13976084
Description
| Question | Answer |
| When do mammals emerge in the fossil record? | 220m years ago (triassic period) |
| What parts of skull structure differentiate mammals? | Dermatocranium which is little bits of skull that covers the chondrocranium and visceral skeleton. Fish, for example. only have the chondocranium and visceral skeleton. |
| The early mammal skull was very heavy. How was this solved? | Holes were made in the dermal elements of the skull to make it more light weight |
| Different skull hole patterns? | Anapsid (no holes in skull, found in tortoise, turtles, etc). Synapsid (one hole at the back, found in mammals) Euryapsid (small hole at the top of the back) Diapsid (two holes at the back, found in dinos, lizards, birds) |
| What are monotremes? | They're 'on their way' to being mammals. Are only two groups (echidnas and platypuses). They hay eggs like reptiles but also have hair, endothermic and produce milk like mammals (despite having no nipples, they just secrete milk onto fur) |
| What are marsupials? | They include opposums, bandicoots, kangaroos and koalas. Young born premature and crawl into mothers pouch to complete development. They do show parallelism to mammals. |
| What are Afrotheria? | Compose of proboscidea, sirenia, tubulidents, hyracoidea |
| What are proboscidea? | They have a trunk, loose skin, tusks. (Elephants) |
| What are Sirenia? | Secondarily aquatic, forelimbs are fins, hindlimbs are absent, herbivorous. Manatees, dugongs ('closely' related to elephants) |
| What are tubuildents? | Aardvarks, tube-like teeth, insectivorous. No enamel teeth, unique prism structure. |
| What are hyracoidea? | Short legs and tail. Herbivores, Complex stomach. Sub-Saharan Africa/Middle East |
| What are Xenarthra? | In North/South America. Have specialised lumbar spine. Teeth reduced or absent. Have peculiar venous systems. Includes sloths, anteaters, armadillos. |
| What are the rodents/lagomorphs? | Lagomorphs (rabbits, hares. Have chisel incisors. Elongated back legs for jumping/running) Rodents (rats, mice, squirrels, beavers, porcupines. Herbivores. Continuously growing incisors) Primates (lemurs, monkeys, chimps, gorillas, humans. Opposable thumbs, forward eyes, big cerebral cortex) |
| What are carnivores? | They all have pointed teeth, sharing molars and are carnivorous. Wolves, lions. |
| What are Artiodactyls? | Sheep, pigs, cattle, deer, giraffes. Have even-toed hooves. Herbivores. |
| What are perrisodactyls? | Horses, zebras, tapirs, rhinos. Have odd-toed hooves. Herbivores. |
| What are cetaceans? | Whales, dolphins, porpoises. Secondary equatic, paddle-like forelimbs, hindlimbs absent, blubber, carnivores |
| What are chiroptera? | Bats. Wings made of skin-fold supported by elongated fingers. Carnovores and herbivores. |
| What are eulipotyphla? | Insectivores, some moles and shrews. |
| What does make a mammal? | They are vertebrates. Have hair/fur, nails/hooves/hornes, mammary glands that make milk. Have facial muscles. Have a diaphragm. High metabolic rate (endothermy). Highly adapted teeth. Upright gait. |
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