Chapter 10 Ecosystems p. 317 - 329

Vocabulary Ecosystem Tropic relationships and networks Producer, Consumer, Decomposer Photosynthesis Food chain/web Organic and Inorganic Matter Primary Productivity Biomass Disturbances Ecological Succession

What is an Ecosystem? A community of living organisms interacting with one another and with non-living parts of the environment they live in. Individual population community ecosystem Examples: forest, lake, island, mountain

Trophic Relationships Feeding connections among living organisms in an ecosystem. Can be represented by a food chain, (p.319). 3 trophic levels: Producers Consumers Decomposers

Producers Primarily plants in terrestrial ecosystems. Primarily algae and phytoplankton in aquatic ecosystems. Producers are autotrophic, (self feeding,) organisms. This means they can convert inorganic matter, (non-living), to organic, (living), matter. For example, plants convert carbon dioxide to glucose with help of solar energy. Autotrophs are at bottom of food chain, they introduce energy to an ecosystem. Photosynthesis is key!

Consumers Heterotrophic, (need others for nourishment), organisms that feed on other living organisms. 4 types: Primary, (1st order), feed on producers, seeds, fruit, (herbivores). 2nd, 3rd, 4th order consumers, eat consumers of preceding order, (usually carnivores, can also be omnivores).

Decomposers Organisms that feed on waste and remains of other living organisms, (detritus). Called detritivores, feed on dead leaves, wood, animal remains, excrement, etc. Decomposers break down organic material and convert it into inorganic material. Examples are worms, fungi, bacteria, some insects.

Trophic Networks More than one food chain is possible in an ecosystem. This means there are many trophic relationships. A trophic network illustrates all of them.

What We’ve Learned so far: Everything in an ecosystem is connected, living and non-living. Food chains link organisms in an ecosystem. Producers are at the bottom of a food chain, then consumers and finally decomposers. Producers convert inorganic material into organic. Decomposers convert organic material into inorganic. A trophic network shows all the possible food chains in an ecosystem.

Material Flow and Chemical Recycling Matter and energy are constantly exchanged between organisms. Law of conservation of mass: matter cannot be created or destroyed, only transformed. Chemical recycling is when decomposers break down organic matter into inorganic matter. This puts necessary nutrients back into the soil that producers will later need for growth. This allows an endless cycle of exchange in an ecosystem.

Flow of inorganic matter Flow of organic matter Decomposers Detritus Consumers Producers Environment Flow of inorganic matter Flow of organic matter

ENERGY = Energy Flow Sunlight is the primary source of energy. The sun is transformed into chemical energy by plants then passed on to consumers who eat them. From one trophic level to another, energy is cycled, but some is lost, (waste, movement, growth, reproduction, heat). So UNLIKE matter, energy is not recycled, we need a constant supply from the sun (p.325). ENERGY =

Primary Productivity in Ecosystems The amount of new biomass generated by producers. Biomass is the total mass of organic matter, (plant and animal), in an ecosystem. Primary productivity is important because it tells us how much energy is available to primary consumers and therefore limits the # of organisms that can live in an ecosystem. Influenced by: Sunlight (needed for photosynthesis) Water (needed for photosynthesis) Nutrients (C, N, P, K) Temperature

Polar Desert: Few producers = low productivity Rainforest: Many producers = high productivity

Disturbances Events that damage an ecosystem. Can lead to elimination of organisms or can alter the availability of resources. 2 types: Natural (environmental), such as storms, flooding, forest fires, volcanic eruptions, drought, etc. Human (caused by people), such as litter, logging, oil spills, etc.

Ecological Succession The series of changes that occur in ecosystems after a disturbance. These changes will continue until a balance is restored. One small change can alter an entire ecosystem.