Ecosystems and Communities

Chapter 4 & 5 Notes

• Every organism affects its environment, and in turn is affected by its environment.  Ecosystems are affected by two kinds of factors

3

The Nonliving EnvironmentThe Nonliving Environment• Abiotic factors-Abiotic factors-

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• Ex. ______________Ex. ______________

4

The Living EnvironmentThe Living Environment•Biotic factors-Biotic factors- ___________ ___________

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•All organisms depend on All organisms depend on others directly or indirectly for others directly or indirectly for food, shelter, reproduction, or food, shelter, reproduction, or protection.protection.

Biotic or Abiotic?

1. Predators ________________ 2. Hot weather ________________ 3. Acid rain ________________ 4. Wood from trees ______________5. Your parents ________________ 6. The river flow ________________ 7. The leeches found in the river

________________

The Role of Climate

• Weather: ____________________________________________________________________________– Temperature– Wind– Precipitation– Humidity– Specific weather

patterns

Weather for Sugar Land, TX

Sunday Sept. 16, 2007

The Role of Climate• Climate: it is the average conditions in a region

over several decades; affects the soil, and in turn the vegetation, and in turn other organisms in an area. It is described by:

1. _______________________2. _______________________

The Role of Climate• __________________________________

__________________________________

The Role of Climate

• Polar: 90-66.5º N or S (within the Arctic and Antarctic circles)

• Temperate: from the lines of Tropic of Cancer and Capricorn to 66.5 º N or S, respectively

• Tropical: between the Tropic of Cancer and Tropic of Capricorn

Polar (blue)Temperate (green)Tropical (red)

Other determinates of weather and climate:

• Coastal or central to the continent?• __________________________________

____________________________________________________________________

Other determinates of weather and climate:

• Upwelling: ___________________________

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Diagram illustrating the principle of equatorial upwelling. Winds along the equator (dotted line) create currents, which are then diverted north and south by the Coriolis force. The cold, deep waters from below rise to the surface to replace these diverted waters, causing upwelling.

http://earthguide.ucsd.edu/virtualmuseum/climatechange1/11_2.shtml

• Greenhouse Effect: the natural situation in which heat is retained by the greenhouse gases (CO2, methane, water vapor, etc.) is called the greenhouse effect. If these gases were not present, the Earth would be 30º C cooler and unlivable

Biomes• -a collection of ecosystems with the same

climate and dominant communities; 2 main areas of biomes– Aquatic- in water– Terrestrial- on land

Aquatic

• Photic zone- _______________________ (shallow water)

• Aphotic zone- ______________________ (deep water)

• Estuary- ______________________________________ (end of a river)

• Tidal zone- __________________________

Tidal Zone

Photic Zone

Aphotic Zone

Community Interactions

• Habitat- ___________________________• Niche- ____________________________

__________________________________• Competition- _______________________

__________________________________– Interspecific competition: between members

of different species– Intraspecific competition: between members

of the same species

Predation

• ____________________________________________________________________ ex: lion eats a zebra

Community Interactions

• Symbiosis- __________________________________________________________

Community Interactions

• Mutualism- _______________________________________________________ (ant live on an acacia tree, ant protects tree from harmful plants, tree gives ant a home)

Clownfish live within sea anemones, which normally sting other fish. The fish gets protection, and the anemone benefits because the clownfish keep it clean of bacteria.

Community Interactions

• Parasitism- __________________________________________________________ (fleas or ticks on a dog; flea gets a home, sucks the dog’s blood and is bothered by it)

Leech sucks the blood of a human

Community Interactions

• Commensalism- ______________________________________________________ (moss growing on trees)

Epiphytes are plants that grow on other plants without harming them. They never set root in the ground!

When grazing cows walk around, they disturb the ground, which

stirs up insects. Birds follow the cows around and eat these

insects.

Cleaner shrimp living in the ocean eat ectoparasites off of larger fish.

The cleaner fish get a meal and the

larger fish get rid of a parasite.

A botfly lays maggots inside a man's head, providing

shelter and nutrition for its young.

Factors Affecting PopulationsThree things affect population size:1. ________________________________2. ________________________________3. ________________________________

________________________________________________________________

Types of Growth

• Exponential Growth- if a population has abundant space and food, no disease or predators; it will grow at an exponential rate. It is a J-shaped curve resembling y = ax2 + b

Types of Growth

• Logistic Growth- population growth slows then stops (stays stable) after a period of exponential growth once resources become less available. The number at which the environment can support this population is known as the carrying capacity.

Limiting factors

• factor that causes a population to decrease in size

• Two types…

Limiting Factors• Density dependent- _________________________

___________________________________________________________________________________________________________________________

• Notice the pattern of population size with predator/prey relationship of hares and lynxes

Limiting Factors

Density independent- ________________

______________________________________________________________________________________________________ Unusual weather natural disasters seasonal cycles certain human activities

Ecological Successiono After such disasters, a community can

start anew by a process called ecological succession (series of predictable changes that occurs in a community over time); there are two types

Succession Primary succession- _________________

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Succession

Secondary succession- _______________

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