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Study Guide for Chapter 11 Evolution – process of change over time Adaptation –having traits that increase an organism’s ability to survive and reproduce. Charles Darwin’s Theory – Species change over many generations and become better adapted to new conditions. Over time natural selection can lead to change. Helpful variations may accumulate in a species, while unfavorable ones may disappear. Natural Selection – process by which individual that are better adapted to their environment are more likely to survive and reproduce more than other members of the same species. Includes: Overproduction- more offspring are produced than can survive (lack of resources) Variation- differences in individuals Competition- direct or indirect struggle for resources to survive Evidence that supports evolution: Fossils, similarities in early development, similarities in body structure, similarities in DNA and Protein structure. Homologous structure – structurally similar body parts in related species that have been inherited by a common ancestor. How do new species form? Isolation – group of individuals remain removed from the rest of its species long enough to evolve different traits that prevent reproduction (ex. Natural barrier) Theories about the RATE of evolution : 1. Gradualism – small changes that add up to major changes over long periods of time 2. Punctuated equilibrium – species evolve during short periods of rapid change and then don’t change much. Biodiversity – number of different species in an area. Important for: source of beauty and recreation, economic value, ecological value Keystone species – species that influences the survival of many other species in an ecosystem. Factors that affect biodiversity: Climate, area, niche diversity, genetic diversity, and extinction of species. Endangered species – in danger of becoming extinct. Threatened species – may be endangered soon. Humans affect biodiversity by habitat destruction, poaching, pollution, and exotic species Humans can protect biodiversity by captive breeding, laws and treaties, and habitat preservation.