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13.2 Biotic and Abiotic Factors
Objective: Students will know that an ecosystem includes both biotic and abiotic factors AND that changing one factor in an ecosystem can affect many other factors.
13.2 Biotic and Abiotic Factors
KEY CONCEPT Every ecosystem includes both living (biotic) and nonliving (abiotic) factors.
13.2 Biotic and Abiotic Factors
• Biotic factors are living things.
– plants
– animals
– fungi
– bacteria
plants
13.2 Biotic and Abiotic Factors
• Abiotic factors are nonliving things.
– moisture
– temperature
– wind
– sunlight
– soilmoisture
sunlight
13.2 Biotic and Abiotic Factors
• List the biotic and abiotic factors in this picture• Share with your neighbors
Every ecosystem contains biotic and abiotic factors
13.2 Biotic and Abiotic Factors
• Biodiversity is the assortment, or variety, of living things in an ecosystem.
– Rain forests have more biodiversity than other locations in the world, but are threatened by human activities. (50% of the world’s plant and animals species are here)
13.2 Biotic and Abiotic Factors
• Biodiversity has to do with:
Number of species NOT Population number
13.2 Biotic and Abiotic Factors
• Extinctions lower biodiversity!!!
13.2 Biotic and Abiotic Factors
• A keystone species is a species that has an unusually large effect on its ecosystem. Ex: A beaver
keystone
• Their removal from the ecosystem may cause a ripple effect felt across an entire ecosystem
13.2 Biotic and Abiotic Factors
• By felling trees to construct dams, Beavers:– Change free flowing streams into ponds, wetlands, and
meadows– Lead to an overall increase in biodiversity
creation ofwetlandecosystem
increased waterfowlPopulation
increased fishpopulation
nesting sites for birds
keystone species
13.2 Biotic and Abiotic Factors
• More variety of fish- Fish attract birds• Insects inhabit pond and dead trees along the shore-
Insects attract birds• Animals that prey on birds are attracted to the pond
creation ofwetlandecosystem
increased waterfowlPopulation
increased fishpopulation
nesting sites for birds
keystone species
13.2 Biotic and Abiotic Factors
Other keystone species