Food Chains

Food Webs

Energy Pyramids

Vocabulary Parts Review Auto self

Hetero different

Troph nutrition

Herb plant

Carn meat

Vore eat/devour

Why do organisms need energy?

To maintain homeostasis

To mate

Autotrophs AUTOTROPH – an organism that collects energy

from sunlight or inorganic substances to produce food

Autotroph are producer

PRODUCERS – organisms that produces their own food

How do autotrophs produce food?

Autotrophs

Photosynthesis is the process of producing sugars using energy from the sun

What is the reaction for photosynthesis?

Autotrophs are the foundation of all ecosystems

Draw a picture of an autotroph in the box.

Heterotroph HETEROTROPH – an organism that gets energy

by consuming (eating) other organisms

Heterotrophs are consumers

CONSUMERS – organisms that eat other organisms

Types of Consumers

HERBIVORE – a heterotroph that eats only plants

Herb plant

Voreeat

Examples: cow, rabbit, grasshopper

Types of Consumers

CARNIVORE – a heterotroph that eats other animals

Carn meat

voreeat

Examples: lynx, wolf, tiger

Types of Consumers

OMNIVORE – a heterotroph that eats both plants and animals

Omni all

voreeat

Examples: humans

Types of Consumers

DECOMPOSER – a heterotroph that breaks down the remains of dead organisms Returns nutrients to the ecosystem

Examples: bacteria and fungi

ALL organisms do cellular respiration to make ATP!!!!!

How does energy flow in an ecosystem?

Diagrams like food chains, food webs, and energy pyramids help us map the flow of energy through an ecosystem

How does energy flow in an ecosystem?

TROPHIC LEVEL – a step (level) in a food chain or food web

Energy is transferred from one trophic level to the next

FOOD CHAIN – a simple model that shows how energy flows through an ecosystem

Typical pattern

Producer Primary Consumer Secondary Consumer Tertiary Consumer

How does energy flow in an ecosystem?

FOOD WEB – a model representing many interconnected food chains and pathways in which energy flows through a group of organisms

Every organism eats or gets eaten by more than one organism

The direction of the arrow shows the direction energy flows.

Energy flows from the rabbit to the snake.

How does energy flow in an ecosystem?

Using your pencil, trace one possible pathway through the ecosystem.

Compare your pathway with two of your neighbors.

Did you have exactly the same pathway?

Which organism consumes the most organisms?

How many producers are found in this ecosystem?

How does energy flow in an ecosystem?

Energy decreases as you move up the food chain

Only 10% of the energy stored in one trophic level can be used or transferred to the next level

Energy is released as heat

Energy is not lost!

How does energy flow in an ecosystem?

Energy Pyramids

ENERGY PYRAMID – a triangular diagram that shows an ecosystem’s loss of energy, which results as energy passes through the ecosystem’s food chain

Which level has the most energy?

Which level has the least energy?

Biomass BIOMASS – the total mass of living matter at each

trophic level

Example: the total mass of all the herbivores in an ecosystem

Because energy decreases at higher trophic levels, biomass also decrease

Biomass is directly related to the amount of available energy

Serengeti Food Web Video Clip

1. How many different food chains exist in your web?

2. Write out the longest chain. Circle the tertiary consumer.

3. Write out the shortest chain. Circle the primary consumer.

4. Which organism is at “the top of the food chain”?

5. Which organisms are most abundant in the Serengeti?

6. Which organisms are both predators and prey?