Ecology Test

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Ecology Test
2010-04-11 21:25:05
bio ecology organisms plants animals energy

Studying for Ecology Test
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  1. producers
    autotrophs who use solar energy to power the production of food. Some autotrophic bacteria carry out chemosynthesis which means they produce carbohydrates by using energy from inorganic molecules. Plants are usually the main producers.
  2. gross primary productivity
    rate at which producers in an ecosystem capture energy.
  3. biomass
    organic material in an ecosystem : producers add biomass to an ecosystem by making organic molecules
  4. net primary productivity
    rate at which biomass accumulates. typically expressed in units of energy per unit area per year. net PP is gross primiary production minus the rate of respiration in producers
  5. detritivores
    consumers that feed on the garbage of an ecosystem
  6. decomposers
    cause decay by breaking down the complex molecules in dead tissues and wastes into simpler molecules
  7. an organism's trophic level
    indicates the organism's prosition in the sequence of energy transfers.
  8. food chain
    single pathway of feeding relationships among organisms in an ecosystem that results in energy transfer. A food web describes the feeding relationships in an ecosystem.
  9. biosphere
    The sum of all living things taken in conjunction with their environment. In essence, where life occurs, from the upper reaches of the atmosphere to the top few meters of soil, to the bottoms of the oceans. We divide the earth into atmosphere (air), lithosphere (earth), hydrosphere (water), and biosphere (life).
  10. ecosystem
    The relationships of a smaller groups of organisms with each other and their environment. Scientists often speak of the interrelatedness of living things. Since, according to Darwin's theory, organisms adapt to their environment, they must also adapt to other organisms in that environment. We can discuss the flow of energy through an ecosystem from photosynthetic autotrophs to herbivores to carnivores.
  11. community
    The relationships between groups of different species. For example, the desert communities consist of rabbits, coyotes, snakes, birds, mice and such plants as sahuaro cactus (Carnegia gigantea), Ocotillo, creosote bush, etc. Community structure can be disturbed by such things as fire, human activity, and over-population.
  12. Species:
    Groups of similar individuals who tend to mate and produce viable, fertile offspring. We often find species described not by their reproduction (a biological species) but rather by their form (anatomical or form species).
  13. Populations:
    Groups of similar individuals who tend to mate with each other in a limited geographic area. This can be as simple as a field of flowers, which is separated from another field by a hill or other area where none of these flowers occur.
  14. Individuals:
    One or more cells characterized by a unique arrangement of DNA "information". These can be unicellular or multicellular. The multicellular individual exhibits specialization of cell types and division of labor into tissues, organs, and organ systems.
  15. Organ System:
    (in multicellular organisms). A group of cells, tissues, and organs that perform a specific major function. For example: the cardiovascular system functions in circulation of blood.
  16. organ
    (in multicellular organisms). A group of cells or tissues performing an overall function. For example: the heart is an organ that pumps blood within the cardiovascular system.
  17. population curves
    Two modes of population growth. The Exponential curve (also known as a J-curve) occurs when there is no limit to population size. The Logistic curve (also known as an S-curve) shows the effect of a limiting factor (in this case the carrying capacity of the environment).
  18. Population Growth Potential Is Related to Life History
    The age within it's individual life cycle at which an organism reproduces affects the rate of population increase. Life history refers to the age of sexual maturity, age of death, and other events in that individual's lifetime that influence reproductive traits. Some organisms grow fast, reproduce quickly, and have abundant offspring each reproductive cycle. Other organisms grow slowly, reproduce at a late age, and have few offspring per cycle. Most organisms are intermediate to these two extremes.
  19. Mutualism
    is a symbiosis where both parties benefit, for example algae (zooxanthellae) inside reef-building coral.
  20. Parasitism
    is a symbiosis where one species benefits while harming the other. Parasites act more slowly than predators and often do not kill their host
  21. Commensalism
    is a symbiosis where one species benefits and the other is neither harmed nor gains a benefit: Spanish moss on trees, barnacles on crab shells. Amensalism is a symbiosis where members of one population inhibit the growth of another while being unaffected themselves.
  22. Removal of Predators
    Predator release is common where humans hunt, trap, or otherwise reduce predator populations, allowing the prey population to increase. Elimination of wolves and panthers have led to increase in their natural prey: deer. There are more deer estimated in the United States than there were when Europeans arrived. Large deer populations often cause over grazing that in turn leads to starvation of the deer.
  23. Pesticides and Competition
    Removal of a competing species can cause the ecological release of a population explosion in that species competitor. Pesticides sprayed on wheat fields often result in a secondary pest outbreak as more-tolerant-to-pesticide species expand once less tolerant competitors are removed.
  24. Introduction of New Species
    Introduction of exotic or alien non-native species into new areas is perhaps the greatest single factor to affect natural populations. More than 1500 exotic insect species and more than 25 families of alien fish have been introduced into North America; in excess of 3000 plant species have also been introduced. The majority of accidental introductions may fail, however, once an introduced species becomes established, its population growth is explosive. Kudzu, a plant introduced to the American south from Japan, has taken over large areas of the countryside.
  25. Habitat disruption
    is the disturbance of the physical environment of a species, for example cutting a forest or draining wetlands. Habitat disruption in currently the leading cause of extinction.
  26. Changes in the biological environment occur in three ways.
  27. Species introduction: An exotic species is introduced into an area where it may have no predfators to control its population size, or where it can gratly out compete native organisms. Examples include zebra mussels introduced into Lake Erie, and lake trout released into Yellowstone Lake where they are threatening the native cutthroat trout populations.
    • Overhunting: When a predator population increases or becomes more efficient at killing the prey, the prey population may decline or go extinct. Examples today include big game hunting, which has in many places reduced the predator (or in this case prey) population. In human prehistory we may have caused the extinction of the mammoths and mastodons due to increased human hunting skill.
    • Secondary extinction: Loss of food species can cause migration or extinction of any species that depends largely or solely on that species as a food source.
  28. re
    • Overkill is the shooting, trapping, or hunting of a species usually for sport or economic reasons. Unfortunately, this cannot eliminate "pest" species like cockroaches and mice due to their large population sizes and capacity to reproduce more rapidly than we can eliminate them. However, many large animals have been eliminated or had their populations drastically reduced (such as tigers, elephants, and leopards).
    • The death of one species or population can cause the decline or elimination of others, a process known as secondary extinction. Destruction of bamboo forests in China, the food for the giant panda, may cause the extinction of the panda. The extinction of the dodo bird has caused the Calviera tree to become unable to reproduce since the dodo ate the fruit and processed the seeds of that tree.
  29. benthic zone
    One of the two basic subdivisions of the marine biome; includes the sea floor and bottom-dwelling organisms
  30. pelagic zone
    One of the two basic subdivisions of the marine biome; consists of the water above the sea þoor and its organisms.