protect our Nation’s heritage.
  • If we protect endangered and threatened species from extinction we can save more of America’s natural history for many future generations (the family you will have and your children’s family, etc).
  • As Americans we take pride in what we can do, not what we can’t. We were proud when we saved our nation’s symbol, the bald eagle. It is a hard task to save endangered and threatened species and many private organizations and governmental agencies are working hard to protect more of these species each year. These groups can’t do it alone and need everyone’s support, including yours.

So how can we help protect and save endangered and threatened species?

Learn more about endangered/threatened species and spread the word to your community.

Here’s How:

  • Get your class, neighborhood, or family involved by “adopting” an endangered species such as a manatee, sea turtle, Florida Panther, Florida black bear. You will learn how efforts are being made to protect it and you will be able to share information about your adoption to others less informed by giving speeches, placing articles in your local newspapers and creating bulletin board displays for other classrooms at your school.
  • Protect endangered and threatened land species such as the Florida black bear, Florida panther, desert tortoises, gray wolves, Key deer, indigo snakes, and Houston toads, by keeping a close lookout for them when you are driving with your parents. Many of their deaths are caused by collisions with cars and trucks. These deaths can be decreased if you and your parents take notice of your surroundings and slow down in areas where wildlife are present (especially if wildlife signs occur). Remember that keeping wildlife safe will also help keep YOU safe as well!
  • Find out how your community’s activities affect endangered species living in your area. Learn the positives as well as the negative effects and what you can do to decrease the negative effects and increase the positive effects.

Get involved in habitat restoration

Here’s How:

  • Learn about the affects of habitat loss in your area and identify areas that have been destroyed by humans.

Habitat (Hab-a-tat): the environment in which a plant or animal lives

  • Get your class involved in helping clean up sensitive habitats in your area. For example take field trips to riverbanks and participate in river cleanups. Learn how improper disposal of trash and dangerous toxic chemicals can seriously harm environmental quality.
  • Consider planting a garden at home with the help of your family or at school with the help of your classmates. Gardens often attract a variety of wildlife, including birds, butterflies, and small mammals. Such projects can be certified by the National Wildlife Federation’s Backyard Wildlife Habitats Program.

Take the first step toward becoming a scientist by learning how to gather data and how to monitor environmental resources and wildlife.

Here’s How:

Get your class to adopt a river, stream, wetland or watershed in your area. By adopting an area of land you will be able to monitor its water quality, plants and animal distribution. At the end of the year your class can discuss your findings. Such findings might include changes in the presence or absence of animals in the area and possibly changes in the water quality. Take the discussion a step further by imagining how these changes may impact the living things within your adopted area and surrounding areas.


Classification 2: A Touch of Class

To show students that many kinds of living things (e.g. plants and animals) can be sorted into groups in many ways using various features to decide which things belong to which group and that classification schemes will vary with purpose.

Context

This lesson is the second of a two-part series on classification. At this grade level, students should have the opportunity to learn about an increasing variety of living organisms, both the familiar and the exotic, and should become more precise in identifying similarities and differences among them. First-hand observation of the living environment is essential for students to gain an understanding of the differences among organisms.

Classification 1: Classification Scheme is intended to supplement students' direct investigations by using the Internet to expose students to a variety of living organisms, as well as encourage them to start developing classification schemes of their own.

Classification 2: A Touch of Class extends this thinking by exposure to the idea that a variety of plants and animals (organisms) can be classified into one or more groups based on the various characteristics of a specific group.

This lesson gives students the opportunity to look at and discuss different classification schemes. Learning about a variety of living organisms helps them identify the similarities and differences among them. Further, this information will help students realize that there are many ways to classify organisms but that any classification scheme depends on its usefulness. It follows that a classification is useful if it contributes either to making decisions on some matter or to a deeper understanding of the relatedness of organisms.

