Lecture 13 - Tetrapods

Question 1

What is a tetrapod? (4 traits)

Answer 1

Includes amphibians reptiles and mammals, usually two pairs of limbs, limbs evolved from lobe fins, lobe fins evolved from ancestral fins

Question 2

Origin of the limb (2 )

Answer 2

Tiktaalik had a shoulder that was separate from the skull, unlike other fish tiktaalik had a neck

Question 3

What is an amphibian? (5 traits)

Answer 3

Adults typically feed on land but lay eggs in freshwater, typically have a larval stage and metamorphosis, larvae breathe with gills, adults have lungs but some gas exchange occurs across the skin, first tetrapods probably exhibited these traits

Question 4

Extant amphibians include three lineages

Answer 4

frogs and toads, salamanders, worm like caecillians

Question 5

Urodela (salamanders) 4 traits

Answer 5

Adults and larvae are carnivorous, external fertilization, aquatic larvae (tadpoles) metamorphose into adults, larvae may be cannibalistic

Question 6

Gymnophiona (cacillians) 5 traits

Answer 6

Lack legs, internal fertilization, some are viviparous with embryos eating cells in mother, some feed their young their own skin, terrestrial and aquatic species

Question 7

Amniotes: origin of the amniotic egg

Answer 7

Includes reptiles and mammals, named for the synapomorphy of amniotic egg, protective covering to reduce the rate of death and do not have to return to water to reproduce, fertilization is always internal

Question 8

Egg design

Answer 8

Egg shell, albumin - water and material support, choroid - allows gas exchange, yolk sac- contains nutrients, amnion- contains embryo, allantoin- contains waste

Question 9

What is a reptile? (3 traits)

Answer 9

adapted for the land with three traits - skin made of watertight layer of keratin scales, well-developed lungs, lay shelled amniotic eggs

Question 10

Reptile 4 major lineages

Answer 10

Lizards tuatara and snakes, turtles, crocodiles and alligators, birds

Question 11

Lepidosauria (snakes, lizards, tuatara) 5 traits

Answer 11

Lizards can be carnivores or herbivores, snakes and tuatara are all carnivores, ovoviviparous oviparous and viviparous species, some do parthenogenesis, snakes are phylogenetically listed within lizards

Question 12

Testitivores (turtles) 4 traits

Answer 12

Most marine turtles are carnivores, most terrestrial turtles are herbivores, many freshwater species are omnivores, reproduce sexaully and are oviparous

Question 13

Aves (birds) 7 traits

Answer 13

carnivores herbivores and scavengers, most can fly, some are good swimmers, reproduce sexually and are all oviparous, extensive parental care, evolved from feathered dinosaurs, feathers evolved from scales and provide insulation display and flight, birds are endothermic