Lecture 23

Question 1

Amniota

Answer 1

amniote clade includes reptiles and mammals, terrestrial adaptations, amniotic egg

Question 2

amniotic egg - 4 extra-embryonic membranes

Answer 2

1. amnion
2. yolk sack
3. allantois
4. chorion
   + most have eggshell impervious to water loss

Question 3

amnion

Answer 3

protects embryo from mechanical shock

Question 4

yolk sack

Answer 4

contains food (absent in most mammals)

Question 5

allantois

Answer 5

waste disposal and gas exchange

Question 6

chorion

Answer 6

in contact with liquid surrounding embryo and eggshell (when present), gas exchange

Question 7

3 amniote characteristics allowing for terrestrial life

Answer 7

1. copulation and internal fertilization
2. waterproof skin (reduces water loss to atmosphere)
3. muscles associated with ribcage efficiently ventilate lungs

Question 8

Hylonomus

Answer 8

earliest fossil amniote, Atlantic Canada

Question 9

2 major amniote clades

Answer 9

1. Reptilia

2. Synapsida

Question 10

diapsid skull

Answer 10

two holes per side behind eye socket

Question 11

synapsid skull

Answer 11

one hole per side behind eye socket

Question 12

anapsid

Answer 12

zero holes behind eye socket (only turtles)

Question 13

characteristics of non-avian reptiles

Answer 13

1. skin covered by thick protective keratinous scales
2. leathery eggshell
3. ectotherms
4. only require 10% calories compared to mammals (no metabolic energy spent on heating)
5. cloacas

Question 14

ectotherms

Answer 14

rely on environmental heat to maintain appropriate temperature, most enzymes only work in a particular range of temperatures, control temperature behaviourally

Question 15

3 main groups of non-avian reptiles

Answer 15

1. testudines
2. lepidosauria
3. crocodilia

Question 16

testudines

Answer 16

turtles and tortoises, bony dorsal and ventral shields, skull is a solid box with large openings behind eyes, sole living representatives of Anapsida, can withdraw head inside carapace for protection, males have an intromittent organ

Question 17

lepidosauria 2 lineages

Answer 17

1. tuataras

2. squamata

Question 18

tuataras

Answer 18

teeth fused to jaw bones, copulate but lack intromittent organ

Question 19

squamata

Answer 19

snakes and lizards, loosely jointed jaws and skull, paired hemipenes in males, lizards have external ear openings snakes do not, snakes have no obvious external limbs and kill prey by suffocation or venom

Question 20

crocodilia

Answer 20

alligators, crocodiles, gharials, cannot chew (swallow prey whole or spin to rip off chunks), can walk about on land, males have single intromittent organ, crocodilians show maternal care

Question 21

economic importance of non-avian reptiles

Answer 21

1. turtle flesh, eggs, and shells harvested
2. lizards and snakes as pets and zoo exhibits
3. some snakes dangerous to humans - antivenins available

Question 22

parareptiles

Answer 22

extinct anapsid reptiles, may be related to turtles

Question 23

2 extinct aquatic diapsids

Answer 23

1. ichthyosaurs (look like reptilian dolphins)

2. plesiosaurs (look like loch ness monsters)

Question 24

archosauria

Answer 24

crocodilians, birds, and extinct non-avian dinosaurs and pterosaurs

Question 25

dinosaurs

Answer 25

largest animals ever to inhabit land, may have been endotherms

Question 26

endotherm

Answer 26

warm-blooded

Question 27

class aves

Answer 27

birds

Question 28

feathers

Answer 28

finely subdivided keratinous scales, most important synapomorphy of birds

Question 29

origin of birds

Answer 29

fossil evidence supports small fast theropod dinosaurs with feathers

Question 30

Archaeopteryx

Answer 30

most famous extinct bird, wings with teeth and wing claws

Question 31

characteristics of birds

Answer 31

1. feathers
2. keratinous beaks that lack teeth (grind hard food in gizzard)
3. no claws
4. adaptations for flight (hollow bones and reduced organs)
5. endothermic
6. care for feathers by preening
7. cloaca
8. all copulate but most do not intromit (press cloacas together)
9. parental care

Question 32

gizzard

Answer 32

muscular part of stomach, often with added pebbles for grinding food

Question 33

endothermy in birds

Answer 33

use metabolic energy to maintain constant body

temperature, homeothermic

Question 34

homeothermic

Answer 34

maintain same temperature

Question 35

preening

Answer 35

1. moves oil from gland at base of tail all over feathers
2. keeps feathers supple
3. may act as antibiotic
4. ‘zips up’ flight and contours feathers to keep in good
   shape, tiny hooks and rays link like velcro
5. removes some parasites (feather lice)

Question 36

flightlessness in birds

Answer 36

evolved several times (penguins, ostriches), denser bones than flighted birds (diving birds also have denser bones)

Question 37

precocial

Answer 37

young able to feed themselves

Question 38

altricial

Answer 38

young born helpless and featherless

Question 39

economic importance of birds

Answer 39

1. meat, eggs, feathers
2. hunting sport
3. pets
4. bird-watching