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 – 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