Vocabulary From Chapter 5 Of Living In The Environment, Miller

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adaptation

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Any genetically controlled structural, physiological, or behavioral characteristic that helps an organism survive and reproduce under a given set of environmental conditions. It usually results from a beneficial mutation.--Miller

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adaptive radiation

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Period of time (usually millions of years) during which numerous new species evolve to fill vacant and new ecological niches in changed environments, usually after a mass extinction.--Miller

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allele

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Slightly different molecular form found in a particular gene.--Miller

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artificial selection

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Process by which humans select one or more desirable genetic traits in the population of a plant or animal and then use selective breeding to end up with populations of the species containing large numbers of individuals with the desired traits.--Miller

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background extinction

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Normal extinction of various species as a result of changes in local environmental conditions.--Miller

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biological evolution

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Change in the genetic makeup of a population of a species in successive generations. If continued long enough, it can lead to the formation of a new species. Note that populations-not individuals-evolve.--Miller

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coevolution

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Evolution in which two or more species interact and exert selective pressures on each other that can lead each species to undergo various adaptations.--Miller

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differential reproduction

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Phenomenon in which individuals with adaptive genetic traits produce more living offspring than do individuals without such traits.--Miller

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ecological niche

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Total way of life or role of a species in an ecosystem. It includes all physical, chemical, and biological conditions a species needs to live and reproduce in an ecosystem.--Miller

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extinction

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Complete disappearance of a species from the earth. This happens when a species cannot adapt and successfully reproduce under new environmental conditions or when it evolves into one or more new species.--Miller

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fossils

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Skeletons, bones, shells, body parts, leaves, seeds, or impressions of such items that provide recognizable evidence of organisms that lived long ago.--Miller

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fundamental niche

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The full potential range of the physical, chemical, and biological factors a species can use if there is no competition from other species.--Miller

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gene flow

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Movement of genes between populations, which can lead to changes in the genetic composition of local populations.--Miller

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gene pool

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The sum total of all genes found in the individuals of the population of a particular species.--Miller

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generalist species

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Species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions. Examples are flies, cockroaches, mice, rats, and human beings.--Miller

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genetic drift

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Change in the genetic composition of a population by chance. It is especially important for small populations.--Miller

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geographic isolation

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Separation of populations of a species for fairly long times into areas with different environmental conditions.--Miller

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macroevolution

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Long-term, large-scale evolutionary changes among groups of species.--Miller

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mass extinction

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A catastrophic, widespread, often global event in which major groups of species are wiped out over a short time compared to normal (background) extinctions.--Miller

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microevolution

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The small genetic changes a population undergoes.--Miller

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mutagen

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Chemical or form of ionizing radiation that causes inheritable changes (mutations) in the DNA molecules in the genes found in chromosomes.--Miller

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mutation

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A random change in DNA molecules making up genes that can yield changes in anatomy, physiology, or behavior in offspring.--Miller

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natural selection

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Process by which a particular beneficial gene (or set of genes) is reproduced in succeeding generations more than other genes. The result of natural selection is a population that contains a greater proportion of organisms better adapted to certain environmental conditions.--Miller

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realized niche

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Parts of the fundamental niche of a species that are actually used by that species.--Miller

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reproductive isolation

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Long-term geographic separation of members of a particular sexually reproducing species.--Miller

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specialist species

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Species with a narrow ecological niche. They may be able to (1) live in only one type of habitat, (2) tolerate only a narrow range of climatic and other environmental conditions, or (3) use only one or a few types of food.--Miller

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speciation

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Formation of two species from one species as a result of divergent natural selection in response to changes in environmental conditions; usually takes thousands of years.--Miller

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theory of evolution

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Widely accepted scientific idea that all life forms developed from earlier life forms. Although this theory conflicts with the creation stories of many religions, it is the way biologists explain how life has changed over the past 3.6-3.8 billion years and why it is so diverse today.--Miller

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chemical evolution

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creation of organic molecules, bipolymers, and systems of chemical reactions needed to form the first protocells -- KK

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hydrothermal vents

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hot, mineral rich vents which sit atop cracks in the ocean floor leading to chambers of molten rock -- KK

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protocells

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small globules that could take up materials from their environment, grow, divide -- KK

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evolution

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the changes in a populations genetic makeup through successive generations -- KK

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genetic variability

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slight variation of genetic makeup in a population -- KK

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adaptive trait

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heritable trait that enables organisms to better survive and reproduce under a given set of environmental conditions -- KK

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directional natural selection

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changing environmental conditions cause allele frequencies to shift so that individuals with traits at one end of the normal range become more common than their midrange forms -- KK

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stabilizing natural selection

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favors individuals with an average genetic makeup -- KK

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diversifying natural selection

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environmental conditions favor individuals at both extremes -- KK

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niche

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the role a species plays in the environment -- KK

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habitat

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physical location where the organisms that make up a species live -- KK

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divergence

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mutation and natural selection operate independently in two geographically isolated areas and the alleles change differently -- KK

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divergent evolution

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when one species becomes two -- KK

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gradualist model of evolution

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macroevolutionary change occurred gradually over many millions of years as a result of steady and small changes -- KK

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punctuated equilibrium hypothesis

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evolution consists of long periods of little changes in species punctuated by brief periods of rapid change -- KK

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fitness

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measure of reproductive success -- KK

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biodiversity

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The planets genetic raw material for future evolution in response to changing environmental conditions -- KK