3. Abiotic vs. Biotic Factors
Abiotic- “non-living” components
-ex) temperature, light, water,
nutrients, weather
Biotic- “living” species
-ex) other organisms including
humans
4. Levels of Ecological Organization
Species- organisms can interbred and
produce fertile offspring
Population- all members of a species in area
Community- every species in area
Ecosystem- all organisms and physical
environment
Biosphere- The entire region earth where
living things found
5. Conditions for Life
In order for an ecosystem to sustain life, several
conditions must be met:
1) Energy source (ex: sun)
2) Living organisms convert energy to organic
molecules (ex): Plants –photosynthesis)
3) Nutrients must move between organisms and
the environment (ex: water, carbon dioxide,
nitrogen, oxygen).
6. Living things need energy…
Producers - organisms can do
photosynthesis
Consumers – organisms eat other
organisms
-herbivores
-carnivores
-omnivores
-decomposers
7. Energy flow in an ecosystem
Energy flows through an
ecosystem from the sun to
producers to consumers.
8. “Who Eats Who”…
Food chain
- straight line pattern shows simple
feeding relationships
-illustrates passing of energy between
organisms
10. “Who Eats Who”…
Food web- illustrates how all the
food chains in an ecosystem related
“Network of feeding relationships”
Keystone species- species that
affects many other species and can
not easily be replaced if lost
11.
12. Nutrients within and
ecosystem…
Three basic nutrient cycles are
present in all ecosystems allowing
organisms to obtain nutrients needed
to function effectively.
13. Nitrogen Cycle
The atmosphere 80% nitrogen gas
(N2).
However, this nitrogen can not be
used by most living things.
Bacteria are the only organisms that
can use nitrogen directly from the
environment.
15. Nitrogen Cycle Terminology
Nitrogen fixation- nitogen gas in the atmosphere
is converted to ammonia (bacteria in soil)
Nitrification- ammonia to nitrate (bacteria in
soil)
Assimilation- absorption of nitrate by plants
Ammonification- break down of dead organisms
returns “unused nitrogen” to soil (bacteria and
fungi)
Denitrification- conversion of ammonia back to
nitrogen gas (returns nitrogen to air)
16. Why is the nitrogen cycle
important?
Why is nitrogen important to
living things?
-major part of DNA and proteins
How do plants obtain nitrogen?
-absorb it from ground
How do we obtain nitrogen?
-eating plants
17. Water Cycle
Driving force is sun.
Consists of alternation between
evaporation and precipitation.
Most water returned atmosphere
from evaporation oceans.
19. Water Cycle Terminology
Evaporation- liquid water becomes gas
enters atmosphere
Transpiration- loss water from plants
Water vapor- water atmosphere (gas)
Condensation- process where water
molecules gather atmosphere “change from
gas to liquid”
Precipitation- water falls atmosphere to
ground (rain, snow, hail, etc)
20. Carbon Cycle
Carbon cycles between living
organisms and non-living components
of ecosystem.
Carbon exists in atmosphere as
carbon dioxide (CO2).
21.
22. Carbon Cycle Terminology
Photosynthesis- PLANTS use sunlight,
carbon dioxide and water to make sugar
Respiration- process organisms use oxygen
and release carbon dioxide back into air
Fossil fuels- dead organisms buried in
sediment change to coal or oil (unused
carbon)
Combustion- burning of fossil fuels
23. Within an Ecosystem…
What is a community?
All organisms in an area.
Many interactions take place
between species.
Ex) Predator and prey
24. What if no one wins?
In some species interactions, neither
species wins.
Results in close, long term
associations called symbiotic
relationships.