option g: conservation ecology g2 ecosystems & biomes (pg 328-338)

Option G: Conservation EcologyG2 Ecosystems & Biomes (pg 328-338)

Gross productivity - the amount of energy trapped in organic matter during a specified interval at a given trophic level.

Interesting Link: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NetProductivity.html#Net_Productivity

Net productivity – gross productivity minus that lost by the respiration of the organisms at that level.

GP – R = NP

One problem with calculating NP is that some animals are omnivores and can affect more then one trophic level. Also there is seasonal variation, and unknown feeding habits.

Ex: Humans, rats

A food web is often used to show these multiple interactions.

Ex: A coyote is both a secondary and tertiary consumer.

10% of energy is passed from one trophic level to the next. This means there is 90% less energy to make the next level resulting in fewer members and less biomass.

Pyramid of Energy (units: kJ m-2yr-1)

Ecosystems have a lifecycle that usually ends with a natural “disaster” such as a forest fire. The result is a clear fertile area for plants to colonize with different abiotic and biotic factors then the preceding forest.

Primary succession involves pioneer species developing and stabilizing the ecosystem. Slowly they change the abiotic & biotic factors of the ecosystem. Secondary succession involves a change in the dominant species of the area over time.

During primary succession gross productivity rises as small plants are replaced by larger plants, productivity increases, biomass increases, diversity increases, soil is built, minerals accumulate, erosion is reduced

A biome is an ecological region dominated by a certain type of ecosystem characterized by certain precipitation and temperature conditions leading to a distinctive biological community adapted to these conditions. The biosphere includes all of the earth’s biomes.

Homework: outline the characteristics of the Earth’s six major biomes. Description should be limited to temperature, moisture and characteristics of vegitation.

Use the climograph on page 331 to help you explain how rainfall and temperature affect the distribution of biomes on Earth.