Chapter 50 An Introduction to Ecology and the Biosphere

Ecology u The study of the interactions between organisms and their environment.

Organisms u All living things. u Studied at many levels.

Ecology - levels 1. Organismal Ecology 2. Population Ecology 3. Community Ecology 4. Ecosystem Ecology 5. Biosphere Ecology

Environment u Abiotic Factors: non-living factors. Ex: Temperature, Light, Water Nutrients u 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 Effects biological processes. u Ex: u Cold – cells will rupture if they expand while freezing. u Hot – many proteins denature above 45 o C. u Point – life can only exist over a fairly narrow temperature range.

Water u Review the properties of water from Chapter 3. u Cells must maintain a correct water potential (keep from exploding or drying out).

Sunlight u Provides energy for Photo- synthesis, which drives most food webs. u Plants often compete for light because of shading or absorption of light by deep columns of water.

Wind u Effects temperature and water conditions for many organisms. u May carry abrasive particles that limit plant growth by killing the SAM areas.

Rocks and Soil u 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.

Disturbance u Disturbance is often an important part of an environment. u Allows organisms to re-colonize an area. u Ex: Fire Humans Wind

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

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

Solar Radiation and Latitude u Changes the amount of light and energy delivered per surface area.

Result u Poles: less light u Equator: more light u The unequal heating causes air and water to circulate.

Seasons u 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.

Global Air Patterns u Air rises when heated, sinks when cools. u Zones of rising/sinking are created. u Earth's rotation causes zones to "twist”.

Result u Air circulation patterns. u Rainfall patterns. u rising air: wet areas u descending air: dry areas

Biomes u Broad geographical regions with characteristic communities of organisms.

Biomes Controlled by: u Temperature u Water u Geography

Tropical Forests u Areas covered with dense growth of trees and vines. u Climate: u Warm temperatures. u Constant day length. u High water.

Tropical Forests

u 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.

Savanna u Grasslands with a few trees. u Climate with three growing seasons: u Cool and dry u Hot and dry u Warm and wet

Savanna u Rich in herbivores and predator species. u Only major biome not found on North America.

Desert u Characterized by plants adapted to dry growing conditions. u Climate: u Dry (<30cm/yr). u May be cold or hot. u Often found in areas of descending air masses. u Low productivity, but still fairly diverse in species.

Chaparral u Characterized by spiny evergreen shrubs. u Climate: u Mild rainy winters u Hot summers u Ex: Southern California

Chaparral u Maintained by fires. u Plants adapted to periodic fires by seeds or re-growing from the roots.

Temperate Grasslands u Grasses and other herbs are the dominant vegetation. u Climate: u Intermediate water u Relatively cold winters

Grasslands u Very productive for agriculture. (wheat, corn) u Need disturbance (fires) to keep trees out. u Come in several types: u Tall grass u Short grass

Temperate Forests u Deciduous trees dominate. u Climate: u Relatively high rain u Cold winters u Very little natural area left. u Good diversity of species.

Taiga u Coniferous trees dominate. u Climate: u Long cold winters u Short wet summers u Long summer daylength

Taiga or Boreal Forest u Relatively low species diversity. u Being logged at an alarming rate.

Tundra u Grasses and sedges dominate. u Climate: u Very cold and dry u Low light in winter

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

Altitude and Latitude u Mirror each other. Their Biomes are similar because the environments are similar. u Ex: Alpine = Tundra

Aquatic Biomes

Fresh water Biomes u Have <1% salt concentration. u Strongly influenced by temperature and light. u Classification – based on water flow patterns.

Marine Biomes u Cover 3/4 of the Earth's surface. u Average 3% salt. u Controlled by light and the distance to the shore.

Light Zones u Photic - Enough light for Photo- synthesis. Red light lost rapidly as depth increases. u 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 Where a freshwater river meets the ocean. u Salinity variable. u Very productive Biome.

Coral Reef u Characterized by coral. u Found in shallow warm waters. u Very productive. u High species diversity.

Benthos u Bottom area. u Usually fed by nutrients drifting down from upper levels. u Fairly rich in life.

Summary u Know what is involved with the study of “Ecology”. u Know the major factors of planet Earth that shape climate. u Know the major terrestrial biomes and the factors that control them.

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

TEST Are you Ready?