Transcript Ecology week 2 - biologyclass.net

Ecology week 2
Community Interactions
 Ecosystems are influenced by a
combination of biological and physical
factors.
 Biological influences are called “biotic
factors”
 Physical, or nonliving, factors that shape
ecosystems are called “abiotic factors”
Community Interactions
 If an organism’s habitat is its address, its
“niche” is its occupation.
 Competition ~ competition occurs when
organisms of the same or different species
attempt to use an ecological resource in the
same place at the same time.
 Predation ~ an interaction in which one
organism captures and feeds on another
organisms
Community Interactions
 Symbiosis ~ Any relationship in which
two species live closely together.
 Mutualism – both species benefit
 Commensalism – one benefits, the other is
neither helped nor harmed
 Parasitism – one organism lives on or inside
another organism and harms it
Ecological Succession
 Ecosystems are constantly changing in
response to natural and human
disturbances. As an ecosystem changes,
older inhabitants gradually die out and
new organisms move in, causing further
changes in the community
Ecological Succession
 Primary succession ~ On land,
succession that occurs on surfaces
where no soil exists
 Pioneer species – the 1st to populate the area
 Secondary succession ~ When a
disturbance of some kind changes an
existing community without removing the
soil.
The Major Biomes
 Ecologist recognize at least 10 different
biomes.
 Tropical rain forest
 Tropical dry forest
 Tropical savanna
 Desert
 Temperate grassland
 Temperate woodland & shrubland
 Temperate forest
 Northwestern coniferous forest
 Boreal forest
 Tundra
BIOMES
 Each of these biomes is defined by a
unique set of abiotic factors – particularly
climate – and a characteristic
assembladge of plants and animals
 South Florida is considered by some
scientists to be tropical others, consider it
to be more temperate. It is commonly
referred to as “sub-tropical”
Aquatic Ecosystems
 Nearly 3/4th of the planet is covered by
water, so it is not surprising that many
organisms make their homes in aquatic
habitats
 Freshwater ecosystems
 Flowing-water
 Standing-water
 wetlands
Aquatic Ecosystems
 Estuaries ~ estuaries are wetlands
formed where rivers meet the sea.
Example: Florida Bay
Aquatic Ecosystems
 Marine ecosystems
 Depending on how much sun-light penetrates the
water, is how salt-water environments are classified
 Photic zone: The area from the surface to about 200
meters light is able to reach therefore, photosynthesis can
occur
 Aphotic zone: below 200 meters, light has difficulty
penetrating. Only chemosynthetic autotrophs are the only
producers able to survive.