Collage created by Kam, photos found online and in lecture slides.

WFC 134 

FINAL STUDY GUIDE

Winter 2024

General:

1. What is herpetology? What are the two major groups that make it up?

2. Are “herps” polyphyletic, monophyletic, or paraphyletic? How does this change depending on other groups added or removed?

   1. Define monophyletic.

   2. Define paraphyletic.

   3. Define polyphyletic.

3. Are the combined groups of reptiles and amphibians monophyletic?

4. Are reptiles more closely related to amphibians than they are to mammals? 

5. What is thermoregulation? Is this an efficient method for small amphibians and reptiles?

6. Define ectothermy and endothermy.

7. Are amphibians and reptiles ectotherms or endotherms? 

8. How does the surface-area to volume ratio impact the way “herps” heat up?

9. What are the costs that relate to ectothermy and how does that impact an individual’s survival?

10. Define extinct and extant. 

11. Define diurnal and nocturnal.

12. Why are amphibians and reptiles studied together in herpetology?

13. What are caudates?

14. What are anurans?

15. What are gymnophiona?

16. What are squamata?

17. Define direct and indirect development.

18. Define oviposition.

19. What does ossified mean?

20. Define viviparity.

21. Define oviparity.

22. Define amplexus.

23. Define archelosauria.

24. What are pedicellate teeth?

25. What triggers metamorphosis?

26. What are some costs and benefits of having a complex, biphasic (two phase) life cycle? 

27. What is metamorphosis? 

28. What is an incomplete-metamorphosis, and what traits does it leave some amphibians with? Can all amphibians undergo this?

29. What are the two distinct phases that separate metamorphosis?

30. What are the two categories of metamorphosis?

31. Explain neoteny.

32. Explain progenesis.

33. What happens, biologically and visibly, to an amphibian during metamorphosis?

34. What is facultative paedomorphosis?

35. What is obligate paedomorphosis? 

36. Amongst the three amphibian groups (anurans, caudata, gymnophiona) what mating signals are used? What about reptile groups?

37. What is divergent evolution? 

38. What are “ring species”?

39. Distinguish between ancestral and derived characteristics. 

    1. For each major group (Reptile and Amphibian) provide general examples of an ancestral condition and a derived trait.

40. What is cutaneous respiration and which groups primarily use it?

41. What does courtship look like in reptiles versus amphibians? 

Amphibians:

1. Did amphibians arise before or after the K-T mass extinction 65 million years ago (dinosaur extinction)?

2. How many species of amphibians (salamanders, frogs, toads, and caecilians) are there, approximately?

3. What is the name for modern amphibians? Is it monophyletic?

4. What are some key characteristics that define an amphibian?

5. What specific external conditions (weather, precipitation, etc) do amphibians live under?

6. What are the three extant clades of amphibians?

7. What are key ancestral characteristics of amphibians?

8. What is the primitive group amphibians derived from?

9. Which is older in origin: reptiles or amphibians?

10. What traits comprise the Temnospondyls?

11. What are some shared characteristics we see in amphibians?

12. When did some of the earliest caecilians evolve?

13. When did some of the earliest salamanders evolve?

14. Define lissamphibia. What are the specific characteristics of lissamphibia? Briefly describe each one.

15. What is the ancestral reproduction condition?

16. What are some costs and benefits of having a complex life cycle?

17. What are the various colors/patterns to an amphibian? Describe each. How do these characteristics help their survival?

18. Green rods are unique to amphibians. Why? What do they help amphibians do?

19. What are the likely reasons as to why amphibians hearing adapted as they moved onto land?

20. Do amphibians have epidermal scales?

21. What three attributes best describe modern amphibian teeth?

22. How many atria and ventricles does the amphibian heart have?

Reptiles:

