Download Final Exam Review, Quarter 4, Ecology, Part 2

Integrated Science - Ms. Klarke, room 2211 - May, 2012
Final Exam Review, Quarter 4, Ecology, Part 2
Ecology is the branch of the science of biology that deals with interactions among organisms and between
organisms and their environment.
More Biogeochemical Cycles
1. The water cycle includes the following processes (see page 75):
● evaporation-liquid water entering the atmosphere as a gas, water vapor
● condensation-water vapor returning to liquid droplets due to cool temperatures or pressure changes
● precipitation-water raining, snowing or hailing from the atmosphere to the surface
● transpiration-water vapor evaporation from leaves of plants
2. The carbon cycle includes the following processes (see page 77):
● photosynthesis-using carbon dioxide (from the atmosphere or dissolved in the ocean), water, and light
to produce carbohydrates and oxygen
● decomposition-decaying dead organisms by converting carbon-based tissues and carbohydrates into
methane and other chemicals
● respiration-breathing in oxygen and breathing out carbon dioxide and water vapor, the opposite of
photosynthesis
● deposition-remains of carbon-based organisms are buried and converted by heat and pressure into
fossil fuels and minerals such as calcium carbonate
3. Organisms need nutrients, such as nitrogen-containing amino acids and phosphorus, in order to carry out
essential life functions.
4. Biogeochemical cycling circulate nutrients throughout the biosphere, by naturally-occurring biological,
geological and chemical processes. Sometimes nutrients will naturally be limited, limiting the growth of
organisms dependent on the nutrient. Sometimes nutrients will naturally be concentrated to the point that
they are toxic to organisms, as oxygen is to many bacteria. Human activities can alter naturally occurring
biogeochemical cycles, as in the burning of fuels or the use of fertilizers.
Factors that Shape an Ecosystem
5. Biotic factors are due to living organisms.
6. Abiotic factors are due to nonliving materials and conditions, including:
● available light
● water, precipitation
● temperature
● soil nutrients and drainage
● available oxygen and carbon dioxide
7. An organism’s ecological niche is defined as the full range of biological (biotic) and physical (abiotic)
conditions in which the organism lives, and the way in which the organism uses those conditions.
8. A habitat is defined as the area in which an organism lives, including its biotic and abiotic factors. The
habitat does NOT include the way the organism uses or interacts with those conditions.
9. Competition is a community interaction between members or the same or different species, when the
organisms attempt to use an ecological resource in the same place at the same time.
10. Competition results in winners and losers, leading to the Competitive Exclusion Principle-no two species
can occupy the same niche in the same habitat at the same time.
11. Symbiosis is a community interaction in which members of two species live closely together. Three types
of symbiosis are teh following:
● mutualism-mutually beneficial, both species benefit, like bees pollinating flowering plants
● commensalism-one species benefits, the other is not harmed, like birds nesting in trees
● parasitism-one species benefits, the other is harmed, like fleas living on the blood of animal hosts
12. The series of predictable changes that occurs in a community over time is called ecological succession.
Ecosystems constantly change in response to natural and human-caused disturbances. Older organisms
may die out and new ones move in ins response to changes, causing even more change themselves.
Succession may occur in response to a sudden disturbance like a flood, or to more gradual, natural
fluctuations such as natural climate change.
13. Primary succession follows when an ecosystem is so disturbed that the soil is gone, exposing bare rock.
Examples are volcanic eruptions and glaciers scraping away the earth. The first species that colonize
such barren areas travel in from outside the area, and are called pioneer species. Examples are lichens,
that can live on rocks.
14. Secondary succession occurs when an ecosystem is seriously disturbed but the soil remains. Examples
are fires and plowed fields left to return to nature. Grasses and flowers can readily grow in the sunny,
exposed soil, and shrubs and trees may germinate from seeds that depend on fire to sprout.
Biomes and Aquatic Ecosystems
15. A biome is a particular physical environment that contains a characteristic assemblage of plants and
animals (ecological community). Abiotic factors characterizing biomes are their average temperature
and precipitation, whether these factors are year-round or seasonal, and soil type. Biotic factors are the
dominant plant and animal communities.
16. To compare two similar biomes, both tropical dry forests and temperate forests have dominant plant
communities including deciduous trees and fertile soils. In contrast, the tropical dry forest experiences
seasonal rainfall and year-round warm temperatures. The temperate forest has even rainfall year-round,
with cold winters and warm summers.
17. To compare two more similar biomes, both tundra and desert have little precipitation, limited plant
growth and poor soils in some respects. They differ in their temperatures; tundra is cold year-round with
permafrost under the soil, a permanently frozen layer. Desert may be cold in winter but hot in summer, or
warm all the time.
18. Aquatic ecosystems are determined primarily by the following characteristics of the water itself:
● depth of water
● flow of water
● temperature of water
● chemistry of water, including salt content, acidity, nutrients and oxygen availability
19. A standing-water ecosystem is a freshwater ecosystem like a pond or a lake. Water may circulate within
a lake or pond due to unequal heating, causing convection currents. These circulation currents distribute
oxygen, heat and nutrients.
20. A flowing-water ecosystem such as a river or stream is the other type of freshwater ecosystem.
21. A wetland is an ecosystem in which water either covers the soil or is present at or near the surface of the
soil for at least part of the year. In a wetland water may be flowing or standing. It may be salty, fresh or
a mixture of both.