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Ecology Test Study Guide
Biology – Mr. Bennett
Name: ___________________________________
Concept Vocabulary
- Ecology - Study of how living things interact with each other and with their
environment.
- Biotic factors – all the living things that affect an ecosystem
- Abiotic factors – non-living things that affect an ecosystem
- Population – group of same species that breed and live in the same area
- Community – all the different living populations in the same area
- Ecosystem – all the living (biotic) and non-living (abiotic) factors in an area
- Biome – environment defined by it’s climate and the biological communities
- Biosphere – the Earth
- Producers – organisms that make their own energy (autotrophic)
- Consumers – organisms that consume other living things for energy
(heterotrophic)
- Herbivore – consumer that eats plants
- Carnivore – consumer that eats animals
- Omnivore – comsumer that eats both plants and animals
- Decomposer – consumer that breaks down living/dead organic matter
- Detritivore – consumer that eats decaying organic matter and feces
- Trophic Level – energy level or step in a food chain/web
- Succession – series of predictable changes in a community over time.
- Symbiosis – two organisms living together in a close relationship
- Mutualism – symbiosis in which both organisms benefit
- Commensalism – symbiosis in which one organism benefits and the other gets no
benefit and is not harmed either
- Parasitism – symbiosis in which one organism benefits (parasite) and one is
harmed (host). The parasite usually lives in or on the host
- Predation – when one organism kills and eats another
- Competition – occurs two individuals try to use the same resource at the same
time and place
- Interspecific competition – competition between 2 members of different species
- Intraspecific competition – competition between 2 members of the same species
- Niche – an organisms way of life and role in an ecosystem. Includes all the biotic
and abiotic factors that a specific organism needs to live.
- Immigration – occurs when individuals move IN to a population
- Emigration – occurs when individuals leave/move OUT of a population
- Exponential growth – “J-curve” – very fast, non linear growth
- Logistic growth – “S-curve” – very fast growth followed by stable population
- Carrying capacity - highest number of individuals that an ecosystem can support
- Limiting factor – anything causing a population to stop growing/decrease in size
- Density dependent – limiting factor that depends on population size and density
- Density independent – limiting factor that affects populations equally regardless
of size or density
MAJOR CONCEPTS
The ecological levels of organization from smallest to largest are:
Individual < Population < Community < Ecosystem < Biome < Biosphere
Energy Flow
Energy in an ecosystem flows in only one direction from the lowest trophic level to
the highest trophic level.
- Only 10% of the energy in one trophic level is transferred to the next
highest level
- Nutrients (such as carbon, water and nitrogen – not energy) flow through
an ecosystem in a circular cycle
Producers make up the lowest trophic level in a food chain or web. Consumers make
up the trophic levels above that. Each step in the food chain is a different trophic
level.
- Every consumer depends on lower trophic levels for energy.
- Producers get their energy from the sun
There are 3 types of ecological pyramids
1. Energy pyramid – shows the energy available at each trophic level
2. Biomass pyramid – shows the amount of living matter at each trophic
level
3. Pyramid of numbers – shows number of living things at each trophic level
Biomes - Study your Biomes Foldable!!!
Biomes are environmental and geographic regions defined by their climate and
biological communites. We studied 10 biomes in class:
Tropical rain forest, Desert, Chapparal, Temperate grassland, Tropical
savanna, temperate deciduous forest, northwestern coniferous forest, boreal
forest/taiga, tundra and estuaries (aquatic biome)
Succession
There are two types of ecological succession that we discussed.
(See the graphic organizer we did in class for details)
1. Primary succession – occurs in areas where there is no soil. Pioneer
species are the first to arrive and begin to break down rock into soil.
Examples: after a glacier melts or a volcano erupts
2. Secondary succession – occurs in an area where there has been a
disturbance or change in the ecosystem and the soil is still intact.
Secondary succession is more common and leads to a stable climax
community.
Examples: McCrephy’s Field, forest fires, natural disasters, clearing land
Community Interactions
Symbiotic relationships occur when two species live together in a close relationship.
There are three types (defined above). You should also know the following chart:
Organism A
Organism B
Mutualism
+
+
Commensalism
+
0
Parasitism
+
–
Draw a ‘+’ if the organism benefits.
Draw a ‘–’ if the organism is harmed
Draw a ‘0’ if the organism does not benefit AND is not harmed
Competition occurs when two organisms try to use the same resource at the same
time and place. There are two types:
1. Interspecific competition – competition between 2 members of different
species
2. Intraspecific competition – competition between 2 members of the same
species
Predation occurs when one organism kills and eats another.
Predators kill and eat other organisms
Prey get eaten.
Ecological Niche
A niche is an organism’s role/job and way of life in an ecosystem.
It includes everything the organism does or needs to live.
Examples: what it eats, predators, when/how it reproduces, what biome it
lives in, what habitat it lives in, what climate it lives in
There are two types of niches:
1. Fundamental niche is the full range of conditions an organism can live in
Includes anywhere an organism could live, anything it could eat or do, etc.
2. Realized niche is the conditions in which an organism is actually found in
nature. Realized niche is SMALLER than fundamental niche due to
COMPETITION
The competitive exclusion principle states that no two species can occupy the same
niche.
Population Ecology
Population Growth
Four (4) factors affect population growth:
Birth rate, Death rate, Immigration, and Emigration
There are two (2) types population growth:
1. Exponential growth = J-curve
Very fast growth, occurs when resources are very abundant
2. Logistic growth = S-curve
Fast growth followed by plateau.
This is what population growth tends to look like in nature
Carrying Capacity and Limiting Factors
Carrying Capacity describes the maximum number of individuals that an ecosystem
can support.
Carrying capacity is limited (made smaller) by limiting factors
Limiting factors are things that cause a population to stop growing or get smaller.
There are two(2) types of limitng factors:
1. Density-dependent – affected by population size and density
Greater effect on large/dense populations
Usually are biotic factors (e.g. competition, predation, disease)
2. Density-independent – not affected by population size/density
Affect all size/density populations equally
Usually are abiotic factors (e.g. natural disaster, weather)
Predator-Prey populations
Look at the graph for hare and lynx populations in your notes
1. Predators cause the population of prey to decrease.
2. When population of prey falls, predator population decreases after.
3. Decrease in predators causes the population of prey to increase.
4. When population of prey rises, predator population increases after.
This interaction between predator and prey, where the population sizes cycle
back and forth in reaction to each other is called dynamic equilibrium.