clues about evolution
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CLUES ABOUT EVOLUTION. Mr. Rethman. 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. . - PowerPoint PPT PresentationTRANSCRIPT
CLUES ABOUT EVOLUTION
Mr. Rethman
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.
INDIRECT EVIDENCE FOR EVOLUTION
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.
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.
Determining Fossil Age
• Relative Dating– Idea of undisturbed areas– Younger rock on top of older rock layers
Compare the ages of rock
Radiometric Dating
• Estimate age of rock using radioactive elements
• Compare the amount of radioactive element with the amount of nonradioactive element in rock.
Embryology
• Study of embryos and their development
Homologous Structures
• Body parts in the same origin and structure
• Also, similar in function
• Indicate more species share common ancestors
Homologous Structures
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
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
DIRECT EVIDENCE FOR EVOLUTION
Direct Evidence
• Antibiotic Resistance• Pesticide Resistance• Genetic Changes in Plants
Evolution of Primates
• Group of Mammals with:– Humans– Apes– Monkeys
I CAN….
• I can describe the differences among living primates
• Identify the adaptations of primates• Discuss the evolutionary history of modern
primates
Characteristics of Primates
• Opposable thumbs – grasp and hold things• Binocular vision – judge distance• Flexible shoulders - swimming
• Indicate all share a common ancestor
Two groups of Primates
• Strepsirhines
• Lemurs• Tarsiers
• Haplorhines
• Monkeys• Apes• Humans
Hominids
• 4-6 million years ago• Both plant and animal eating• Walked upright on two legs…bipedal
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
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
Homo Sapiens “wise human”
• 400,000 years ago
• 125,000 – two groups lived Neanderthals and Cro-Magnon humans
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
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
• Modern Human – Homo Sapiens sapiens evolved from Homo Sapiens