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?