Birds & Mammals

Life Science - Middle School

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Birds A bird is an endothermic vertebrate animal that lays eggs, has feathers and a four chambered heart. The body of most birds is adapted to flying. The nearly hollow bones and feathers make the bird light weight. In addition, birds have large chest muscles which move the wings and extra air sacs that provide a plentiful supply of oxygen to the flight muscles. Scientists believe that today’s birds descended from some kind of reptile, possibly a dinosaur, since they still retain several features similar to reptiles. If you examine the leg of a bird, you’ll notice that it’s covered with scales and has claws. Like some reptiles, birds have a tough beak, and develop in shelled eggs. Mammals A mammal is an endothermic vertebrate that has skin covered with fur or hair, a four chambered heart and a wide arrangement of teeth. Fertilization in mammals occurs internally. There are a few species that lay eggs that are shelled, but most offspring develop completely within the mother and are then born. Most mammals are born alive and are fed with milk produced by the mother’s body. The nervous system of mammals is highly developed and has adapted to the lifestyle of each individual species. Diversity of Mammals There are approximately 4,000 different species of mammals on Earth today. The majority of mammals live on land, but some species have adapted to live in the air and in the oceans. There are three groups of mammals - monotremes, marsupials, and placental mammals - that differ in how their young develop. The monotremes are egg-laying mammals. Their young develop in shelled eggs. Pouched mammals are called marsupials. These mammals partially develop within the female and complete their development within a pouch on the mother’s body. Placental mammals are mammals that develop completely inside the mother’s body. This group of mammals gets its name from the placenta, an organ that passes nutrients and wastes between the mother and the developing embryo. Elephants, mice, horses, dolphins, and humans are all examples of placental mammals. Diversity of Birds Birds are the most diverse land vertebrates with almost 10,000 different species. Egret Owl Geese Pelican Obtaining oxygen Nervous system Nervous system Keeping conditions stable Keeping conditions stable Movement Movement Obtaining food Obtaining food Some photos courtesy of USFWS. © Copyright NewPath Learning. All Rights Reserved. 94-4710 www.newpathlearning.com Birds & Mammals heart air sacs air sacs bone lungs
Birds A bird is an endothermic ________________ animal that lays eggs, has feathers and a four chambered heart. The body of most birds is adapted to ________________. The nearly ________________ bones and feathers make the bird light weight. In addition, birds have large __________________________________ which move the wings and extra air sacs that provide a plentiful supply of ________________ to the flight muscles. Scientists believe that today’s birds descended from some kind of ________________, possibly a dinosaur, since they still retain several features similar to ________________. If you examine the leg of a bird, you’ll notice that it’s covered with ________________ and has ________________. Like some reptiles, birds have a tough beak, and develop in shelled eggs. Mammals A mammal is an endothermic ________________ that has skin covered with ________________ or ________________, a four chambered ________________ and a wide arrangement of ________________. Fertilization in mammals occurs ________________. There are a few species that lay eggs that are shelled, but most offspring develop completely within the mother and are then born. Most mammals are born ________________ and are fed with ________________ produced by the mother’s body. The ________________ system of mammals is highly developed and has adapted to the lifestyle of each individual species. Diversity of Mammals There are approximately _____________________ different species of mammals on Earth today. The majority of mammals live on _____________________ , but some species have adapted to live in the air and in the oceans. There are three groups of mammals - _____________________ , _____________________ , and _____________________ - that differ in how their young develop. Monotreme mammals __________________________________ __________________________________ Marsupial mammals __________________________________ __________________________________ __________________________________ Placental mammals __________________________________ __________________________________ __________________________________ Diversity of Birds Birds are the most diverse land vertebrates with almost ________________ different species. Obtaining oxygen Obtaining oxygen Nervous system Nervous system Keeping conditions stable Keeping conditions stable Movement Movement Obtaining food Obtaining food Key Vocabulary Terms air sac monotremes bird nervous system eggs placental endothermic reptile fertilization species mammals vertebrate marsupials © Copyright NewPath Learning. All Rights Reserved. 94-4710 www.newpathlearning.com Birds & Mammals \|xiBAHBDy01755kzU