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

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

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

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

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

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

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

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.

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!