Chapter 50
An Introduction to
Ecology and the
Biosphere
Ecology
u
The study of the
interactions
between
organisms and
their
environment.
Organisms
All living things.
u Studied at many levels.
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Ecology - levels
1. Organismal Ecology
2. Population Ecology
3. Community Ecology
4. Ecosystem Ecology
5. Biosphere Ecology
Environment
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Abiotic Factors: non-living
factors.
Ex: Temperature, Light, Water
Nutrients
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Biotic Factors: effect of other
organisms.
Ex: Competition, Predation
Abiotic Factors
1. Temperature
2. Water
3. Sunlight
4. Wind
5. Rocks and Soil
6. Disturbance
Temperature
u
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Effects biological processes.
Ex:
Cold – cells will rupture if they
expand while freezing.
u Hot – many proteins denature
above 45 oC.
u
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Point – life can only exist over a
fairly narrow temperature range.
Water
Review the properties of
water from Chapter 3.
u Cells must maintain a correct
water potential (keep from
exploding or drying out).
u
Sunlight
Provides energy for Photosynthesis, which drives most
food webs.
u Plants often compete for light
because of shading or
absorption of light by deep
columns of water.
u
Wind
Effects temperature and
water conditions for many
organisms.
u May carry abrasive particles
that limit plant growth by
killing the SAM areas.
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Rocks and Soil
Physical structure, pH,
mineral composition of rocks
and soil limit where plants
can grow.
Ex. Se soils.
u Plants limit what animals can
be found in an area.
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Disturbance
u
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Disturbance is often an important
part of an environment.
Allows organisms to re-colonize
an area.
Ex: Fire
Humans
Wind
Climate
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Shapes environments and
what organisms can live in a
particular area.
Climatic Factors
Solar Radiation and Latitude
u Axis Tilt/Seasons
u Air/Water Circulation Patterns
u
Solar Radiation and
Latitude
u
Changes the amount of light
and energy delivered per
surface area.
Result
Poles: less light
u Equator: more light
u The unequal heating causes
air and water to circulate.
u
Seasons
Caused by the Earth's tilt.
u Day length changes over time.
u Many organisms are restricted
in range by how well they
adapt to changing seasons.
u
Global Air Patterns
Air rises when heated,
sinks when cools.
u Zones of rising/sinking are
created.
u Earth's rotation causes zones
to "twist”.
u
Result
Air circulation patterns.
u Rainfall patterns.
u
u rising
air: wet areas
u descending air: dry areas
Biomes
u
Broad geographical regions
with characteristic
communities of organisms.
Biomes Controlled by:
Temperature
u Water
u Geography
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Tropical Forests
Areas covered with dense
growth of trees and vines.
u Climate:
u
u Warm
temperatures.
u Constant day length.
u High water.
Tropical Forests
Tropical Forests
Have the greatest diversity of
species of any area on Earth.
u Soil is usually very infertile.
Most of the nutrients are in
the plant life.
u One of the most endangered
Biomes.
u
Savanna
Grasslands with a few trees.
u Climate with three growing
seasons:
u
u Cool
and dry
u Hot and dry
u Warm and wet
Savanna
Rich in herbivores and
predator species.
u Only major biome not found
on North America.
u
Desert
u
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Characterized by plants adapted to
dry growing conditions.
Climate:
Dry (<30cm/yr).
u May be cold or hot.
u
u
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Often found in areas of descending
air masses.
Low productivity, but still fairly
diverse in species.
Chaparral
Characterized by spiny
evergreen shrubs.
u Climate:
u
u Mild
rainy winters
u Hot summers
u
Ex: Southern California
Chaparral
Maintained by fires.
u Plants adapted to periodic
fires by seeds or re-growing
from the roots.
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Temperate Grasslands
Grasses and other herbs are
the dominant vegetation.
u Climate:
u
u Intermediate
water
u Relatively cold winters
Grasslands
Very productive for
agriculture. (wheat, corn)
u Need disturbance (fires) to
keep trees out.
u Come in several types:
u
u Tall
grass
u Short grass
Temperate Forests
Deciduous trees dominate.
u Climate:
u
u Relatively
high rain
u Cold winters
Very little natural area left.
u Good diversity of species.
u
Taiga
Coniferous trees dominate.
u Climate:
u
u Long
cold winters
u Short wet summers
u Long summer daylength
Taiga or Boreal Forest
Relatively low species
diversity.
u Being logged at an alarming
rate.
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Tundra
Grasses and sedges
dominate.
u Climate:
u
u Very
cold and dry
u Low light in winter
Tundra
Permafrost present.
u Plants low in height.
u Poor species diversity.
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Altitude and Latitude
Mirror each other.
Their Biomes are similar
because the environments
are similar.
u Ex: Alpine = Tundra
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Aquatic Biomes
Fresh water Biomes
Have <1% salt concentration.
u Strongly influenced by
temperature and light.
u Classification – based on
water flow patterns.
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Marine Biomes
Cover 3/4 of the Earth's
surface.
u Average 3% salt.
u Controlled by light and the
distance to the shore.
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Light Zones
u
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Photic - Enough light for Photosynthesis. Red light lost rapidly
as depth increases.
Aphotic - Lacks enough light for
Photosynthesis and depends on
food made in photic zone for
energy. Part of the most
extensive biome on the planet.
Marine Biomes
1. Estuaries
2. Intertidal
3. Coral Reefs
4. Pelagic
5. Benthos
Estuaries
u
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Where a
freshwater river
meets the
ocean.
Salinity variable.
Very productive
Biome.
Coral Reef
u
u
u
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Characterized by
coral.
Found in
shallow warm
waters.
Very productive.
High species
diversity.
Benthos
Bottom area.
u Usually fed by nutrients
drifting down from upper
levels.
u Fairly rich in life.
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Summary
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u
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Know what is involved with the
study of “Ecology”.
Know the major factors of planet
Earth that shape climate.
Know the major terrestrial
biomes and the factors that
control them.
Summary
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Know the major types of
aquatic biomes and the
factors that control them.
TEST
Are you Ready?