Community Relationships A biological community is all of the living organisms that interact within a...

Community Relationships

A biological community is all of the living organisms that interact within a

particular ecosystem

What makes up an ecosystem?

• Biotic factors--All of the living components that influence an ecosystem

• Abiotic factors--All of the nonliving components that influence an ecosystem.

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Some abiotic factors

• Average rainfall• Type of soil• Humidity

• Pollution• Groundwater• Annual temperature

Niche

• Each organism place a specific role in its respective community.

• What is the niche of a rabbit in the meadow?



Food Web--shows transfer of energy



As a result of the transfer of energy…





Where do decomposers get their energy?

Biomes

• Ecosystems defined by their abiotic and biotic factors.

• Typical food webs exist within biomes.

• Needham belongs to a Temperate Forest Biome– Cold winter; hot summer– Trees lose their leaves in

the winter– Animals must hibernate



Activity

• In class you will virtually visit a biome and create a team post card.

• On the front of your paper--Draw a food web that exists in your biome (6 organisms).

• On the back, describe the abiotic factors that influence the community living in that biome.



Other community relationships

• Symbioses:– Endosymbiosis

– Mutualism

– Commensalism

– Parasitism

– Predator-Prey



Mutualism

• Both organisms benefit

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Commensalism

• One organism benefits the other remains neutral.

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Parasitism

• One organism benefits the other is harmed.

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Predator-Prey

• One organism benefits the other is eaten.

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Amount of Predators & Prey remains balanced



Communities Change over Time

• Ecological Succession--the systematic change in a biological community– Primary: formation of

community where none existed.

– Secondary: rebuilding of a community after drastic change.



http://www.restoringearth.co.uk/education/science/geography/ecology/succession/success1.gif




Rebuilding

• Pioneer Species--first species to inhabit an area.

• Climax community--relatively stable community

• ?Does a climax community really exist?



Bioaccumulation in a community

• Bioaccumulation: Buildup of toxins through a food web.

• Predators contain more toxins than organisms lower on the food chain!



Example…DDT

• Used to kill insects.• Almost wiped out

predatory birds.• Rachel Carson--

environmentalist went to the popular press “Silent Spring” to bring awareness





Imagine a Silent Spring

• Listening Activity--Listen to a Podcast from Silent Spring

• How would life as we know it be different if Rachel Carson had not brough awareness to this issue?



Follow-up

• What type of relationship is it?!– Identifying symbioses

activity

• Ecological Succession and Bioaccumulation Worksheet



Community Relationships A biological community is all of the living organisms that interact within a...

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