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EcologyEnergy Flow
Producers• Sunlight is the MAIN source of energy for all
life on Earth• Only plants, some algae, and certain
bacteria can capture energy from the sun and convert it into a USABLE form of energy
• Autotrophs – organisms that capture and convert the sun’s energy• Also called PRODUCERS!
Producers
• Producers use a process known as photosynthesis
• Light energy is used to convert carbon dioxide (CO2) and water (H2O) into oxygen (O2) and carbohydrates (C6H12O6)
Carbon Dioxide + Water + Sunlight Carbohydrates + Oxygen
Producers• Some autotrophs can produce food without
light by using a process called chemosynthesis
• Chemical energy is used to convert hydrogen sulfide (H2S), carbon dioxide (CO2), and water (H2O) into carbohydrates (C6H12O6) and sulfur compounds (H2SO4)
• This usually occurs in remote locations (e.g. ocean floor and hot springs)
• Bacteria are the most common autotrophs that use chemosynthesis
Producers
• Photosynthesis• “photo-” means
“light”• Uses light for energy
• Chemosynthesis• “chemo-” means “chemicals”• Uses chemicals for energy
Consumers• Many organisms cannot use sunlight as food
• Animals, fungi, some bacteria, some protists• These organisms must consume other organisms
to obtain energy• These organisms are called heterotrophs
• Also called CONSUMERS!
Consumers• Five (5) main types of heterotrophs:
1) Herbivore – consumes only plants2) Carnivore – consumes only animals
• Some scavengers are considered carnivores3) Omnivore – consumes plants and animals4) Detritivores – consumes decaying and rotting
material (such as rotting leaves, etc.)• Some scavengers are considered detritivores
5) Decomposers – breaks down organic (living) material• Finishes the job that scavengers and detritivores
start
Feeding Relationships
• Energy flows through an ecosystem in one direction
Sun/ Inorganic Compounds
Autotrophs Heterotrophs
Feeding Relationships• Food Chain –
series of steps in which organisms transfer energy by eating and being eaten• Shows one-way
flow of energy in an ecosystem
Feeding Relationships• Most feeding relationships are more complicated
than a food chain• Food Web – network of complex interactions and
feeding relationships in an ecosystem
Terrestrial Food Web
Marine Food Web
Feeding Relationships• Trophic Levels – steps in the food chain/web
• Producers – 1st trophic level• Consumers – 2nd, 3rd, or higher trophic levels
• Each consumer depends on the previous trophic level
1st Trophic Level
1st Trophic Level
2nd Trophic Level
2nd Trophic Level
3rd Trophic Level
3rd Trophic Level
4th Trophic Level
4th Trophic Level
5th Trophic Level
5th Trophic Level
Ecological Pyramids
• Ecological Pyramid – diagram that shows the relative amount of energy or matter contained within each trophic level of a food chain/web
• 3 Types• Energy Pyramid – shows the relative amount of
energy available at each trophic level• Biomass Pyramid – shows the amount of living
organic material at each trophic level• Pyramid of Numbers – shows the relative number of
individual organisms at each trophic level
Energy Pyramid• Only part of the energy that is stored at one
trohpic level can be passed to the next trophic level• 10% of the energy at one level is transferred to the next
• Why isn’t ALL the energy transferred to the next level?• The other 90% is used by the organism at the previous
level
Energy Pyramid
Light or Chemical Energy
Biomass Pyramid• Biomass – total amount of living tissue within a
given trophic level• Usually expressed in terms of grams of organic matter per
unit area
• Biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem
Biomass Pyramid
10 %
10 %
10 %
10 %
Pyramid of Numbers• Based on the actual number of individuals at each
trophic level• Does not always resemble the shape of a pyramid
• Ex: tree may be at bottom of “pyramid”
Pyramid of Numbers
Pyramid of Numbers