Energy Flow Through an Ecosystem

Levels of Ecological Organization Energy flows through these levels

Levels of Organization Species: similar organisms that can produce fertile offspring. Populations: individuals that are of the same species and live together

Communities: Different populations that live together in an area Ecosystems: All the biotic and abiotic factors of an area. Give an example of a population, community and ecosystem at ETHS

Energy Flow Through an Ecosystem Thermodynamics: the study of energy transformations Law 1: Energy can be transferred and changed but it CANNOT be created nor destroyed. Energy only flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers) Sunlight is the main energy source for life on Earth Inorganic compounds (minerals) can also be energy sources (deep ocean)

Trophic Level: classification of an organism based on their source of energy Energy flows through the different levels of an ecosystem

1st Trophic Level-- Producers Can harness energy directly from their physical environment (sun) Transform this energy into chemical energy used as food, combine or break down molecules, make cells… Called autotrophs because they can make their own food Examples: plants, bacteria and some algae

2nd Trophic Level -- Consumers: Organisms that rely on other organisms for chemical energy Cannot harness energy directly from their physical environment Called heterotrophs because they cannot make their own food Examples: animals, fungi, many bacteria Q: Do all consumers eat the same thing?

Herbivores: Energy source comes from eating only producers Also called primary consumers Examples: cows, caterpillars, ducks, deer

3rd Trophic Level-- secondary consumers Organisms whose energy source comes from other consumers Divided into two groups Omnivores Carnivores

Omnivores: Eat both consumers and producers Examples: bears, crows, humans Carnivores: Only eat other consumers Considered “meat eaters” Examples: tigers, snakes, owls, dogs

4th Trophic Level -- Top Carnivores Carnivores that consume other carnivores Example: a hawk that eats a snake

Detritivores and Decomposers: Consumers whose energy source comes from waste and dead bodies from organisms of all trophic levels Cause decay or the break down of molecules Examples: scavengers, bacteria, fungi Q: Why are detritivores and decomposers useful?

Food Chain: Shows only one path of energy flow Food Web: Shows multiple paths of energy flow

Some is stored in the body used later for things like growth Q: What happens to the energy? Some is stored in the body used later for things like growth Some is lost in waste what the body can’t digest or already has enough of Most leaves as heat Only about 10% of available energy is actually transferred from one trophic level to the next as you go up in trophic levels, the amount of useable energy goes down

Primary Consumers (45,000 cal) Energy Pyramid Producers (450,000 cal) Primary Consumers (45,000 cal) Secondary Consumers (4,500 cal) Top Consumers (450 cal) Energy is lost One calorie = the amount of energy needed to raise the temp of 1g (1mL) water 1ºC

Energy pyramids are NOT drawn based on the # of organisms at that level Energy pyramids ARE drawn based on biomass and amount of available energy at that level Biomass = total amount of living tissue, usually referring to what can be used as fuel. The producers level usually has the most biomass