Natural Selection and Adaptive Evolution
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Questions and Answers

What defines relative fitness in the context of natural selection?

  • The direct competition for resources among individuals
  • An individual's contribution to the next generation's gene pool (correct)
  • The ability of an organism to survive harsh environmental conditions
  • The number of offspring produced in a single breeding season
  • Which type of selection favors individuals at both extremes of a phenotypic range?

  • Disruptive selection (correct)
  • Stabilizing selection
  • Sexual selection
  • Directional selection
  • In stabilizing selection, what happens to phenotypic variation within a population?

  • Variation decreases as intermediate traits are favored (correct)
  • Variation increases as extreme traits survive
  • Variation remains unchanged over time
  • Variation shifts towards one extreme trait
  • Which of the following is a potential result of directional selection?

    <p>An increase in the population's average trait value (B)</p> Signup and view all the answers

    What role do environmental changes play in natural selection?

    <p>They often trigger directional selection (C)</p> Signup and view all the answers

    How do natural selection and adaptive evolution relate to one another?

    <p>Natural selection enhances traits that may lead to adaptive evolution (A)</p> Signup and view all the answers

    An example of disruptive selection can be observed in which of the following?

    <p>Birds with small or large bills are more successful with specific seed types (D)</p> Signup and view all the answers

    Which example illustrates a trait arising due to natural selection for adaptive evolution?

    <p>Fish developing larger fins to escape predators (D)</p> Signup and view all the answers

    What is the main consequence of reduced gene flow between populations?

    <p>It contributes to the formation of new species. (A)</p> Signup and view all the answers

    Which type of reproductive barrier occurs before fertilization?

    <p>Mechanical isolation (A), Gametic isolation (D)</p> Signup and view all the answers

    What limitation does the biological species concept have?

    <p>It cannot be applied to asexual organisms. (D)</p> Signup and view all the answers

    How does the morphological species concept define species?

    <p>By body shape and structure. (B)</p> Signup and view all the answers

    Which factor did Darwin use to support his ideas about change over time?

    <p>Fossil evidence (C)</p> Signup and view all the answers

    What did Georges Cuvier believe caused extinctions?

    <p>Sudden catastrophic events (A)</p> Signup and view all the answers

    What principle did Lamarck propose related to evolution?

    <p>Inheritance of acquired characteristics (D)</p> Signup and view all the answers

    Charles Darwin's initial interest was primarily focused on which subject?

    <p>Plant biology (A)</p> Signup and view all the answers

    How did Darwin's view on classification differ from that of Linnaeus?

    <p>He believed it should reflect evolutionary relationships. (B)</p> Signup and view all the answers

    Which of the following concepts allows for species that occupy different ecological niches but may interbreed?

    <p>Ecological species concept (D)</p> Signup and view all the answers

    What does postzygotic barrier refer to?

    <p>Interference in hybrid development or fertility (A)</p> Signup and view all the answers

    Which statement about sedimentary rocks is true?

    <p>They can reveal the age of fossils based on their depth. (A)</p> Signup and view all the answers

    Which factor does NOT contribute to reproductive isolation?

    <p>Environmental adaptation (B)</p> Signup and view all the answers

    What was a significant influence on Darwin's conclusion about the age of the Earth?

    <p>The study of fossils (A)</p> Signup and view all the answers

    What drives adaptive evolution consistently among populations?

    <p>Natural selection (C)</p> Signup and view all the answers

    How does heterozygote advantage contribute to maintaining genetic variation?

    <p>It allows heterozygotes to have greater fitness than homozygotes. (D)</p> Signup and view all the answers

    What type of selection results in the oscillation of frequency-dependent phenotypes within a population?

    <p>Balancing selection (B)</p> Signup and view all the answers

    Which process involves competition within the same sex for mating opportunities?

    <p>Intrasexual selection (C)</p> Signup and view all the answers

    Sexual selection can lead to differences in size, color, or ornamentation between males and females, known as what?

    <p>Sexual dimorphism (A)</p> Signup and view all the answers

    Why might natural selection not produce perfect organisms?

    <p>Existing variations limit the traits available for selection. (B)</p> Signup and view all the answers

    What does the biological species concept emphasize as the key factor in defining a species?

    <p>Reproductive compatibility (C)</p> Signup and view all the answers

    What maintains genetic variation at loci affected by selection in diploid organisms?

