Questions and Answers
What are the three types of natural selection?
Natural selection is a blend of?
Chance and the sorting of alleles
What does natural selection favor?
Some alleles over others so the outcome is not random
How does natural selection affect allele frequencies?
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What is relative fitness?
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What occurs during directional selection?
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What happens during disruptive selection?
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What is stabilizing selection?
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What does sexual selection involve?
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What is sexual dimorphism?
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Study Notes
Types of Natural Selection
- Natural selection includes three main types: disruptive, stabilizing, and directional.
- Each type plays a unique role in shaping population dynamics and allele frequencies.
Natural Selection Mechanics
- It is a combination of chance events and the sorting of alleles based on adaptive advantages.
- Unlike random processes, natural selection consistently favors certain alleles, leading to predictable outcomes.
Effects of Natural Selection
- The process increases frequencies of alleles that contribute to reproductive success.
- This leads to adaptive evolution, enhancing an organism's fitness in its environment.
Relative Fitness
- Relative fitness measures an individual's contribution to the gene pool of the next generation compared to others.
- It is a critical factor for understanding natural selection and evolutionary success.
Directional Selection
- Directional selection occurs when environmental changes favor one extreme phenotype over others.
- This results in a shift in the population's phenotype frequency in the direction of that favored trait.
Disruptive Selection
- Disruptive selection promotes individuals at both extremes of a phenotype range.
- It reduces the prevalence of intermediate phenotypes, increasing variation within the population.
Stabilizing Selection
- Stabilizing selection acts against extreme phenotypes, favoring more common, intermediate forms.
- This type reduces overall genetic variation within a population, maintaining a status quo.
Sexual Selection
- Sexual selection involves individuals with certain inherited traits having a better chance of attracting mates.
- This mechanism drives the evolution of traits that may not necessarily enhance survival but improve mating success.
Sexual Dimorphism
- Sexual dimorphism refers to the distinct differences in secondary sexual characteristics between males and females.
- These differences can manifest in size, coloration, or other phenotypic traits, often enhancing reproductive success.
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Description
Explore the three types of natural selection: disruptive, stabilizing, and directional. Understand how natural selection is influenced by chance and the sorting of alleles, and how it affects allele frequencies. Use these flashcards to reinforce your knowledge on the concepts and mechanisms of natural selection.