Download Unit 6 Ecology Part 2 * Energy Flow

Notes
Energy
Flow in an
Ecosystem
Initial Energy Source
• Sunlight is the main energy source for life on
Earth!
Ecological Roles
• Producers:
– Make their own food
from sunlight energy or
chemical energy
– Base of energy for a
system
Ecological Roles
• Producers:
– Photoautotrophs: Use sunlight to make
energy/food
• Photosynthesis
– Chemoautotrophs: Use chemical reactions to
make energy/food
• Chemosynthesis
Ecological Roles
• Consumers:
– Heterotrophs: Acquire energy
and food from other organisms
– Types of heterotrophs
• Herbivores: eat only plants
• Carnivores: eat only other animals
• Omnivores: eat both plants and
animals
• Scavengers: eat dead organisms
(not the same as decomposers!)
Ecological Roles
• Decomposers:
– Break down organic
matter
– Release energy and
nutrient back into the
system
– Bacteria + fungi
Feeding Relationships
• Energy flow pathway:
Sun/chemicals
Autotrophs (producers)
Heterotrophs (consumers)
Food Chain
• Series of steps in which organisms transfer
energy by eating and being eaten
Food Web
• Complex feeding relationships in an
ecosystem.
Trophic Levels
• Each step in a food chain or web
• Begins with producers
• 2nd, 3rd, 4th and higher levels are made up of
consumers
Energy Pyramid
• Limited energy as you move
along a food chain.
• Only 10% of energy from one
level is transferred to the next
level.
• The other 90% is used by the
organisms for growth,
development, and activity.
Energy Pyramid
3
°
2
°
1
°