Vertebrate Adaptations Final Exam Study Guide
Vertebrate Adaptations Final Exam Study Guide
- Diving Adaptations
- Morphology of marine mammals
- Why do toothed (odontocete) whales have asymmetric skulls?
- Why are the cervical vertebrae of cetaceans compressed?
- How do marine mammals achieve laminar flow?
- what is the consequence of a blubber layer?
- where are the nipples and genitals?
- What is a mandibular stay, and why do baleen whales have them?
- Why do whales use dorsal-ventral undulation rather than lateral undulation?
- Physiology of marine mammals
- How is it possible the bottle-nosed whales can dive to depths of 2.5 mi for 2 hours?
- How do whales avoid the bends?
- How is the rib cage of whales modified for diving.
- Why do whales exhale before diving?
- How are rete mirabile and bradycardia related to diving?
- Whale bones are extremely oily, even after laying on a beach for a year. Before they can be put into a collection or displayed in a museum, the oils must be removed. What is the oil all about?
- Why is large size advantageous in diving?
- How does feeding in odontocetes and mysticetes differ?
- Why do grey whales not feed during their southward migrations to Baja?
- Evolution of Mammals
- Major themes in mammalian evolution
- Simplification of the jaw to involve only the dentary bone.
- jaw mechanics: effort and load arms, speed ratios and mechanical advantage.
- bite force.
- diversification of temporalis and masseter muscles.
- Evolution of the dentary squamosal jaw articulation.
- what happened to the quadrate and articular bones?
- in terms of sound conduction routes, why is this interesting?
- What is the significance of the synapsid jaw design?
- Evolution of the secondary palate.
- isolation of food from airway
- permits breathing while eating – important because of high metabolic rate.
- Diversification of dentition: be able to identify teeth associated with herbivory, carnivory, and omnivory.
- Modification of posture – loss of sprawling gait.
- Regionalization of vertebral column.
- Modification of pelvic and pectoral girdles.
- animals like cheetahs and horses use the scapula as a limb element, functionally increasing stride length.
- animals like elephants modify the pelvic girdle to handle graviportal limbs.
- Important point: mammals have a high cost of maintenance, and must feed the metabolic fires. Thus, much of their evolution is all about getting and processing food.
- Thermoregulation
- what came first, insulation or high metabolic rate.
- What are the constraints of hibernation?
- what is the thermal neutral zone?
- Mammalian evolution
- Are mammals monophyletic or diphyletic?
- Where did the marsupials have their evolutionary origin, and why are they now restricted primarily to Australia and New Guinea?
- Are monotremes mammals or reptiles?
- What reptilian characters do they have?
- What mammalian characters do they have?
- Describe the marsupial fauna of South America (historically and present). What happened to the bulk of this fauna, and why?
- Reproduction in marsupials and placentals is fundamentally different, even though marsupials do have a placenta.
- what problem did marsupials not solve (that is, why does parturition occur so soon after implantation of the embryo?)
- what is the advantage of delayed implantation?
- why do female kangaroos wait until relative old age to produce sons?
- I made the comment that much of marsupial evolution can be interpreted in light of foot morphology. How so?
- Marsupial morphological diversity mirrors that of placentals. Explain.
- Why were there no marsupial bats or whales?
- Evolution of Birds
- Understand the arguments about birds as dinosaurs.
- Physiological arguments (major player: Robert Baker)
- flight requires sustained aerobic metabolism, which reptiles do not have.
- did insulation come first, or did high metabolism come first?
- birds have 4-chambered hearts, but so do crocodilians.
- Flying reptiles lack a large keeled sternum, and are clearly not birds.
- Did flight evolve top-down or bottom-up (major player: Kevin Padian)
- Top-down: birds did not get into trees.
- Bottom-up
- Running and leaping to catch insects results in loss of speed and prey.
- Running involves asynchronous movement of pectoral appendages while flight involves synchronous movement of pectoral appendages.
- Misc
- Large dinosaurs probably did not run for the same reason that large mammals (elephants) do not run.
- Cost of locomotion goes down for large animals, but control issues become more important for small ones. Were the first fliers large or small?
- Archaeopteryx is the wrong age (Jurrasic) to be very helpful in the argument about the link between birds and dinosaurs.
- Protoavis is the right age, and if truly a birds, casts doubt on the birds as dinosaurs hypothesis.
- Mesozoic Reptiles
- What is the relationship between diapsid, anapsid, and synapsid reptiles?
- Describe the end-Permian mass extinction.
- What caused the extinction event.
- What proportion of the world’s species went extinct?
- How did land masses shift during this perioe?
- How did climate change?
- How did vegetation change?
- Describe the end-Cretaceous mass extinction.
- What caused the extinction event.
- What proportion of the world’s species went extinct?
- How did land masses shift during this perioe?
- How did climate change?
- How did vegetation change?
- How do dinosaurs differ morphologically from other reptiles?
- Ichthyosaurs and pleisiosaurs were not dinosaurs, but were contemporaraneous with them. How did their morphology relate to that of modern cetaceans.
- Modern Reptiles
- What is the relationship between lizards and snakes?
- How is body shape related to habitat use in snakes?
- What evidence do we have that snakes have a fossorial origin?
- Morphology of the eye.
- Limb loss.
- How does lizard morphology relate to locomotor mode and thermoregulatory mode?
- So what’s the deal with the pineal eye?
- Explain thermoregulatory strategies in reptiles.