Community Community InteractionsInteractionsRemember…it’s the Remember…it’s the

INTERACTIONS that are INTERACTIONS that are important in ecology!important in ecology!

Compare and ContrastCompare and Contrast

SpeciesSpecies

PopulationPopulation

CommunityCommunity

DefinitionsDefinitions

Species: A class of individuals having common Species: A class of individuals having common characteristics (ex. Mankind, cats etc.)characteristics (ex. Mankind, cats etc.)

Population: the number of individuals that Population: the number of individuals that occupy a certain area. (ex. People in occupy a certain area. (ex. People in Wilmington)Wilmington)

Community: Different species interacting Community: Different species interacting together in a certain environment (ex. Plants, together in a certain environment (ex. Plants, squirrels, and fox)squirrels, and fox)

CompetitionCompetition

Same or different species Same or different species attempt to use an ecological attempt to use an ecological resource in the same place at resource in the same place at the same timethe same time resource = necessity of life (water, resource = necessity of life (water,

nutrients, light, food, space)nutrients, light, food, space)

Community InteractionsCommunity Interactions

NoNo two species can occupy two species can occupy the same niche the same niche in the same habitat in the same habitat at the same timeat the same time

Direct competition in nature Direct competition in nature often results in winner and loser often results in winner and loser – losing organism fails to survive– losing organism fails to survive

Food ChainFood Chain

A food chain is a food pathway that A food chain is a food pathway that links different species in a community. links different species in a community.

In a food chain, energy and nutrients In a food chain, energy and nutrients are passed from one organism to are passed from one organism to another. another.

A series of steps in which organisms A series of steps in which organisms transfer energy by eating and being transfer energy by eating and being eaten.eaten. i.e. Wheat i.e. Wheat mouse mouse snake snake hawk hawk

Food Chain ExampleFood Chain Example

Food Chains rarely contain more than six Food Chains rarely contain more than six species because amount of energy species because amount of energy passed on diminishes at each stage, or passed on diminishes at each stage, or trophic level.trophic level.

The longest chains usually involve The longest chains usually involve aquatic animals. aquatic animals. In a food chain, an animal passes on In a food chain, an animal passes on only about 10 percent of the energy only about 10 percent of the energy it receives.it receives. The rest is used up in The rest is used up in maintaining it's body, or in movement, or maintaining it's body, or in movement, or it escapes as heat.it escapes as heat.

Food ChainFood Chain

Food WebFood Web• A community of living things A community of living things

may contain hundreds or even may contain hundreds or even thousands of different species.thousands of different species.

• Each species is usually involved Each species is usually involved in several different food chains. in several different food chains.

• Different food chains often Different food chains often interconnect to form a large interconnect to form a large network, called a food web. network, called a food web.

Food WebFood Web

Trophic LevelsTrophic Levels

A trophic level of an organism is the A trophic level of an organism is the position it holds in a food chain. position it holds in a food chain.

1.1. Trophic level 1are primary producers Trophic level 1are primary producers or or autotrophsautotrophs

2.2. Trophic level 2 is herbivores Trophic level 2 is herbivores (organisms that eat primary (organisms that eat primary producers) - organisms at this level producers) - organisms at this level are also called primary consumers. are also called primary consumers.

3. Trophic level 3 is predators that eat 3. Trophic level 3 is predators that eat herbivores - organisms at this level are herbivores - organisms at this level are also called secondary consumers. also called secondary consumers.

4. Trophic level 4 is predators that eat 4. Trophic level 4 is predators that eat secondary consumers. Tertiary consumerssecondary consumers. Tertiary consumers

5. Trophic level 5 is predators that eat 5. Trophic level 5 is predators that eat secondary consumers/tertiary consumers secondary consumers/tertiary consumers

Decomposers (such as bacteria) start the Decomposers (such as bacteria) start the cycle again.cycle again.

Trophic LevelsTrophic Levels

Each step in a food chain or food Each step in a food chain or food webweb11stst level = producers level = producers22ndnd, 3, 3rdrd, or higher levels = , or higher levels = consumersconsumers

Usually no more than 5 levels Usually no more than 5 levels because 90% of energy is lost at because 90% of energy is lost at each level.each level.

