1. Class Mammalia

2. Mammalian Characteristics
Endothermy - mammals produce and maintain body heat through metabolism.

3. Mammalian Characteristics
HAIR
All mammals have hair.
It is useful for insulation against heat loss
and for camouflage.

4. MILK
A nutritious fluid that contains fats, proteins, sugars, and antibodies.

5. MORE MILK Produced by females in the mammary glands to feed offspring.
Mammary glands are modified sweat glands located in the thorax or abdomen

6. FOUR CHAMBERED HEART
Separated ventricles keep oxygenated and de-oxygenated from mixing.
Allows more efficient pumping of blood through both circuits of the circulatory system.

7. Single Jaw Bone and Specialized Teeth
Teeth in front are for biting, cutting or seizing prey.
Teeth along the side are for grinding and crushing.
Lower jaw is composed of a single jaw bone.

8. Mammalian Evolution Synapsids Therapsids Early Mammals Monotremes
Marsupials
Placental Mammals

9. Synapsids
• 1st Ancestors to Mammals.
• Appeared 300 million years ago.
• Single opening in the skull just behind eye socket.

10. Therapsids • Appeared in the late Permian period.
• Gave rise to mammals.
• Differentiation of teeth.
• Limbs positioned directly beneath body.
• Probably endothermic and hair in some.

11. Early Mammals • Appeared during the Triassic period.
• About 10 cm (4 in.) in length.
• Large eye sockets (nocturnal).
• Underground dwellers & insect feeders.
Morganucodon
was one of the
first mammals.

12. Monotremes
Duck billed platypus
Echidna

13. Monotremes • Only egg laying (oviparous) mammals.
• Eggs are reptilian in structure & development.
• Mothers secrete milk through skin (no nipples).
• Baby sucks milk from the fur.
• Evidence suggests that monotremes descended from
an early branch in mammalian genealogy.

14. Mammal Reproduction - Monotremes
Female monotreme typically lays
one or two leathery, shelled eggs.
The developing embryo is
nourished by the yolk within the
egg.
The mother protects the
underdeveloped hatchling and
feeds it milk until it is ready to
survive on its own.

15. Marsupials
• Opossums, kangaroos, bandicoots, tasmanian devils, koalas, and wallabies are some examples.
• Give birth to live young ( viviparous).
• Premature young complete embryonic development
while nursing in a maternal pouch.
Newborn wallaby

16. Mammal Reproduction - Marsupials
Short period of development in the uterus.
Newborns crawl into pouch and attach to nipple.
Newborn’s development and growth continue in the pouch.

17. Marsupials
In Australia, marsupials filled niches occupied by eutherian mammals in other parts of the world.
The opossum in the only North American marsupial.

18. Eutherian (Placental) Mammals
• Longer period of pregnancy by completing embryonic development within the uterus.
• Placental young are nourished through a placenta.
• Fossil evidence suggests eutherians and marsupials
diverged from a common ancestor 80 to 100 mya.

19. Mammal Reproduction - Eutherians
Longer period of development in the uterus.
The mother provides nourishment and oxygen to her developing offspring through the placenta.
Nutrients & oxygen diffuse into blood of offspring, and CO2 &
waste diffuse into mother’s blood.

20. Respiratory System
Lungs of mammals have a larger surface area available for gas exchange than all other animals.
The Diaphragm is a sheet of muscle below the rib cage. Contraction of the diaphragm draws air into the lungs.

21. Teeth
Mammals have specialized teeth.

22. Carnivores vs. Herbivores
Carnivores, such as this lion
skull, have large, sharp
incisor and canine teeth that
are able to cut and tear
flesh.
Herbivores, such as the
horse, have flat teeth that
are useful for grinding
grass and grain, which are
the staples of their diet.

23. Baleen Baleen whales, such as the blue whale, do not have teeth.
Baleen is thin plates of
fingernail-like material
that hang from the
roof of the mouth.

24. Adaptations for Digesting Plants
• Plants contain cellulose that vertebrates cannot break down.
• Many hoofed mammals have a large four-chambered
stomach.
• The Rumen is the first chamber that contains bacteria that
breaks down cellulose.

25. Adaptations for Digesting Plants
Found in horses, rodents, rabbits & elephants.
Large sac that branches from the small intestines.
Microorganisms that live in caecum complete digestion.

26. Nervous System & Sense Organs
The brain of a mammal
is about 15 times heavier
than the brain of a similarly
sized fish, amphibian or reptile.
Enlargement of the
cerebrum accounts for
most of the size increase.
The cerebrum evaluates
input from sense organs,
controls movement, and
initiates and regulates behavior.

27. Nervous System & Sense Organs
Using a process called echolocation, bats emit high
frequency sound waves, which bounce off objects,
and then they analyze the returning echoes to determine the size, distance, direction and speed of the object.

28. Order Monotremata Ornithorhynchus anatinus Tachyglossus aculeatus
Australia & New Guinea are the
only places where you can find
both monotremes and marsupials.
Tachyglossus aculeatus

29. Order Marsupialia
Embryonic development
completed in marsupial pouch.

30. Order Insectivora
Insect eating mammals

31. Order Chiroptera Adapted for flying; possess a broad
skinfold that extends from
elongated fingers to body and legs.

32. Order Primates Opposable thumb Forward facing eyes
Well developed brain
Omnivorous

33. Order Carnivora Carnivorous Have sharp, pointed canine
teeth and molars
for shearing.

34. Order Proboscidae Long muscular trunk Thick loose skin
Upper incisors elongated as tusks

35. Order Perissodactyla Odd toed ungulates – animals with hooves.
Have a caecum in which bacteria break down cellulose.

36. Order Artiodactyla Even toed ungulates Have a rumen in which bacteria
break down cellulose.

37. Order Pilosa
Reduced or NO teeth

38. Order Cingulata
Reduced or NO teeth

39. Order Cetacea Marine mammals with fish-shaped bodies.
Paddle-like forelimbs – no back limbs
Thick layer of insulating blubber.

40. Order Tubulidentata Insectivores with pig-like bodies and long snouts.
Found in Southern Africa.

41. Order Rodentia
Chisel-like continuously growing incisor teeth.

42. Order Lagomorpha Chisel-like incisors
Hind legs longer than forelegs and adapted for running or jumping.