ES CH 4 TEST ITEMS
1. Ecology is the study of how organisms interact with each other and with their environments.
2. Aspecies is a group of individuals that interbreed and produce fertile offspring.
3. Members of a species that live in the same area at the same time makeup a population.
4. All of the populations in a particular area make up acommunity.
5. Community ecologyis thestudy of interactions among species.
6. An ecosystem includes all of theliving things and their physical environments within a particular area.
7. The biosphereincludes all parts of Earth that host life, with all of its organisms and environments.
8. Parts of an ecosystem that are living or used to be livingare called biotic factors.
9. Parts of an ecosystem that have neverbeen living are abiotic factors.
10. The specific environment in which an organism lives is itshabitat.
11. Aresource is anything an organism needs
12. Population size describes the number of individual organisms presentin a given population at a given time.
13. Population density describes the number of individualswithin a population per unit area.
14. Population distribution (sometimes called population dispersion) describes how organisms are arranged within an area.
15. Random distribution: individual organisms are arranged in no particular pattern.
16. Uniform distribution: individual organisms are evenly spaced throughout an area.
17. Clumped distribution: individual organisms arrange themselves according to the availability of the resources they need to survive.
18. Age structure, or age distribution, describes the relativenumbers of organisms of each age within a population.
19. Age pyramids,or age structure diagrams, are visual tools scientists use to show the agestructure of populations.
20. A population’s sex ratio is its proportion of males tofemales.
21. To show how the likelihood of death varies with age, population ecologists use graphs called survivorship curves.
22. Immigration is the arrival of individuals from outside a given area.
23. Emigration is the departure of individuals from a given area.
24. Migration is a seasonal movement into and out of an area.
25. When a population increases by a fixed percentage each year, it is said to undergo exponential growth.
26. Limiting factors are characteristics of the environment that limit population growth.
27. Carrying capacity is the largest population size a given environment can sustainably support.
28. Logistic growth describes how a population’s initial exponential increase is slowed and finally stopped by limiting factors.
29. Density dependent factors are influenced by changes with population density.
Density independent factors are NOT.
30. Biotic potential: maximum ability to produce offspring in ideal conditions.