120 likes | 324 Views
The Theory of Evolution. What is the Theory of Evolution?. Theory : well-supported testable explanation of phenomena that have occurred in the natural world Evolution : change over time; process by which modern organisms have descended from ancient organisms. Who is Darwin?.
E N D
What is the Theory of Evolution? • Theory: well-supported testable explanation of phenomena that have occurred in the natural world • Evolution: change over time; process by which modern organisms have descended from ancient organisms
Who is Darwin? • Charles Darwin is considered the father of modern evolutionary theory • Darwin’s 5 year voyage as the naturalist on the HMS Beagle helped him develop the theory of how evolution occurs
Figure 15–1 Darwin’s Voyage Section 15-1
DarwinPresentsHisCase • Through his observations on the Galapagos Islands, he concluded that naturalvariation or differences occur among individuals of a population • Scientists later found out that these variations among individuals were caused by mutations
Natural Selection(Darwin’s main point) • Organisms with more favorable traits or variations tend to survive and reproduce; organisms with less favorable traits are less likely to survive
2 Main Points of Natural Selection • Struggle for existence: competition for territory, food, water, and mates • Survival of the fittest: some organisms are better suited to survive in an environment as a result of adaptations (mimicry or camouflage)
Evidence for Evolution • Fossils: by using fossils, scientists can show the sequence of evolution in an organism • Geography: organisms that are similar but live in different parts of the world Beaver Muskrat Beaver andMuskrat Coypu Capybara Coypu andCapybara
Evidence for Evolution • Homologous Structures: structures that are similar and seen in different species • Ex: forelimbs of humans/bats
Evidence for Evolution • Embryology: by studying unborn organisms, we can see structures in common during development in different organisms
Genetic Relationships: DNA comparisons help establish evolutionary relationships between different species