ecology test

• sunlight
• availability of water
• wind
• pH
• mineral content in soil

• Plant roots, lichens, and microorganisms help break down rocks into soil.
• Dead material and wastes add organic matter and nutrients to soil
• Roots and organic matter hold soil particles together, reducing erosion.
• Transpiration from forests increases humidity, forming clouds and promoting rainfall.

• total quantity of living matter
• declines at higher trophic levels

• rate at which new biomass forms
• declines with each trophic level, highest among primary producers

An array of organisms and their physical environment, all of which interact through a one-way flow of energy and a cycling of materials

• demonstrates relationship between energy and trophic levels in an ecosystem
• number of individuals at a given trophic level (pyramid of numbers)
• amount of biomass at a given trophic level (pyramid of biomass)
• amount of energy at a given trophic level (pyramid of energy)

can make a trophic level look like it contains more energy than it actually does

• most useful
• measures number of calories per trophic level
• uses 10% rule

conditions that regulate the number of organisms that can live in an area

• pattern of dispersal of individuals in an area
• (uniform, random, clumped)

numbers of members grow rapidly, often when limits are removed

growth slows, curving to a stable maximum

largest population of a species that the environment can support

• exponential growth leads to overshoot (numbers go beyond carrying capacity)
• population crashes

• the number of organisms present influences the effect of the factor
• -predation
• -competition

No two species can occupy the same niche at the same time.

• parasitism (1 benefits, 1 is harmed)
• commensalism (1 is benefited, 1 is not affected)
• mutualism (both benefit)

cell respiration and carbon fixation

• dry
• cold
• cannot support trees
• shallow, frozen soil

• fairly dry
• cold winters
• shallow, acidic soil
• conifers and mosses

• 80-140 cm rain per year
• hot summers, cold winters
• deciduous trees lose leaves in the fall

• moderate temperatures, can vary
• 25-75 cm/year
• rich soil
• too dry for trees
• -mostly grasses, fire important

• arid: little/no precipitation
• hot day, cold night
• vegetation adapted to conserve water

• 68-77 degrees F
• wet all year
• acidic, nutrient-poor soil
• -rapid decomposition
• plants have competition for light

• littoral zone: close to shore, photosynthesis occurs and producers are found
• limnetic zone: layer of open water where photosynthesis can occur
• profundal zone: no light, mostly decomposers

• shallow water over continental shelf
• past shelf is oceanic zone

open water not associated with the seafloor

region of seafloor that receives some light

area of benthic zone where light does not penetrate

where freshwater streams or rivers flow into the ocean

an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health

any species, including its seeds, eggs, spores, or other biological material capable of propagating that species, that is not native to a particular ecosystem

• Scientific name: Pueraria montana
• Native To: Asia
• Date of U.S. Introduction: Late 1800s
• Means of Introduction: Introduced as an ornamental vine and for erosion control
• grows rapidly, covering anything in its path

• Scientific name: Lythrum salicaria
• Native To: Eurasia
• Date of U.S. Introduction: Early 1800s
• Means of Introduction: As an
• ornamental
• takes over floodplains and freshwater marshes

• Scientific name: Dreissena polymorpha
• Native To: Eurasia
• Date of U.S. Introduction: 1988
• Means of Introduction: Ballast water

• Negative impact upon sport fishing
• –Can interfere with cooling systems of boats
• –Cause problems with buoys and lead to premature deterioration of docks
• Clog water intake pipes that serve homes and
• entire municipalities, causing millions of dollars in damage.
• Zebra mussels can produce lacerations of the
• feet of swimmers

• Scientific name: Flavivirus
• Native To: Africa, Western Asia and Middle East
• Date of U.S. Introduction: First cases described in 1999
• Means of Introduction: Unknown