03-13 Human Evolution and Races key

03-13 Human Evolution and Races key - Biology 105 Human...

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Biology 105 Human Evolution and Races . I Human Evolution . : A Scientific classification of humans Kingdom Animalia ( ) all animals : Phylum Chordata ( ) animals with notochords ( ) Subphylum Vertebrata animals with backbones : Class Mammalia ( , ) animals with hair feed young milk : Order Primates : Family Hominidae : Genus Homo : Species sapiens . B Human traits . , , 1 Human history like the history of all living things goes back to the beginning of life . on Earth . , , a Human genes and human traits evolved over billions of years starting from - . genes in those first bacteria like cells , All life has a common ancestor and we still carry . many genes descended from those first cells . . i We know this because we share many traits with all other cells on Earth All . cells use the same molecules in the same way as our cells . , . b A long time after those first cells animals had a common ancestor It passed : , , on to its descendants the common animal traits ingestion of food cells with no cell wall , . and similar developmental patterns among others , For example it has recently been discovered that humans and jellyfish have similarities in the genes that lay out body . patterns . , . c Later on the vertebrates had a common ancestor Its descendants inherited its , , , . body plan and organs such as the heart digestive system brain etc It has been , , / estimated for example that 3 4 of human genes have similar counterparts in the pufferfish . genome . , . d Eventually the first mammals evolved , After the dinosaurs were killed off the . mammals diverged into a great number of different types , These descendants including , , , us retain many of the genes and features of the original mammals such as hair , - . warmbloodedness and a 4 chambered heart % About 90 of the mouse genome is similar . to parts of the human genome . , . e As mammals took over many different habitats one kind began to live in trees , . It began the primate line to which we belong . , , 2 Humans traits like those of other animals persisted in the population because . they gave an advantage to the people carrying them Natural selection shaped humans . and our ancestors , , Our traits therefore were selected over time to give characteristics . and abilities that helped us survive . , a Humans belong to the order of primates which appeared around 60 million . years ago . Some of our most primitive adaptations are derived from basic primate traits , . As evolution proceeded we modified these traits for our new environments and life styles . . 3 Primates adapted to living in trees . a They have grasping hands and feet with nails rather than claws on fingers . and toes to help them cling to limbs securely , When apes stopped living in trees the . hands could be useds for carrying and manipulating objects . , b They have very mobile shoulders allowing movement of the arm through -- . almost all points of a sphere no other animals can do this This allows a huge range of ; ; movement of the arms apes use it for swinging hand over hand in trees humans use it
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03-13 Human Evolution and Races key - Biology 105 Human...

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