Ecology &
Environmental Science
Chapter 3
Definitions….
• Ecology:
– the study of how
organisms interact w/
each other & their
physical environment
• Environmental science:
– adds the impact of
humans
More Vocabulary….
• Biotic:
– living
– Plants, trees, fish
• Abiotic:
– non-living
– Water, sunlight,
temperature,
precipitation
Ecosystem Organization
review
• Organism
• Wolf
• Population
• How many wolves
• Community
• Wolves, squirrels, deer,
trees, grass
• Forest – wolves,
squirrels, trees, rocks,
weather, temperature and
water
• Ecosystem
biome
ecosystem
Food Chains
Producers
Consumers: primary, secondary, tertiary
Decomposers
What do the arrows indicate?
Food Web
Food Webs
Trophic Levels
• Biomass is largest at
producer level
• Energy is greatest at
producer level
• # of organisms &
energy decreases as
you move up the
pyramid
• 10% rule
Recycling in the Environment
• Energy & matter must be recycled back
into the environment or life would cease!!!
• Decomposers are vital to this process
• Important cycles are water, nitrogen, &
carbon
Water Cycle
Carbon Cycle
Nitrogen Cycle
Denitrifying
Bacteria
convert to N2
Nitrogen-fixing
bacteria