Transcript Document

13.4 Food Chains And Food Webs
KEY CONCEPT
Food chains and food webs model the flow of
energy in an ecosystem.
13.4 Food Chains And Food Webs
• A food chain is a model that shows a sequence of feeding
relationships.
– A food chain follows the connection between one
producer and a single chain of consumers within an
ecosystem.
GRAMA GRASS
DESERT COTTONTAIL
HARRIS’S HAWK
13.4 Food Chains And Food Webs
• A food web emphasizes complicated feeding relationships
and energy flow in an ecosystem.
ENERGY
13.4 Food Chains And Food Webs
• Consumers are not all alike.
– Herbivores eat only plants. Ex: grasshopper
– Carnivores eat only animals. Ex: Lion
– Omnivores eat both plants and animals. Ex: Bears
– Detritivores eat dead organic matter. Ex: Worms, slugs
– Decomposers are detritivores that break down organic
or dead matter into simpler compounds. Ex: bacteria,
Fungi
carnivore
decomposer
13.4 Food Chains And Food Webs
• Specialists are consumers that primarily eat one specific
organism (they only eat one thing) Ex: Bamboo is 99% of a
panda’s diet
• Generalists are consumers that have a varying diet (they
eat a lot of different things) Ex: Gray wolf eats elk, moose,
deer, and mice
13.4 Food Chains And Food Webs
• Trophic levels are the nourishment levels in a food
chain.
13.4 Food Chains And Food Webs
• Carnivores that eat carnivores
Ex: Hawk eating rabbit
ENERGY
• Carnivores that eat herbivores
Ex: Rabbit eating grasshopper
• Herbivores that eat producers
Ex: grasshopper eating grass
13.4 Food Chains And Food Webs
Omnivores, such as humans that eat both
plants and animals, may be listed at different
trophic levels in different food chains.
• If you are eating a salad you are….?
• a primary consumer (omnivore eating a
producer)
• If you are eating a hamburger you are….?
• a secondary consumer (omnivore eating a
herbivore)
• If you are eating shark soup, you are….?
• a tertiary consumer (omnivore eating a
carnivore)