Endotherms - birds

What were the first bipedals on land?

dinosaurs

Clade archosauria includes…

• dinosaurs

• birds

• pterosaurs

• crocodilians

What makes an organism endothermic?

capable of keeping the body warm through metabolism

• ex burning their fuel

Characteristics of endotherms

• need to eat more frequently to maintain warmth

• have external coverings for insulation (feathers, hair)

Birds are ___ (clade)

archosaurs

Modifications birds have undergone to adapt to flight

• loss of teeth → beak

• loss of long tail bones

• internal anatomy changes

  • 4 chambered heart

  • air sacs

  • keeled sternum

  • hollow bones

  • reduced paired organs

Birds evolved from bipedal dinosaurs called ___

theropods

What do birds have in common with theropods?

• hip and wrist bone structure

• wishbone

Arboreal theory of how flight evolved

tree-dwelling precursors to modern birds jumped from branch to branch using their feathers for gliding before becoming fully capable of flight

Terrestrial theory of how flight evolved

running was the stimulus for flight, wings could be used to improve running then became used for flapping flight

Characteristics of mammals

• hair or fur

• mammary glands - supply milk

• give birth to live young

• parental care

• well developed nervous systems and brains

• 4 chambered heart

• ossicles - inner ear bones

• vibrissae

• differentiation of teeth

Mammals evolved from ___ in the late ___ period.

Synapsids therapsids

Triassic (~200mya)

What are monotremes?

mammals that lay eggs

What are traits of marsupials?

• live primarily in australia

• posses a pouch

• young reside in pouch after birth receiving milk and continuing to develop