Part 1: Food Chains, Food Webs, and the Transfer of Energy Chapter 5: Energy Part 1: Food Chains, Food Webs, and the Transfer of Energy
Autotrophs An organism capable of making its own organic substances from inorganic compounds Also called Producers Without autotrophs, there would be no life on this planet
There are 2 types of autotrophs: The first type is the… Photoautotrophs A group of organisms that can change light energy into chemical energy (glucose) – Photosynthesis! Example: green plants, algae, cyanobacteria
Photoautotrophs
The second type of autotrophs are the … Chemoautotrophs Autotrophs that get their energy from inorganic substances, such as sulfur Live deep down in the ocean where there is no sunlight Ex. Some bacteria
Heterotrophs Organisms that do not make their own food (needs to eat) Another term for Heterotroph is Consumer because they consume other organisms in order to live. Heterotrophs give off carbon dioxide, which is required for green plants in photosynthesis Ex. Rabbits, Deer, Mushrooms
Heterotrophs
Heterotrophs: Herbivores 1st Order Consumer = Herbivore Herbivores – eat ONLY plants Ex. – Cows, Elephants, Giraffes
Heterotrophs 2nd Order Consumer They are carnivores (eat meat) Eats first order consumers Ex. – Lions, Tigers, Sharks
Heterotrophs 3rd Order Consumer eats 2nd order consumers 4th Order Consumer eats 3rd order consumers
Heterotrophs: Omnivores Omnivores – eat BOTH plants and animals Ex. – Bears and Humans
Heterotrophs: Scavengers Scavengers – feed on the tissue of dead organisms (both plants and animals) Ex. – Vultures, Crows, and Shrimp
Heterotrophs: Decomposers Decomposers – absorb any dead material and break it down into simple nutrients or fertilizers Ex. – Bacteria and Fungi (such as mushrooms
Ok, now that we know the words… Let’s put them together to show the flow of energy through the ecosystem … Food web video
Transfer of Energy When a zebra eats the grass, it does not obtain all of the energy the grass has (much of it is not eaten) When a lion eats a zebra, it does not get all of the energy from the zebra (much of it is lost as heat)
Transfer of Energy No organism EVER receives all of the energy from the organism they just ate Only 10% of the energy from one trophic level is transferred to the next – this is called the 10% law Trophic level = energy level (each step of the food chain is a trophic level)
Transfer of Energy: The 10% Rule Who eats who in the food chain Steps along which materials & energy pass heat activity
The 10% Rule
Food Chains The energy flow from one trophic level to the other is known as a food chain It involves one organism at each trophic level
Food Chain Identify: Source of the energy Producer Herbivore Carnivore
Food Chain Identify: Source of the energy Producer Herbivore Carnivores 1st order consumer 2nd order consumer 3rd order consumer
Food Web Food Web – all of the feeding relationships in an ecosystem Food webs are more complex and involve lots of organisms
Food Web
Food Web Notice the direction the arrow points The arrow points in the direction of the energy transfer, NOT “what ate what”
Marine Food Web
Ecological Pyramids 4th order consumers 3rd order consumers 2nd order consumers 1st order consumers (herbivores) Producers
Ecological Pyramid An ecological pyramid shows the relationship between consumers and producers at different trophic levels in an ecosystem Shows the relative amounts of energy or matter contained at each trophic level The Pyramid shows which level has the most energy and the highest number of organisms
Ecological Pyramids Illustrates: Food Chain of numbers of biomass of energy
Pyramid of Numbers
Biomass The total mass of the organic matter at each trophic level is called biomass Biomass is just another term for potential energy – energy that is to be eaten and used. The transfer of energy from one level to another is very inefficient (10% Law)
Pyramid of Biomass
Energy Pyramid
Which level has the most energy? Which level has the most organisms? Which level has the least organisms? Which level has the least energy?