Ecology Test Study Guide
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 organism’s way of life and role in an ecosystem. Includes all the biotic
and abiotic factors that a specific organism needs to live.
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 - 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.
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.