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APES CH 6&7
| Term | Definition |
|---|---|
| population | the individuals that belong to the same species and live in a given area at a particular time. |
| community | All of the populations of organisms within a given area. |
| population ecology | The study of factors that cause populations to increase or decrease. |
| population size | (N) The total number of individuals within a defined area at a given time. |
| population density | The number of individuals per unit area at a given time. |
| population distribution | A description of how individuals are distributed with respect to one another. |
| carrying capacity | K |
| density-dependent factor | A factor that influences an individual’s probability of survival and reproduction in a manner that depends on the size of the population. |
| density-independent factor | A factor that has the same effect on an individual’s probability of survival and the amount of reproduction at any population size. |
| population growth models | Mathematical equations that can be used to predict population size at any moment in time. |
| population growth rate | The number of offspring an individual can produce in a given time period, minus the deaths of the individual or its offspring during the same period. |
| intrinsic growth rate | (r) The maximum potential for growth of a population under ideal conditions with unlimited resources. |
| exponential growth model | (Nt = N0ert ) A growth model that estimates a population’s future size (Nt ) after a period of time (t), based on the intrinsic growth rate (r) and the number of reproducing individuals currently in the population (N0) |
| j-shaped curve | the curve of the exponential growth model when graphed |
| limiting resource | A resource that a population cannot live without and that occurs in quantities lower than the population would require to increase in size. |
| logistic growth model | A growth model that describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the environment. |
| s-shaped curve | The shape of the logistic growth model when graphed. |
| overshoot | When a population becomes larger than the environment’s carrying capacity. |
| die off | A rapid decline in a population due to death. |
| k-selected species | A species with a low intrinsic growth rate that causes the population to increase slowly until it reaches carrying capacity. |
| r-selected species | A species that has a high intrinsic growth rate, which often leads to population overshoots and die-offs. |
| type 1 survivorship curve | A pattern of survival over time in which there is high survival throughout most of the life span, but then individuals start to die in large numbers as they approach old age. |
| type 2 survivorship curve | A pattern of survival over time in which there is a relatively constant decline in survivorship throughout most of the life span. |
| type 3 survivorship curve | A pattern of survival over time in which there is low survivorship early in life with few individuals reaching adulthood. |
| corridor | Strips of natural habitat that connect populations. |
| metapopulation | A group of spatially distinct populations that are connected by occasional movements of individuals between them. |
| interbreeding depression | When individuals with similar genotypes—typically relatives—breed with each other and produce offspring that have an impaired ability to survive and reproduce. |
| symbiotic relationship | The relationship between two species that live in close association with each other. |
| competitive exclusion principle | The principle stating that two species competing for the same limiting resource cannot coexist. |
| resource partitioning | When two species divide a resource based on differences in their behavior |
| mutualism | an interaction between two species that increases the chances of survival or reproduction for both species. |
| commensalism | A relationship between species in which one species benefits and the other species is neither harmed nor helped. |
| keystone species | A species that plays a far more important in its community than its relative abundance might suggest. |
| ecosystem engineer | A keystone species that creates or maintains habitat for other species. |
| ecological succession | The predictable replacement of one group of species by another group of species over time |
| primary succession | Ecological succession occurring on surfaces that are initially devoid of soil. |
| secondary succession | The succession of plant life that occurs in areas that have been disturbed but have not lost their soil. |
| demography | The study of human populations and population trends. |
| demographer | A scientist in the field of demography. |
| crude birth rate | The number of births per 1,000 individuals per year. |
| doubling time | The number of years it takes a population to double. (Rule of 70) |
| replacement-level fertility | the total fertility rate required to offset the average number of deaths in a population in order to maintain the current population size. |
| net migration rate | The difference between immigration and emigration in a given year per 1,000 people in a country. |
| population momentum | Continued population growth after growth reduction measures have been implemented. |
| affluence | The state of having plentiful wealth including the possession of money, goods, or property. |
Created by:
calliethompson