Final Exam Flashcards
What is an example of a paraphyletic group?
Non-avian reptiles (Class Reptilia). A group that includes some but not all descendants of one common ancestor.
What is an example of polyphyly?
Ectotherms or “herps.” Hodge podge of some descendants of different common ancestors.
What is a monophyletic group?
A group that contains all and only the descendants of one common ancestor.
What is true of living amphibians?
Frogs and salamanders are more related to each other than to caecilians.
Microsauria, Nectridia, and Aistopoda are extinct and outgroups to living amphibians.
They are the only surviving members of Temnospondylii.
When did most amphibian families arise?
After the KT extinction event.
When did most reptile families arise?
Before the KT extinction event.
What were reasons behind amphibian adaptations for hearing low frequency sounds?
To detect predators and approaching rainstorms.
What is true of adaptations to tetrapod hearing?
Sounds waves travel faster in water
Parts of gill structures evolved into structures for hearing
What does the amphibian heart look like?
Two atria and one ventricle
What orders breathe through their skin?
Caudata, anura, gymnophiona
Advantages of ectothermy
Ectotherms use less energy for the same size. Being small isn’t energetically costly.
Critical adaptations that enabled terrestrial life and evolution of tetrapods
Development of intrinsic musculature in the extremities
Limb girdles became more firmly attached to the spinal column
How do tetrapods conserve water?
Postures and behaviors that limit water loss
Concentrating nitrogenous wastes using kidneys
Who is in archelosauria?
Turtles, crocodiles, and birds
What is the ancestral skull condition?
Synapsid
Who are lobe-finned fish descendants?
Amniota, sarcopterygii, dipnoi, and actinistia
Fossils in order that gave rise to tetrapods:
Glyptolepis, eusthenopteron, panderichthys, tiktaalik, acanthostega, ichthyostega, tulerpeton (GEPTAIT)
What does the amnion do?
Surrounds the embryo, forms space filled with amniotic fluid, contributes to gas exchange, protects the embryo from concussion and dessication
What is the chorion?
The outermost membrane within the shell.
What is the allantois?
Sac formed from the posterior part of GI that collects water during development
What is the yolk sac?
Filled with nutrient source for embryo, shrinks as yolk is used up
What is the shell of an egg
Formed by mother, involved in gas exchange and protection
Adaptations to dry habitats?
Shelled eggs, increased keratinization, deposition of lipids in epidermis
Lissamphibia traits
Green rods, pedicillate that are uniform and continuously growing teeth, gelatinous capsules with yolk house embryo, no epidermal scales, 10 pairs of cranial nerves, single sacrum, larger limbs that make a joint with pectoral girdle, three chambered heart, mucous and poison glands, cutaneous respiration, fewer cranial bones, low frequency hearing with ear connected to pecs
What is neoteny
Paedomorphosis where metamorphosis doesn’t happen. Somatic growth slows and reproductive growth continues normally
What is progenisis
Paedomorphosis where sexual development accelerates and metamorphosis happens normally
Facultative paedomorphism
Metamorphosis can occur
Obligate paedomorphism
Metamorphosis can never occur (secondarily lost like in Sirenidae)
Paedomorphism among lissamphibians
Widely in salamanders, common in caecilians, never in frogs
Amphibian diversity
Tied to direct development, can venture further from water
Ancestral frog conditions
9 pre-sacral vertebrae, inguinal amplexus, arciferal girdle (more cushioned)
Derived frog conditions
Firmisternal pectoral girdle, fewer pre-sacral vertebrae, any non-inguinal amplexus, direct development
Caecilian traits
No limbs or girdles, burrowers, retractable tentacle, compact skull, most derived jaw relies on interhyoideus muscle, dermal scales, vestigial eyes, reduced left lung, phallodeum
