1 / 36

Mammals

Mammals. Early Mammals. First mammalian fossil found in Mesozoic era (hair, single jawbone, specialized teeth, & endothermic) Early mammals were small, shrew like, insect eaters that had large eye sockets making them probably nocturnal

ora
Download Presentation

Mammals

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Mammals

  2. Early Mammals • First mammalian fossil found in Mesozoic era (hair, single jawbone, specialized teeth, & endothermic) • Early mammals were small, shrew like, insect eaters that had large eye sockets making them probably nocturnal • When dinosaurs became extinct, new habitats & food supplies opened up for mammals • "Age of mammals" occurred during Cenozoic era

  3. Main Characteristics of mammals • Endothermic - maintain high, constant body temperature through their metabolism

  4. Main Characteristics of mammals • hair or fur made of protein called keratin covering all or part of the body • The primary function of hair is insulation. The hair of some mammals helps them blend in with their surroundings. In some mammals, specialized hairs serve a sensory function

  5. fur

  6. Main Characteristics of mammals • Single jawbone • Specialized teeth for biting, cutting, & chewing • Mammals have only two sets of teeth throughout their lives: baby teeth or milk teeth, then permanent teeth. • Mammals have four kinds of teeth: incisors, canines, premolars, and molars.

  7. Mammary glands in females are modified sweat glands that make milk containing sugars, proteins, & fats to nourish young Young mammals are nourished on milk from birth until weaning, the time when the mother stops nursing them.

  8. Respiratory • Mammalian lungs are more efficient at obtaining oxygen than are reptilian and amphibian lungs. • Mammalian lungs contain alveoli, small chambers that provide a very large surface area. • Diaphragm - muscle below lungs that aids respiration

  9. Highly developed brain (large cerebrum) • Four chambered heart ( two atria & two ventricles) keep oxygenated & deoxygenated blood from mixing; double circulation

  10. Reproduction • All mammals reproduce by internal fertilization. • Mammals are divided into three groups based on differences in how and where the fertilized egg develops.

  11. Monotremes

  12. Mammals that lay eggs • Monotremes are mammals that have a cloaca and lay hard-shelled amniote eggs. • In Greek it means single hole/opening • comes from the fact that their urinary, defecatory, and reproductive systems all open into a single duct, the cloaca. • Examples: duckbill platypus and spiny anteater of Australia.

  13. Mammals that lay eggs • Female duckbill platypus lays her eggs in a burrow in the ground where she incubates them. • After hatching, young lick milk seeping from modified sweat glands on abdomen of males and females

  14. Mammals that lay eggs • Spiny anteater has a pouch formed by swollen mammary glands and muscle; egg moves from cloaca to pouch and hatches; young remain for 53 days and live in burrow where mother feeds them

  15. Marsupials

  16. Mammals That Have Pouches • Marsupials begin development inside mother's body but are then born in a very immature state. • include kangaroos, koalas, wallaby, wombats, Tasmanian devils, and opossums. • Newborns crawl up into a pouch on their mother's abdomen. • Inside a pouch they attach to nipples of mother's mammary glands and continue to develop

  17. Mammals That Have Pouches • New borns are called joeys • It will not re-emerge for several months, during which time it develops fully. • After this period, the joey begins to spend increasing lengths of time out of the pouch, feeding and learning survival skills. • Joeys stay in the pouch for up to a year in some species, or until the next joey is born.

  18. Mammals That Have Placentas • Placental mammals use a placenta, an organ of exchange between maternal and fetal blood. • Placenta supplies nutrients to and removes wastes from blood of developing offspring. • Placenta also allows mother to move about while offspring develop. • Placenta enables young to be born in a relatively advanced stage of development.

  19. Mammals That Have Placentas • Placental mammals are very active animals; possess acute senses and a relatively large brain. • Brains of placental animals have cerebral hemispheres proportionately larger than other animals. • Young go through a long period of dependency on parents after birth.

  20. Mammals That Have Placentas • Placental mammals populate all continents except Antarctica. • Most are terrestrial, but some are aquatic, and bats can fly. • There are 19 orders of placental mammals, which include more than 90 percent of all mammal species. • The vast majority of mammal species are found within 12 orders.

  21. Order Rodentia • About 40 percent of all mammal species are rodents. Rodents have teeth that are specialized for gnawing. • Most rodents are small in size. Rodents have a rapid rate of reproduction.

  22. Order Chiroptera • This order is composed of bats, the only mammals capable of true flight. Most bats live in groups and are active only at night. • Most bats eat insects, using echolocation to catch insects while in flight.

  23. Order Insectivora • This order consists of small mammals, such as the shrew, mole, and hedgehog that eat mainly insects.

  24. Order Carnivora • Most species in this order are flesh-eating hunters. • Carnivores consist of lions, cats, dogs, foxes, wolves, bears, raccoons, otters, skunks, weasels, and more… • Carnivores have excellent senses of smell, vision, and hearing.

  25. Suborder Pinnipedia • This suborder of marine carnivores includes seals and sea lions. • All four limbs of pinnipeds are modified as flippers for swimming. Their bodies are streamlined for rapid movement through the water.

  26. Order Primates • Humans belong to the order Primates. • Other members of this order include the prosimians, monkeys, and apes. • Most nonhuman primates are tree-dwellers.

  27. Order Artiodactyla

  28. Order Artiodactyla • mammals with hooves. They have an even number of toes. • Includes pigs, hippopotamuses, camels, llamas, deer, giraffes, antelope, sheep, goats, and cattle. • Many artiodactyls have a stomach with a storage chamber called a rumen. Mammals with a rumen regurgitate partially digested food, called cud, rechew it, and swallow it again for further digestion

  29. Order Perissodactyla • They have an odd number of toes within their hooves • includes horses, zebras, and rhinoceroses. • They lack a rumen and do not chew their cud.

  30. Order Cetacea • It is divided into two groups: the predatory toothed whales, dolphins, and porpoises, and the filter-feeding baleen whales.

  31. Order Lagomorpha • This order is composed of rabbits and hares. • They have long, continually growing incisors. • They also have another pair of incisors that grow behind the first pair. • Rabbits and hares have long hind legs and are specialized for hopping.

  32. Order Sirenia • They include dugongs and manatees, barrel-shaped marine animals that eat aquatic plants. • They have front limbs modified as flippers. • Sirenians are closely related to elephants and are often called sea cows.

  33. Order Proboscidea • There are two living species in this order, the African elephant and the Asian elephant. • These animals are the largest land animals alive today

More Related