Energy flow in the Ecosystem

Energy 1 st law of thermodynamics – energy can not be created or destroyed, only transformed from one form to another.

Life depends on… The SUN!!! (In Deep areas of the ocean special bacteria live, the sun never reaches this area!!)

What eats what? Producer – makes own food (photosynthesis) Consumers – eat other organisms 1) Herbivores – eat plant material only 2) Carnivores – eat other animals only 3) Omnivores – eat both plants & animals Decomposers – break down dead decaying things

How do we get energy from what we eat? Cell Respiration O 2 + C 6 H 12 O 6  CO 2 + H 2 O + energy We breathe oxygen, we eat sugars (glucose) & we make carbon dioxide, water & energy!

How do plants make their own food? PHOTOSYNTHESIS!! CO 2 + H 2 O + light  O 2 + C 6 H 12 O 6 Plants take in carbon dioxide, water and light and produce oxygen & glucose (sugars)

So how does the energy get around the ecosystem 1)Food chain – linear sequence of feeding relationships. Grass  grasshopper  mouse  hawk

Food chain

2) Food web – diagram showing ALL feeding relationships within an ecosystem

Food web

Energy Flows Through the food chain or food web in an ecosystem, but how much energy is available?

Trophic Levels Each step in the transfer of energy through the ecosystem = trophic level

Energy loss Energy is lost as heat at each level. RULE OF 10 – Each level only has about 10% of the available energy from the lower level.

Why are there fewer organism at the top of the trophic pyramid? Not enough energy available to support a large population of tertiary or quaternary consumers. Very few ecosystems have a 4 th or 5 th level!