Presentation on theme: "WHAT IS EVOLUTION? Evolution is the gradual change in a species over time. A species is a group of similar organisms that can mate with each other and."— Presentation transcript:
1WHAT IS EVOLUTION?Evolution is the gradual change in a species over time.A species is a group of similar organisms that can mate with each other and produce fertile offspring.Theory of Evolution: What isthe difference between a theory,hypothesis, and a law?
2CHARLES DARWIN – 1809-1882 English naturalist Developed the theory of evolution by natural selectionObserved many species and fossilsTraveled around the world on the ship Beagle – Famous in the Galapagos IslandsWhy did some species survive while others became extinct?
3Charles Darwin – Galapagos Islands What did Darwin observe on the Galapagos Islands that led him to propose his theory of evolution?
4EVIDENCE OF EVOLUTIONAdaptations: A trait that helps an organism survive and reproduce.MimicryCamouflageBeak shape/size.
6WHAT IS NATURAL SELECTION? Natural Selection is the process by which individuals that are better adapted to their environment are more likely to survive and reproduce that other members of the same species.Factors that affect the process of natural selection:~ Overproduction~ Competition~ Variations: Any difference between individuals of the same species..
7Natural SelectionOver a long period of time, natural selection can lead to evolution. Helpful variations gradually accumulate in a species, while unfavorable ones disappear. Explain why variations are needed for natural selection to occur.
8How Do New Species Form?A new species can form when a group of individuals remains separated from the rest of its species long enough to evolve different traits.Speciation- Geographic Isolation- Reproductive Isolation
9Geographic Isolation Continued… Continental Drift –Motion of continents about Earth's surface on plates of crust floating on the hot mantle.
10OTHER EVIDENCE OF EVOLUTION FOSSILSEARLY DEVELOPMENT (Embryos)ANATOMY (Body Structure)HOMOLOGOUS STRUCTURESSIMILARITIES IN DNA
11Homologous Structures – similar structures that related species have inherited from a common ancestor.
12FOSSIL RECORDFossil – The preserved remains or traces of an organism that lived in the past.How Do Fossils Form?Most fossils form when organisms that die become buried in sediments (particles of soil and rock). Others can be preserved in ice, tar pits, or sap.
13FOSSIL RECORDThe fossil record refers to the millions of fossils scientists have collected.What Do Fossils Reveal about extinct species?~ How it looked~ How it behaved~ How it evolved (related species)Group of jellyfish fossils has been uncovered in Wisconsin, US
14How Fast Does Evolution Occur? Gradualism~ The theory that evolution occurs slowly but steadily.Punctuated Equilibria~ The theory that species evolve during short periods of rapid change
15Combining The Evidence Branching Tree – A diagram that shows how scientists think different groups organisms are related.
16Geologic Time Scale Earth’s history is organized into 4 eras: PrecambrianPaleozoicMesozoicCenozoic
17Some Questions to Ponder… Human evolution so far…10,000 years from now…Where will humans live?How will our environment change?What will the world look like?How Will The Forces of Evolution Work On Our Species?