1. Unit 2: Lesson 2 Food Chains, Food Webs, and energy pyramids

2. TEKS: 7.5C
Diagram the flow of energy through living systems, including food chains, food webs, and energy pyramids.

3. Food Chain A food chain is a linear sequence of organisms
Each organism feeds on the one before it
Nutrients are transferred
Energy is passed on
Arrows show which way the energy moves

4. food chains Each step in a food chain is called a trophic level
Plants are called producers
they create their own food through photosynthesis
phytoplankton, large plants, algae
Animals are consumers (primary, secondary, tertiary, quaternary)
They must eat plants or other animals to get the energy that they need
Bacteria and Fungi are decomposers
These organisms break down already dead materials
Usually organisms increase in size as you add them to the chain

5. Four types of consumers
Herbivores: animals that eat only plants
Carnivores: animals that eat only other animals.
Omnivores: animals that eat animals and plants.
Detritivores: Animals that eat dead materials and organic wastes

6. Other Ways to Classify Consumers
Primary Consumers: Herbivores.
Secondary Consumers: Carnivores that eat herbivores, or omnivores that eat both
Tertiary Consumers: Carnivores that eat other carnivores.
Quaternary Consumers: Carnivores that tend to be top predators

7. Food Web A food web is an interlocking pattern of food chains.
More complex
Energy flow takes various paths
More organisms interconnected
Allows for better survival

8. Energy Pyramid Shows Trophic levels Numbers of organisms
Amounts of energy
Producers ALWAYS on the bottom
Amounts and numbers decrease as you move UP
10% Rule:
Only 10% of available energy is passed from one trophic level to the next
The energy not passed is used up by that organism
Producers get energy from Sun by photosynthesis.

9. ANSWER USING COMPLETE SENTENCES!
Did you get it?
1. What is each level in a food chain called?
2. What name is given to plants in the food chain?
3. How does a food web allow more organisms to survive?
4. Why are producers always at the bottom of the energy pyramid?
5. Explain the 10% rule from the energy pyramid.
ANSWER USING COMPLETE SENTENCES!