Warm-up 9-22-2009Producers

• Using complete sentences answer the question below in your Composition Notebook.

• What is the role of producers in the environment? What do they do for other organisms?

Answer

• Provide food source

• Provide medicines

• Provide Oxygen

• Prevent erosion

• Identify positive and negative conditions in an ecosystem

Today’s Objective:

Can be found in the book: Pg. 65 - 69

Life In an Ecosystem

• Conditions in one part of the world are suitable for supporting certain forms of life, but not others.

• The ability of an organism to withstand fluctuations in biotic and abiotic environmental factors is known as tolerance.

Ranges in Tolerance

For example, some crops may

survive a long drought period- They may not produce as as

well, but they’re able survive.

This makes me think of “Children of the Corn”

Common Limiting Factors

SunlightClimate

Atmospheric gases

Temperature

Water

Nutrients/FoodFire

Soil chemistry

Amount of Space

Other organisms

• A limiting factor is any biotic or abiotic factor that can affect the existence of an

organism.

• Factors that limit one population in a community may also have an indirect effect on another population.

Limiting Factors

For instance, what if a drought caused grass to reduce the number of seeds it produces…

What would happen to the mice that feed on those seeds?

What would happen to the hawks that feed on those mice?

• The maximum amount of organisms that can survive in an ecosystem is the carrying capacity.

– It is determined by the amount of resources available, such as:

• Habitat• Water• Food

No population can live beyond the environment’s carrying capacity for

very long.

● The “J” shape shows growth at a constant rate (exponential growth).

● When the “J” becomes an “S” shape…it means the population has reached carrying capacity.

Warm-up 9-23-2009Ecological Pyramid

• Using complete sentences answer the question below in your Composition Notebook.

• What is the purpose of an ecological pyramid? How much energy is passed on to each level? What happens to the rest of the energy that is not passed?

• Ecologists refer to the natural changes and species replacements that take place in an ecosystem as succession.

• Succession occurs in stages.

• At each stage, different species of plants and animals may be present.

Succession: Changes over Time

• As succession progresses, new organisms move in.

• Others may die out or move out.

There are two types of succession—

• primary

• secondary.

Succession: Changes over Time

• The colonization of organisms in a completely barren land is called primary succession.

• Primary succession takes place on land where there are no living organisms.

Succession: Changes over TimePRIMARY SUCCESSION

• The first species to take hold in an area like this are called pioneer species.

PRIMARY SUCCESSION

• As these organisms die, more soil builds- and it has more nutrients in it.

­

Exposed rock Primary succession

MossLichen

Pioneer species

PRIMARY SUCCESSION

• Secondary succession is the sequence of changes that takes place after an existing community is

severely disrupted in some way.

• Secondary succession, however, occurs in areas that previously contained life, and on land that still contains soil.

SECONDARY SUCCESSION

• Because soil already exists, secondary

succession takes less time than primary

succession to become a rich ecosystem again.

Succession: Changes over TimeSECONDARY SUCCESSION

Question 1

D. limiting factor

C. tolerance factor

B. biotic factor

A. abiotic factor

A(n) _____ is something that restricts the existence, numbers, reproduction or distribution of organisms.

The answer is D. A limiting factor may be a abiotic factor. Tolerance refers to an organism’s ability to withstand fluctuations of environmental factors.

Common Limiting Factors

Sunlight

ClimateAtmospheric gases

Temperature

WaterNutrients/Food

FireSoil chemistrySpaceOther organisms

Question 2

D. mature trees growing

C. pine seedlings sprouting

B. wildflowers growing where forest fires had burned

A. moss growing on a lava bed

Which of the following best illustrates primary succession?

Discuss with the person next to you:

The difference between primary and secondary succession.

The answer is A. Primary succession is the colonization of barren land by pioneer species, such as moss or lichens.

Question 3

What is required in order for secondary succession to occur?

Secondary succession occurs in areas that previously contained life. Soil must be present on this land, and the species that grow will differ from pioneer species.