1. How many species of reptiles (snakes, turtles, crocodilians, tuatara, and lizards) are there, approximately?

2. Did reptiles arise before or after the K-T mass extinction 65 million years ago (dinosaur extinction)?

3. What clades comprise extant reptiles?

4. What are the 15 major reptile characteristics seen across all extant reptiles (barring unique exceptions)?

5. How do these characteristics differ from those of amphibians?

6. Are there exceptions to certain characteristics? Which reptile groups are such exceptions in?

7. How many pairs of cranial nerves do reptiles have?

8. Does their head move more readily than amphibians’?

9. Do they have homodont or polyphyodont teeth? Both?

   1. Describe acrodont teeth. Which reptiles have these?

   2. Describe pleurodont teeth. Which reptiles have these?

   3. Describe thecodont teeth. Which reptiles have these?

10. Describe ecdysis and what the process looks like. 

11. Do they perform direct or indirect development? Oviparity, Viviparity, Ovoviparity, or all of the above?

12. What is Jacobson’s organ? How does it work?

Tetrapods:

1. When did tetrapods evolve onto land?

2. What are the three outgroups of tetrapods?

3. What characteristics make up Actinopterygii?

4. What characteristics make up Sarcopterygii?

5. What are the major groups in Sarcopterygii?

6. Describe the group actinistia.

7. Describe the group dipnoi. 

8. Describe the group tetrapoda.

9. What are the characteristics for primitive tetrapods?

10. What two lineages did tetrapods split into?

11. What are the most significant traits/adaptations that primitive tetrapods evolved to deal with terrestrial life? Briefly describe each characteristic. 

12. How can the hearing adaptations for tetrapods be described? 

13. What were some adaptations evolved by tetrapods to conserve water?

Amniotes:

1. When did amniotes evolve?

2. What are the outgroups to extant amniotes?

3. What is an amniote?

4. What are the synapomorphies of amniotes?

5. Describe the amniotic egg. What parts consist of it?

6.  Is an amniote’s life cycle dependent or independent of water? What are their adaptations for this trait?

7. What are the three major amniote groups?

8. How are these groups differentiated? (Think: temporal fenestration).

9. Define anapsid.

10. Define synapsid.

11. Define diapsid. 

12. Which of these three are derived?

13. In the amniotic egg, what directly surrounds the embryo and helps protect it from desiccation and concussion?

14. In the amniotic egg, what is formed from the gastrointestinal tract and grows as it collects waste?

Anurans:

1. What are some characteristics that are unique to anurans (frogs)?

2. What is a reproductive mode?

3. What are some generalizations about amphibian reproduction?

4. What are some reproductive deviations among amphibians?

5. Identify and describe the types of amplexus (mating positions). Which groups have various types?

6. Describe the trends in oviposition (egg laying), the costs involved, how these costs are dealt with by different groups, and potential trade-offs.

7. What is parental care and what kinds are seen by various groups? Is one kind more prevalent than others, and if so, which is it?

8. Intercalary elements are an adaptation for what? Which groups/families have these adaptations?

9. Identify the different types of anuran sternums. Which are associated with ancestral or derived frogs?

10. What are the three largest anuran clades? What are some characteristics that differentiate them?

11. Identify unique characteristics or species from the various families.

12. Identify the different features that make up the various families.

13. Which frog family has the most species? 

14. Which family genus has the most species?

15. What is the ancestral condition of amplexus? What is the more advanced/derived form of amplexus?

16. Where are the many frog families found and distributed? Are there any odd outliers, and if so, where are they located?

17. How do anurans reproduce? What cues (environmental or biological) do they use?

18. Can anurans have an incomplete metamorphosis? 

19. What constitutes tadpole morphology?

20. What are the differences between ancestral and modern ways frogs hop?

21. For each of the following families, please provide a brief description of their specific traits, region distribution, number of species and genera, and any unique characteristics established.

    1. Ascaphidae.

    2. Triadobatrachus massinoti.

    3. Leiopelmatidae.

    4. Bombinatoridae.

    5. Alytidae.

    6. Pipidae.

    7. Rhinophrynidae.

    8. Scaphiopodidae.

    9. Bufonidae.

    10. Hylidae.

    11. Eleutherodactylidae.

    12. Myobatrachidae.

    13. Rhinodermatidae.

    14. Dendrobatidae.

    15. Ranidae.

    16. Mantellidae.

    17. Microhylidae.

22. What is the smallest frog in the world and where is it found?

23. What is the largest frog species in the world and where is it found?

24. What tactics do frogs use to protect themselves against predators? 

Caudates:

1. What is the crucial difference between anuran and caudata (salamander) larvae? 

2. What does urodela mean?

3. Which families of salamanders would be found in Australia and Southern Africa?

4. How is it possible for salamanders to have internal fertilization without a copulatory organ? In what salamander families does this occur in?