    <p>Balancing selection mechanisms (A)</p> Signup and view all the answers

    In frequency-dependent selection, fitness changes based on what factor?

    <p>The prevalence of a phenotype (A)</p> Signup and view all the answers

    Which of the following is an example of a compromise in adaptation?

    <p>Seals evolving flippers for swimming (C)</p> Signup and view all the answers

    What indicates that a male gray tree frog has superior genetic quality?

    <p>Long mating calls (D)</p> Signup and view all the answers

    What is a result of balancing selection in populations?

    <p>Maintenance of multiple phenotypes (D)</p> Signup and view all the answers

    What is defined as the transfer of alleles between populations?

    <p>Gene flow (C)</p> Signup and view all the answers

    Which of the following is NOT a constraint on the perfection of organisms produced by natural selection?

    <p>Emergence of new traits (D)</p> Signup and view all the answers

    How did the introduction of larger fruit in certain regions affect soapberry bug populations?

    <p>It resulted in the evolution of longer beaks. (B)</p> Signup and view all the answers

    What is a primary factor contributing to the rapid evolution of drug-resistant pathogens?

    <p>The overuse and misuse of antibiotics. (B)</p> Signup and view all the answers

    Which of the following best describes how natural selection functions?

    <p>It selects for existing traits based on environmental pressures. (A)</p> Signup and view all the answers

    How do homologous traits provide evidence for evolution?

    <p>They show that similar features arise from a common ancestor, modified by evolution. (C)</p> Signup and view all the answers

    What role do vestigial structures play in understanding evolution?

    <p>They indicate shared ancestry through remnants of ancestral features. (A)</p> Signup and view all the answers

    Which example illustrates convergent evolution?

    <p>The similarities in sugar gliders and flying squirrels. (A)</p> Signup and view all the answers

    What did the rapid spread of methicillin-resistant Staphylococcus aureus (MRSA) after the introduction of methicillin demonstrate?

    <p>Natural selection can quickly promote resistant strains in response to antibiotic use. (C)</p> Signup and view all the answers

    What is the significance of studying early developmental stages in different animal species?

    <p>To demonstrate evolutionary relationships and shared ancestry. (C)</p> Signup and view all the answers

    What mechanism allows bacteria to quickly develop resistance to new antibiotics?

    <p>Resistance mechanisms are inherited from parent strains. (C)</p> Signup and view all the answers

    Which statement about natural selection is true?

    <p>It favors traits that enhance survival and reproduction in specific environments. (D)</p> Signup and view all the answers

    Why is it important to understand molecular homologies in evolutionary biology?

    <p>They indicate genetic similarities that point to a common ancestor. (A)</p> Signup and view all the answers

    In the context of antibiotic resistance, what does the term 'gene exchange' refer to?

    <p>The transfer of resistance genes between bacteria. (B)</p> Signup and view all the answers

    How do similar environmental pressures affect species in different regions?

    <p>They result in analogous features through convergent evolution. (A)</p> Signup and view all the answers

    What can cause homologous structures to perform different functions across species?

    <p>Environmental changes leading to different adaptations. (D)</p> Signup and view all the answers

    What was the primary purpose of Darwin's voyage on the HMS Beagle?

    <p>To chart South America's coastline (B)</p> Signup and view all the answers

    Which observation contributed to Darwin's understanding that Earth was older than traditionally believed?

    <p>The discovery of marine fossils in the Andes (D)</p> Signup and view all the answers

    What mechanism did Darwin propose to explain how new species arise?

    <p>Natural selection (D)</p> Signup and view all the answers

    What term did Darwin use to describe the concept of organisms sharing a common ancestor?

    <p>Descent with modification (A)</p> Signup and view all the answers

    How did Darwin utilize the analogy of a branching tree in his explanation of evolution?

    <p>To represent the diversity of life from common ancestors (C)</p> Signup and view all the answers

    Which factor did Darwin connect with natural selection to explain population dynamics?

    <p>Overpopulation and resource scarcity (B)</p> Signup and view all the answers

    What evidence did Darwin use to support his argument for natural selection?

    <p>Observations of artificial selection (B)</p> Signup and view all the answers

    Which group of animals did Darwin study to observe adaptations specific to the Galápagos Islands?

    <p>Finches (C)</p> Signup and view all the answers

    What characteristic is essential for the process of natural selection?

