Chapter 3 Ecology.pdf · Community Ecology . What is a community? ... What effects a community?

Chapter 3 Section 1

Community Ecology

What is a community?   Interacting populations that occupy the same space

at the same time.   Plants   Animals   Bacteria

  Fungi

What effects a community?   How well the organisms have adapted to the

environment.   Wolves have thick fur coats for harsh winters.

  How well animals adapt to changes in the environment.   When a drought occurs, animals need to find different

sources of food.

  Most organisms can survive in specific environments.   A fish can’t survive on land.   A fly can’t survive in the arctic.

What is a limiting factor?   A factor in an environment, biotic or abiotic, that

restricts life to succeed.   Abiotic

  Sunlight

  Climate

  Temperature

  Water

  Nutrients

  Fire

  Soil chemistry

  Space

  Biotic   Other animals and plants

Tolerance   The ability to survive a situation that is not an ideal

living condition.   Extreme heat or cold   Monsoons or droughts   Pollution   Introduction of a new species

  For any factor, there is an upper limit and a lower limit.

  This determines the range in which the organism can survive

Tolerance

What is ecological succession?   An ecological succession is when one community

replaces another due to the changes in abiotic and biotic factors.

  ecosystems are constantly changing.   tree falling down

  forest fire

How does succession take place?

  Primary succession-The establishment of a community in an area of exposed rock that does not have any topsoil is.

Primary Succession

Secondary succession   The orderly and predictable change that takes place

after a community of organisms has been removed but the soil has remained intact

Determining a successions end point

  Due to the many factors that an ecosystem has it is difficult to determine if succession has ever reached an endpoint.   Human interference

  The time it takes for succession to happen   Ecosystems changing from one to another during a

process that is already occurring.