5. How many species of salamanders are there?

6. What were early salamander traits? What evolutionary traits first began?

7. How do salamanders mate? What do they rely on?

8. Is paedomorphosis common in salamanders?

9. What does the term “basal salamander” mean?

10. What is a spermatophore? How do salamanders use them for reproduction?

11. What are crucial characteristics that define a salamander?

12. In bodies of water with high concentrations of CO2, would you expect to find aquatic salamanders with larger or smaller external gills?

13. Describe the recent taxonomic hypothesis.

14. In which groups does direct development occur?

15. Which salamander family has the largest (size wise) species?

16. Which salamander family has the most (numerous) amount of species?

17. What is unken reflex? How is it supposed to warn off predators?

18. Is maternal care in salamanders a derived or ancestral trait?

19. What are key characteristics of salamanders’ morphology, ecology, and life history?

20. What is the Red Queen Effect?

21. What are expanded transverse traits/processes?

22. For each of the following families, please provide a brief description of their specific traits, region distribution, number of species and genera, and any unique characteristics established.

    1. Hynobiidae.

    2. Cryptobranchidae.

    3. Sirenidae.

    4. Salamandridae.

    5. Ambystomatidae.

    6. Dicamptodontidae.

    7. Proteida.

    8. Rhyacotritonidae.

    9. Amphiumidae.

    10. Plethodontidae.

23. What is the largest salamander species and where is it found?

24. What is the smallest salamander species and where is it found?

Gymnophiona:

1. What constitutes gymnophiona?

2. How do caecilians reproduce?

3. What are the key distinguishable characteristics of caecilians?

4. Are caecilians earthworms?

5. What is the very peculiar sensory organ associated with caecilian’s eyes?

6. What is the very unique jaw morphology of caecilians and why do they have it?

7. What is the characteristic evolved by caecilians that has also been evolved by snakes, though they are entirely unrelated?

8. What are annuli and what do they represent? What is their function, if they have one?

9. Where are caecilians distributed throughout the world?

10. How is it possible for baby caecilians to gain body mass, while the mother loses body mass, if they are burrowed in a tight space with no obvious food sources? What is this method called? 

11. What are the major patterns in caecilian phylogeny?

12. What is the longest tetrapod without lungs, and why is it not the Giant Salamander?

13. For each of the following families, please provide a brief description of their specific traits, region distribution, number of species and genera, and any unique characteristics established.

    1. Rhinatrematidae.

    2. Ichthyophiidae.

    3. Typhlonectidae.

    4. Caeciliidae.

    5. Siphonophidae.

14. What are reproductive deviations of caecilians, and in what groups do these occur?

15. What are some synapomorphies unique to caecilians?

16. Are there any morphological specializations that allow caecilians to live where they do? Think about their global distribution.

Turtles:

1. What skull type do turtles have? What does it lack? Because of this skull, was it easy or difficult to place turtles evolutionarily? 

