Energy Flow Relationships

The energy must flow from organism to organism. * If an ecosystem is to be self-sustaining it must contain supply of energy which is available to all the organisms within the ecosystem. The energy must flow from organism to organism.

SUN (radiant energy) Energy Energy Energy

All organisms need energy for their life activities. Energy Flow All organisms need energy for their life activities. The pathways of energy through the living components of an ecosystem are represented by food chains and food webs.

Food Chain Green plants convert radiant energy from the Sun into chemical energy (food). Food chain: a series of organisms through which food energy is passed in an ecosystem.

SUN (radiant energy) Energy Energy Energy

Each consumer level utilizes approx Each consumer level utilizes approx. 10% of its energy to build new tissue - the food for the next feeding level.

The remaining energy is lost in the form of heat and unavailable chemical energy.

SUN 10% 10% 90% Energy 90% 10% 90% lost as heat, unavailable

Loss of energy Loss of energy between levels of food chain To where is the energy lost? The cost of living! 17% growth energy lost to daily living only this energy moves on to the next level in the food chain 33% cellular respiration 50% waste (feces)

* There’s more energy at the 1st consumer level than at the 2nd consumer level.

Pyramid of Energy There must be much more energy at the producer level in a food web than at the consumer levels.

A pyramid of energy can be used to illustrate the loss of usable energy at each feeding level.

Pyramid of Energy

The Energy Pyramid

Eventually, the energy in an ecosystem is lost and is radiated from the Earth’s system. * Thus, an ecosystem cannot sustain itself without the constant input of energy from the Sun.

4) Biomass Pyramid The decrease of energy at each feeding level means less biomass (amount of organic matter) at each level.

Pyramid of biomass

Thus, the total mass of carnivores in a particular ecosystem is less than the total mass of the producers.

Pyramid of biomass Hawk Snake Rabbit Grass

* The biomass relationship is a good example of the balance in nature, the homeostasis of an ecosystem.

2. Which level of consumers has the greatest energy? 3. Which organisms are the producers? 4. Which organisms have the greatest biomass? 5. Which organism is the secondary consumer? 6. Which organism is the tertiary consumer? 7. Which organism(s) are predators? 8. Which organism(s) are herbivores? 9. Which organism(s) are autotrophs? 10. What is the food chain represented by this pyramid?

1. 2. What are two food chains represented in this food web?   3. Which organism(s) are the secondary consumers? 4. Which organism(s) are the producers? What would happen to the toad population if there was a decrease in the snake population? 6. What would happen to the raccoon population if there was a decrease in the deer population? What would happen to the grasshopper population if there was a increase in the snake population?