Ecology Packets 3+4 Vocab

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evolution
a theory that explains how random changes in genetic material and competition for scarce resources cause species to change gradually
mutations
a change, either spontaneous or by external factors, in the genetic material of a cell; mutations in the gametes (sex cells) can be inherited by future generations of organisms
natural selection
the mechanism or evolutionary change in which environmental pressures cause certain genetic combinations in a population to become more abundant; genetic combinations best adapted for present environmental conditions tend to become predominant
speciation
a lineage-splitting event that produces two or more separate species
symbiosis
unlike organisms living together, whether it involves positive, negative, or neutral interactions
mutualism
a positive interaction between individuals of different species in which both partners benefit
commensalism
a relationship between two living organisms where one benefits and the other is not significantly harmed or helped
competition
occurs between members of separate species (interspecific) or between members of the same species (intraspecific), but in both cases neither species nor individuals benefit
parasitism
occurs when an organism spends a significant portion of its life history attached to or inside a host organism -- depending on the organism, it may or may not kill the host
predator-prey
relationship in which one organism benefits while the second has a negative experience because all or part of it is eaten
biological community
the collection of all living organisms within a given area in a given time
biological succession
the change within a community following an environmental disturbance; the process by which organisms occupy a site and gradually change environmental conditions so that other species can replace the original inhabitants
primary succession
an ecological succession that begins in an area where no biotic community previously existed; succession in newly formed areas with little to no soil
secondary succession
succession on a site where an existing community has been disrupted; succession in areas that previously held life with fertile soil
climax community
a relatively stable, long-lasting community reached in a successional series; usually determined by climate and soil type
pioneer species
first organisms to colonize an area undergoing succession
ex primary. bacteria, lichens, mosses, (soil builders)
ex secondary. annual plant species that can grow, flower and set seed fast in sub-par conditions