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Questions and Answers
What is the primary mechanism by which natural selection acts on a population?
What is the primary mechanism by which natural selection acts on a population?
What is the primary limitation of the fossil record?
What is the primary limitation of the fossil record?
What type of natural selection favors extreme traits?
What type of natural selection favors extreme traits?
What is the term for a trait that enhances an individual's fitness in a specific environment?
What is the term for a trait that enhances an individual's fitness in a specific environment?
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What is an example of a physiological adaptation?
What is an example of a physiological adaptation?
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What is the term for the process by which a new species emerges from an existing one?
What is the term for the process by which a new species emerges from an existing one?
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Which of the following is NOT a type of natural selection?
Which of the following is NOT a type of natural selection?
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What is the term for the random change in the frequency of a gene or genetic trait in a population?
What is the term for the random change in the frequency of a gene or genetic trait in a population?
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What is the primary difference between adaptation and speciation?
What is the primary difference between adaptation and speciation?
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What is the term for the remains or imprints of ancient organisms?
What is the term for the remains or imprints of ancient organisms?
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Study Notes
Evolution
Natural Selection
- Process by which individuals with favorable traits are more likely to survive and reproduce
- Key components:
- Variation in population: differences in traits among individuals
- Heritability: traits are passed down from parents to offspring
- Differential reproduction: individuals with favorable traits produce more offspring
- Types of natural selection:
- Stabilizing selection: favors average traits
- Directional selection: favors extreme traits
- Disruptive selection: favors different traits in different environments
Fossil Record
- Chronological record of evolution through fossilized remains
- Provides evidence for:
- Gradual changes in species over time
- Transitional forms between different groups
- Extinction events
- Fossil record limitations:
- Fossilization is a rare process
- Many species may not have fossilized remains
Adaptation
- Trait that enhances an individual's fitness in a specific environment
- Types of adaptation:
- Structural adaptation: physical changes, e.g. development of wings
- Physiological adaptation: changes in internal functions, e.g. increased oxygen efficiency
- Behavioral adaptation: changes in behavior, e.g. migration patterns
- Adaptation vs. exaptation:
- Adaptation: trait evolves for a specific purpose
- Exaptation: trait evolves for one purpose, but is used for another
Genetic Drift
- Random change in allele frequency over time
- Causes:
- Random sampling error
- Genetic hitchhiking
- Bottleneck effect
- Effects:
- Loss of genetic variation
- Fixation of alleles
- Changes in population size
Speciation
- Process by which a new species emerges from an existing one
- Mechanisms:
- Allopatric speciation: geographic isolation
- Sympatric speciation: reproductive isolation within a population
- Parapatric speciation: partial geographic isolation
- Types of speciation:
- Adaptive radiation: rapid adaptation to new environments
- Ecological speciation: adaptation to different ecological niches
Evolution
Natural Selection
- Favorable traits increase an individual's chance of survival and reproduction
- Variation in population is necessary for natural selection to occur
- Heritability of traits ensures that beneficial characteristics are passed down to offspring
- Differential reproduction leads to an increase in the frequency of favorable traits in a population
Fossil Record
- Fossil record provides a chronological history of evolution
- Fossils demonstrate gradual changes in species over time
- Transitional forms between different groups are found in the fossil record
- Fossil record is incomplete due to the rare process of fossilization
- Many species may not have left behind fossilized remains
Adaptation
- Adaptations are traits that enhance an individual's fitness in a specific environment
- Structural adaptations involve physical changes, such as the development of wings
- Physiological adaptations involve changes in internal functions, such as increased oxygen efficiency
- Behavioral adaptations involve changes in behavior, such as migration patterns
- Adaptations evolve for a specific purpose, whereas exaptations evolve for one purpose but are used for another
Genetic Drift
- Genetic drift is the random change in allele frequency over time
- Random sampling error, genetic hitchhiking, and bottleneck effect contribute to genetic drift
- Genetic drift leads to a loss of genetic variation, fixation of alleles, and changes in population size
Speciation
- Speciation is the process by which a new species emerges from an existing one
- Allopatric speciation occurs when a population is geographically isolated
- Sympatric speciation occurs when a population is reproductively isolated within a population
- Parapatric speciation occurs when a population is partially geographically isolated
- Adaptive radiation is a type of speciation that involves rapid adaptation to new environments
- Ecological speciation is a type of speciation that involves adaptation to different ecological niches
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Description
Understand the process of natural selection, its key components, and types. Learn how favorable traits increase survival and reproduction rates in a population.
