Food Chains/Webs

Investigative Science

Basha High School

Review: Biotic vs. Abiotic

Review: Biotic vs. AbioticBiotic

Plants Animals Fungi Protists Bacteria Organisms

once living

Abiotic sunlight (solar radiation) water

sources/precipitation wind nutrients in soil heat (geothermal) humidity temperature

Food Chain vs. Food Web Food Chain - A single pathway of feeding

in which organisms transfer energy by eating or being eaten.

Food Web – The interrelated food chains in an ecosystem. All the food chains put together in an ecosystem.

Food Web

Producers vs. Consumers Producers (Autotrophs) - make their own

food Consumers (Heterotrophs) - get energy

from consuming producers or other consumers

Producers vs. Autotrophs Producers- capture

energy from sunlight or chemicals and use the energy to produce food.

Autotrophs- make food from their environment Chemoautotrophs Photoautotrophs

They are the same!!!

Types of AutotrophsPhotoautotrophs - get

energy from the sun-by photosynthesis

Chemoautotrophs - get energy without light- by chemosynthesis

Consumers vs. Heterotrophs

Consumers vs. Heterotrophs Consumers are heterotrophs- get energy

from other organisms There are levels of consumers: primary,

secondary, tertiary, quaternary All consumers are heterotrophs!!

Types of Consumers Herbivores- eat only plants Carnivores- eat only animals Omnivores- eat both plants and animals Detritivores- eat waste and dead matter (plants and

animals). They break down the complex compounds of dead and decaying plants and animals to be recycled as nutrients for producers.

Levels in Food Chain/Web Producers – At the bottom of the food chain/web. These are

green plants, algae, or bacteria that communities depend on. They are autotrophs.

Primary Consumers– These are the herbivores. Examples: butterflies, rabbits, mice

*Secondary Consumers – Organisms that feed on primary consumers. Examples: foxes, owls, frogs

*Tertiary Consumers – Organisms that feed on secondary consumers. Examples: snakes, hawks

*Quaternary Consumers – Organisms that feed on tertiary consumers.

Decomposers – Organisms that feed on waste and dead remains of other organisms for energy. Also known as detritivores.

* Depends on food chain within food web!!!

Third Level Consumers

Second Level Consumers

First Level (Primary) Consumers

Energy Flow in an EcosystemEnergy moves in one direction from:

1. the sun or inorganic compounds

2. To autotrophs (producers)

3. To heterotrophs (consumers)

4. Decomposers (detritivores) get energy from waste and decomposing dead organisms

Trophic (Energy) levels Each step in a food chain/web is called a trophic

level. Producers make up the first trophic level Consumers make up the second, third, and higher

trophic levels

Each trophic level depends on the one below for energy

Types of Pyramids Energy Pyramid – shows energy amounts

at each level of the food chain. Biomass Pyramid – shows physical matter

amounts at each level of the food chain.

Energy Pyramid

Only part of the energy stored in one level can be passed to the next- most energy is consumed for life processes (respiration, movement, etc., and heat is given off)

10% Rule - Only 10% of the energy available within one trophic level is transferred to organisms in the next trophic level

Biomass Pyramid Biomass- the total

amount of living tissue within a given trophic level.

A biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem.

Your Challenge… Draw a food web on your dry erase board.

You don’t have to use pictures, you can use just words.

Label producer, primary consumer, secondary consumer, tertiary consumer, detritivore, carnivore, omnivore, herbivore, sun.

Identify the energy trend as you move up the food web.

Trophic Level Questions (Bio Talk)

1. What is the source of energy that enters the food chain?

2. What limits the size of a community?

3. Energy “lost” from a system usually takes what form?

4. What is a trophic level?

5. What percent of energy is passed from one trophic level to the next?

Types of Species InteractionsPredator-prey- one individual captures, kills, and

consumes anotherParasitism- one individual feeds on another; does not

result in the immediate death of the hostMutualism- a symbiotic relationship where both species

benefit from each otherCommensalism- a symbiotic relationship where one

species benefits and the other is not harmed but does not receive any benefit

Competition- some organisms that live in the same place compete for the same limited resource