2. Do turtles have teeth? If not, what do they have instead?

3. What are the three parts to the bony shell? What are scutes?

   1. What is the trade off between having a shell?

4. What is the relationship between pressure (atmospheric, water, gravity) and shells?

5. Where are the pectoral and pelvic girdles on the turtle? Why is this so unique?

6. Describe some features to turtle mating. I.e. copulatory organs, male plastron concave, etc.

7. Are they oviparous or viviparous? 

8. How is offspring sex determined? What is the current trend in regards to the state of the Earth/atmosphere?

9. Describe Type 1A TSD.

10. Are turtles more R-Selected or K-Selected species? Why?

11. What is senesce? Do turtles do this or not?

12. What was the first major split in clades? 

13. Describe Clade 1: Suborder Pleurodira and the features of turtles in that clade.

    1. Family Chelidae. 

       1. Suction feeding, what is it and who does it?

    2. Family Pelomedusidae.

    3. Family Podocnemidae.

14. Describe Clade 1: Suborder Cryptodira and the features of turtles in that clade.

    1. Family Chelydridae.

       1. What is unique about the Alligator Snapping Turtle?

    2. Family Cheloniidae.

       1. Compare the historic green sea turtle abundance estimates to the current ones.

    3. Family Dermochelyidae.

       1. Leatherbacks: Are they the largest extant turtles?

       2. What is regional ectothermy?

    4. Family Dermatemydidae.

    5. Family Kinosternidae (“musk” turtles).

    6. Family Carettochelyidae.

    7. Family Trionychidae (soft shelled turtles).

       1. What species is the largest freshwater turtle?

    8. Family Testudinidae (Tortoises).

       1. What is their distribution? How do characteristics change based on region?

    9. Family Platysternidae.

    10. Family Emydidae.

    11. Family Geomyidae.

15. Which families have very few species? 

16. Which families are monotypic?

17. How are these major families distinguished?

18. Which families have the most species?

19. Which families are the sea turtles? 

20. Which families are freshwater turtles?

21. Which families are tortoises?

Squamates:

1. Describe the Subclass Lepidosauria.

   1. What orders are in this? What suborders are in those orders?

2. What are the characteristics of Lepidosauria?

3. What is Caudal Autotomy? 

   1. Why has it evolved?

   2. Is it the pulling apart of the backbone, or the splitting of the backbone?

   3. What are the costs and benefits of having this characteristic?

4. Is ecdysis synchronous or asynchronous?

5. Describe the paired copulatory organs hemipenes. How do they work?

6. Squamates have an egg tooth. Do amphibians? 

   1. How is an egg tooth used by hatchlings?

7. Do they have Temperature Dependent Sex Determination (TSD), like turtles do?

   1. How does it differ from Type 1A in turtles?

8. Squamates have another way to determine sex. What is it? 

   1. What are female chromosomes? Males?

9. What is parthenogenesis? 

   1. How does this work in a hypothetical all female population?

   2. When does parthenogenesis happen?

10. Is the ancestral characteristic a fleshy tongue or a keratinized tongue?

11. Describe the relationship between squamate phylogeny and molecular data. Which holds up better?

Lizards:

1. Describe the order Squamata.

   1. How many species are in it?

2. What are the lineages/families following the order Gekkota?

3. Describe the characteristics seen in Gekkota.

   1. What does this group rely heavily on for communication?

4. What happens to reptiles under 10kg when they emerge on an island?

5. What happens to reptiles over 10kg when they emerge on an island?

6. For each of the following families, please provide a brief description of their specific traits, region distribution, number of species and genera, and any unique characteristics established.

   1. Gekkota: Gekkonidae.

   2. Gekkota: Eublepharidae.

      1. How do geckos communicate?

   3. Scincomorpha: Scincidae.

   4. Scincomorpha: Xantusiidae.

      1. What was unique about the species Xantusia riversiana?

   5. Lacertoidea: Teiidae.

      1. Are these New World or Old World families?

   6. Lacertoidea: Lacertidae.

      1. Are these New World or Old World families?

      2. The oddball species to this group is the Lacerta vivipara. Why? What makes this species unique?

7. Describe characteristics for the clade Amphisbaenia. 

   1. Why are they called “Worm Lizards”?

   2. What are some traits they have evolved and why?

   3. Which evolved trait is similar to the one seen in caecilians and snakes? Why?

8. For each of the following families in Amphisbaenia, briefly describe them, their distribution, and any traits that have evolved because of their way of life.

