Ecosystems

Questions for Today:

• What are the major components of an Ecosystem?

• How do abiotic factors affect Ecosystems?

• How do biotic factors affect Ecosystems?

• Describe the Energy flow and nutrient cycling in Ecosystems.

Ecosystems have Living and Nonliving Components

• An Ecosystem is a community of different species interacting with one another and with their nonliving environment of matter and energy.

• Two components:– Abiotic – nonliving components– Biotic – Living components

Ecosystems have Living and Nonliving Components• Each population in an ecosystem has a

range of tolerance to variations in its physical and chemical environments.

How do Abiotic Factors affect Ecosystems?

• Abiotic Factors affect Ecosystem through limiting factors.– Limiting factors are any abiotic factor that

affects the number of organisms in a population.

• Limiting Factor Principle states:“Too much or too little of any abiotic factor can limit

or prevent growth of a population, even if all other factors are at or near the optimal range of

toletance.”

Limiting Factors

• On land, the major limiting factors are:– Precipitation– Soil Nutrients– Temperature

• In aquatic life zones, the major limiting factors are:– Temperature– Nutrient Availability– Sunlight– Dissolved Oxygen– Salinity– pH

Living Components of an Ecosystem

• All living organisms are assigned a trophic level or feeding level.

• The first trophic level are the producers.

• Producers are autotrophs that make their own food through the use of photosynthesis or chemosynthesis

• On land, producers are usually green land plants that capture 1% of the sun’s energy.

Living Components of Ecosystems

• In aquatic lifezones, the major producers are algae and phytoplankton.

• Photosynthesis uses light to make glucose

• Chemosynthesis may use inorganic compounds to create organic compounds.– Found near hydrothermal vents.

Living Components of Ecosystems

• Consumers eat producers and other consumers.• Consumers are heterotrophs• Several types of consumers:

– Primary Consumers (Herbivores)– Secondary Consumers (Carnivores)– Tertiary and Higher Consumers (Large Carnivores)– Omnivores– Decomposers– Detritus Feeders

Living Components of Ecosystems

• In order to obtain the energy from the sun, consumers breakdown the bonds in organic compounds using cellular respiration.

• Two types:– Aerobic and anaerobic.

• All organisms, plant and animal, carry out respiration. Only plants carry out photosynthesis.

Energy Flow and Nutrient Cycling

• Ecosystems are sustained through a combination of one-way energy flow, nutrient cycling.

• Decomposers and Detritus Feeders are essential in environments because they can cycle nutrients back into the soil and help producers to grow.