Presentation on theme: "Ch. 43 - Mammals Fossils show that mammals evolved nearly 200 million years ago. Age of Mammals Cenozoic Example of mammalian development was the horse."— Presentation transcript:
1 Ch MammalsFossils show that mammals evolved nearly 200 million years ago.Age of Mammals CenozoicExample of mammalian development was the horse.4 toes 3 toes 1 toe
2 Mammal Characteristics 1. Hair2. Endothermic4-chambered heartDiaphragm to aid in breathingMainly viviparousMammary glandsHighly developed brainVideo
3 What are some advantages of endothermic vs. ectothermic? Hunt at nightRegulate their own body temperatureMore efficientHow does hair help mammals?InsulationHow does the diaphragm & 4-chambered heart help mammals?More efficient and higher metabolic rates to help maintain a constant body temperature.
4 Types of teeth in mammals 1. Incisors – bite & cut2. Canines – grip, puncture, & tear3. Bicuspids – shear & shred4. Molars – grind & crushWhy are the shapes & sizes of teeth different in mammals?
5 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)
6 Classification 3 main groups of mammals 1. Placental mammals – they nourish their young in the uterus through the placenta.Most mammals2. Monotremata – egg-laying mammals3. Marsupialia – pouched mammalsMainly in Australia
7 Mammal Orders 1. Monotremata The only order of mammals that is oviparous (egg laying).Duck-billed platypus & spiny anteaterVideo2. MarsupialiaThese 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.
8 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 periodHuman’s is 9 monthsMore advanced mammals have longer gestation periods.
9 3. InsectivoraShrews, moles, & hedgehogsShrews are the smallest mammalsMole’s fur goes both ways. Why?Video4. RodentaLargest mammal orderSquirrels, chipmunks, gophers, mice, rats, beaverWhat’s the largest rodent in N. America?Beaver
10 5. LagomorphaRabbits & hares4 upper incisors instead of 2Video6. EdentataMeans “without teeth”Anteaters, armadillos, & sloth7. ChiropteraBatsOnly mammals capable of true flight.What is echolocation?