ECOSYSTEMS & BIOMES

• ECOSYSTEMS SUPPORT LIFE

• MATTER CYCLES THROUGH ECOSYSTEMS

• ENERGY FLOWS THROUGH ECOSYSTEMS

• BIOMES CONTAIN MANY ECOSYSTEMS

ECOSYSTEMS SUPPORT LIFE

• Living things depend on the environment

• Biotic factors interact with an ecosystem

• Many abiotic factors affect ecosystems

Living things Depend on the Environment

• Ecology: scientific study of how organisms interact with their environment & all other organisms in that environment.

• Ecosystem: particular environment & all the living things that are supported by that environment. (pond or desert)

• Biotic factor = living part of ecosystem.

• Living things depend on ecosystem for food, air, water & other survival needs.

• Plants are important biotic factor (important food source, can block sunlight & affect temp., roots hold soil in place, clean air, etc.)

• Animals are also imp. Biotic factor (beaver builds dams, large herds may eat grassland & cause erosion; coral gives food & cover in oceans.

Many Abiotic Factors affect Ecosystems

• Abiotic factors are the physical & chemical parts of an ecosystem.

• Physical (temp., water, sunlight) & chemical (minerals, compounds in soil/water) factors determine the types of organisms that an ecosystem can support.

• Some abiotic factors are: temperature, light, soil, and water.

Abiotic Factor: Temperature• TEMPERATURE: Affects types of plants that

will do well (thereby determining what animals). Tropics support lush plants supporting many types of organisms (monkey, birds, reptiles, etc.)

• Animals are sensitive to temperatures too. Musk oxen have thick fur & can survive in very cold temp. (-40o F), but water buffalo with light coat lives where it only gets about 48oF.

Abiotic Factor: Light

• The strength of sunlight in an area determines the types of plants found there (cacti in strong light, moss & ferns in weaker light/blocked light)

• Light is factor in ocean too: deep ocean with little light has very different organisms, compared to shallow water organisms.

• Light can be captured through photosynthesis in the first hundred meters below the ocean’s surface.

•Sunlight warms the Earth’s surface & atmosphere. Energy from the sun supports most life on Earth. Plants capture sun’s energy to make food via photosynthesis. This gives food for other organisms.

Abiotic Factor: Soil• Soil: mixture of small rock and mineral particles.• Organisms within soil break down remains of dead

plants & animals. This decay is important in giving raw materials to living parts of ecosystem.

• Characteristics of soil affect plant growth. If a lot of decaying, organic matter, can hold water well (unlike sandy soil or clay soil). Minerals in soil also affect plant growth.

Abiotic Factor: Water• All living things need water to carry out life

processes. Plants need it for photosynthesis, animals need it to digest food & release energy stored in food.

• If Ecosystem has lots of water, can support many different types of plants & thereby animals.

• Tropical rain forest is the wettest ecosystem & holds the most diverse organisms. Deserts have very limited plants & animals.