Download What Happens When an Ecosystem Changes?

What Happens
When an
Ecosystem
Changes?
Chapter 4 Lesson 3
pg.A130
6th Grade Ms. Lourdes
Martinez
Environmental Changes
• Changes are a natural part of the history of any ecosystems. Fires,
drought, floods, or shifts in temeprature can and do change
ecosystems.
• As conditions in an ecosystem change, populations in the
ecosystem might also change.
– All organisms have a certain range of conditions in which they can
survive. The amount of light an ecosystem gets is also a condition that
affects its population.
• Read pg. A131
Competition
• Whithin an ecosystem, populations of different species live
together an interact. You’ve already learned that one way
organisms in an ecosystem interact is as consumers and
producers in food webs.
• Another way organisms interact is by competition.
• Organisms can live only in ecosystems where there needs
are met. These needs include:
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Food
Water
Space
Shelter
Light
Minerals
Gases
• These resources, however, are in limited supply in an
ecosystem. When two or more organisms try to use
the same resource, competition results.
• Members of different species may compete for
food, water, and space.
• Whenever resources are limited, the organisms that
survive will be those that are best adapted to the
new conditions.
People Affect Ecosystems
• Ecosystems change naturally, but they may also be
changed by humans. All the materials that people use and
the food that people eat come from the environment.
• People also change ecosystems when they introduce
new species to areas.