Chapter 18 - Building Biological Communities

Chapter 18 - Building Biological Communities

A. Ecosystem: ecological system encompassing a community and all the physical aspects of its habitat

B. Biodiversity: the variety of living organisms present in a community

C. Species Live & Evolve in response to One Another

1.  Co-evolution: Back and forth adjustments between interacting members of an ecosystem. (pollinators and the plants they pollinate)

2.  Predation : one organism feeding on another

a.  Parasitism: predation in which one (typically smaller) organism lives on or in another (larger) organism. (fleas, hookworms)

b.  Secondary compounds: defensive chemicals used by plants

3.  Symbiosis : two or more species living together in a close, long-term association

a.  Mutualism : symbiotic relationship in which both species benefit

b.  Commensalism : symbiotic relationship in which one species benefits and the other is neither harmed or helped

4.  Competition : when shared resources are limited species will engage in a fierce rivalry for that resource

a.  Competitive exclusion elimination of a competitive species

5.  Niche : the roll of a species in its environment, (its “job”)

a.  Fundamental Niche : the entire range of conditions in which an organism can live within an ecosystem

b.  Realized Niche : the actual part of the fundamental niche in which an organism lives

6.  Habitat : the place where an organism lives

7.  Climate : the prevailing weather patterns in a given area, important factors are temperature and moisture

D. Land Ecosystems

1.  Biome : major biological community that occurs over a large area of land (7 biomes exist)

a.  Tropical Rain Forrest

b.  Deserts

c.  Savannas

d.  Temperate Deciduous Zones

e.  Temperate Grasslands

f.  Taiga

g.  Tundra

E. Water Ecosystems

1.  Freshwater Communities

a.  Littoral Zone : shallow zone near the shore

b.  Limnetic Zone : area father away from shore but close to the surface

c.  Profundal Zone : deep-water zone below the level of effective light penetration

2.  Marine Communities

a.  Shallow ocean waters

b.  Surface of the open sea

i. Home of Plankton microscopic organisms that float freely on the surface of the ocean

c.  Depths of the ocean