Download Chapter 3.1 – Communities Limiting Factors = Factors that affect an

Chapter 3.1 – Communities
 Limiting Factors = Factors that affect an organism’s ability to survive in its environment,
such as the availability of water and food, predators, and temperature
 Tolerance = The ability of an organism to withstand fluctuations in biotic and abiotic
environmental factors
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Succession = orderly, natural changes and species replacements that take place in the
communities of an ecosystem.
o Succession occurs in stages. At each stage, different species of plants and animals
may be present.
o 2 types of succession—primary and secondary.
Primary Succession = The colonization of barren land by communities of organisms.
o Takes place on land where there are no living organisms.
o The first species to take hold in an area like this are called pioneer species.
o After some time, primary succession slows down and the community becomes fairly
stable, or reaches equilibrium.
A stable, mature community that undergoes little or no change in species is a climax
community.
Secondary succession = the sequence of changes that takes place after an existing
community is severely disrupted in some way.
o Secondary succession, however, occurs in areas that previously contained life, and on
land that still contains soil.
o Because soil already exists, secondary succession may take less time than primary
succession to reach a climax community.
3.2 BIOMES
1. What is a biome? Large group of ___ecosystems____ that share the same ___climax___
_____community______.
2. Aquatic Biomes. ~75% of the Earth’s surface = _water__.
Types: ___Freshwater____, ____Saltwater_____, _____wetlands_____
3. Marine Biomes. Ecologists study different zones…
Shallow, sunlit zone = __photic __ zone
Deeper, unlighted zone = _aphotic___ zone
4. Estuaries = Where __river__ meets __ocean__...freshwater mixes with saltwater.
5. Intertidal zone. The gravitational pull of the _sun_ & _moon_ causes the rise & fall of ocean
tides. It’s the portion of the shoreline bw the high & low lines.
6. Plankton = __small__ organisms that drift & float in the _photic_ zone.
Includes autotrophs, eggs, juvenile stages of marine animals.
They form the __base_ of aquatic food chains!
7. Terrestrial Biomes: _Tundra__, __Taiga___, ___Desert__, ___Grasslands__, __Temperate
Deciduous Forest______, ___Rain Forest_______
8. Tundra.
Rarely rises above ___freezing____.
Top layer of soil thaws during summer. Supports _shallow__-_rooted_ plants. Soil _lacks__ _in_
__nutrients_____.
__Permafrost______ = frozen layer of soil. Treeless.
9. Taiga.
Aka Boreal or Northern Coniferous Forest.
__Coniferous____ trees (cones, like spruce, fir)
Soil is waterlogged, __lacks__ ____nutrients____.
Slightly warmer & wetter than tundra.
Supports lynx, hare, caribou, elk, moose.
10. Desert.
_Arid_, sparse plant life.
_<25__ cm of precipitation annually (major limiting factor!)
Adaptations to conserve water…waxy.
11. Grassland.
_25-75__ cm of precipitation annually.
__Rich__ __soil__, grasses.
Dry season. Breadbasket of the world…grains!
__Grazing___ & __Prairie__ animals (bison, deer, elk, jack rabbits, prairie dogs)
Similar = African Savanna
12. Temperate Deciduous Forest.
__70-150__ cm of precipitation annually.
__Broad_ - __leaved__ hardwood trees (maple, oak).
Soil = _rich__ top layer, clay deeper layer
Squirrels, mice, rabbits, deer, bear, birds.
13. Rain Forest.
Greatest __biodiversity____!
Tropical rain forests = warm, wet, lush plant growth. _200-600__ cm of precipitation annually.