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General Biology: Evolution and Natural Selection

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Termini in questo insieme (43)

  • Major points Darwin made in The Origin of Species

    Species change over time by descent with modification. Natural selection is the mechanism driving evolutionary change.

  • Carolus Linnaeus' contribution to Darwin's theory

    Developed the binomial nomenclature system and hierarchical classification, helping organize species relationships.

  • Taxonomic hierarchy levels in order

    Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

  • Jean Baptiste Lamarck's model for adaptation

    Proposed that organisms evolve by inheritance of acquired traits through use and disuse.

  • Lyell's contribution to geology and influence on Darwin

    Proposed uniformitarianism, suggesting Earth changes gradually over time, implying a much older Earth.

  • Darwin's observations from HMS Beagle voyage

    Observed species variation, fossils, and geographic distribution supporting evolution by natural selection.

  • Alfred Wallace's contribution to evolution

    Independently proposed natural selection as a mechanism for evolution, prompting Darwin to publish.

  • Evidence supporting Darwin's descent with modification

    Fossils, endemic species, homologies (structural, developmental, molecular), transitional forms, and vestigial traits.

  • Importance of fossil record in evolution

    Provides chronological evidence of past life forms and evolutionary transitions.

  • How fossils form

    Organisms buried in sediment, mineralization replaces organic material preserving shape.

  • Relative dating vs absolute dating

    Relative dating orders fossils by strata; absolute dating uses isotopes to determine exact age.

  • Use of isotopes in absolute dating

    Measures radioactive decay of isotopes to calculate fossil age based on known half-life.

  • Half-life and radiometric dating

    Half-life is the time for half of a radioactive isotope to decay; radiometric dating uses this to date fossils.

  • Darwin's process of evolution

    Variation exists; individuals with advantageous traits survive and reproduce more, changing population traits over time.

  • Conditions leading Darwin to natural selection

    Overproduction, variation, competition, differential survival, and inheritance of traits.

  • Importance of variation in Darwin's theory

    Variation provides raw material for natural selection to act upon.

  • Artificial selection vs natural selection

    Artificial selection is human-driven breeding; natural selection is environmental pressures shaping traits.

  • Why population is smallest unit that can evolve

    Evolution occurs as changes in allele frequencies within populations, not individuals.

  • Microevolution definition

    Change in allele frequencies within a population over time.

  • Five factors affecting Hardy-Weinberg equilibrium

    Mutation, gene flow, genetic drift, nonrandom mating, natural selection.

  • Genetic drift and its importance

    Random changes in allele frequencies, especially impactful in small, isolated populations.

  • Two special cases of genetic drift

    Bottleneck effect and founder effect.

  • Consequences of nonrandom mating

    Alters genotype frequencies, can increase homozygosity and reduce genetic diversity.

  • Inbreeding and inbreeding depression

    Breeding among relatives increases homozygosity, often reducing fitness due to harmful recessive alleles.

  • Four types of natural selection

    Directional, stabilizing, disruptive, and balancing selection.

  • Heterozygote advantage

    Heterozygotes have higher fitness than either homozygote, maintaining genetic variation.

  • Sexual selection and its two types

    Selection based on mate choice: intersexual (mate choice) and intrasexual (competition).

  • Gene flow and mutation effects

    Gene flow introduces alleles between populations; mutation creates new alleles, both affecting evolution.

  • Three species concepts

    Biological, morphological, and phylogenetic species concepts.

  • Prezygotic isolating mechanisms

    Temporal, habitat, behavioral, mechanical, and gametic isolation preventing mating or fertilization.

  • Postzygotic isolating mechanisms

    Reduced hybrid viability and reduced hybrid fertility.

  • Allopatric vs sympatric speciation

    Allopatric: geographic isolation; sympatric: speciation without geographic barriers.

  • Autopolyploidy vs allopolyploidy

    Autopolyploidy: chromosome duplication within species; allopolyploidy: hybridization between species.

  • Phylogeny and phylogenetic tree

    Phylogeny is evolutionary history; tree depicts relationships among species.

  • Monophyletic, paraphyletic, polyphyletic groups

    Monophyletic includes ancestor and all descendants (natural grouping); others exclude some descendants or combine unrelated taxa.

  • Adaptive radiation

    Rapid diversification of species into new ecological niches.

  • Mass extinction effects

    Large-scale species loss opens niches, influencing evolution of survivors.

  • Age of Earth and oldest fossils

    Earth ~4.6 billion years old; oldest fossils ~3.5 billion years, mainly prokaryotic stromatolites.

  • Effect of photosynthetic prokaryotes on atmosphere

    Produced oxygen, enabling aerobic life and ozone layer formation.

  • Evolution of modern eukaryotes

    Likely via endosymbiosis of prokaryotes forming mitochondria and chloroplasts.

  • Major animal phyla emergence

    Occurred during the Cambrian explosion ~540 million years ago.

  • Land colonization by multicellular organisms

    Plants and animals colonized land ~450 million years ago.

  • Likely cause of dinosaur extinction

    Asteroid impact evidenced by iridium layer and crater, causing mass extinction.