    <p>Survival of the fittest (D)</p> Signup and view all the answers

    How did Darwin's views on species adaptation change after visiting the Galápagos Islands?

    <p>He hypothesized distinct species evolved from common ancestors (C)</p> Signup and view all the answers

    What concept did Darwin's observation of soapberry bugs illustrate?

    <p>Natural selection can result in adaptations to introduced species (C)</p> Signup and view all the answers

    What did Darwin fear would result from publishing his work on natural selection?

    <p>Controversy and backlash (C)</p> Signup and view all the answers

    During his studies, how did Darwin perceive the relationship between artificial and natural selection?

    <p>Artificial selection can cause rapid changes, similar to natural selection (D)</p> Signup and view all the answers

    Which aspect of evolution does the decline of various elephant-related lineages highlight?

    <p>The importance of fossils in understanding evolutionary history (C)</p> Signup and view all the answers

    How do fossils contribute to our understanding of evolution?

    <p>By documenting changes in organisms over time. (D)</p> Signup and view all the answers

    Which type of selection favors individuals at both extremes of a phenotype spectrum?

    <p>Disruptive selection (A)</p> Signup and view all the answers

    What is an example of a prezygotic reproductive isolating mechanism?

    <p>Mechanical isolation (C)</p> Signup and view all the answers

    How does biogeography support the theory of evolution?

    <p>By revealing how continental drift influences species distribution. (A)</p> Signup and view all the answers

    What is a defining characteristic of allopatric speciation?

    <p>It results from the differentiation of geographically isolated populations. (D)</p> Signup and view all the answers

    Which statement best describes Darwin's view on evolution?

    <p>Descent with modification leads to diverse life forms. (C)</p> Signup and view all the answers

    What does the term 'fitness' refer to in the context of natural selection?

    <p>The ability to survive and reproduce in a given environment. (C)</p> Signup and view all the answers

    Which of the following best describes the role of transitional fossils?

    <p>They fill gaps in our understanding of evolutionary history. (D)</p> Signup and view all the answers

    What is the significance of Darwin's idea of island biogeography?

    <p>It explains that islands are colonized by species from faraway mainland areas. (A)</p> Signup and view all the answers

    What is the primary distinction between prezygotic and postzygotic reproductive isolating mechanisms?

    <p>Prezygotic mechanisms prevent fertilization; postzygotic mechanisms occur after fertilization. (C)</p> Signup and view all the answers

    What did Lamarck's theory of evolution emphasize?

    <p>The inheritance of acquired traits. (A)</p> Signup and view all the answers

    Which statement about the fossil record is accurate?

    <p>It has uncovered significant transitional forms in evolution. (A)</p> Signup and view all the answers

    What has recent research revealed about the origin of cetaceans?

    <p>Cetaceans are distantly related to even-toed ungulates. (D)</p> Signup and view all the answers

    Flashcards

    Relative Fitness

    An individual's contribution to the next generation's gene pool.

    Directional Selection

    Favors individuals with one extreme of a trait, shifting the population's average trait in that direction.

    Disruptive Selection

    Favors individuals at both extremes of a phenotypic range, disadvantaging those with intermediate traits.

    Stabilizing Selection

    Favors intermediate phenotypes and reduces variation, maintaining the status quo.

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    Natural Selection

    The process where traits that increase reproductive success become more common in a population.

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    Adaptive Evolution

    The change in a population's traits over time, due to natural selection enhancing favorable traits.

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    Phenotype

    Observable characteristics of an organism, directly influenced by the genotype.

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    Genotype

    An organism's genetic makeup, indirectly influencing its observable traits.

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    What is balancing selection?

    A type of selection where multiple alleles are maintained in a population because they are advantageous in different situations or combinations.

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    Heterozygote Advantage

    When heterozygous individuals have a higher fitness than both homozygous individuals for a specific trait, leading to the maintenance of multiple alleles.

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    Frequency-Dependent Selection

    The fitness of a phenotype depends on its prevalence in the population, leading to oscillating allele frequencies.

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    Sexual Selection

    A process where individuals with specific traits are more likely to secure mates, often leading to differences between males and females.

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    Intrasexual Selection

    Competition within the same sex for access to mates, often involving physical conflict or dominance displays.

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    Intersexual Selection

    One sex, usually females, choosing mates based on specific traits such as appearance or behavior.

