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 (+/+)