Do Now Activity What is the difference between a homologous and vestigial structure? A long time ago, there were scientists that probably observed giraffes with really short necks. We do not see these giraffes with short necks anymore. What could have happened during the evolution of the giraffe? True/False: An example of evolution is when chameleons change their color to blend into their environments. If #3 was False, re-write the sentence to make it a true statement.

Section 5-3: Natural Selection Essential Question: How does competition for limited resources lead to an adaptation within a species? Learning Target Explain the four factors that result in evolution of a species Explain the relationship between the factors of evolution and the adaptation of a species that results from competition for limited resources. Section 5-3: Natural Selection

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all species, living and extinct, came from the same original species. overview Common Ancestor all species, living and extinct, came from the same original species.

overview Each living species has descended, with changes, from other species over time.

A single “tree of life” for all living things on Earth. overview A single “tree of life” for all living things on Earth.

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Individuals have different traits. Natural selection Individuals have different traits.

Traits can be passed on to offspring. Natural selection Individuals have different traits. Traits can be passed on to offspring.

More offspring are made then can survive to reproduce. Natural selection Individuals have different traits. Traits can be passed on to offspring. More offspring are made then can survive to reproduce.

high birth rates + limited resources = competition Natural selection high birth rates + limited resources = competition

Organisms struggle to exist when there is _____ for resources. Natural selection competition Organisms struggle to exist when there is _____ for resources. competition

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Factors that cause evolution 1. Carrying Capacity: species growth limited by the environment The potential for a species to increase in number

Factors that cause evolution 1. Carrying Capacity: species growth limited by the environment The potential for a species to increase in number

Factors that cause evolution 1. Carrying Capacity: species growth limited by the environment The potential for a species to increase in number

Factors that cause evolution 1. Carrying Capacity: species growth limited by the environment The potential for a species to increase in number

Factors that cause evolution 1. Carrying Capacity: species growth limited by the environment The potential for a species to increase in number

Factors that cause evolution 2. Variation: differences The heritable genetic variation of individuals in a species due to mutation and sexual reproduction

Factors that cause evolution 3. Competition: limited resources Competition for limited resources

Factors that cause evolution 4. Fitness: survive and reproduce Adaptations: traits that increase survival Proliferation of those organisms that are able to better able to survive and reproduce in the environment

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“Survival of the Fittest” Darwin called this Natural Selection. Best fit to the environment can survive and reproduce. Over time natural selection changes genes in population. New species = Evolution

“Survival of the Fittest” Variations  Adaptations  Fitness Natural Selection/Survival of the Fittest A Very Long Time  EVOLUTION!

Do now activity Give an example of homologous structures. Give an example of vestigial structures. True/False: The 5 forms of evolutionary evidence are: embryo development, fossil record, competition, DNA, & variation. If #3 was False, re-write the sentence to make it a true statement.