Chapter 56The Biosphere

Ecology

The study of the interactions between organisms and their environment.

Organisms All living things. Studied at many levels.

Ecology - levels

1. Organismal Ecology

2. Population Ecology

3. Community Ecology

4. Ecosystem Ecology

5. Biosphere Ecology

Environment

Abiotic Factors: non-living factors.

Ex: Temperature, Light, Water Nutrients

Biotic Factors: effect of other organisms.

Ex: Competition, Predation

Abiotic Factors

1. Temperature2. Water3. Sunlight4. Wind5. Rocks and Soil6. Disturbance

Temperature

Effects biological processes. Ex:

Cold – cells will rupture if they expand while freezing.

Hot – many proteins denature above 45 oC.

Point – life can only exist over a fairly narrow temperature range.

Water

Review the properties of water from Chapter 3.

Cells must maintain a correct water potential (keep from exploding or drying out).

Sunlight

Provides energy for Ps, which drives most food webs.

Plants often compete for light because of shading or absorption of light by deep columns of water.

Wind

Effects temperature and water conditions for many organisms.

May carry abrasive particles that limit plant growth by killing the SAM areas.

Rocks and Soil

Physical structure, pH, mineral composition of rocks and soil limit where plants can grow.

Ex. Se soils. Plants limit what animals can

be found in an area.

Disturbance

Disturbance is often an important part of an environment.

Allows organisms to re-colonize an area.

Ex: Fire Humans Wind

Climate

Shapes environments and what organisms can live in a particular area.

Climatic Factors

Solar Radiation and Latitude Axis Tilt/Seasons Air/Water Circulation Patterns

Solar Radiation and Latitude

Changes the amount of light and energy delivered per surface area.

Result

Poles: less light Equator: more light The unequal heating causes

air and water to circulate.

Seasons

Caused by the Earth's tilt. Day length changes over time. Many organisms are restricted

in range by how well they adapt to changing seasons.

Global Air Patterns

Air rises when heated, sinks when cools.

Zones of rising/sinking are created.

Earth's rotation causes zones to "twist”.

Result

Air circulation patterns. Rainfall patterns.

rising air: wet areas descending air: dry areas

Biomes

Broad geographical regions with characteristic communities of organisms.

Biomes Controlled by:

Temperature Water Geography

Tropical Forests Areas covered with dense

growth of trees and vines. Climate:

Warm temperatures. Constant day length. High water.

Tropical Forests

Tropical Forests

Have the greatest diversity of species of any area on Earth.

Soil is usually very infertile. Most of the nutrients are in the plant life.

One of the most endangered Biomes.

Savanna

Grasslands with a few trees. Climate with three growing

seasons: Cool and dry Hot and dry Warm and wet

Savanna

Rich in herbivores and predator species.

Only major biome not found on North America.

Desert Characterized by plants adapted to

dry growing conditions. Climate:

Dry (<30cm/yr). May be cold or hot.

Often found in areas of descending air masses.

Low productivity, but still fairly diverse in species.

Chaparral

Characterized by spiny evergreen shrubs.

Climate: Mild rainy winters Hot summers

Ex: Southern California

Chaparral

Maintained by fires. Plants adapted to periodic

fires by seeds or re-growing from the roots.

Temperate Grasslands

Grasses and other herbs are the dominant vegetation.

Climate: Intermediate water Relatively cold winters

Grasslands

Very productive for agriculture. (wheat, corn)

Need disturbance (fires) to keep trees out.

Come in several types: Tall grass Short grass

Temperate Forests

Deciduous trees dominate. Climate:

Relatively high rain Cold winters

Very little natural area left. Good diversity of species.

Taiga

Coniferous trees dominate. Climate:

Long cold winters Short wet summers Long summer daylength

Taiga or Boreal Forest

Relatively low species diversity.

Being logged at an alarming rate.

Tundra

Grasses and sedges dominate.

Climate: Very cold and dry Low light in winter

Tundra Permafrost present. Plants low in height. Poor species diversity.

Altitude and Latitude

Mirror each other. Their Biomes are similar because the environments are similar.

Ex: Alpine = Tundra

Aquatic Biomes

Fresh water Biomes

Have <1% salt concentration. Strongly influenced by

temperature and light. Classification – based on

water flow patterns.

Marine Biomes

Cover 3/4 of the Earth's surface.

Average 3% salt. Controlled by light and the

distance to the shore.

Light Zones

Photic - Enough light for Ps. Red light lost rapidly as depth increases.

Aphotic - Lacks enough light for Ps 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

Where a freshwater river meets the ocean.

Salinity variable. Very productive

Biome.

Coral Reef

Characterized by coral.

Found in shallow warm waters.

Very productive. High species

diversity.

Benthos

Bottom area. Usually fed by nutrients

drifting down from upper levels.

Fairly rich in life.

Summary

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

Know the major types of aquatic biomes and the factors that control them.