October 2017 Journal: What is a theory? Are theories always true?

Evolution

Evolution Definition Process of genetic changes occurring within a population over many generations

Charles Darwin: The Father of Evolution A. Darwin was NOT the first person to propose evolution… B. He did propose a way evolution happens called Natural Selection

Theory of Evolution by Natural Selection Over time, the number of individuals that carry an advantageous trait in a population will increase Success of the trait depends on the environment that the organism lives in

Examples of Natural Selection

Steps of Natural Selection Overproduction: more offspring than can survive are produced

Steps of Natural Selection Variation: there are differences between the traits in these offspring

Steps of Natural Selection Selection: In a given environment, having a particular trait can make individuals more or less likely to survive

Steps of Natural Selection Adaptation: Over time, the traits that improve fitness will become more common. Fitness: The ability for an organism to survive and reproduce.

Types of Adaptations Physical Adaptations Behavioral Adaptations Warning Coloration Mimicry Behavioral Adaptations Horned Lizards Octopus

October 2017 Journal: Give an example of an adaptation.

Speciation The selection of various adaptations can help lead to speciation The formation of a new species Species – Group of organisms that are closely related and can mate to produce fertile offspring

How does speciation occur? Reproductive Isolation: When two species can no longer interbreed to produce offspring Geographic Isolation Mating Behavior and Timing

Microevolution Process that cause changes in the inherited traits observed in a population over time Natural Selection Migration Mutation Mate Choice Genetic Drift: Random effects of everyday life that cause differences in survival and reproduction rates

Macroevolution Convergent Evolution: Species in similar environments have similar adaptations

Macroevolution Coevolution: Species that alive in close contact often evolve adaption to each other

Adaptive radiation: Over time, species split into one or more lines of descendants

Gradualism Evolutionary change comes about gradually over time

Punctuated Equilibrum Rapid change that results in a new species quickly

Descent with Modification A. Over time, natural selection produces organisms with different structures B. Today’s species look different from their ancestors C. Each species descended with changes over time from a common ancestor

Extinction All members of a lineage die off Tasmanian Tiger Quagga