Vertebrates

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Monotremes are a small group of egg-laying mammals consisting of echidnas and the platypus.

Slide 46

an Australian monotreme

Slide 47

Marsupials

Marsupials include opossums, kangaroos, and koalas.

The embryo develops within a placenta in the mother’s uterus.

A marsupial is born very early in its development. It completes its embryonic development while nursing in a maternal pouch called a marsupium.

Slide 48

Australian marsupials

(a) A young brushtail possum

(b) Long-nosed bandicoot

Slide 49

Evolutionary convergence of marsupials and placental mammals

Plantigale

Marsupial

mammals

Eutherian

mammals

Marsupial

mammals

Eutherian

mammals

Marsupial mole

Flying squirrel

Sugar glider

Deer mouse

Mole

Tasmanian devil

Wombat

Kangaroo

Woodchuck

Patagonian cavy

Wolverine

Slide 50

Eutherians - Placental Mammals

Compared with marsupials, eutherians = placental mammals have a longer period of pregnancy.

Young complete their embryonic development within a uterus, joined to the mother by the placenta.

Molecular and morphological data give conflicting dates on the diversification of eutherians.

In Australia, convergent evolution has resulted in a diversity of marsupials that resemble the eutherians in other parts of the world.

Slide 51

Mammalian Diversity

ANCESTRAL

MAMMAL

Monotremata

Marsupialia

Monotremes

(5 species)

Marsupials

(324 species)

Eutherians

(5,010 species)

Xenarthra

Rodentia

Lagomorpha

Primates

Dermoptera (flying lemurs)

Scandentia (tree shrews)

Carnivora

Cetartiodactyla

Perissodactyla

Chiroptera

Eulipotyphla

Pholidota (pangolins)

Proboscidea

Sirenia

Tubulidentata

Hyracoidea

Afrosoricida (golden

moles and tenrecs)

Macroscelidea (elephant

shrews)

Slide 52

Mammalian diversity

Slide 53

Primates

The mammalian order Primates includes lemurs, tarsiers, monkeys, and apes.

There are three main groups of living primates:

Lemurs, lorises, and pottos

Tarsiers

Anthropoids (monkeys and apes)

Humans are members of the ape group.