1. Unit 3 Ecosystems

2. Ecosystem
Ecosystem - the network of relationships among plants, animals and the non-living parts in an environment.

3. Other examples:
Grasses
Trees shrubs
Water lilies
Flowers
Vegetables
Fruits
Producer - a plant which can synthesize carbohydrates using carbon dioxide and the sun’s energy.
Actually “produce” their own food and food for the rest of the ecosystem.

4. Consumers = All those organisms that have to eat (consume) plants or animals to obtain their food.

5. Types of consumers
Primary Consumers: Animals that eat producers. Also called 1st. order consumers. (Ex. Rabbit, squirrels, grouse, insects)
Secondary Consumers: Animals that eat primary consumers. Also called 2nd. order consumers. (fox, owl, mink )
Tertiary Consumers: Animals that eat secondary consumers. Also called 3rd. order consumers. (Wolf, coyote, hawk)

7. Examples:
Worms
Bacteria
Fungi
Protozoa
Decomposers = Simple organisms that obtain their food from dead/decaying organisms and wastes.

8. Consumers, producers & decomposers….
Similarities
All three are terms referring to the way organisms obtain food & energy
Differences
The way they obtain food
Producers make it,
Consumers eat it,
Decomposer feed on wastes & dead material.

9. Food chain - linear sequence representing the nutrition of various species from the simplest plant to the top carnivore.
Food web - a series of interconnecting food chains in an ecosystem.

10. Food Chain vs Food Web

11. Similarity
Both food chains and food webs show the flow of nutrients and energy in an ecosystem.
Difference
Food web is more complex
Food web is composed of several food chains
Food web is a more realistic picture of an ecosystem.

12. Identify examples of producers & consumers and decomposers.
Primary Consumers
Secondary Consumers
Tertiary Consumers
Decomposers
Shrubs, grass, trees
Grasshopper, rabbit, deer, squirrel
Mountain lion, snake, shrew, insect-eating bird, hawk
Hawk, snake, mountain lion
Bacteria, fungi

13. Give an example of a food chain from fig. 6.4. P. 95
Tree →
insect
insect eating bird
hawk
Producer
Primary consumer
2nd order consumer
3rd order consumer
Note: The arrows indicate the flow of energy & nutrients from one level to the next

14. Sample Food Chain

15. What happens to energy at each level?
10-15% is stored and:
Is available or transferred to other animals when it is eaten.
85-90% is LOST or USED up:
in maintaining the organism (Ex. metabolism, reproduction etc.)
And as heat!!!
IF NOT EATEN:
This energy is transferred to the decomposers.

16. What happens to the energy at the decomposer level?
Same thing….ALMOST !?
Most is lost or used up through heat and maintaining the organism.
If eaten (Ex. A mushroom) energy gets passed on.
HOWEVER, once a decomposer dies….
The energy is LOST FOREVER!!!

17. Summary – Energy & Food Webs
The ultimate source of energy (for most ecosystems) is the sun.
The ultimate fate of energy in ecosystems is for it to be lost as heat, metabolism, reproduction, etc..
Energy and nutrients are passed from organism to organism through the food chain as one organism eats another.
Decomposers remove the last energy from the remains of organisms.

18. Summary – Energy & Food Webs