This document discusses key concepts in ecology including limiting factors, ecological succession, biomes, and properties of communities. It defines limiting factor as any biotic or abiotic factor that limits a species' numbers. Ecological succession is described as the process by which one community replaces another over time due to changes in biotic and abiotic factors. Primary succession occurs on newly exposed surfaces like rock, while secondary succession follows a disturbance. Biomes are classified by plant communities and determined by factors like latitude, altitude, and climate. Properties of communities discussed include species richness, the species-area effect, species interactions, and community stability.

1. Communities,
Biomes, &
Ecosystems
CH3

2. LIMITING FACTOR: Any biotic or abiotic
Factor that limits the numbers of a
species. Food, water, shelter, predation

3. RANGE OF TOLERANCE: For any
environmental factor (biotic or abiotic), there is
always an upper & lower limit that any species
can live between.

4. ECOLOGICAL SUCCESSION
Ecosystems may change, so that one
community may replace another because of
changes in biotic and abiotic factors.
Primary Succession: A community is established
on exposed rock that does not have any soil.
Pioneer species break down rock, make soil.
Other species then move in, until a stable,
mature Climax Community is established.

5. Pioneer Species
breaking rock down
with roots and acids
to make soil.

7. Secondary Succession: A disturbance destroys
the community, which slowly reestablishes itself
on the remaining topsoil.

8. 3.2 BIOMES:
Zones classified by plant communities;
determined by Latitude, Altitude, and Climate.
Variations in temperature, sun exposure, and
water availability result in selective pressures that
determine which plants may grow in a particular
area.

12. PROPERTIES OF COMMUNITIES
Species richness: The number of species a
community contains. Varies with latitude.
Generally, equatorial regions have more species,
with numbers reducing as you approach the
poles.
Species-Area effect: Larger areas generally
contain more species than smaller ones. Greater
diversity of habitats can support more species.
Reducing size of habitat will reduce number of
species, and number of individuals within
surviving species.

14. PROPERTIES OF COMMUNITIES
Species interactions & richness: Predators
prevent competitive exclusion among their prey.
Superior competitors cannot become dominant if
subject to predation.
Community Stability: Species rich areas are
more resistant to change; in a disturbance, less
species are lost, and recovery time is faster.