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The Biosphere
Ecology
● the scientific study of interactions among organisms and between
organisms and their environment
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Plant Biome Ecosystem Community Population Species
Biome: a group of ecosystems that share similar climates and typical organisms
Ecosystem: All organisms that live in a place together within their environment
- abiotic factors interacting with biotic factors
Community: Different populations that live together in a defined area
- forest plants, animals, and fungus interacting
Population: individuals that belong to the same species and live in the same
area
- a group of Bison living in the same area
Species: similar organisms that can breed and produce fertile offspring
Environmental Factors
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biotic factors: any living part of the ecosystem in
which organisms can interact
Example: Bullfrog
• tadpole→ eats algae
• bullfrog→ insects
• Other species competing with the bullfrog for
food
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abiotic factors: physical components of an
ecosystem (environment)
Examples: sunlight, tornados, wind
Energy Consumption: Producers
● Organisms need energy to carry out daily functions→
metabolism, reproduction, growth
● They cannot produce energy; they need to get it from other
sources
Autotrophs (producers): organisms that can convert energy
from the sun into useable energy
• Example: bacteria, algae, plants
Primary producers are essential to life on Earth because they
produce the essential energy for other living organisms
● Photosynthesis: capturing light energy to transform
carbon dioxide and water into oxygen energy-rich
carbohydrates (sugars)
o Equation: light + CO2 + H2O → C6H12O6 +O2
● Without photosynthesis, there would not be enough
oxygen to breathe
Chemosynthesis: taking in carbon dioxide, hydrogen
sulfide, and oxygen to produce carbohydrates (sugars)
and sulfur
Chemosynthetic organisms live in harsh environments
• deepest part of the ocean
• deep-sea volcanic vents
• hot springs
Energy Consumption: Consumers
● Heterotrophs (consumers): organisms that have to aquire
energy from other organisms through ingestion
o Example: birds, cheetah, snakes
● 6 Types of Consumers
1.Carnivores: kill and eat other animals
a.Examples: tiger, alligator,
2.Scavengers: animals who eat other dead animals
that have already been killed
a.Example: vulture
3.Decomposers: feed by chemically breaking down
organic matter
a.Examples: bacteria, fungi
Energy Consumption: Consumers
4. Herbivores: organisms that obtain energy through
eating plants
a.Examples: cows, caterpillars
5. Omnivores: organisms who eat both animals and
plants
a.Examples: Humans, pigs
6. Detritivores: feed on detritus (waste or debris)
material
a.Examples: snails, shrimp
The categories are in place but they do not always remain
100% -- extrenuating circumstances may push an
organism to obtain energy any way they can
Energy Flow: Food Chains/Webs
Energy flow through an ecosystem is one-way
food chain: series of steps in wihch organisms transfer
energy
Food Chain
Energy Flow: Food Chains/Webs
food web: a network of feeding interactions
Food webs are more complicated than a simple food
chain
Food chains are found within food webs
Are decomposers important?
YES! They recycle nutrients to feed the primary
producers.
Food Web
Trophic Levels/Ecological Pyramids
trophic level: each step in a food chain or food web
ecological pyramids: shows the relative amount of energy
or matter in each trophic level
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Any energy that is passed on to the next level is stored
in the organisms
Not all energy moves to the next trophic level→ it is
released as heat
About 10% moves on to the next level→ divide by 10
Trophic Levels/Ecological Pyramids
Biomass/Numbers Pyramids
• A pyramid of biomass illustrates the relative amount of living organic
matter available at each trophic level
• A pyramid of numbers shows the relative number of individual
organisms at each trophic level
• As you increase through the pyramid, the biomass and the numbers
decrease
• Biomass decreases because there are less numbers as you travel through
the pyramid
Cycles of Matter: The Water Cycle
Water continuously moves between the oceans,
atmosphere, and land
The Water Cycle
Water becomes vapor in the process of evaporation
transpiration: water evaporating from the leaves of
plants
As water cools and condenses (condensation), it falls to
the Earth in the form of precipitation
Groundwater: precipitaiton that is soaked into the
ground and taken up by plants
Runoff: Precipitation that enters a stream, river, or
lakes
Water Cycle
Cycles of Matter: Carbon Cycle
Carbon is a major component in all organic compunds, such
as carbohydrates, lipids, and proteins
Coal, oil, and natural gas are referred to as fossil fuels
because they are fossilized carbon
The Cycle
Plants take in CO2 during photosynthesis and convert it
to carbohydrates
Animals eat the plants and absorb the carbohydrates
Animals exhail CO2 back into the atmosphere
When animals die, they are decomposed and the
carbohydrates become rocks or fossil fuels
Carbon Cycle
Cycles of Matter: Nitrogen Cycle
All organisms required nitrogen to make amino acids→
building blocks of protein
Forms of Nitrogen
a. N2→ nitrogen gas makes up 78% of the atmosphere
b. NH3→ ammonia
Only certain bacteria can use nitrogen directly (nitrogen
fixation)
a. primary producers consume the ammonia, nitrates,
or nitrites
The Nitrogen Cycle
Bacteria turns nitrogen into ammonia, nitrites, or
nitrates
Primary producers consume the nitrogen and make
proteins
Consumers eat the plants, which makes nitrogen
compounds
Decomposers break down the nitrogen in dead consumers
Humans add nitrogen to the atmosphere through fertilizers
Small amounts of nitrogen are converted into usable forms
by lightning
Nitrogen Cycle
Cycles of Matter: Phosphorus Cycle
Phosphorous is essential because it is a part of DNA and RNA
It is NOT abundant in the atmosphere
The Phosphorous Cycle
Phosphates are released when rocks and sediments are
worn down
Plants bind the phosphates when they take it up through
the roots
It moves through the food web from producers to
consumers
Other phosphates wash into the river where it dissolves
Phosphorous Cycle