Transcript Evolution
EVOLUTION Ch. 23 Evolution Evolution Outline • Formation of the earth & chemical evolution • Early beginnings of cells • Critical events leading to evolution Evidence • Evidence supporting evolution • Early Primate evolution • Evolution of the Genus Australopithecines • Evolution of the Genus Homo & modern humans 4.5 billion years ago the earth formed QuickTime™ and a TIFF (Uncompressed) decom pressor are needed to s ee this picture. •Dr. Stanley Miller (1930-2007) Miller’s Experiment showed: • Organic molecules can be formed from components of Earth’s early atmosphere. heterotrophs autotrophs Collections of polymers. SUMMARY Earth formed Chemical Evolution began 4.5 billion years ago 4 billion years ago First Prokaryotes emerged 3.5 billion years ago First Eukaryotes emerged 1.2 billion years ago Insects 40 million years ago trapped in amber Ocean First species to invade the land came from the oceans were likely plants. Soon after the plants invaded, animals came ashore. First animals were probably scropion-like. Evolutionary changes • Anatomical • Functional • Behavioral How do these changes occur? Charles Darwin: 1809-1882 1831-1836 1859 DARWIN’s TRAVELS 2 conflicting theories Key components of evolutionary process • Genetic variation • Natural selection • Survival of the Fittest Evidence supporting natural selection 1. Fossil records 2. Homologous structures 3. Biochemical similarities (DNA of fossils is also being studied) – DNA – Amino acids Humans 98% similar Chimpanzees 4. Embryologic development Mouse Human Cockatiel Sea urchin • 5. Biogeography Super continent 240 million years ago • 6. Experimental Evidence Primate Evolution Earliest primates included the Tarsiers Ruff lemur tarsier Consist of Prosimians Old world monkeys Primates (order) Anthropoids New world monkeys hominoids Consist of: Great Apes Lesser Apes Hominids Genus:Australopithecus Mandrill Spider Monkey Genus: Homo Australopithecus afarensis “Lucy” Approx. 25-30 years old Approx. 60 pounds Approx. 3 ft tall Discovered by Dr. Donald Johanson mid 70’s Approx. 3.2 mya Australopithecus afarensis • Bipedal • Approximately 3 to 5.6 ft in height • Over 1 million years ago Australopithecus disappeared. Homo habilis “skillful man” • Lived 1.8 million years ago • Discovered 1960 in Tanzania by Dr. Mary Leakey Brain is 50% larger than Australopithecus Homo erectus “upright man” • Lived 1.6 million years ago • H. erectus moved from Africa to Europe and Asia Used fire Homo erectus (stood approximately 5 ft tall) Turkana Boy Found in 1984 in Kenya male Approximately 12 years old Lived approximately 1.6 million years ago Homo sapien “thinking man” • Emerged approx. 300,000 years ago • 2 subspecies – neaderthalensis – sapien Skull of Homo sapien neanderthalensis Lived in small clans and had elaborate burial rituals. Homo sapien sapien • Neaderthanls disappeared about 40,000 years ago • About 300,000 years ago enter Homo sapien sapien Skull of early Homo sapien sapien Cro-Magnon Man Homo sapien sapien Cro-Magnon Man Artistic with perhaps a well developed language Excellent hunters Lived in communities Homo sapien sapien “modern man” • Appeared approximately 10,000 years ago • Very little change over the past 40,000 years The End (or beginning !) An artist’s interpretation of how “Lucy” may have looked.