Research suggests that upper elementary-school students tend to group certain organisms in mutually exclusive groups rather than a hierarchy of groups. Because of this tendency, students may have difficulty understanding that an organism, for example, can be classified as both a bird and an animal. Further, students do not recognize that trees, vegetables, and grass are all plants. Students also tend to group things either based on observable features or based on concepts. For example, when students distinguish between plants and animals, they often use such criteria as number of legs, body covering, and habitat to decide whether things are animals. Finally, elementary-school students typically use criteria such as movement, breath, reproduction, and death to decide whether things are alive. For example, some students believe fire, clouds, and the sun are living organisms, while others think plants and certain animals are nonliving. (Benchmarks for Science Literacy, p. 341.)

Motivation

As a way to stimulate student thinking about classification and to review what they learned in the first lesson of this series, conduct a class brainstorming session asking questions like these:

    What is an organism?
      (An individual living thing that carries on the activities of life by means of organs which have separate functions but are dependent on each other.)
      (Answers may vary.)
      (Some similarities are that they are both organisms that are multicellular [made of more than one cell] and they both have a life cycle. Some differences are that most plants use photosynthesis [use of sunlight] as their mode of nutrition whereas animals use ingestion as their mode of nutrition plants and animals have different ways of reproduction and animals have sensory and nervous systems whereas plants do not.)
      (Answers may vary. Encourage students to support their ideas with explanation.)
      (For animals, the basic needs are air, water, and food. For plants, the basic needs are air, water, and light.)

    You may want to write down students' responses on a piece of newsprint so that the class can revisit these questions and their responses at the end of the lesson.

    Next, review with students why it is useful to sort/classify things. You might ask:

      In Classification 1: Classification Scheme, you learned how to group things (e.g. animals) based on certain features. What features did you use?
        (Run, hop, swim, crawl, and fly.)
        (Answers may vary.)
        (Classification is useful because it enables one to make decisions about things [e.g., if one knows that a mammal is part of a group termed primates, then one knows that the animal is intelligent, can grasp things with its hands, etc.]. It is also useful because it allows us to identify similarities and differences among living things.)

      Development

      In this activity, students will classify plants and animals into groups based on certain characteristics (e.g., plants, animals, things that lay eggs, things that live underwater). By doing this, they will visualize and learn how the same plant or animal can be classified into more than one group depending on the features of a specific group.

      Have students use the A Touch of Class student esheet to access the A Touch of Class online interactive activity. The esheet includes both instructions on how to play the online activity* and questions regarding the activity. Answers to the questions can be found in the Learn More section or by playing the game.

      *Note: You can decide how to have students keep score. The computer will calculate the score but, if this is important, then you can ask students to record scores on paper.

      The following questions are found on the student esheet. Students can either respond to the questions online, using the online question and answer tool, or using the printable Grouping Organisms student sheet. You may want to encourage your students to take notes on what they learn by playing the game or from the Learn More section.

      • What do some plants need to make their own food? (Sunlight.)
      • What living things eat insects? (Some animals and some plants.)
      • Name some animals that fall under the mammal category. (Humans, whales, and the duck-billed platypus.)
      • What are some characteristics of mammals? (They are a group of animals that usually have hair, fur, and nurse their babies with their own milk.)
      • What birds cannot fly? (Ostriches and penguins.)
      • In what ways can animals protect themselves? (Some examples are by using poison or venom, by blending into their environment, and by playing dead.)
      • Can you think of any animals that do not have backbones? (Insects and jellyfish.)
      • What living thing is an arachnid but is often mistakenly classified as an insect? (Spider.)
      • Name an example where the same plant or animal can be classified in more than one group depending on the features of a specific group. (One example is a robin [a bird] can be grouped under "things that fly" or "things that have a tail.")

      Assessment

      Review with students that they should now understand that many kinds of living things (e.g. plants and animals) can be sorted into groups in many ways using various features to decide which things belong to which group and that classification schemes will vary with purpose.

      As a group, revisit the questions and answers from the beginning of the Motivation section. Have students' responses changed after going through this lesson?

      To further assess their understanding, have students create a new "screen" for the online activity they did in the Development section. That is, they should create a category (e.g., Animals that Hibernate) and 16 possible plants and animals (some that are the correct answers and some that are not) from which to choose.

