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CLUES ABOUT EVOLUTION Mr. Rethman
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I CAN’S I can identify the importance of fossils as evidence of evolution. I can explain how relative and radiometric dating is used to estimate the age of fossils. I can list examples of five types of evidence for evolution.
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INDIRECT EVIDENCE FOR EVOLUTION
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Clues from Fossils Paleontologists – scientists who study the past by collecting and examining fossils. Plants and Animals covered with silt and mud Green River Formation in Wyoming, Utah, and Colorado – one of the richest fossil deposits in the world.
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Types of Fossils Fossil – remains or imprint or trace of a prehistoric organism Found in Sedimentary Rock with layers of silt, sand, clay, mud compacted or when minerals are deposited. Examples of rock include: limestone, sandstone, and shale.
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Determining Fossil Age Relative Dating – Idea of undisturbed areas – Younger rock on top of older rock layers Compare the ages of rock
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Radiometric Dating Estimate age of rock using radioactive elements Compare the amount of radioactive element with the amount of nonradioactive element in rock.
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Embryology Study of embryos and their development
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Homologous Structures Body parts in the same origin and structure Also, similar in function Indicate more species share common ancestors
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Homologous Structures
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Vestigial Structures Structures with no function Example: Manatees, snakes, and whales no longer have back legs but still have pelvic bones. Human appendix – helpful for digestion
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DNA Molecule that directs heredity Found on genes that make up chromosomes Dogs close relatives of bears Apes, gorillas, and chimps = 24 pairs of chromosomes Humans = 23 pairs Match in chromosome # 2 Similar proteins found – such as hemoglobin – found in red blood cells
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DIRECT EVIDENCE FOR EVOLUTION
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Direct Evidence Antibiotic Resistance Pesticide Resistance Genetic Changes in Plants
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Evolution of Primates Group of Mammals with: – Humans – Apes – Monkeys
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I CAN…. I can describe the differences among living primates Identify the adaptations of primates Discuss the evolutionary history of modern primates
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Characteristics of Primates Opposable thumbs – grasp and hold things Binocular vision – judge distance Flexible shoulders - swimming Indicate all share a common ancestor
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Two groups of Primates Strepsirhines Lemurs Tarsiers Haplorhines Monkeys Apes Humans
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Hominids 4-6 million years ago Both plant and animal eating Walked upright on two legs…bipedal
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African Origins 1920 – fossil skull found in South Africa Small brain Humanlike jaw and teeth Australopithecus – oldest hominid “Lucy” – full skeleton found in 1974. – Found to be 2.9 to 3.4 million years old
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Homo Habilis “Handy Man” Simple stones found near him 1.5 to 2 million years old Gave rise to Homo Erectus – larger brain Traveled from Africa to Southeast Asia and Europe
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Homo Sapiens “wise human” 400,000 years ago 125,000 – two groups lived Neanderthals and Cro-Magnon humans
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Neanderthals Short, heavy bodies with thick bones Small chins Heavy browridges Lived in caves Well-made stone tools Disappeared 30,000 yrs ago Side branch of evolution – not direct ancestors
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Cro-Magnon Humans Found in Europe, Asia, and Australia 10,000 to 40,000 years ago Stood 1.6 or 1.7 m high Lived in Caves Made Stone Carvings Buried their dead
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Modern Human – Homo Sapiens sapiens evolved from Homo Sapiens
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