Lecture 14 - Mammals

Question 1

What are mammals? (6 traits)

Answer 1

Extensive parental care, mammary glands that produce milk, milk nourishes developing young (lactation), endothermic, only vertebrates with cheek muscles and lips, hair and fur made of keratin

Question 2

Three major lineages of mammals alive today

Answer 2

Egg laying monotremes, pouch bearing marsupials, placental mammals (eutherians)

Question 3

Monotremata (platypus and echidnas) 6 traits

Answer 3

Native to australia, only mammals that lay eggs, hunt using electroreceptors on their snouts, male platypus have venous spurs for fighting (venom is rare in mammals), lack nipples (babies lick milk directly off of fur), do not have cheek muscles

Question 4

Marsupials (kangaroos, koalas, opossums, wallabies) 4 traits

Answer 4

Pouch bearing mammals, choncateline placenta - formed by yolk sac and chorion which does not connect to the mother, young born early when yolk is depleted and crawl to pouch to find nipple, marsupials travelled to Australia from South America 50 mya during the Supercontinent Gondura

Question 5

Eutheria (placental mammals)

Answer 5

Chorioallantoic placenta - formed by chorion and allantois , this type of placenta provides embryos sustenance directly from mother so young can be born after the latest stages of development, herbivores carnivores and omnivores, includes swimmers walkers runners and flyers