Mammals: Endothermic Animals with Diverse Adaptations

1. Mammals ( remember reptiles/amphibians are ectotherms) Eukaryotic, multicellular, heterotrophic, endothermic animals with an endoskeleton

2. Mammals ECTO ENDO Body Temp COLD HOT Environment Endotherm- ( “inside heat”) –they depend on their own metabolism to keep their body temperature up (many mammals die naturally from exposure),thus metabolism has to be very fast so they can keep their body temperature stable  and they must eat a lot more often than ectotherms (daily instead of weekly)

3. Mammals • The size of the mammal also determines how easy it is to maintain a stable body temperature • Elephants can maintain 90 to 100°F body temp easier than a shrew can • Elephants have more fat and a better surface area-to-volume ratio Shrew Elephant

4. Since smaller mammals lose heat more easily than larger ones, they must constantly eat to keep body temp stable and survive • Often will go into hibernation in winters to survive the extreme colds (next slide-the major adaptation of mammals)

5. Mammal Adaptations • Fur/Hair- an adaptation most mammals have. • Functions: • Insulation –keep in heat • Camouflage (Tigers, Polar Bears) • Defense (Porcupine, Echidnas) • Warning signal to others (skunk, “deer-rears”) • Sense of touch (Whiskers, arm hair in people)

6. Mammal Adaptations • Diversification of Glands Cells that release fluids that directly effect mammalian body chemistry • Types of glands mammals have: • Mammary Gland–produces milk • Sweat Glands- releases H2O to help stabilize body temp • Saliva Glands: For help with chewing and keeping mouth bacteria amounts low • Hormone Glands: Thyroid - produces hormones like estrogen and testosterone • Scent/Musk Glands: territory marking, courtship, defense

7. Mammal Adaptations Teeth: Unlike the basic reptile tooth, mammals evolved 4 variety of teeth: Herbivores Omnivores Insectivores Incisors- for cutting (like a chisel) or holding Canines- for shearing (like scissors), stabbing, and piercing Carnivores Omnivores Premolars & Molars- for crushing things like seeds or chewing fruits/grasses/leaves/herbs Herbivores Omnivores

8. Omnivore

9. MAIN CHARACTERISTICS ORDERS AND EXAMPLES ORDERS AND EXAMPLES MAIN CHARACTERISTICS Marsupialia Kangaroos, opossums, koalas Lay eggs; nonipples; young suck milk fromfur of mother Embryo completes development in pouch on mother Monotremata Platypuses, echidnas Echidna Koala Teeth consisting of many thin tubes cemented together; eats ants and termites Tubulidentata Aardvark Long, musculartrunk; thick, loose skin; upper incisors elongated as tusks Proboscidea Elephants African elephant Aardvark Short legs; stumpy tail; herbivorous; complex, multichambered stomach Aquatic; finlikeforelimbs and no hind limbs; herbivorous Hyracoidea Hyraxes SireniaManatees,dugongs Rock hyrax Manatee Rodentia Squirrels, beavers, rats, porcupines, mice   Chisel-like, continuously growing incisors worn down by gnawing;herbivorous Reduced teeth orno teeth; herbivorous(sloths) or carnivorous (anteaters, armadillos) Xenarthra Sloths, anteaters,armadillos Red squirrel Tamandua Primates Lemurs, monkeys, apes, humans Opposable thumbs; forward-facing eyes; well-developed cerebral cortex; omnivorous Chisel-like incisors; hind legs longer than forelegs and adapted for running and jumping Lagomorpha Rabbits, hares, picas Golden lion tamarin Jackrabbit Perissodactyla Horses, zebras, tapirs, rhinoceroses Hooves with an odd number of toeson each foot; herbivorous Carnivora Dogs, wolves,bears, cats, weasels, otters, seals, walruses Sharp, pointed canineteeth and molars for shearing; carnivorous Indian rhinoceros Coyote Adapted for flight; broad skinfold that extends from elongated fingers to body and legs; carnivorous or herbivorous CetartiodactylaArtiodactylsSheep, pigs cattle, deer,giraffes Hooves with an even number of toes on each foot; herbivorous Chiroptera Bats Frog-eating bat Bighorn sheep Aquatic; streamlinedbody; paddle-like forelimbs and no hind limbs; thicklayer of insulating blubber; carnivorous Eulipotyphla “Core insecti- vores”: some moles, some shrews Diet consists mainly of insects and other small invertebrates CetaceansWhales,dolphins,porpoises Star-nosed mole Pacific white-sided porpoise

10. 3 Main Groups of Mammals • 1) Monotremes-the egg-layers (3 species alive in Australia or New Zealand) • Duck-billed Platypus, 2 types of Echidnas • Secrete milk on hair on their torso (no nipples) • Eggs are very small • Young will nurse for several weeks before fully developed Australia

11. 3 Main Groups of Mammals • 2) Marsupials-the pouched mammals like Kangaroos, Opossum, Koala, Wombats, etc • Young are born very early (4-5 weeks developed); in the pouch, will attach to a nipple and milk for weeks until development is completed (most are found in Australia) (a) A young brushtail possum. The young of marsupials are born very early in their development. They finish their growth while nursing from a nipple (in their mother’s pouch in most species).

12. Marsupialmammals Eutherian mammals Plantigale Deer mouse Mole Marsupial mole Sugar glider Flying squirrel Wombat Woodchuck Wolverine Tasmanian devil Patagonian cavy Kangaroo

13. 3 Main Groups of Mammals 3) Placental Mammals- young develop “fully” inside the mothers uterus, Baby exchanges its O2 , food/waste via the placenta. The length of time between fertilization and full development (birth) is called Gestation: Gestation Length is often connected to the baby’s size Bigger babies take longer to develop (no siblings) Baby Body Size Mouse/Shrew 17 days Gestation Length Whales/Elephants 18 months/25months

14. Mammals generally also have a higher levels of parental care than reptiles (again related to the length of development and baby‘s size) Bigger Babies need long term parental care, this also relates to the time it takes learning capacities to fully develop Last advantage of Mammals ?? Higher Intelligence & Learning\Interpreting Skills? STILL DEBATED: Birds and Octopi also show high levels of intelligence in many areas like memory & problem solving …possibly connected to the amount of socialization with in a species

15. Paranthropusrobustus Homoneanderthalensis Homosapiens 0 Paranthropusboisei Homoergaster ? 0.5 1.0 Australopithecusafricanus 1.5 2.0 Kenyanthropusplatyops 2.5 Australopithecusgarhi Homoerectus 3.0 Millions of years ago Australopithecusanamensis 3.5 Homohabilis Homorudolfensis 4.0 4.5 Ardipithecusramidus Australopithecusafarensis 5.0 5.5 Orrorin tugenensis 6.0 6.5 Sahelanthropustchadensis 7.0