Post on 25-May-2015
Mrs. Nelson
What is Ecology?
Study of interactions between organisms and their environment
Abiotic vs. Biotic Factors
Abiotic- “non-living” components-ex) temperature, light, water, nutrients, weather
Biotic- “living” species -ex) other organisms including humans
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
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).
Living things need energy…
Producers - organisms can do photosynthesis
Consumers – organisms eat other organisms
-herbivores-carnivores-omnivores-decomposers
Energy flow in an ecosystem Energy flows through an
ecosystem from the sun to producers to consumers.
“Who Eats Who”…
Food chain
- straight line pattern shows simple feeding relationships-illustrates passing of energy between organisms
Example Food Chain …
“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
Nutrients within and ecosystem…
Three basic nutrient cycles are present in all ecosystems allowing organisms to obtain nutrients needed to function effectively.
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.
Nitrogen Fixation Denitrification
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)
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
Water Cycle
Driving force is sun. Consists of alternation between
evaporation and precipitation. Most water returned atmosphere
from evaporation oceans.
Water CycleCondensation
Water Vapor
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)
Carbon Cycle
Carbon cycles between living organisms and non-living components of ecosystem.
Carbon exists in atmosphere as carbon dioxide (CO2).
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
Within an Ecosystem…What is a community?
All organisms in an area. Many interactions take place
between species. Ex) Predator and prey
What if no one wins?
In some species interactions, neither species wins.
Results in close, long term associations called symbiotic relationships.
3 Kinds Symbiotic Relationships
Parasitism (+/-) Commensalism
(+/0) Mutualism (+/+)