Food Chains/Webs Investigative Science Basha High School

Review: Biotic vs. Abiotic

Biotic 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 Autotrophs Photoautotrophs - get energy from the sun- by photosynthesis Chemoautotrophs - get energy without light- by chemosynthesis

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 Ecosystem Energy 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 Interactions Predator-prey- one individual captures, kills, and consumes another Parasitism- one individual feeds on another; does not result in the immediate death of the host Mutualism- a symbiotic relationship where both species benefit from each other Commensalism- 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