   1. Rhuneuridae.

   2. Bipedidae.

   3. Amphisbaenidae.

9. Why is the clade Toxicofera in debate between herpetologists and evolutionary biologists?

   1. What does the shared “venom” suggest about these orders?

10. How are Iguania split? By what feature?

11. Describe the characteristics seen in the Iguania.

    1. What does this group rely heavily on for communication?

12. A lizard is perched on a rock seen doing push ups. Are they working out or is there a reason for their activity?

13. Why is the Iguania Pleurodonta classified as a separate group? 

    1. Where are species found?

    2. Is this a New World or an Old World classification?

    3. Describe key characteristics and features found in this clade.

    4. What is a pineal/parietal eye? What does it allow individuals to do?

14. For each of the following families in Iguania Pleurodonta, describe them and point out any notable species.

    1. Corytophanidae.

    2. Polychrotidae.

    3. Crotaphytidae.

15. Why is the Iguania Acrodonta classified separately from Iguania Pleurodonta?

    1. Where are species found?

    2. Is this a New World or an Old World Classification?

    3. Describe key characteristics and features found in this clade.

    4. What traits do they share with Iguania Pleurodonta? What is different? 

16. For each of the following families in Iguania Acrodonta, describe them and point out any notable species.

    1. Agamidae.

    2. Chamaeleonidae.

       1. What is a key distinction/uniqueness between other families and this family?

       2. What are zygodactylous feet? What do they allow species to do?

       3. What is a prehensile tail? What does it allow species to do?

       4. What kind of behaviors do they participate in?

17. For the following families, please describe how they subdue prey, how they are similar, what features make them up, and what is unique about them.

    1. Anguimorpha: Helodermatidae.

       1. What notable species is in this family?

       2. Is a bite from a gila monster generally lethal? What is the most recent case mentioned in class that is rather unique to this question?

    2. Anguimorpha: Varanidae.

       1. What is so unique about the monitor lizard? Describe speed, length, lung capacity, etc.

       2. What is the smartest lizard across this phylogeny?

       3. What is the largest extant lizard? How big do they get?

Serpents:

1. What are the key characteristics of suborder serpents? There were 7 mentioned in lecture, excluding locomotion and foraging strategies. Describe them below. 

2. What characteristic is shared, not directly (ancestorally or evolutionarily) by snakes and caecilians? Why has this been derived?

3. Snakes have an elongated body. Is this because of the addition of vertebrates over time, or is it the elongation of bones like salamanders?

4. Can snakes hear? If so, how? What bone system allows for them to comprehend noise or vibrations?

5. Can legless lizards perform the same type of locomotion that snakes can? If so, what type(s) of locomotion can a legless lizard potentially do?

6. Describe the four types of locomotion below. Provide examples for what type of species move like this, and in what cases they use these in (type of environment, etc).

   1. Lateral Undulation.

   2. Concertina Locomotion.

   3. Side-Winding.

   4. Rectilinear Locomotion.

      1. Which is used when swimming?

      2. Which is used when moving across sand?

      3. Which is used when flying through the air (from tree to tree, as seen in the video in class)?

7. There are two different types of foraging strategies used by snakes, they are outlined below. Describe what they are, include when they are used, how they are used, what type (body characteristics) of snakes use these methods.

   1. Active Foragers.

      1. Do snakes performing active hunting generally eat larger or smaller prey?

   2. Ambush Foragers.

      1. Do snakes performing ambush hunting generally eat larger or smaller prey?

8. How do snakes subdue prey? There were three mentioned in lecture. Describe what they are and what type/species of snakes perform these methods. 

9. During constriction, do snakes suffocate their prey or do they cause their prey to have a heart attack?

10. Describe the features of a snake swallowing their prey. What are the three mentioned parts of the jaw bones and how do they work?

    1. Do they move the prey down or do they move themselves over the prey? 

    2. Does the bottom jaw detach or is it entirely flexible and connected via ligaments?

11. What are Opisthoglyphous teeth? 

12. What is the Duvernoy’s Gland? Where is it? What does it do?

    1. What group of snakes is it unique to?

13. What are Front Fanged venom snakes? What are examples of species that have this?

14. Describe Hollow Fangs. What species/families use this structure?

15. What are Proterglyph teeth? How do they work?

    1. How do Viperid use these teeth?

    2. How do Elapids use these teeth?

16. What are Aglyphous teeth?

17. For each of the following serpent classifications, what type(s) of venom are they known to use/have? Why is it more complicated than it seems? Can there be overlaps?

    1. Elapids.

    2. Viperids.

    3. Colubrids. 

18. Fun question to break up the nitty gritty questions: Dr. Todd brought two of his snakes into lecture today (03/06) for a show-and-tell.

