Download 7CDE Natural Selection

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Review
B.7CDE: Natural Selection
B.7C: Analyze and evaluate how natural selection produces change in populations, not
individuals. Supporting Standard
B.7D: Analyze and evaluate how the elements of natural selection, including inherited
variation, the potential of a population to produce more offspring than can survive, and a
finite supply of environmental resources, result in differential reproductive success.
Supporting Standard
B.7E: Analyze and evaluate the relationship of natural selection to adaptation and to the
development of diversity in and among species. ✪ Readiness Standard
1. The principles of Natural Selection state that overpopulation results in
competition and struggle for existence; populations have variation; and
populations have an unequal ability of individuals to survive and reproduce. Only
the best fit individuals survive and get to pass on their traits to their offspring.
2. Differential reproductive success occurs as the frequency of alleles changes due
to the variation within a population as some variants will leave more offspring
than others; also as more individuals are produced than the environment can
support.
3. Natural selection takes many generations, and changes do not happen to
individuals; they happen to populations.
4. Species are defined as a population that produces viable, fertile offspring
(interbreed in nature). When interbreeding can no longer naturally occur,
speciation occurs. Speciation can be allopatric or sympatric. Organisms over time
(many generations) accumulate mutations for better survival and adaptations
over time can result in the formation of new species.
Vocabulary
adaptation,
allopatric
speciation,
differential
reproductive
biodiversity,
success,
gene
biological
pool,
fitness,
generation,
Charles
natural
Darwin,
selection,
overpopulation, population, resources, species, subspecies, sympatric speciation,
Fundamental Questions
Use the Key Concepts information as well as the information in your Stemscopedia
beginning on page 69 to answer the fundamental questions below.
1. Why does natural selection not affect individual organisms?
2. How do the elements of natural selection result in differential reproductive success?
3. How does natural selection and adaptation relate to diversity of species?
Analysis
Complete the following in the space provided.
1) Describe how natural selection produces a change in a population?
2) The finches on the Galapagos Island originated from a common ancestor. Describe
some of the changes that occurred in the original species.
3) Detail the relationship between natural selection and diversity within a species.