Before You Read
The difference between a chain and a web is that a chain is from the animal that eats the most food and
makes the biggest impact on the environment is highest up on the “chain”, and web is when one thing is the centre,
and it is the main thing of importance that sustains everything around it.
Energy Flow
1. Biomass refers to the total mass of living plants, animals, fungi, and bacteria in a given area.
2. The flow of energy from an ecosystem to an organism and from one organism to another is called
energy flow.
3. Plants are called producers because they “produce” food in the form of carbohydrates during
photosynthesis.
4. An insect, such as a bee, that feeds on a plant is called a consumer.
5. Decomposition is the breaking down of organic wastes and dead organisms.
6. The action of living organisms, such as bacteria, to break down organic matter is called biodegration.
7. Decomposers change waste and dead organisms into usable nutrients.
8. Food chains are models that show the flow of energy from plant to animal and from animal to animal.
Each step is called a trophic level.
9. Plants and phytoplankton, such as algae, are at the first trophic level and are referred to as primary
producers.
10. Primary consumers obtain their energy from primary producers. Secondary consumers obtain their
energy by eating primary consumers.
11. In the fourth trophic level are tertiary consumers that feed on secondary consumers to obtain
energy.
12. Food webs are models of the feeding relationships within an ecosystem. Food pyramids show the loss
of energy from one trophic level to another.
Food Chains, Food Webs, Food Pyramids
Questions
1.
2.
3.
4.
5.
6.
7.
8.
9.
Bunchgrass and algae are the primary producers in the food chain.
Frogs and crabs belong to trophic level 3.
Tertiary consumers feed on secondary consumers, otherwise known as animals in the third tropic level.
A chipmunk that eats seeds or fruit is called a herbivore.
Omnivores eat both plants and animals.
Two examples of detrivores are earthworms and beetles.
A food pyramid is a model that shows the loss of energy from one trophic level to another.
Producers store the most energy in a food pyramid.
The top carnivores store the least amount of energy.
Modelling a local ecosystem
1.
Owl – fourth trophic level
Grizzly bear – fourth trophic level
Coyote – fourth trophic level
Wolf – fourth trophic level
Frog – third trophic level
Deer – second trophic level
Elk – second trophic level
Grasshopper – second trophic level
Grass – first trophic level
Algae - first trophic level
Raccoon – third trophic level
Cougar – fourth trophic level
2.
Owl
Frog
Grasshopper
Grass
3.
Deer
Cougar
Raccoon
Wolf
Elk
grass
Algae
Frog
Owl
wolf
bear,
coyote,
owl
Frog, raccoon
Deer, elk, grasshopper
Grass, algae
Energy Flow in Ecosystems
1.
2.
3.
c
f
h
coyote
Grizzly Bear
grasshopper
4.
5.
6.
7.
8.
a
e
g
b
d
9.
d, plants
10. d, water
11.
b, frog
12. c
13. d, 90%
14. d