PREDATORPREDATOR

An animal that hunts and kills An animal that hunts and kills animals for foodanimals for food• The term predator usually refers to The term predator usually refers to

animals that catch and kill.animals that catch and kill.• They have special adaptations to help They have special adaptations to help

them find and catch their food. These them find and catch their food. These include good vision, a keen sense of include good vision, a keen sense of smell, or strong legs for rapid smell, or strong legs for rapid movement. movement.

PREYPREY

Prey are animals that are lower on Prey are animals that are lower on the food chain that are eaten by the food chain that are eaten by predators.predators.

Prey also have special adaptations to Prey also have special adaptations to help them survive the attack of their help them survive the attack of their predators. Camouflage helps them predators. Camouflage helps them blend in, sharp senses warn them of blend in, sharp senses warn them of attack, and speed allows them to attack, and speed allows them to escape.escape.

Write if the organism is a producer, Write if the organism is a producer, consumer or decomposer. Tell what trophic consumer or decomposer. Tell what trophic

level they are at as well.level they are at as well.OrganismOrganism TypeType Trophic LevelTrophic Level

HumanHuman

DeerDeer

Pine TreePine Tree

BearBear

RabbitRabbit

BacteriaBacteria

OrganismOrganism TypeType Trophic Trophic LevelLevel

MouseMouse

SnakeSnake

WheatWheat

MaggotMaggot

BluegrassBluegrass

HawkHawk

OrganismOrganism TypeType Trophic Trophic LevelLevel

MillipedeMillipede

TroutTrout

SparrowSparrow

CatCat

FrogFrog

AlgaeAlgae

Draw a Food ChainDraw a Food Chain

Draw a food chain with the Draw a food chain with the organisms you worked with above. organisms you worked with above. Try to make your food chain with at Try to make your food chain with at least 5 organisms. least 5 organisms.

If you want to you can also work with If you want to you can also work with other animals you can think of to other animals you can think of to make your food chainmake your food chain

Example of a Food ChainExample of a Food Chain

BioticBiotic

Are living things in an environment Are living things in an environment that interact with non-living.that interact with non-living.

What are some biotic things that What are some biotic things that could be an environment?could be an environment?

Plants and animalsPlants and animals Why are these important to have an Why are these important to have an

environment?environment?

AbioticAbiotic

Are the non-living factors in an Are the non-living factors in an environment.environment.

What are some non-living things that What are some non-living things that should be in an environment?should be in an environment?

Temperature, rocks and minerals, Temperature, rocks and minerals, waterwater

How could these factors affect the How could these factors affect the environment?environment?

Biological InteractionsBiological Interactions

Symbiosis-is a close ecological relationship Symbiosis-is a close ecological relationship between the individuals of two (or more) between the individuals of two (or more) different species.  different species.  

Sometimes a symbiotic relationship Sometimes a symbiotic relationship benefits both species, sometimes one benefits both species, sometimes one species benefits at the other's expense, species benefits at the other's expense, and in other cases neither species and in other cases neither species benefits. benefits.

Biological interaction typesBiological interaction types

• MutualismMutualism

    --   both species benefit--   both species benefit• CommensalismCommensalism

    --   one species benefits, the other is --   one species benefits, the other is unaffectedunaffected

• ParasitismParasitism

    --   one species benefits, the other is --   one species benefits, the other is harmedharmed

AquatiAquatic Food c Food WebWeb

Energy & Matter Energy & Matter in an Ecosystemin an Ecosystem

Other Community Other Community InteractionsInteractions

PredationPredation SymbiosisSymbiosis

ParasitismParasitism MutualismMutualism CommensalismCommensalism

PredationPredation

OneOne organism captures and organism captures and feeds on another organismfeeds on another organism Predator – the one killing and Predator – the one killing and

eatingeating Prey – the foodPrey – the food

herbivory is a form ofpredation

SymbiosisSymbiosis

When two species live close When two species live close together.together.

Three types:Three types: Parasitism – one is harmed (host), one Parasitism – one is harmed (host), one

benefits (parasite)benefits (parasite) Mutualism – both benefitMutualism – both benefit Commensalism – one is neutral, one Commensalism – one is neutral, one

benefitsbenefits

Parasitism

Mutualism

Commensalism

Mutualism

Parasitism

Commensalism