Download Ecology - Crestwood Local Schools

Ecology!
Ch.3 - 1
Ecology - study of interactions among organisms
and between them and their surroundings.
Biosphere - contains all life on the planet
Levels of Organization:
1.) Individual - make up species which interbreed
and produce offspring
2.) Populations - groups of the same species that
live in a defined area
3.) Communities - more than one population in a
defined area
4.) Ecosystem - collection of all organisms within an
area along with their physical environment
5.) Biome - group of ecosystems with the same
climate and similar communities
6.) Biosphere - all living things together
See Fig.3-2 pg. 64
Use observation, experiments, and modeling to help
understand the workings of ecology.
Energy flow:
C-3-2
Without constant input of energy, living systems
can't function!
Sun - main energy source
~ less than 1% is used by living org.!
Some org. get energy from inorganic things:
*mineral water
Autotrophs - make own food from sunlight and
inorganic cds. ~ are producers - bottom of the
food chain
~Get food in 2 dif. ways:
~ undergo photosynthesis
~ chemosynthesis - use chemical energy to
produce carbs
Heterotrophs - rely on other org. for food - are
consumers
4 types:
* herbivore - eat plants
* carnivore - eat meat
* omnivore - eat both plants and animals
* decomposer - break down organic matter
Food chain: energy flows through an ecosystem in
one direction...
sun  autotrophs  heterotrophs
Food web: a network of complex interactions they link all the food chains together in an
ecosystem!
Each step in a food chain or web is a trophic level 1st - producers ; 2nd-4th - consumers
Only about 10% of the energy of one trophic level
is transferred to the next.
Cycles of Matter
C-3-3
Biogeochemical cycles - matter is recycled
between and within ecosystems.
Several ways this can occur:
1.) Water cycle - evapotranspiration
Pg. 75
2.) Carbon cycle - moves carbon through ecosystem
* biological processes take up and release C
and O
Ex: photosynthesis, cell. resp. decomp.
* geochemical processes release CO2 into
atmos. and oceans
Ex: erosion, volcanic eruption
*mixed biogeochemical processes ctore C
underground
Ex: decomp. of org. into fossil fuels
*human activities release CO2 into atmos.
Ex: mining, burning fuels
Pg. 77
3.) Nitrogen Cycle - N is used to make AA and
build proteins
*bacteria either convert N gas into ammonia
by N fixation or vice versa
* producers use the nitrates to make proteins
*consumer then eat the producers and reuse
the N to make their own proteins!
* when org. die, the N goes back to the soil
and will either become N gas or ammonia
via denitrification
Phosphorous gets cycled in a similar way, but is
stored in inorganic sediments of rock, soil, and
sand.
Energy carried by electrons:
*Chemical bonds store energy that is released when the
bonds are broken
*Food energy is stored in C-H covalent bonds
*e- energy is portable & can be transferred to new
chemical bonds by transferring the eOxidation-reduction reactions – chemical rxns that pass e- from
one atom to another
*oxidation – loss of eRemember - LEO GER
*reduction – gain of e-