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Evolution and Natural Selection in General Biology

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Terms in this set (20)

  • What is biological evolution?

    Biological evolution is the heritable change in one or more characteristics of a population or species from one generation to the next.

  • Difference between microevolution and macroevolution

    Microevolution involves small-scale changes in a single gene in a population over time, while macroevolution involves larger-scale changes such as the formation of new species or groups of species.

  • List the five major theories of Darwinism according to Ernst Mayr

    1. Perpetual change
    2. Common descent
    3. Multiplication of species
    4. Gradualism
    5. Natural selection

  • What are the three key components required for natural selection?

    1. Variation in traits
    2. Heredity of traits
    3. Differential reproductive success

  • How did the 1978 drought affect Galapagos finch populations?

    The drought reduced small seeds, causing small-beaked birds to struggle and suffer heavy mortality, demonstrating natural selection favoring larger beak sizes.

  • Define adaptive radiation

    Adaptive radiation is the production of several ecologically diverse species from a common ancestral species, typically occurring within a short geological time interval.

  • Who independently conceived the mechanism of natural selection alongside Darwin?

    Alfred Russel Wallace, a naturalist working in the Amazon and Southeast Asia, independently conceived natural selection around 1848.

  • How did Thomas Malthus influence Darwin's theory?

    Malthus' essay on population growth showed populations increase exponentially while food supply grows linearly, implying competition and limited resources, inspiring Darwin's natural selection concept.

  • What must be present for natural selection to work?

    Variation in heritable traits, more offspring than can survive, limited resources causing competition, and differential survival and reproduction based on traits.

  • What is the result of natural selection over time?

    Natural selection leads to adaptations, traits that increase an organism's survival and reproductive success in its environment.

  • Name five lines of evidence supporting the theory of evolution

    Fossil record, biogeography, observations of natural and artificial selection, homologies (anatomical, developmental, molecular).

  • What is a fossil and how is its age estimated?

    A fossil is a trace of a past organism usually preserved in sedimentary rock; its age is estimated by the depth of the rock layer (strata) where it is found.

  • What is a transitional form in the fossil record?

    A transitional form is an intermediate fossil showing traits between an ancestral form and its descendant, illustrating gradual evolutionary change.

  • What does biogeography study in relation to evolution?

    Biogeography studies the spatial distribution of species, showing how isolated continents and islands have many endemic species due to evolutionary history.

  • What is artificial selection?

    Artificial selection is selective breeding by humans choosing parents to produce desired traits, made possible by existing genetic variation.

  • Define homology in evolutionary biology

    Homology is the fundamental similarity in traits due to descent from a common ancestor, seen in anatomical, developmental, and molecular features.

  • What is convergent evolution?

    Convergent evolution occurs when two species from different lineages develop similar traits because they occupy similar environments.

  • How does genetic variation arise?

    Genetic variation arises from random mutations, exon shuffling, sexual reproduction (reshuffling genes), and horizontal gene transfer.

  • What evidence supports molecular homology?

    All living species use DNA to store information, and closely related species have more similar DNA sequences than distantly related species.

  • Why do whales have hind limb bones despite lacking hind limbs?

    Whales retain hind limb bones as vestigial structures because their terrestrial ancestors had legs, showing evolutionary descent.