*S Largent* Environmental Science Ch 3 Terms
Terms
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- Evolution
- inherited changes in populations of organisms over a period of time; which leads to differences among them.
- Natural Selection
- mechanism for evolution; environmental pressures cause certain genetic combinations in a population to become more abundant; organisms with certain traits are selected for (and will survive/reproduce); while other organisms with different traits are selected against (and will not survive/reproduce).
- Species
- all organisms genetically similar enough to breed and produce live; fertile offspring in nature.
- Community
- the populations of all species in a particular area/habitat
- Population
- subgroup of a species (all members of a population belong to one species); a group of organisms; of the same species; which are found in a specific area at a specific time.
- Habitat
- the physical and chemical features of an area where you normally observe certain organisms.
- Niche
- the total of all activities and relationships in which individuals of one species deal with as they go about their daily lives (i.e.; survival and reproduction).
- Predation
- interaction between two species; a predator (the organism in pursuit of a food source) and the prey (the food source); predators are any organism that hunts and kills its food (i.e.; the prey).
- Competition
- interaction between organisms of the same or different species; in which they “compete” or fight for a share of the limited resources.
- Camouflage
- “hiding out in the open”; an organism blends in with its surroundings making it harder to be seen.
- Warning Coloration
- prey exhibit this display of bright colors (red; orange; yellow; etc.) which warn the predator that the prey is toxic and could either kill or seriously harm the predator.
- Mimicry
- the display of warning colors by prey that are not toxic/harmful if eaten by predators.
- Symbiosis
- a close interaction generally between two species; this interaction may produce neutral; positive; or negative effects on each organism. The three types of symbiosis include: parasitism; commensalism; and mutualism. With parasitism; a parasite is attached to a host organism and feeds off of the body fluids of the host. With commensalism; one species benefits while the other is neither harmed nor helped. With mutualism; both species benefit from the relationship.
- Keystone Species
- a species or group of species whose impact on its community is much larger and more influential than would be expected from mere abundance.
- Exponential Population Growth
- growth at a constant rate of increase per unit of time. (NOTE: No populations can exhibit exponential growth indefinitely. They can exhibit this type of growth for a short period; followed by a crash/dieback; where the population sharply decreases.)
- Logistic Population Growth
- growth rates regulated by internal and external factors that establish an equilibrium with environmental resources. (Logistic begins just like exponential; but there is a slowing in the increase in population; and then upon reaching the carrying capacity it will oscillate around this level.)
- Carrying Capacity
- the maximum number of individuals of any species that can be supported by a particular ecosystem on a long-term basis.
- Productivity
- the rate of biomass produced (the conversion of solar energy into chemical energy stored in living/once-living organisms.
- Abundance
- the number of individuals of a species in an area.
- Diversity
- the number of different species in an area.
- Spatial Distribution
- the distribution/arrangement of members of a population in a given space; which can be a) random; b) ordered/uniform; or c) clustered/clumped.