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    Good Genes Hypothesis

    The idea that female preference for male traits may evolve because these traits signal a male's genetic quality.

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    Why are organisms not perfect?

    Organisms are not perfectly adapted due to constraints like limited variations, historical constraints, compromises, and random events.

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    Existing Variations

    Natural selection can only act on traits already present in a population, not creating new ones.

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    Historical Constraints

    Evolution modifies existing structures, adapting them for new purposes.

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    Compromises

    Adaptations often involve trade-offs, where a beneficial trait for one function might be detrimental for another.

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    Biological Species Concept

    Defines a species as a group of populations that can interbreed in nature and produce viable, fertile offspring but cannot do so with other groups.

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    Gene flow

    Transfer of alleles between populations, maintaining the gene pool of a species.

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    What is a species?

    A group of populations whose members can interbreed in nature and produce viable, fertile offspring, but cannot do so with members of other such groups.

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    Reproductive Isolation

    When biological barriers prevent interbreeding between different species, stopping them from producing viable, fertile offspring.

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    Prezygotic Barriers

    Factors that prevent fertilization by interfering with mating attempts, successful mating, or blocking fertilization.

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    Postzygotic Barriers

    Factors that affect hybrid offspring after fertilization, resulting in issues like developmental errors, infertility, or reduced survival.

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    Limitations of the Biological Species Concept

    It cannot be applied to fossils, asexual organisms, or species that occasionally interbreed.

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    Morphological Species Concept

    Classifies species based on their body shape and structure, applicable to both sexual and asexual organisms.

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    Scala Naturae

    Aristotle's concept of a ladder of nature, where species were arranged in a fixed hierarchy with humans at the top.

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    Binomial Nomenclature

    Linnaeus's system for naming species using a two-part name, with the first part being the genus and the second being the species.

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    Fossils

    Preserved remains or traces of past organisms, often found in sedimentary rock layers.

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    Strata

    Layers of sedimentary rock that reveal the order in which organisms lived.

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    Paleontology

    The study of fossils, providing insights into the history of life on Earth.

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    Catastrophism

    Cuvier's theory that sudden catastrophic events caused extinctions and shaped Earth's features.

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    Gradualism

    Hutton and Lyell's idea that Earth's features are formed by slow, continuous processes.

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    Use and Disuse

    Lamarck's idea that body parts used frequently become stronger, while those not used weaken and disappear.

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    Inheritance of Acquired Traits

    Lamarck's theory that traits gained during an organism's lifetime are passed on to offspring.

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    Drug resistance in bacteria

    The ability of bacteria to survive and reproduce in the presence of antibiotics that would normally kill them.

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    How does antibiotic overuse lead to drug resistance?

    Overusing antibiotics creates an environment where only resistant bacteria survive and reproduce, making them the dominant strain.

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    Natural selection 'editing' process

    Natural selection doesn't create new traits, but selects for traits that already exist in a population.

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    Rapid evolution in bacteria

    Bacteria reproduce quickly, allowing natural selection to shape their evolution at a faster pace.

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    Homology

    Similarities between organisms due to common ancestry, hinting at evolutionary relationships.

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    Anatomical Homologies

    Shared bone structures between different species despite different functions, suggesting common ancestry.

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    Developmental Homologies

    Similarities in embryonic development despite adult differences, indicating shared ancestry.

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    Vestigial Structures

    Remnants of features present in ancestors but reduced or non-functional in modern species.

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    Molecular Homologies

    Similarities at the genetic level, revealing shared ancestry even between distantly related organisms.

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    Convergent Evolution

    Evolution of similar features in distantly related species due to similar environments.

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    Analogous Features

    Features with similar function but different evolutionary origins, not due to shared ancestry.

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    Homologous Features

    Features with shared ancestry but different functions, indicating evolutionary relationships.

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    What is the difference between homologous and analogous features?

    Homologous features have shared ancestry but possibly different functions (like forelimbs), while analogous features have similar function but different evolutionary origins (like wings).

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    Evolutionary remodeling

    Evolution modifies existing structures and functions over time, leading to diversity and adaptation.

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    Shared ancestry

    The idea that all life on Earth is interconnected through a series of common ancestors.

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    HMS Beagle Voyage

    Darwin's five-year expedition aboard the HMS Beagle, where he observed and collected specimens from various regions, leading to his groundbreaking theory of evolution.

