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Questions and Answers
Which type of isolation occurs when species breed at different times?
Which type of isolation occurs when species breed at different times?
Which reproductive barrier occurs after fertilization?
Which reproductive barrier occurs after fertilization?
Which of the following is a significant contributor to genetic diversity in populations?
Which of the following is a significant contributor to genetic diversity in populations?
Adaptive radiation is primarily driven by which of the following factors?
Adaptive radiation is primarily driven by which of the following factors?
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Which scenario exemplifies mechanical reproductive isolation?
Which scenario exemplifies mechanical reproductive isolation?
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What is the primary outcome of postfertilization barriers?
What is the primary outcome of postfertilization barriers?
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Which reproductive isolation mechanism is primarily associated with courtship behaviors?
Which reproductive isolation mechanism is primarily associated with courtship behaviors?
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Speciation is least likely to occur in which scenario?
Speciation is least likely to occur in which scenario?
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Which of the following is an example of mechanical reproductive isolation?
Which of the following is an example of mechanical reproductive isolation?
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What is an example of temporal reproductive isolation?
What is an example of temporal reproductive isolation?
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Which of the following illustrates postfertilization barriers?
Which of the following illustrates postfertilization barriers?
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Which of the following provides evidence for genetic diversity among species?
Which of the following provides evidence for genetic diversity among species?
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Speciation processes can be driven by which factor?
Speciation processes can be driven by which factor?
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What is the primary characteristic of mechanical reproductive isolation?
What is the primary characteristic of mechanical reproductive isolation?
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Which scenario best illustrates temporal reproductive isolation?
Which scenario best illustrates temporal reproductive isolation?
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Which of the following is a postfertilization barrier?
Which of the following is a postfertilization barrier?
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What evidence supports that modern humans arose in Africa?
What evidence supports that modern humans arose in Africa?
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Which process is NOT a step in speciation?
Which process is NOT a step in speciation?
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What does a high level of genetic diversity in a population indicate?
What does a high level of genetic diversity in a population indicate?
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What example illustrates the founder effect in genetic drift?
What example illustrates the founder effect in genetic drift?
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How does sexual selection contribute to evolution?
How does sexual selection contribute to evolution?
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Which of these best describes spatial reproductive isolation?
Which of these best describes spatial reproductive isolation?
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Which trait is NOT commonly influenced by natural selection in specific human populations?
Which trait is NOT commonly influenced by natural selection in specific human populations?
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Study Notes
Biological Evolution
- Biological evolution is the process of organisms changing over generations through variations in traits and natural selection.
- Non-evolutionary changes are not genetic, resulting from short-term environmental changes.
Theory of Common Descent
- All living organisms share a common ancestor.
- Phylogenetic trees illustrate evolutionary relationships between species.
- Branches represent evolutionary changes.
- Branch points indicate common ancestors.
Darwin's Theory of Evolution
- Influences:
- Collection of diverse animals and plants
- Principles of Geology
- Divergence between island organisms and mainland species
- The Linnaean system categorizes organisms based on shared traits and evolutionary relationships, revealing common ancestry.
Linnaean System
- Domain: Eukarya
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Primates
- Family: Hominidae
- Genus: Homo
- Species: Homo sapiens
Anatomical Homology
- Similarities in skeletal structures.
Convergent Evolution
- Structural similarities in unrelated species due to similar lifestyles.
Vestigial Traits
- Non-functional or greatly reduced traits.
Developmental Homologies
- Similarities in developmental processes from fertilized egg to adulthood.
Molecular Homologies
- Similarities in DNA sequences.
- Embryonic development
Biogeography
- Distribution of species on Earth.
Fossil Record
- Radiometric dating:
- Estimating the age of rocks using ratios of radioactive elements.
- Direct evidence of change in organisms over time.
Why is Evolution a Good Explanation?
- Good explanation of a wide variety of observations. Well-supported by a wide variety of evidence.
- Anatomy, geology, molecular biology and genetics provide evidence.
- Consilience - agreement among observations from various sources.
Chapter 12: Natural Selection
- Use the Natural Selection Worksheet
Chapter 13: Biological Species
- A group of individuals that can interbreed and produce fertile offspring but cannot reproduce with members of other species.
Reproductive Isolation
- Prevents gene flow between species
- Pre-zygotic barriers:
- Spatial isolation
- Behavioral isolation
- Mechanical isolation
- Temporal isolation
- Post-zygotic barriers:
- Gamete incompatibility
- Hybrid inviability
- Hybrid sterility
Speciation
- Three steps of speciation:
- Isolation of gene pools
- Evolutionary changes in gene pools
- Evolution of reproductive isolation.
Races
- Race as defined using the geological species concept - organisms able to interbreed- descended from a common ancestor, representing independent evolutionary lineage.
Humans' African Origin
- Humans have less genetic diversity than any other great ape which suggests a relatively young species.
- African populations have the greatest genetic diversity, indicating the oldest human population.
Genetic Evidence of Race
- Allele frequencies: The percentage of gene copies of a specific allele in a particular population.
- Human races are not isolated.
- More variations exist within groups than between groups.
Traits Due to Natural Selection
- Traits that have become common due to natural selection in specific populations such as skin, sickle cell, and nose shape.
Genetic Drift
- Changes in allele frequency due to chance.
- Examples: Founder effect and bottleneck effect.
Sexual Selection
- When a trait influences the likelihood of mating.
Chapter 14
- Estimated number of species: 1.3 million (estimate).
- Only about 20% of species are known.
- Three major domains: Bacteria, Archaea, Eukarya.
- Broad overview of life's history: Prokaryotes evolved into more complex eukaryotes.
Prokaryotes
- Found anywhere and able to resist extreme conditions.
- Endospores allow some to survive.
Endosymbiotic Theory
- Mitochondria and chloroplasts descended from bacteria inside primitive eukaryotes.
Four Kingdoms of Eukarya
- Protista (mostly single-celled).
Resembling life forms: Animals, fungi, and plants.
- Most members are unknown. Some are photosynthetic (algae). Others consume cellulose/ organic molecules.
Animalia
- Vertebrates and invertebrates. Eukaryotic and multicellular, heterotrophic.
Fungi
- Immobile and Multicellular. Heterotrophic and decomposers. Examples include spores, yeast, and molds.
Plantae
- Multicellular and eukaryotic. Autotrophic. Include first plants, flowering/nonflowering plants.
Adaptive Radiation
- Rapid diversification of species into a large group of descendants, often due to evolutionary breakthroughs or the extinction of competing species.
Viruses
- Not considered living organisms because they cannot maintain homeostasis and require assistance for reproduction and growth.
Evolutionary Classifications
- Phylogeny: Evolutionary relationships
- Cladistic analysis: Technique to examine variation in related species
- Fossil examination and DNA provide verification.
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Description
Explore the fascinating concepts of biological evolution, the theory of common descent, and Darwin's influential ideas. This quiz covers the Linnaean system of classification and the significance of anatomical homology in understanding evolutionary relationships among species.
