Term
| 3 important characteristics of a population |
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Definition
| geographic distribution, density, and growth rate |
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Term
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Definition
| number of individuals per unit area. number can vary depending on species and ecosystem |
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Term
| 3 factors that affect population size |
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Definition
| number of births, number of deaths, and the number of individuals that leave or enter the population |
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Term
| if birthrate equals deathrate |
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Definition
| population generally keeps it size and doesn't change |
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Term
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Definition
| movement of individuals into an area- cause population to grow |
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Term
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Definition
| movement of individuals out of an area- cause population to decrease in size |
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Term
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Definition
| occurs when the individuals in a population reproduce at a constant rate. population grows larger and larger over time. under ideal conditions with unlimited resources, a population will grow exponentially. |
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Definition
| when populations growth slows or stops following a period of exponential growth. as resources become less available, growth of pop. slows or stops and when death rate exceeds birth rate |
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Definition
| largest number of individuals of a population that a given environment can support |
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Definition
| a factor that causes population growth to decrease- competition, predation, parasitism and disease, extreme climates, human distrubances |
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Term
| density-dependent limiting factor |
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Definition
| a limiting factor that depends on population size. become limiting only when population density reaches a certain level. include competition, predation, parasitism, and disease. |
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Term
| predator-prey relationship |
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Definition
| a good way to regulate population. as predator preys on prey, the prey's population falls, decline in prey population leads to decline in predator population, decline in predator population leads to increase in prey population and cycle starts again |
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Term
| density-independent limiting factors |
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Definition
| affect all populations in similar ways, regardless of population size. unusual weather, natural disasters, seasonal cycles, and certain human activities- such as damming rivers and clear-cutting forests- are all examples of density-independent limiting factors. population usually crashes and gradually builds up again. |
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Term
| size of human population seems to ___________ over time |
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Definition
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Term
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Definition
| scientific study of the human population. birthrates, death rates, and the age structure of a population help predict why some countries have high growth rates while other countries grow more slowly. |
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Term
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Definition
| a dramatic change in birth and death rates. populations that are beginning to slow dramatically like U.S., Japan, and Europe, are said to have completed demographic transition. |
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Term
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Definition
| population growth depends on how many people of different ages make up a given population. demographers use age structure diagrams, or population profiles, to predict future growth |
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