| A | B |
|---|
| 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 equivalents | organisms that share a similar niche but live in different geographical 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 members 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 (parasite) benefits by harming another organism (host) |
| population density | measure of number 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 populations |
| exponential growth | dramatic increase in population over a short period of time |
| logistic 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 has become overly crowded |
| density-independent limiting factor | environmental resistance that affects a population regardless of population 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 |
