Clade Reptiles: Classe Aves

Question 1

Clade Reptiles Class Aves

Answer 1

Birds evolved from theropods

Question 2

Origin of birds

Answer 2

Early feathers might have evolved for insulation (thermoregulation), camouflage, or courtship displays

Question 3

Similarities of theropods and birds

Answer 3

Hollow, thin-walled bones

Egg laying and brooding

Feathers are homologous with theropod scales and scales present on bird feet

Numerous organ similarities including brain, heart, and muscle arrangement

Question 4

Phylogeny of birds

Answer 4

Birds and crocodilians are extant sister taxa

Birds form a monophyletic lineage that underwent rapid adaptive radiation

Question 5

Shared Derived Traits of Birds

Answer 5

1. Wings with keratin feathers off of modified tetrapod forelimbs
2. Lightweight, hollow bones
3. Beaks that lack teeth
4. Bird digestive systems adapted for fight including gizzard to grind food
5. Organ reduction
6. Endothermy
7. High metabolic rate supported by a 4-chambered heart and complex respiratory systems

Question 6

Characteristics of extant birds

Answer 6

Various dietary preferences, including predators, herbivores, scavengers, and omnivores

Defining feature of feathers that facilitate flight, provide insulation, courtship, and grooming

Question 7

Birds Reproductive Strategies

Answer 7

Internal fertilization via copulation

Press cloacas together to reporduce

Oviparous laying shelled eggs

Some degree of parental care