Download Unit 11: Ecology 1/14 Vocabulary to Define

Unit 11: Ecology
Vocabulary to Define:
ecology
producers, autotrophs
consumers, heterotrophs
carnivore
herbivore
omnivore
detritvore
ecosystem
biotic
abiotic
predation
competition
parasitism
population
community
ecological succession
pioneer species
ozone layer
acid rain
carrying capacity
renewable resource
nonrenewable resource
What you should know…
 A food chain shows the simplest pathway of energy through ecosystem (basically what eats what)
 As energy moves through an ecosystem, is it lost at different “levels” called trophic levels
o Trophic levels are: (1) primary producers (2) primary consumers
(3)
secondary consumers
(4) tertiary consumers
o Most primary producers are green plants
o Examples of primary consumers include grasshoppers, rabbits and zooplankton.
○ Examples of consumers include humans, wolves, frogs, and minnows.
 Food web: shows many food chains describing the various paths that energy takes through an ecosystem
 Ecological pyramids: models that show how energy flows through ecosystems; base always represents
producers; energy is lost as you move to the top of the pyramid; 3 types
○ An energy pyramid represents the energy available for each trophic level in an ecosystem.
○ A number pyramid represents the number of individual organisms available for energy
○ A biomass pyramid represents the total mass of living organic matter (biomass) at each trophic level
 A stable ecosystem is one where: population numbers of each organism and the supply of resources
fluctuate at predictable rates; energy flows through the ecosystem at a fairly constant rate over time.
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A graph of predator–prey density over time shows how the cycle of
fluctuations results in a stable ecosystem.
○ As the prey population increases, the predator population increases.
○ As the predator population increases, the prey population decreases.
Competition can be among the members of the same or different species
and usually occurs with organisms that share the same niche (the role of
an organism in its environment - type of food it eats, how it obtains its
food and how it interacts with other organisms)
Symbiotic relationship exists between organisms of 2 different species that live together in direct contact.
○ 3 relationships: parasitism, mutualism, and commensalism
Parasitism that results in the rapid death of the host is devastating to both the parasite and the host. It is
important that the host survive and thrive long enough for the parasite to reproduce and spread.
Example of mutualism: bacteria, which can digest wood, live within the digestive tracts of termites
Example of commensalism: seeds that attach to organisms are carried to locations where they can grow
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Unit 11: Ecology
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Population density measures number of organisms living in a defined space; effected by a number of factors
○ Density-dependent: factors that operate more strongly on large populations than on small ones; include
competition, predation, parasitism, and disease.
○ Density-independent: factors that occur regardless of the size of the population; are mostly abiotic (such
as weather changes), human activities (such as pollution), and natural disasters (such as fires).
Primary succession occurs in an area that has not previously been inhabited: example, bare rock surfaces
from recent volcanic lava flows, rock faces that have been scraped clean by glaciers, or a city street.
Secondary succession begins in an area where there was a preexisting community and well-formed soil: for
example, abandoned farmland, vacant lots, clear-cut forest areas, or open areas produced by forest fires.
Geochemical cycles: movement of a particular form of matter through the living and nonliving parts of an
ecosystem; includes carbon cycle, water cycle, nitrogen cycle
Processes of the carbon cycle: Photosynthesis and respiration
○ Decomposition: When organisms die, decomposers break down carbon compounds
○ Conversion of biochemical compounds within an organism’s body
○ Combustion: When wood or fossil fuels (which were formed from once living organisms) are burned
○ Weathering of carbonate rocks: Bones/shells at bottom of oceans are incorporated into rocks
Processes of the nitrogen cycle: Decomposition
○ Nitrogen-fixation: bacteria - found in the soil, root of plants, or aquatic ecosystems, are capable of
converting nitrogen found in the air or in water into the forms that are available for use by plants
○ Intake of nitrogen into the organisms: Plants take in the nitrogen through their roots in the form of
ammonia or nitrate and in this way, nitrogen can enter the food chain
○ Denitrification: bacteria break down the nitrogen in the soil and release nitrogen into the atmosphere.
Processes of the water (hydrologic) cycle: Respiration and Elimination of waste products
○ Intake of water into the organisms: Organisms take in water and use it to perform life functions
Transpiration: the evaporative loss of water from plants into the atmosphere
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The greenhouse effect is the normal warming effect when gases trap heat in the atmosphere.
 Greenhouse gases (carbon dioxide, oxygen, methane, and water) trap heat and maintain Earth’s temp
Amount of Greenhouse
Average
Plant
Rate of
Amount Amount of
CO2 in the
effect
Global
cover on photosynthesis of CO2
CO2 in the
atmosphere
Temperature
Earth
absorbed atmosphere
by plants
higher
increases
increases
increases
increases
increases
decreases
lower
decreases
decreases
decreases
decreases
decreases
increases
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Population growth world-wide has grown exponentially.
The natural slowing of population growth is due to an increase in the death rate and a decrease in the birth
rate as a result of: Food and water shortages; Pollution of the environment; Spread of diseases
Human population growth has depleted the amount of fertile soil, clean water and available land in many
areas of the world; decreasing resources can affect geochemical cycles
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Technological advances in agriculture, industry, and energy can have a positive or negative impact on Earth.
As the population increases and technology expands, the demand for Earth resources also increases.
However, there is a limited supply of these resources available to sustain the human population.
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