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    Darwin's Focus on Adaptation

    Darwin's shift from classifying species to investigating the processes that led to their adaptations, particularly how traits help organisms survive and reproduce in specific environments.

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    What are adaptations?

    Inherited characteristics that enhance an organism's ability to survive and reproduce in its environment, shaping how species evolve over time.

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    Galápagos Finches

    A group of finches with diverse beak shapes and feeding behaviors, observed by Darwin on the Galápagos Islands, providing evidence for adaptation and natural selection.

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    Descent with Modification

    Darwin's term to describe how all organisms are related through a common ancestor and have diverged over time, accumulating changes as they adapted to different environments.

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    Common Ancestor

    A single species from which all living organisms are descended, highlighting the shared commonality of life on Earth.

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    Artificial Selection

    The process where humans selectively breed organisms to accentuate desired traits, often resulting in domesticated species with distinct characteristics.

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    Overreproduction

    Organisms produce more offspring than their environment can support, leading to competition for resources and a selective pressure for survival and reproduction.

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    Direct Observations of Evolutionary Change

    Evidence for evolution from observed shifts in populations, such as how soapberry bugs adapted their beak length to feed on different fruit types.

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    Soapberry Bug Adaptation

    The change in beak length of soapberry bugs to efficiently feed on different fruit types, demonstrating natural selection favoring traits that improve feeding efficiency.

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    Darwin's Contribution to Evolutionary Theory

    Darwin's work established the concept of natural selection as the mechanism behind evolution, providing evidence and explanations for the diversity of life.

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    Impact of Darwin's Theory on Evolution

    Darwin's work revolutionized our understanding of life, shifting the perspective from a fixed hierarchy to a dynamic system of change and adaptation.

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    What is the evidence for evolution?

    Evolutionary theory is supported by an overwhelming amount of evidence from various fields, including fossil record, anatomical similarities, molecular data, and direct observations.

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    Fossil Record

    The preserved remains or traces of past organisms, providing evidence for evolution by showing how species have changed over time.

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    Transitional Forms

    Fossils that exhibit traits of both ancestral and descendant groups, bridging the gap between them.

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    Biogeography

    The study of species' geographic distributions, influenced by continental drift and other factors.

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    Continental Drift

    The gradual movement of Earth's continents over millions of years, impacting species distributions.

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    Island Biogeography

    The study of species on islands, often showing unique adaptations and relationships to mainland counterparts.

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    Scientific Theory

    A well-supported explanation for a wide range of observations and phenomena, continually tested and refined.

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    Adaptation

    A trait that enhances an organism's ability to survive and reproduce in a specific environment.

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    Speciation

    The process of forming new species from existing ones, often due to reproductive isolation.

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    Allopatric Speciation

    Formation of new species due to geographic isolation of populations.

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    Sympatric Speciation

    Formation of new species within the same geographic location, often due to ecological or behavioral differences.

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    Evolution

    Change in the genetic makeup of a population over time, leading to diversity and adaptation.

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    Study Notes

    Natural Selection and Adaptive Evolution

    • Natural selection consistently drives adaptive evolution.
    • Relative fitness measures an individual's contribution to the next generation's gene pool. It's influenced by factors like resource efficiency, survival traits (e.g., camouflage), and reproductive success (not always direct competition).
    • Natural selection primarily acts on phenotype, with genotype influencing selection indirectly.

    Modes of Natural Selection

    • Directional selection: Favors one extreme of a phenotypic range, shifting the population's traits in that direction. (e.g., finches with deeper beaks due to abundant large seeds)
    • Disruptive selection: Favors individuals at both extremes of a phenotypic range, disadvantageous to those with intermediate traits. (e.g., black-bellied seed cracker finches with small or large bills)
    • Stabilizing selection: Favors intermediate phenotypes, reducing variation and maintaining the status quo. (e.g., human birth weights typically between 3-4 kg)

    The Role of Natural Selection in Adaptive Evolution

    • Adaptations (e.g., octopus camouflage, snake jaws, cold-adapted enzymes) arise through natural selection, increasing the frequency of advantageous alleles.
    • Environments change, so ideal adaptations change as well; thus evolution is a dynamic process.
    • Different environments lead to genetic variation between populations.