      Then have them share their screen with a classmate and have the other student choose the correct animals and/or plants.

      How did they do? Review their screens, as well as how they scored their partner's work.

      Extensions

      The Science Update called All Species Inventory takes a look at taxonomy, the science of classifying and naming living things according to how similar they are to other creatures, and how a group of scientists and Silicon Valley entrepreneurs is trying to bring the musty field of taxonomy into the twenty-first century.

      National Geographic Kids would be a good place to go for students to learn more about various animals, from bats to warthogs.


      Section Summary

      Chytridiomycota (chytrids) are considered the most primitive group of fungi. They are mostly aquatic, and their gametes are the only fungal cells known to have flagella. They reproduce both sexually and asexually the asexual spores are called zoospores. Zygomycota (conjugated fungi) produce non-septated hyphae with many nuclei. Their hyphae fuse during sexual reproduction to produce a zygospore in a zygosporangium. Ascomycota (sac fungi) form spores in sacs called asci during sexual reproduction. Asexual reproduction is their most common form of reproduction. Basidiomycota (club fungi) produce showy fruiting bodies that contain basidia in the form of clubs. Spores are stored in the basidia. Most familiar mushrooms belong to this division. Fungi that have no known sexual cycle were classified in the form phylum Deuteromycota, which the present classification puts in the phyla Ascomycota and Basidiomycota. Glomeromycota form tight associations (called mycorrhizae) with the roots of plants.


      Plants

      More than 300,000 known species of plants are threatened with extinction.plants provide the oxygen we breathe and the food we eat.they’re also the source of a majority of medicines in USA today and over 50% of medicines derived from plants.

      Impact of extinction on human disease:

      Many different species have unique bodily processes that can cure human disease.for example the toxins produced by dart-poison frogs in the rainforest have invaluable information about how alkaloid compounds behave in living organisms.so the loss of these resources could prove a terrible blow to humans.

      Impact of the tiger disappeared:

      Tiger,in particular,is a super predator.it is at the very top of its food chain.this means that animal has no natural predators.tigers are important in Asian cultures too.its disappearance would be a huge cultural loss and feline is also one of the most endangered species.

      When elephants go,so do trees !

      In recent study found that there is a stark correlation between lower elephant populations and less trees.elephants are regarded as the architects of their environment.in fact after humans,elephants have the largest ability to influence their natural environment.

      Effects of animals extinction:

      When we lose the animals through extinction,we lose biodiversity.

      Biodiversity refers to the total number species.animals extinction is a threat to the human life.so we can say that it has got more disadvantages than advantages however,the extinction of a species may not always be a bad thing according to the Natural History Museum.

      The exhibition will show that without the demise of animals like dinosaurs,which died out 66 million years ago,birds would never come to dominate the planet.

      The relationship between extinction and food cycle:

      Every living thing plays a role in the food chain and earth’s ecosystems,and the extinction of certain species,whether predators or prey can have serious impacts.think about large animals like the grizzly bear,when a predator goes extinct,all of its prey are released from the predation pressure and they may have big impacts on ecosystems.or for example Arctic foxes are only canine species that can change the color with the season.if they become extinct it will upset the food chain which can disturb the ljfe cycle of other species.

      The extinction of many species depends on the survival of others,and don’t think human beings are an exception .

      Ants turn up more soil than earthworms!

      when ants dig tunnels,they aerate the soil and recycle nutrients.they have also been essential to production of coffee and chocolate.

      They are responsible for pollinating the world’s food supply and also produce buzzing sounds when they sense toxic chemicals in the air.

      Conclusion:

      In this world there are many plants and animals going extinct and humans never know how valuable a species of animal and plant may be for us in the future,perhaps as food,medicine or for specific information.


      Watch the video: Φυτά που Εκρήγνυνται για τη Διασπορά Σπόρων (July 2022).


Comments:

  1. Angus

    very funny play

  2. Zologrel

    Congratulations, I think this is the brilliant idea

  3. Zeeman

    Wacker, by the way, that phrase just came up

  4. Richie

    It agrees, the information is very good



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