Day 2 SCI 10 Ecology

Food Chains Grass grasshopperrobinhawk -Primary Consumer: eat producers -Herbivore: only eat plants -Heterotroph: hetero = others, troph = food Producer: makes its own food through photosynthesis which uses energy from the sun -Autotroph: auto = self, troph = food Secondary Consumer Tertiary consumer Energy transfer (10% passed on at each step)

Other Definitions Omnivore: eats everything (plants and meat) Ex. Human, brown bears Carnivore: only eats meat Ex. Lions Scavengers: eat dead things, don’t kill prey ex. Vultures, raccoons Decomposers: consume dead material and recycle (return) nutrients to the soil ex: worms, bacteria, fungi

Trophic Levels First trophic level = producers (plants) Second trophic level = primary consumers (herbivores) Third trophic level = secondary consumers (carnivores) Fourth trophic level = tertiary consumers

In which trophic level do each of the following organisms belong?: grass crow coyote maple tree bacteria snake mouse deer porcupine red squirrel seeds Producers Primary consumers Secondary consumers/ Decomposers

Energy What is the primary source of energy for all food chains? The sun – without it we would not have food

Food Web: many food chains interlinked Identify 3 food chains in the food web below deer snake wolf mouse grass rabbit frog shrubs hawk insect

Abiotic vs. biotic Abiotic factors: components of an ecosystem that are non-living “non-living” Ex: soil, water, sunlight Biotic factors: components of an ecosystem that are, or use to be, living “living or was living” Ex: trees, birds, insects, bacteria

Complete the diagram using the following terms : primary consumer (herbivore) , secondary consumer (carnivore), tertiary consumer, decomposers, second trophic level, first trophic level, producer, fourth trophic level, third trophic level

Transfer of Energy -Food energy ingested by a consumer is used for many processes Only around ____ % is converted into body mass. Why do we rarely see more than 4 links in a food chain? Because energy decreases along the chain and so higher level consumers can’t be supported

Organisms are interconnected Look at the following food chain : Grass  deer  wolf If the deer population increases, what would happen to: The grass population? The wolf population?

The grass population would decrease The wolf population would increase because: More food increases reproductive rates (more babies) Eventually, the wolf population would start to decrease because food would run out

Definitions Ecosystem: interactions among organisms and their environment Sustainable ecosystem: able to handle pressure and support many different organisms

Day 2 Questions Which type of organism is at the beginning of all food chains? Which organisms can eat all other organisms ? In an ecosystem, the abiotic factors include…? 3 examples of decomposers are …? What is the importance of decomposers in an ecosystem? What is the principal source of energy for all ecosystems?