Mammals Eukaryotic multicellular heterotrophic endothermic animals with an

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

Mammals 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) ECTO Body Temp ENDO COLD HOT Environment

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-tovolume ratio Shrew Elephant

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)

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)

Mammal Adaptations Diversification of Glands Cells that release fluids that directly effect mammalian body chemistry Types of glands mammals have: • Mammary Gland–produces milk Gland • Sweat Glands- releases H 2 O 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

Mammal Adaptations Teeth: Unlike the basic reptile tooth, mammals evolved 4 variety of teeth: Incisors- for cutting (like a chisel) or holding Herbivores Omnivores Insectivores 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

Omnivore

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

3 Main Groups of Mammals 1) Monotremes-the egg-layers (3 species alive in Australia or Monotremes New Zealand) Australia • 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

3 Main Groups of Mammals 2) Marsupials-the pouched mammals like Kangaroos, Marsupials 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).

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

3 Main Groups of Mammals 3) Placental Mammals young develop “fully” inside the mothers uterus, Baby exchanges its O 2 , 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/25 months

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 & LearningInterpreting 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

Paranthropus robustus 0 Paranthropus boisei 0. 5 Homo neanderthalensis sapiens Homo ? ergaster 1. 0 Australopithecus africanus 1. 5 Millions of years ago 2. 0 2. 5 3. 0 3. 5 Kenyanthropus platyops Australopithecus garhi Australopithecus anamensis Homo rudolfensis habilis 4. 0 4. 5 5. 0 Ardipithecus ramidus Australopithecus afarensis 5. 5 6. 0 6. 5 7. 0 Homo erectus Orrorin tugenensis Sahelanthropus tchadensis