Ecosystem Study Guide
Name _______________________________ Class _____
1. Ecosystems include all of the living (biotic) and nonliving (abiotic) parts of an environment as well
as the interactions among them.
 Ecosystems may be aquatic (water) or terrestrial (land).
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Interactions may include:
producers (obtain energy by making their own food; plants -photosynthesis)
consumers (obtain energy by consuming their food)
decomposers ( get energy by breaking down dead organisms and the wastes of living things);
bacteria, fungi, worms, mold, termites, mushrooms, etc.
2. Abiotic Factors (nonliving) include: - water - shelter – sunlight - soil - rocks - nutrients oxygen/air, nitrogen - temperature/climate – space – salinity - pH
3. Biotic Factors(living) include: food – grass – trees – animals – insects – plants – bacteria – fungi
4. Terrestrial = land ecosystems: Forest- -Desert – Grassland - Mountain
5. Aquatic = water ecosystems:
Marine Ecosystems: the biggest ecosystems, which cover around 71% of Earth's surface and
contain 97% of out planet's water.
 Many kinds of organisms live in marine ecosystems: the brown algae, corals, dinoflagellates,
phytoplankton (plant), zoo plankton (animal) sharks and much more.
Freshwater Ecosystems: covers only 0.8% of Earth's surface and contains 0.009% of the total
water.
 pools, lakes or ponds, streams and rivers.
 Wetlands: Places in which the soil is saturated for a lengthy period of time.
 The ecosystems are habitats to reptiles, amphibians and around 41% of the world’s fish species.
The faster moving turbulent waters typically contain a greater concentrations of dissolved
oxygen, supporting greater biodiversity than slow moving waters in pools
6. The Ecosystem Hierarchy: (smallest to largest components)
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Organisms: individuals of a species
Populations: groups of organisms of the same species
Communities: the interaction of different populations; communities live within an ecosystem
Ecosystem: all of the abiotic and biotic parts of an ecosystem
Biosphere: The life supporting zone of the earth where atmosphere, hydrosphere and
lithosphere meet, interact and make life possible, is known as biosphere.
7. Disruptions to Physical (abiotic/nonliving)Components: *Volcanic eruptions * Pollution
*Hurricanes * Clear cutting * Fires * Floods * Drought * Nuclear Bomb * Habitat
depletion (human and natural- i.e. urban sprawl)
How could these events change nutrients, water, light, salinity, shelter, soil, temperature,
climate, etc. in an ecosystem?
8. Disruptions to Biological (biotic/living) Components: * Volcanic eruptions * Pollution (land &
water) * Hurricanes
* Urban Sprawl * Fires * Clear Cutting * Drought * Introduction
of exotic (non native) species * Overharvesting
* Habitat depletion (human and natural)
How could these events change the biological (living/biotic) components in an ecosystem?
9. Population Density:
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the number of people living per unit of an area (e.g. per square mile); the number of people
relative to the space occupied by them
how full an area is: the concentration of people or things within an area in relation to its
size
10. Limiting Factor: environmental factors that limit population sizes in a particular ecosystem
11. Limiting Factors in an Ecosystem:
 Density-dependent Factors: limiting factors that are associated with the population density and
may negatively affect the population in an area
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operate more strongly on large populations and disease
triggered by increases in population density (crowding)
 Density- independent Factors: limiting factors that occur regardless of how large the
population is and reduce the size of all populations in the area; mostly abiotic
12.
weather changes
human activities (pollution, u. sprawl, etc.)
natural disasters (i.e. fires)
A change in an abiotic or biotic factor may:
- decrease the size of a population if it cannot acclimate/adapt to or migrate from the change.
- increase the size of a population if that change enhances its ability to survive, flourish or
reproduce.
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