Objectives:

• Understand the elements that make up ecosystems and significance

• Make thorough observations of the elements of an ecosystem

• Make contributions to the construction of a food web

• Demonstrate comprehension of the interaction abiotic and biotic factors in ecosystems

Environmental InteractionsEcology- scientific study of the interactions between organisms and

their environment

Environment- surroundings

The environment consists of 2 parts:1. biotic factors- all living things that inhabit the environment

ex. Plants, bacteria, animals2. abiotic factors- nonliving parts of the environment

ex. Temperature, light, soil, air

Must have abiotic factors in order for biotic factors to exist

Limiting factors- factors that restrict the size of a population.ex. The amount of food, space

Organization of Life(simplest to largest)

1. organism- 1 living thing2. Population- group of organisms of the

same species living in the same area

-they compete for resources like food

3. community- all organisms living in the same

area (all populations in an area)-each population affects othersex. Fox affects rabbits

4. ecosystem- all living organisms plus their surroundings in an area2 general types of ecosystemsterrestrial- land ex. Forestaquatic-water

5. biosphere- highest level-all living and nonliving

parts of the earth-all living thingsare found here

How do organisms live in the same community without running out of resources?-they feed on different types of food-illustrated by food chain and food web

All organisms feed in 1 of 3 ways:1. producers- makes own food (ex. Plants)2. Consumers- ingest food from other organisms

(ex. Human)3. decomposer- breaks down organic matter to nutrients

(ex. Bacteria)

Types of feeding relationships in a community:

1. Autotroph (self-feed)- get energy from

the sun to make own food

2. heterotroph- organism that consumes

other organisms for food

types of heterotrophs:

a. herbivore- eats plants

b. carnivore- kills and eats animals

c. scavenger- feeds on animals already

dead (ex. Buzzard)

d. omnivore- feeds on plants and animals

ex. Human

3. decomposer- breakdown and absorb nutrients

from dead organisms (ex. Bacteria, fungi)

How is energy moved or cycled through the ecosystem?

By the food chain and food web

Food chain- model used to show how energy is moved from 1 organism to another

-shows one feeding relationship

ex. autotroph > heterotroph> carnivores

(arrow points to the animal that is doing that the energy is going to)

Each link on the food chain is called a trophic level

Food web• Shows multiple feeding relationships in an

ecosystem • It is the more reliable than the food chain

Each link in the food chain has 3-5 links only (no more). Why?

Energy is used at each link (each transfer)*Only 10% is passed on to the next level

Ex. Plant > grasshopper> fish> human

1000 cal 100 cal 10 cal 1 cal

energy pyramid- shows less energy transfer with each link of the food chain-organism number decreases with eachlevel

Components of an energy pyramid

Producers- always at the base/beginning of food chain

ex. Grass (bottom of pyramid)

Primary consumer- consumes plants directly man

ex. grasshopper fish

Secondary consumer- eats primary consumer grasshopper

ex. Fish plant

Tertiary consumer- eats secondary consumer

ex. man

Niche-role a species plays in its community (job)habitat-place where an organism lives out its life (ex. Aquatic habitat)

Questions for review:

• What is an ecosystem?• What elements make up an ecosystem?• How are the elements of an ecosystem related?• What is the relationship between producers and

consumers in an ecosystem?• How do organisms coexist in an ecosystem?• What is a food web?

Examples of organism interactions:

• Predation

• Competition

• Symbiotic relationships

Predation

• Predation-when one organism kills

anotherpredator- organism that kills

prey- organism killed

Each affects the size of the other’s population

competition• 2 organisms strive to obtain

the same limited resources (ex. Food)

• Both organisms are harmed somewhat

• Competition may be between the same species or between different

species

• “survival of the fittest”- the stronger of a species wins which weeds out the weaker ones

Close feeding relationships:Symbiosis-close feeding relationship in which one lives in or on another

organismTypes of symbiosis:

1. commensalism- relationship inwhich one organism benefits and the other is not affectedex. Moss on treeex. Cowbird on cow

2. mutualism- relationship in whichboth organisms benefitex. Bacteria in cowsex. Bee and flower

3. parasitism- relationship in whichone benefits and the other isharmedex. Tapeworm in stomachex. Mosquito sucking blood

Involves 4 processes:1. evaporation- changing from liquid to a gas (evaporation from

plants is called transpiration)2. condensation- changing from a gas to a liquid droplets (occurs in

clouds)3. precipitation- liquid returns to earth as rain, sleet, snow, hail4. respiration- water is breathed out from the lungs

Carbon cycleSource of carbon is Carbon dioxide in atmosphere

It is converted by plants to glucose by photosynthesis

Animals ingest the glucose and then die.

When they die carbon is returned to the air as carbon dioxide by bacteria when the matter decays.

                                                                                                              

                                                              

                                                                                          

       student lab

       home 

Nitrogen cycle

• Nitrogen makes up 78%

of atmosphere.

• Problem: we cannot use it

unless it is converted to

nitrate.

• Only 2 things can convert

nitrogen to the form

we use.

These are:

lightning and

nitrogen fixing bacteria.

Do not copy—this is reviewExample of Food chains

Example of food web

Food web

• Everglade web

Consumer evolution host symbiosisDecomposer extinction limiting factor trophic levelDetritus food chain mutualismEcology food web omnivoreEcosystem habitat parasiteEnvironment herbivore predation