1. Chapter 32-2 Mammals

2. 32-2 Diversity of Mammals
Photo Credit: ©Zefa (RM)/M. Botzek/Masterfile 2

3. Mammals: Monotremes 3

4. Mammal Classification
Monotremes, egg-layers
Includes duck-billed platypus & spiny anteater

5. Monotreme: Egg Layers Mammal that reproduced by laying eggs
Monotremes are found only in Austria, Tasmania, & New Guinea
Only 3 species of Monotremes are alive today:

6. Monotremes: Duck-Billed Platypus Broad, flat tail, (like a beaver),
rubbery snout (like the bill of a duck);
webbed front feet for swimming, but sharp claws on its front & hind feet for digging; body covered with tick brown fur.

7. 2 Species of Spiny Anteaters
Monotremes:
2 Species of Spiny Anteaters
Coarse, brown hair & its back & sides are covered with sharp spines that can erect for defensive purposes when threatened.
Mouth located at the end of a long snout, it extends its long, sticky tongue to catch insects.

8. Monotremes
Monotremes are a small group of egg-laying mammals consisting of echidnas and the platypus.
Monotremes are oviparous mammals.
Eggs have a thin, leathery shell.
Babies hatch in a relatively undeveloped state.
Echidnas have an abdominal pouch where they keep the young.
Young feed on milk secreted by the mother’s mammary glands.

9. Mammals: Marsupials 9

10. Mammal Classification
Marsupials, pouched mammals
Includes Kangaroo, Koala, Opossum

11. Marsupials Marsupials include opossums, kangaroos, and koalas.
Before it is a born, an embryonic marsupial receives nourishment by absorbing nutrient secretions in the uterus.
Red kangaroos: mother immediately becomes pregnant after young (joey) is born (in pouch). But the embryo doesn’t begin to grow as long as the joey is in the pouch. When he leaves the pouch the embryo begins to mature and is born a month later.

12. Marsupials
Young have a short period of development within the mothers body, followed by a second period of development inside a pouch made of skin & hair found outside the mothers body

13. Marsupials
A marsupial is born very early in its development and completes its embryonic development while nursing within a maternal pouch called a marsupium.

14. Most Marsupials are found…
Marsupial Mole
In Australia & surrounding islands due to Pangaea
Opossum originated in Mexico

15. Koala
Tasmanian Devil

16. Mammals: Placental 16

17. Mammal Classification
Placentals (90% of all Mammals)
Placenta is an organ that nourishes the young while inside the uterus (womb)
Gestation, period of time young develops in uterus; ensures offspring are protected from predators & environment

18. Placental Mammals
Mammals that carry their young inside the uterus until birth
Nourishment takes place inside the uterus through the placenta

19. Placenta
The placenta also functions in passing oxygen to and removing waste from the developing embryo
95% of all mammals are placental

20. Eutherians: Placental Mammals
Compared to marsupials, eutherians have a longer period of pregnancy.
Usually larger placental mammals have longer gestations.

21. Eutherians: Placental Mammals
Young eutherians complete their embryonic development within a uterus, joined to the mother by the placenta.

22. Orders of Placental Mammals
Artiodactyla (hoofed, with even number of toes)
Carnivora (specialized hunters)

23. Orders of Placental Mammals
Cetacea (adapted to aquatic environment)
Chiroptera (only mammal with true flight)

24. Orders of Placental Mammals
Insectivora (includes world’s smallest mammals)
Lagomorpha (includes some of the fastest runners, with pairs of incisors)

25. Orders of Placental Mammals
Perissodactyla (hoofed,with odd number of toes)
Primates (superior intelligence, opposable thumbs)

26. Orders of Placental Mammals
Proboscidea (trunk-nosed)
Rodentia (largest order, gnawing incisors)

27. Placental Mammals
In placental mammals, nutrients, oxygen, carbon dioxide, and wastes are exchanged efficiently between the embryo and mother through the placenta
This is the type of animal that human beings along with just about the majority of all mammals belong to

28. Artiodactyls
Hoofed mammals with an even number of toes on each foot are Artiodactyls
Giraffes along with the rest of the Artiodactyls are grazing animals

29. Carnivores Meat-eating predators are Carnivores
Grizzly Bears, like the one showed here, among a few other animals in this family are not completely Carnivorous. When meat is not readily available, they are able to eat plants as well

30. Cetaceans
Dolphins and whales, like this Blue Whale, are called Cetaceans
Cetaceans are carnivorous marine mammals that live and breed in the ocean coming up to the surface only to breathe

31. Chiropterans The only mammals capable of true flight
Bats feed mainly on nectar, insects, and fruit
Only three species of Bats feed on the blood of other invertebrates

32. insectivores
Insectivores have sharp claws and pointy snouts that help them seek all the insects that they like to eat
African Hedgehogs, like the one pictured here, have calm natures and make nice pets

33. Lagomorphs
Like Rodents, Lagomorphs are herbivorous. Unlike rodents, they have two pairs of incisor teeth in the upper jaw, and strong back legs which are better adapted for leaping and hopping
A great example of Lagomorphs are Rabbits

34. Perissodactyls
Hoofed mammals with an odd number of toes are Perissodactyls
Among the animals in this family are the Rhinoceros, which are very defensive herbivores who blindly charge at whoever or whatever they feel is a threat to their baby

35. Primates
Primates have a highly developed brain and set of complex behaviors unlike any other animal on Earth
Ring-Tailed Lemurs, like the one showed here belong to the Primate family as well as Human Beings

36. Proboscideans
Mammals with trunks are Proboscideans, like this baby Elephant
Many species existed at one time, but now only African and Asian Elephants remain

37. Rodents Capybaras are the largest type of Rodent there is
Like all rodents, they have a single pair of long, curved incisor teeth in their upper and lower jaw
Rodents love gnawing on wood and other tough plant material

38. Sirenians
Sirenians are herbivorous sea mammals, just like these Manatees
When Columbus first sailed to America and spotted these animals at sea, they were mistaken for mermaids

39. Xenarthrans
Three-Banded Armadillos like the one pictured here are Xenarthians
Xenarthians are herbivorous creatures with very simple teeth with no enamel or no teeth at all
Three-Banded Armadillos are the only mammal that can perfectly roll itself into a ball

40. Biogeography of Mammals
Convergent Evolution in Mammals
Nine-Banded Armadillo
Chinese Pangolin
Similar ecological opportunities on different continents have resulted in convergent evolution among these and other mammals. Mammals that feed on ants and termites evolved not once but five times in different regions. Powerful front claws; a long, hairless snout; and a tongue covered with sticky saliva are common adaptations in these insect-eating animals.
Common Echidna
Giant Anteater
Aardvark
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32-2 Quiz
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32-2
Most mammals are
monotremes.
marsupials.
placental mammals.
placental marsupials.
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32-2
Monotremes are the only group of mammals that
lay eggs
have hair.
feed their young with milk.
are endotherms.
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32-2
Rabbits belong to an order of mammals called the
cetaceans.
lagomorphs.
proboscideans.
chiroptera.
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32-2
Ant-eating mammals on different continents look similar to each other because they are all
a result of divergent evolution.
adapted to similar ecological opportunities.
recently evolved from a common ancestor.
evolved from an ant-eating reptile.
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32-2
What is the function of the placenta?
production of milk
exchange of materials between fetus and mother
digestion of food
protection of a young mammal after birth
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