Podcast
Questions and Answers
What is the term for changes in gene/allele frequency over generations?
What is the term for changes in gene/allele frequency over generations?
What causes new species to emerge?
What causes new species to emerge?
Which process explains the build-up of genetic changes in a population over time?
Which process explains the build-up of genetic changes in a population over time?
What can cause gene pools to become increasingly different from the original pool?
What can cause gene pools to become increasingly different from the original pool?
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Which barrier leads to the fragmentation of gene pools during speciation?
Which barrier leads to the fragmentation of gene pools during speciation?
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What process occurs when genetic changes result in a population hunting in water versus on land, like Garter snakes?
What process occurs when genetic changes result in a population hunting in water versus on land, like Garter snakes?
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What is the primary source of gene pools for future speciation?
What is the primary source of gene pools for future speciation?
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Which statement best describes homologous structures?
Which statement best describes homologous structures?
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Why can species have very different phenotypes despite being closely related?
Why can species have very different phenotypes despite being closely related?
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Which pairs of traits are examples of convergent evolution?
Which pairs of traits are examples of convergent evolution?
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What is the relationship between apes and humans according to the text?
What is the relationship between apes and humans according to the text?
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Which of the following is NOT a theory according to the text?
Which of the following is NOT a theory according to the text?
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What is the definition of microevolution?
What is the definition of microevolution?
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What is the primary cause of genetic diversity in a population?
What is the primary cause of genetic diversity in a population?
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What does the term 'gene pool' refer to?
What does the term 'gene pool' refer to?
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How is the genetic composition of a population measured?
How is the genetic composition of a population measured?
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What is the outcome of gene flow?
What is the outcome of gene flow?
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What is the first mechanism of microevolution?
What is the first mechanism of microevolution?
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What is the primary cause of allele frequency change in genetic drift?
What is the primary cause of allele frequency change in genetic drift?
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Which of these circumstances makes genetic drift likely?
Which of these circumstances makes genetic drift likely?
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What is a population 'bottleneck'?
What is a population 'bottleneck'?
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What is the definition of 'relative fitness'?
What is the definition of 'relative fitness'?
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What is the primary cause of allele frequency change in natural selection?
What is the primary cause of allele frequency change in natural selection?
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Which of these is an example of natural selection?
Which of these is an example of natural selection?
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Which phylum do starfish belong to?
Which phylum do starfish belong to?
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What type of endoskeleton do chondrichthyes have?
What type of endoskeleton do chondrichthyes have?
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Which class of chordates includes animals that are the first to colonize land?
Which class of chordates includes animals that are the first to colonize land?
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What is a unique feature of some reptiles that is not a defining mammalian trait?
What is a unique feature of some reptiles that is not a defining mammalian trait?
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What percentage of all mammals belong to the two most species-rich mammalian orders?
What percentage of all mammals belong to the two most species-rich mammalian orders?
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What major event occurs in the life cycle of amphibians?
What major event occurs in the life cycle of amphibians?
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Study Notes
Microevolution
- Microevolution: changes in gene/allele frequency over generations, causing a change in the phenotype of a population over time
- Mechanisms of microevolution:
- Genetic drift: allele frequency change due to chance, regardless of the allele's usefulness
- Natural selection: allele frequency change due to the allele's associated phenotype being an advantage or disadvantage in a particular environment
- Gene flow: migration adds or removes alleles from a gene pool
- Mutations: brand new alleles that can occur before any of the other three mechanisms
Genetic Drift
- Genetic drift: allele frequency change due to chance, regardless of the allele's usefulness
- Circumstances that make drift likely:
- The associated phenotype is not an advantage or disadvantage
- Small populations: more likely to change due to a chance event, regardless of the allele's usefulness
- Population bottleneck: population crashes over a short time, alleles lost regardless of allele value
- If the population begins to increase again, the lost alleles may not be recovered
Natural Selection
- Natural selection: allele frequency change due to the allele's associated phenotype being an advantage or disadvantage in a particular environment
- Allele's associated phenotype is defined as an advantage or disadvantage if it is associated with reproductive success
- Relative fitness: the number of surviving offspring over a lifetime, relative to others in the population
Speciation
- Speciation: the process of population divergence, resulting in new species
- Two key steps:
- Gene pool fragmentation: a reproductive barrier occurs, causing geographic isolation, habitat isolation, behavioral isolation, or temporal isolation
- New gene pools become increasingly different: microevolution, mutations, natural selection, and genetic drift occur, leading to the formation of new species
Patterns of Evolution
- Diversification: new species and whole new lineages occur due to speciation
- Transitional species: have ancestral and new traits, may have intermediate phenotypes
- Homologous structures: related species have shared structures, same source, subsequently modified by natural selection
- Divergent evolution: species can have very different phenotypes even if they are fairly closely related
- Convergent evolution: species can have very similar phenotypes even if they are not closely related
Macroevolution
- Macroevolution: the development of new species and families of species
- Six patterns of evolution:
- Diversification
- Transitional species
- Homologous structures
- Divergent evolution
- Convergent evolution
- Speciation
- Evolution is not a guess, but a scientific theory, like germ theory, cell theory, and genetic theory
Kingdom Characteristics
- Kingdom Plantae: characteristics
- Kingdom Fungi: characteristics
- Kingdom Animalia: characteristics
- Levels of biological organization
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Description
Explore the concepts covered in Unit 4 of BIO 105 with Professor Craddock, including microevolution, macroevolution, taxonomy, and biological organization. Learn about genetic diversity, mechanisms of microevolution, and the development of new species and families.
