Energy Flows

Aim: To be to explain energy flows in food chains trophic levels

Quick test:

1.What is a biome?

2.What is an ecosystem?

3.What is biomass?

4.What is the difference between abiotic and biotic?

5. Which factors lead to different biomes?

Energy = Insolation

INSOLATION = PHOTOSYNTHESIS= MORE BIOMASS

Question: What is missing that plants require to grow? (as well as starch?)

Energy Flows- Food chain

Stages in food chain. Once food/photosynthesis has been used to build the plant, that plant then becomes available to other organisms, which in turn will become available to other organisms. This flow of energy through plants and animals, then back into the soil, is called a FOOD CHAIN.

Trophic levels

This diagram shows a simple food chain/trophic levels. TASK: think of suitable organisms for each level. As you can see from the arrows there is a loss of energy at

each stage (respiration, excretion, heat into atmosphere). Also, you can see that as levels go up there are less organisms, this is due to organisms becoming more complex and thus more lower level organisms are required to support each level as they go up.

The fall in biomass As you climb the

trophic levels the amount of biomass decreases due to the reduction in organisms.

Energy found within any plant and animal material is known as biomass, and it can be measured in a variety of ways:

Calories. Dry weight. Ash weight (weight

after burning).

Trophic Level:

Producer / Consumer:

Name / Example: Action: Energy transfer:

Level 1 Producer.Autotrophs (self

feeders). For example, green plants.

Plants are capable of producing all their own food.

Only one energy transfer, from sun to plants.

Level 2 Consumer.Herbivores (primary

consumers). For example, caterpillars.

Eat the green plants (producers).

Two energy transfers have occurred.

Level 3 Consumer.Carnivore (secondary

consumer). For example, blackbird.

Meat eaters, feed upon the herbivores, fewer in number than primary consumers.

Three energy transfers have occurred, more chance for energy to be lost via respiration, excreta.

Level 4 Consumer.Omnivores

(Deversivores). For example, hawks, humans.

Have two sources of food, because eat both plants and animals.

Four energy transfers.

Food chains, Trophic levels & Energy

Plants represent the first trophic/energy level in the chain. They are called producer organisms (self feeding autotrophs) as they produce their own food via photosynthesis. All other trophic/energy levels are filled with consumers (heterotrophs- these are unable to ‘fix’ their own carbon so take it to grow from other organisms)

Primary and secondary consumers differ due to their diets- primary are vegetarians or herbivores and secondary consumers are meat eaters or carnivores. The final trophic/energy level sees the top predators known as omnivores as they eat both plants and other animals.

The transfer of energy is not 100% efficient, as energy is lost via respiration, dead organisms, decay, excreta, and heat given off. The result is that fewer organisms are supported at each level, but the individual size of each organism increases at each trophic level.

Reducer OrganismsMeet EarthWorm Jim- a gang of detritivores. His team of friends include lice and vultures. This gang are experts at eating dead and decaying organisms.

His arch enemies in returning any remaining nutrients to the soil are the decomposer crew Brenda the bacteria and fungi. This crew are experts at the breakdown of dead plants, animals and even excrement, aka poo poo!

First 21 secs

Study-

Page 112- read and make notes- marine food web

& 113-Activities 1 & 2 (not 3)