Term | Definition |
habitat | combined biotic and abiotic factors found in the area where an organism lives |
ecological niche | all of the physical, chemical, and biological factors that a species needs to survive, stay healthy, and reproduce in an ecosystem |
competitive exclusion | theory that states that no two species can occupy the same niche at the same time |
ecological equivalent | organisms that share a similar niche but live in different geological regions |
competition | ecological relationship in which two organisms attempt to obtain the same resource |
predation | process by which one organism hunts and kills another organism for food |
symbiosis | ecological relationship between a member of at least two different species that live in direct contact with one another |
mutualism | ecological relationship between two species in which each species gets a benefit from the interaction |
commensalism | ecological relationship in which one species receives a benefit but the other species is not affected one way or another |
parasitism | ecological relationship in which one organism benefits by harming another organism |
population density | measure of individuals living in a defined area |
population dispersion | way in which individuals of a population are spread out over an area or volume |
survivorship curve | graph showing the surviving members of each age group of a population over time |
immigration | movement of individuals into a population |
emigration | movement of individuals out of a population |
exponential growth | dramatic increase in population over a short period of time |
logistical growth | population growth that is characterized by a period of slow growth, followed by a period of exponential growth, followed by another period of almost no growth |
carrying capacity | number of individuals that the resources of an environment can normally and persistently support |
population crash | dramatic decline in the size of a population over a short period of time |
limiting factor | environmental factor that limits the growth and size of a population |
density-dependent limiting factor | environmental resistance that affects a population that as become overly crowded |
density-independent limiting factor | environmental resistance that affects a population regardless of a population's density |
succession | sequence of biotic changes that regenerate a damaged community or start a community in a previously uninhabited area |
primary succession | establishment and development of an ecosystem in an area that was previously uninhabited |
pioneer species | organism that is the first to live in a previously uninhabited area |
secondary succession | reestablishment of a damaged ecosystem in an area where the soil was left intact |