Energy Transfer 22-1

Energy Organisms need energy for essential functions: growth, movement, maintenance, repair, and reproduction.

Energy The amount of energy an ecosystem receives and the amount that is transferred from one organism to another affects the structure and stability of an organism.

Pathway The sun is the ultimate source of energy in many ecosystems. sun  autotrophs  heterotrophs

Autotrophs Producers capture energy and use it to make organic molecules. ~Terrestrial – plants ~Aquatic – protists & bacteria

Autotrophs Photosynthetic organisms use energy from the sun to make organic compounds.

Autotrophs Chemosynthetic organisms use energy from inorganic molecules to produce carbohydrates.

Autotrophs Gross primary production is the rate at which producers capture energy.

Production The sugars produced fuel: cell respiration, maintenance and repair AND make new organic molecules through growth or reproduction.

Net Primary Productivity The rate at which biomass accumulates. energy/area/year kcal/m2/y mass/area/year g/m2/y

Net Primary Productivity NPP = GPP – rate of respiration *the rate of respiration represents the energy used by the organisms themselves

Biomass Organic material. Energy that is available to other organisms (in the form of food) ******10% rule******

Net Primary Productivity The tropical rainforest occupies only 5% of the surface area BUT produces 30% of the Earth’s NPP.

Productivity The NPP of the terrestrial biomes are affected by light, and precip. The NPP of aquatic biomes are limited by available light and nutrients T Nitrogen Phosphorus

All animals, fungi, most protists and many bacteria are consumers. Heterotrophs All animals, fungi, most protists and many bacteria are consumers.

They get energy by eating other organisms Heterotrophs They get energy by eating other organisms

Herbivores - consume autotrophs Heterotrophs Herbivores - consume autotrophs

Carnivores - eat other consumers Heterotrophs Carnivores - eat other consumers

Omnivores - eat other consumers as well as producers Heterotrophs Omnivores - eat other consumers as well as producers

Detritovores - consume dead matter Heterotrophs Detritovores - consume dead matter

Heterotrophs Decomposers - break down complex molecules into simpler ones; making chemicals available (nutrient recycling)

Organisms are grouped based on how they obtain energy Energy Flow Organisms are grouped based on how they obtain energy

Indicates the position in a sequence of energy transfers Trophic level Indicates the position in a sequence of energy transfers

Single path of feeding relationships Food Chain Single path of feeding relationships

Food Web Feeding relationships in an ecosystem represented by intertwining food chains.