Download The Biosphere

Principles of Ecology
Chapter 2
Ecology
The study of interactions among organisms
and between organisms and their
environment.
The Biosphere
The portion of the planet
in which life exists
– Land
– Water
– Air
– 8 km above Earth’s
surface
– 11 km below the surface
of the ocean
Living vs. Nonliving
• Abiotic Factors: nonliving factors
– Examples?
• Biotic Factors: living factors
– Examples?
• Ecology studies the interaction of biotic
and abiotic.
Levels of Organization
Species – group of organisms that
interbreed to produce fertile offspring
Levels of Organization
• Population – group of individuals
that belong to the same species
and live in the same area
– Example: the alligator population of
Greenfield Lake
Levels of Organization
• Communities – groups of populations
that live together in a defined area
– Example: the Cape Fear River community
Levels of Organization
• Ecosystem
–Organisms and nonliving environment
they inhabit
Levels of Organization
• Biome – group of ecosystems with the same
climate and similar communities.
•Niche: Organisms “occupation”
(where it lives, its place in the
food web etc.)
Ecological Methods
• Observing
• Experimenting
• Modeling
Community Interactions
1. Competition: compete over
resources
2. predation: one organism
feeds on another
3. Symbiosis: any relationship
where 2 animals live closely
together
Types of Symbiosis
1. Mutualism: both species benefit
Ex. Flowers & insects
2. Commensalism: one member
benefits and the other is neither
helped nor harmed
ex. Barnacles
3. Parasitism: one organism lives on
or in another and harms it.
ex. tapeworms
Where does the energy from your
favorite foods ultimately come from?
Energy Flow
• Producers
(autotrophs): harness
sunlight to produce
food
Energy Flow
• Chemoautotrophs: use energy from
chemical compounds (in hydrothermal
vents) to produce food
• Consumers (heterotrophs)
– Herbivores – eat plants
• Heterotrophs (continued)
– Carnivores – eat meat
– Omnivores – eat both plants and
animals
– Detritivores (Decomposers) – eat
dead remains (detritus)
Energy Flow
• Food Chain
– Series of steps in which organisms
transfer energy by eating and being
eaten
Energy Flow
• Food Web
– The depiction of a
network of feeding
relationships
Energy Flow
• Trophic Levels:
Each step in a food
chain
– Producers make up
the bottom level
– Consumers make
up the upper levels
– Each level depends
on the level below it
Energy Levels
• Energy Pyramids:
amount of energy
contained in each
trophic level
– 10% of the energy in
one trophic level is
transferred to the
one above.
Energy Flow
• Biomass Pyramid: amount
of potential food available
for each trophic level
– Biomass: amount of living
tissue
• Pyramid of Numbers: based
on the numbers of
individual organisms
Cycles of Matter
• The water cycle:
– All living things require
water to survive
– Precipitation, transpiration,
evaporation etc
Cycles of Matter
• The Carbon Cycle:
– Carbon is the key
ingredient of living tissue
– Respiration,
photosynthesis, feeding,
erosion etc.
Cycles of Matter
• The Nitrogen Cycle
– Necessary for amino acids
– Nitrogen fixing bacteria on roots “fix”
atmospheric nitrogen to be used by plants.
– Consumers get nitrogen by eating
producers
Limiting Nutrient
• When an ecosystem is limited by a
single nutrient – controls the number of
producers
– Fertilizers