Ecosystem All the organisms and abiotic factors in a community.

Ecosystem Studies 1. Energy Flow – the movement of energy through trophic levels. 2. Chemical Cycling – the movement of matter from one part of the ecosystem to another.

Trophic Levels Division of an ecosystem based on the source of nutrition (energy).

Trophic Levels 1. Primary Producers 2. Primary Consumers 3. Secondary Consumers 4. Detritivores

Primary Producers Usually plants, capture energy and store it in chemical bonds. Are the source of the energy available to an ecosystem.

Primary Consumers Organisms that feed on the producers. Ex: Herbivores

Secondary Consumers Organisms that feed on the Primary Consumers. Ex: Carnivores

Comment There may be several layers of Secondary Consumers in an ecosystem.

Detritivores Get their energy from the organic waste produced by all levels. Ex: bacteria and fungi

Food Chain Linear pathway of who eats who in an ecosystem.

Food Webs Network showing all the feeding relationships in an ecosystem.

Primary Productivity The rate at which light energy is captured by autotrophs or primary producers. Gross PP – the maximum of energy capture Net PP – the amount left after Rs

Primary Productivity NPP = GPP – Rs GPP = NPP + Rs NPP = Net Primary Productivity GPP = Gross Primary Productivity Rs = Respiration

Available Energy Daily joules of solar radiation. 1% - captured by Ps. About 150 billion tons of organic matter is created each year.

Primary Producers % of GPP is lost to Rs by the primary producers. NPP = % Animals - use only NPP, which limits the food webs.

Limiting Factors Material or nutrient that is not present in sufficient quantity for the primary producers. Ex: N, P, K, Mg Light, CO 2

Energy Transfers Not 100% efficient. Why? Second law of thermodynamics. Waste. Materials that can’t be digested etc.

Energy Transfer Averages 10% with each Trophic Level change. Exam expectations – may give you data in energy units and ask you to calculate the %.

Question ? Why do most ecosystems have only trophic levels? There isn’t enough energy passed up through the food web to support more levels.

Implications There has to be fewer high level consumers in a food web. The higher level consumers usually need a large geographical area.

Question Which would support more humans per area? Eating meat? Eating plants?

Pyramids Graphical representation of relationships in ecosystems. Ex: 1. Productivity 2. Biomass 3. Numbers

Chemical Cycling Matter is recycled through ecosystems. Ex: Biogeochemical Cycles

Matter Reservoirs 1. Organic Materials 2. Inorganic Materials Available  Unavailable

Representative Cycles Water Carbon Nitrogen Know one or more of these cycles for an essay question.

Energy vs Matter Energy - flows through ecosystems and is mostly lost as heat. Matter - cycles in ecosystems.

Question ? What is Man's influence on Ecosystems ? Humans have had many negative impacts.

Hubbard Brook

Biological Magnification The concentration of toxins in successive levels of a food web. Ex: DDT Heavy metals (Hg, Cd Pb)

Causes Not broken down by digestion/decomposition. Lipophilic. Concentrates and effects the upper levels of the food web.

Greenhouse Effects The trapping of heat by the Earth's atmosphere. (CO 2, H 2 O).

Carbon Dioxide Levels Prior ppm ppm ppm Point: the levels of CO 2 are rising. The cause is probably due to humans.

Causes Industrialization. Burning of fossil fuels. Loss of forests.

Result Earth will heat up. Ice caps melt and sea levels will rise. Climate shifts. Increased Ps (?)

Acid Rain Caused by air pollution. Lowers the pH of rainfall. Is seriously damaging many ecosystems.

Acid Rain

Habitat Destruction Worst problem threatening most species today.

Comment Man has a major impact on the Biosphere. Man needs to learn how to work with the Biosphere.

Summary Know the tropic levels of ecosystems. Know an example of a food chain and a food web. Know how energy moves through an ecosystem.

Summary Know how matter moves through an ecosystem. Know one or more examples of matter cycling. Be able to discuss in detail a human impact problem on ecosystems.

Thank You For all the work you’ve done this year (semester). For being attentive students that wanted to learn. For doing your best on the National AP Bio exam.