Ch. 43 - Mammals Fossils show that mammals evolved nearly 200 million years ago. Age of Mammals  Cenozoic Example of mammalian development was the horse. 4 toes  3 toes  1 toe

Mammal Characteristics 1. Hair 2. Endothermic 4-chambered heart Diaphragm to aid in breathing Mainly viviparous Mammary glands Highly developed brain Video

What are some advantages of endothermic vs. ectothermic? Hunt at night Regulate their own body temperature More efficient How does hair help mammals? Insulation How does the diaphragm & 4-chambered heart help mammals? More efficient and higher metabolic rates to help maintain a constant body temperature.

Types of teeth in mammals 1. Incisors – bite & cut 2. Canines – grip, puncture, & tear 3. Bicuspids – shear & shred 4. Molars – grind & crush Why are the shapes & sizes of teeth different in mammals?

What is viviparous? Bear live young, in which the females care for and nourish the young. How do the females provide nourishment for their young? Mammary glands (milk)

Classification 3 main groups of mammals 1. Placental mammals – they nourish their young in the uterus through the placenta. Most mammals 2. Monotremata – egg-laying mammals 3. Marsupialia – pouched mammals Mainly in Australia

Mammal Orders 1. Monotremata The only order of mammals that is oviparous (egg laying). Duck-billed platypus & spiny anteater Video 2. Marsupialia These mammals are born before their development is complete. Thus, the newborns use their front legs to pull themselves into the mother’s pouch. Inside the pouch are mammary glands for them to feed on.

Placental Mammals (Orders) What is a placenta? An organ that allows nutrients and oxygen to get to the fetus through the mother’s blood. What is the period of development in the mother’s uterus called? Gestation period Human’s is 9 months More advanced mammals have longer gestation periods.

3. Insectivora Shrews, moles, & hedgehogs Shrews are the smallest mammals Mole’s fur goes both ways. Why? Video 4. Rodenta Largest mammal order Squirrels, chipmunks, gophers, mice, rats, beaver What’s the largest rodent in N. America? Beaver

5. Lagomorpha Rabbits & hares 4 upper incisors instead of 2 Video 6. Edentata Means “without teeth” Anteaters, armadillos, & sloth 7. Chiroptera Bats Only mammals capable of true flight. What is echolocation?

8. Cetacea Whales & dolphins Breathe through a blowhole Video 9. Sirenia Manatees & dungongs 10. Carnivora Dogs, cats, raccoons, wolves, bears, lynx, mountain lions, tigers, weasels, ect. Have large canines (mainly carnivores) 11. Pinnipedia Sea lions, walruses, & seals

12. Perissodactyla Have an odd # of toes (ungulates) Ungulates are hoofed mammals. Horses, zebras, rhinos Video 13. Artiodactyla Even # or ungulates & rumen Deer, elk, bison, cows, moose, pigs, sheep, giraffes, camels, antelope, ect. 14. Proboscidea Trunk nosed mammals Elephants.

Specific epithet: sapien 15. Primates Monkeys, apes, & humans Chimps are 97.9% same genes as humans. Video Human Classification Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primate Family: Hominidae Genus: Homo Specific epithet: sapien

Mammals Heart Draw out the following parts: R. Atrium, R. Ventricle, L. Atrium, L. Ventricle, Vena Cava, Tricuspid, Semilunar valves, Lungs, bicuspid, aorta, arteries, veins, capillaries.

What are the differences in the vertebrate’s hearts? 2 –chambers? Fish, larva amphibian 3-chambers? Reptile(divided some), adult amphibian 4-chambers? Birds, mammals

Respiratory Systems Fish  gills Amphibians  gills, lungs, skin Reptiles  lungs Birds  lungs Mammals  lungs & diaphragm

The bigger & more complex the vertebrate the larger the brain. Nervous System The bigger & more complex the vertebrate the larger the brain. All vertebrates use kidneys as an excretory system.

External Fertilization Fish & Amphibians Internal Fertilization Reproductive Systems External Fertilization Fish & Amphibians Internal Fertilization Reptiles, Birds, & Mammals Oviparous  birds, some reptiles Oviviparous  some reptiles Viviparous  mammals