1. Unit 3 Ecosystems
Powerpoint #1
December

2. Define Ecosystem
Ecosystem = the network of relationships (interactions) among living (plants, animals) and the non-living parts (soil, climate, water etc.) in an environment.

3. Differentiate the terms producers, consumers decomposers. P. 93
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. Differentiate the terms producers, consumers, decomposers. P. 93
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. Differentiate the terms producers, consumers, decomposers. P. 94
Examples:
Worms
Bacteria
Fungi
Protozoa
Decomposers = Simple organisms that obtain their food from dead/decaying organisms and wastes.

8. Differentiate the terms food chain & food web. P. 94
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.
Food web is more complex and is composed of several food chains
Food web is a more realistic picture of an ecosystem.

9. Food Chain vs Food Web

10. Identify ALL examples of each trophic level.
Producers
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

11. 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

12. Sample Food Chain

13. Draw an example of a food web containing humans. P. 94
Mosquito
Hawk
Cow
Grass
Man
Decomposer
Phytoplankton
Fish

14. Draw an example of a food web containing humans. P. 94
Hawk
Mosquito
Cow
fish
Man
Phytoplankton
Grass
Decomposer

15. What happens to energy? 10-15% is stored: 85-90% is LOST or USED up:
Available or transferred to other animals when it is eaten.
85-90% is LOST or USED up:
maintaining the organism (Ex. metabolism, reproduction etc.)
And as heat!!!
IF NOT EATEN:
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.
Inorganic nutrients are cycled, energy is not.

18. Summary – Energy & Food Webs
Question #14, 15 & #16 p. 98 make perfect review questions for the test.