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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.