Chapter 5

Cycling chemical elements Flow of energy

Made up of two major parts Living (ecological community) Non living (physical & chemical environment)

For complete recycling of chemical elements, several species must interact Photosynthetic organisms produce sugar from carbon dioxide and water From sugar inorganic compound they make other organic compounds (protein, woody tissue) Need decomposers to get back to inorganic compounds

Use energy from the sun and Carbon dioxide from the air tonphotosynthesizes Green plants, algae and certain bacteria Called autotrophs

Organisms that feed on autotrophs Called herbivores

Feed directly on herbivores Called carnivores (meat eaters)

Carnivores that feed on third-level carnivores

Feed on waste and dead organisms of all trophic levels

Movement of energy through an ecosystem from the external environment through a series of organisms and back to the external environment

Law of conservation of energy In any physical or chemical change, energy is neither created nor destroyed Energy merely changed from one form to another

As energy flows through a food web, ItI is degraded and less and less is useable Entropy Energy must be continually added to an ecosystem in useable form

Total amount of organic matter on Earth or in any ecosystem or area Measured as the amount per unit surface area

Capture of useable energy from the environment to produce organic compounds

Increase in stored energy before any is used

Change in biomass over a given time

Biomass Energy stored Carbon stored

Autotrophs (&chrmoautotrophs) Photosynthesize or chemosynthesize Make their own organic matter room energy source and inorganic compounds

Heterotrophs Cannot make their own organic compounds and must feed on other living things

Use of energy from organic matter by most heterotrophic and autotrophic organisms Organic matter combines with oxygen Releases energy, carbon dioxide and water Use of biomass to release energy that can be. Used to do work

Ratio of production of one trophic level to the production of the next trophic level Never very high 1-3% in natural ecosystems 10% may be maximum 90% of all energy lost as heat

Establishment and development of an ecosystem where one did not exist previously

Reestablishment of an ecosystem following disturbance Remnants of previous biological community

Dunes Bog Abandoned farm field

Small size Grow well in bright light Withstand harshness of environment