    1. What species of snakes were they? What groups/orders do they fall under?

    2. What were their names? Hint: Both start with “A”. 

19. What was the first major split in serpent phylogeny? Are these clades monophyletic, paraphyletic, or polyphyletic? 

    1. Is this split a well supported hypothesis?

20. Why are Alethinophidia called “genuine snakes”?

21. What makes Scolecophidia considered “worm snakes” or “blind snakes”?

    1. Why do they have a reduced eye? What is this an adaptation of?

    2. How many million years ago did they resurface from the ground? Hint: This was mentioned in the David Attenborough video on the Flower Pot snake, along with swallowing its small prey whole.

    3. Do they lay eggs or give live birth? Is it a mix of both?

22. For each of the following Scolecophidia families describe any notable characteristics, evolutionary traits, distribution, and sizing; and answer the following questions. 

    1. Leptotyphlopidae.

       1. Is this a fossorial group? Why or why not? (What indicates it?)

       2. At a glance, people can get these snakes and earthworms confused. What are the key phenotypic differences between these and an earthworm that you can point out to someone who has no knowledge of herpetology or phylogeny? 

       3. Does it have teeth? If so, describe where they are, how many there are, and what their purpose is. If they don’t, why?

       4. Is their upper jaw located longitudinally or transversely? What is the difference between the two and why does Leptotyphlopidae have their jaw this way?

    2. Typhlopidae. 

       1. Do they have teeth? Where are they located (Dentary or Maxilla) and how many are there? What are they used for?

       2. What makes Indotyphlops braminus special? Why was it highlighted in lecture?

       3. They have a “stinger” on the end of their tail. It doesn’t sting, but it does serve a purpose. What is that purpose?

23. For the following families of Alethinophidia, the other group in the major serpent split, describe key characteristics, distribution, and answer the following questions.

    1. Boidae.

       1. What other families/subfamilies are associated with this family?

       2. Are they mostly oviparous or viviparous?

       3. Historically, what was the largest snake in the world? Was it likely closely related to today’s heaviest snake globally? 

       4. What is the heaviest snake in the world?

       5. What kind of teeth do they have? 

       6. Why do their lower jaws appear disconnected from the upper jaw in a skeletal reconstruction?

       7. What species can be found in Canada and up into the 

    2. Pythonidae.

       1. Is this treated as a sister lineage to the boas or is it treated as a larger family that the boas are also in? 

       2. What is “shivering”? What is it used for?

       3. Are these the Old World or New World counterpart to boas?

       4. Are labial pits more or less wide spread in pythons or boas?

       5. “Spurs” are vestigial limbs on these snakes. Where are they located? How are they used and for what?

       6. What is the longest snake in the world?

       7. How do they swallow prey? How does their jaw and teeth help with this?

       8. Are pythons ambush or active predators?

       9. Pythons can grow to extreme sizes. When they do, does anything feed or prey on them?

    3. Viperidae.

       1. What are the three subfamilies to this family?

       2. Is this group very species rich?

       3. These snakes are seen worldwide except for a few cases. What are they?

       4. What do the jaw and teeth systems look like on this snake? How big are the teeth and why is this notable?

       5. What species is considered the most deadly to humans in the world?

       6. What species is the only New World viper that lays eggs?

       7. What species is the European Old World viper that can reach into the Arctic Circle?

       8. The “Don’t Tread on Me” flag has which species of viper on it? What does it represent? What did Benjamin Franklin once say about this snake species? 

    4. Colubridae.

       1. Again, is this a very species rich group?

       2. Why are they considered a “cosmopolitan” family?

       3. Why are snakes often lumped in this group? Hint: Think of how they give birth. 

       4. This is a very colorful family which often uses mimicry. Why is this? What does it have to do with hunting?

       5. Do they have specialized teeth? 

       6. Describe the specialized family Elapidae. 

          1. Are they all venomous?

          2. What species does this family feature?

          3. What are some key characteristics they have? Think about their teeth, their body size and shape, their coloration, etc.

       7. For the following Elapidae families, describe some of the key characteristics associated with them. (Think: Color, distribution, evolutionary traits, unique characteristics, etc).

          1. Hydrophiinae.

             1. What niches have these snakes filled?

             2. True or False: Respiratory needs can be filled by cutaneous respiration.

          2. Atractaspididae. 

24. How do snakes breathe while swallowing? What at the back of the throat is used to do this?

25.  The Burmese Python was introduced to the Florida Everglades. They are non-native and destroy ecosystems. Why can they not be removed from the system? What has their presence resulted in? Hint: How does this species impact the trophic cascade? What preys on them? Etc.

