BIO Exam 4: Chordata VI (birds)

What is the reptile called that birds descended from?

Archosaurian

What is the dinosaur called that birds descended from?

theropod

In the Class Aves what were modified to become wings?

forelimbs

In the Class Aves what were adapted for walking, swimming, or perching?

hindlegs

The evolution of what led to flight?

feathers

What does flight restrict?

morphological diversity

What are some requirements for flight?

forearms develop into wings, lightweight but strong bones, high metabolic rate, efficient respiration and circulation

What are the 7 defining traits of birds?

1. Feathers 

2. Light, strong skeleton

3. Powerful flight muscles

4. Nervous and sensory organs

5. Feeding and beak morphology

6. Efficient circulation and respiration

7. Reproduction

What are feathers made out of and homologous to reptile scales?

Keratin

How is the skeleton of birds light?

there are air cavities (pneumatized)

What are the characteristics of birds powerful flight muscles?

large pectoralis muscles for downstroke and supracoracoideus for upstroke with the main muscle near center of gravity

What are the characteristics of a birds nervous and sensory organs?

more complex brain, good hearing an vision 

What is beak morphology strongly tied to?

diet

True or false: Birds have a 4 chambered heart

True

What are the lungs of birds modified for?

efficient air flow

True or false: Most birds are genetically or socially monogamous

True

What is brood paraticism?

lag eggs in other species nests

What are the several strategies of brood paraticism?

mimetic eggs, outcompeting for food, killing other nestlings

What percent of birds migrate?

50%