    Balancing Selection

    • Genetic variation at loci affected by selection persists through mechanisms like:
      • Recessive unfavorable alleles persist in heterozygous individuals.
      • Balancing selection maintains multiple phenotypic forms (e.g., heterozygote advantage, frequency-dependent selection).

    Heterozygote Advantage

    • Heterozygotes have higher fitness than either homozygote.
    • This maintains multiple alleles at a locus.
    • Can be stabilizing or directional selection, dependent on genotype-phenotype relationships.
    • Example: Sickle-cell allele in humans—heterozygotes are resistant to malaria, maintaining the allele's frequency in malaria-prone regions, despite its harmful effects in homozygous recessives.

    Frequency-Dependent Selection

    • Phenotype fitness depends on its prevalence in the population.
    • Example: Scale-eating fish—left-mouthed and right-mouthed fish, survival depends on which phenotype is more common. This dynamic maintains both phenotypes.

    Sexual Selection

    • Individuals with preferable inherited traits are more likely to find mates. This leads to sexual dimorphism (differences between sexes).
    • Intrasexual selection: Competition within the same sex (often males) for mates. (e.g., physical combat)
    • Intersexual selection (mate choice): One sex (usually females) selecting mates based on specific traits. (e.g., brightly colored plumage). These traits may increase predation risk, but persist if reproductive benefits outweigh the risks.
    • Female preference for showy traits may signal "good genes," benefitting both sexes' reproductive success.

    Why Natural Selection Cannot Achieve Perfection

    • Natural selection acts on existing variations; new advantageous traits cannot arise on demand.
    • Evolution modifies existing structures rather than creating new ones.
    • Adaptations often involve trade-offs (e.g., seals' flippers).
    • Random events (e.g., storms) shape evolution in unpredictable ways.
    • Imperfections support the evolutionary process; organisms are "better than" or not perfect.

    The Biological Species Concept

    • Species are groups of populations whose members can interbreed in nature to produce viable, fertile offspring but cannot with other groups.
    • Gene flow maintains the gene pool of a species.
    • Lack of gene flow contributes to new species formation.

    Reproductive Isolation

    • Species formation relies on reproductive isolation.
    • Prezygotic barriers impede mating or fertilization.
    • Postzygotic barriers affect the hybrid.
    • These barriers limit gene flow.
    • The biological species concept has limitations (e.g., fossils, asexual organisms).

    Other Species Concepts

    • Morphological species concept: Classifies based on body shape and structure. Useful for sexual and asexual species, but relies on subjective criteria.
    • Ecological species concept: Defines species by their ecological niche. Useful for species with different niches but may interbreed. Accommodates both sexual and asexual species; highlights disruptive selection.

    The Darwinian Revolution

    • Scala Naturae and Species Classification: Aristotle believed species were fixed and unchanging; Linnaeus classified species honorarily.
    • Ideas about Change over time: Fossils document past organisms and show change; Paleontology (Cuvier) showed extinction. Hutton and Lyell proposed gradual geological processes; Darwin extended this to biological change.
    • Lamarck’s Hypothesis of Evolution: Use and disuse, and inheritance of acquired characteristics (incorrect).

    Darwin's Research and Voyage

    • Darwin's interest in nature led to the HMS Beagle voyage.
    • Darwin observed adaptations in diverse environments.
    • Extensive observations (e.g., fossils, finches) supported his hypothesis.

    Darwin's Ideas from "The Origin of Species"

    • Descent with modification: All organisms share common ancestry, adaptations through time.
    • Natural selection: Overproduction, selection of advantageous traits, and gradual modification.
    • Artificial selection: Provides an analogy to how natural selection works and the changes in domesticated species.

    Evidence for Evolution

    • Direct observations of evolutionary change: Drug-resistant bacteria, soapberry bugs, both driven by natural selection.
    • Homology (anatomical and molecular): Similar traits indicate common ancestry; Vestigial structures.
    • Convergence evolution: Distantly related organisms have similar traits due to similar environments.
    • Fossil record: Demonstrates change over time and transitional forms.
    • Biogeography: Distribution patterns are influenced by continental drift; island species share traits with nearest mainland.

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    Description

    Explore the principles of natural selection and adaptive evolution through various modes like directional, disruptive, and stabilizing selection. This quiz covers relative fitness and how phenotypes affect survival and reproduction. Test your understanding of these fundamental concepts in evolutionary biology.

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