26. Dr. Todd has/had a Rubber Boa (Boidae). During “wintering”, Dr. Todd has put this snake in his fridge, where it “hibernates” for several months (4 was mentioned).

    1. Does this snake lose calories/mass while it's playing Captain America (on ice)? 

    2. How long can they go without eating?

27. Snakes use the Jacobson Organ very intimately, going as far as picking up 1/10,000th of a scent. Describe how snakes use them. How does their forked tongue come into play?

Crocodilians:

1. Which group/clade are crocodilians grouped with?

2. Including testudines, what is this group now called?

3. Describe the key characteristics seen in crocodilians.

4. What trait(s) do they have in common with birds? This is evolutionarily explained by…

5. What are crocodilian’s typical behavior as a highly aquatic group?

6. How does parental care present itself in this group?

7. Historically, crocodilians experienced a severe decline in numbers. Why? What threatened them?

   1. True or False: Since, they have become a group that has responded well to management by the ESA, and many of their populations have recovered.

8. What kind of sex determination do crocodiles have? What does this mean for the sex of the offspring produced?

9. For the following families, please describe key characteristics seen. Include notable species, behavior, coloration, distribution, size, prey, causes of decline, etc.

   1. Alligatoridae.

   2. Crocodylidae.

   3. Gavialidae. 

      1. What is the False Gavial? What ways does it differ from the real gavial?

      2. Why is it believed that this population (Gavialidae) has declined dramatically within 10-15 years?

      3. What conservation efforts have brought this population back from the brink of extinction? 

      4. Why do conservationists have a habit of waiting until a population is near extinction to step in and do something? (Or is that just the way conservation has always been and people are silly?)

Tuatara:

1. What group are the tuatara in? 

2. Who do they share a common ancestor with, and what is that common ancestor?

3. Are they, or are they not, closely related to the crocodiles?

4. For the order Rhynchocephalia, answer the following questions.

   1. How long does this order date back to?

   2. Which group/clade did they split from early on? 

   3. Why did this order survive the extinction that killed off the dinosaurs?

   4. True or False: Before lizards were occupying certain niches and regions, the Rhynchocephalia filled those roles. 

   5. This is an entirely monotypic family, genus, and species. How long has it been estimated that this order has been this way?

   6. Where are they spread out throughout the globe, and about how many are there?

5. For the only Rhynchocephalia family, Sphenodontidae, describe the key characteristics and answer the following questions.

   1. What kind of skull and teeth do they have? Describe characteristics of both.

   2. Is the skull type similar or different from other lepidosaurs? Is it more or less developed than lepidosaurs in this family?

   3. Are these teeth similar or different to squamate (snake and lizard) teeth?

      1. Do these teeth regrow or do they wear down? If they wear down, how does this affect their diet?

   4. When they were first discovered, were they considered their own order? Why or why not?

   5. Do they have an intromittent organ? If not, what is their method of reproduction? 

      1. What group of organisms is this method similar to?

   6. What kind of sex determination do they have? Why can it be problematic for their populations?

   7. Tuatara share a most recent common ancestor (MRCA) with squamates. However, this skeletal characteristic is something they do not share with the squamates. What is it?

      1. What is the function of this? What does it allow Sphenodontidae to do (behaviorally and ecologically?)?

      2. What other groups (extant or extinct) is this seen in? Is it assumed that birds have this or that they have lost this?

   8. What does their reproduction and maturing look like? (Think: rate, number of offspring, viviparity or oviparity, parental care, senescing, etc).

   9. This is the only vertebrate that can do or that has what genomic feature? 

      1. What is the estimated purpose of this evolutionary trait? (Think: metabolism, habitat, prey, etc).

      2. What is the percent difference in genome between a human and a chimpanzee? Related to that, what is the difference in genome between a tuatara’s mitochondrial genomes?

      3. What is the only other “animal” to be known to have this feature?

   10. Tuatara are considered a “living fossil”. Why is this controversial? What does “living fossil” imply?