Download Chapter 4 Section 2 What Shapes an Ecosystem?

Chapter 4 Section 2
What Shapes an Ecosystem?
• Objectives:
• -Explain how biotic and abiotic factors
influence an ecosystem
• -Identify the interactions that occur within
communities
• -Describe how ecosystems recover from a
disturbance
Biotic Factors
• Biological (living) influences on
organisms within an
ecosystem
Abiotic factors
•Nonliving factors that
influence an ecosystem
•ie: temperature,
precipitation, etc.
Abiotic Factors
Biotic Factors
ECOSYSTEM
• Together, biotic and abiotic factors determine
the survival and growth of an organism, and
the productivity of the ecosystem in which the
organism lives
Niche:
• The full range of physical and biological
conditions in which an organism lives and the
way the organism uses those conditions
• Includes biotic and abiotic factors as well as
the way in which the organism uses physical
and biological conditions
• No two species can share the same niche in
the same habitat, however they can be similar.
See pg. 92 Figure 4-5
Cape May Warbler
Feeds at the tips of branches
near the top of the tree
Bay-Breasted Warbler
Feeds in the middle
part of the tree
Spruce
tree
Yellow-Rumped Warbler
Feeds in the lower part of the tree and
at the bases of the middle branches
Competitive Exclusion Principal :
• No two species can occupy the same niche.
• Competition results in organisms of the same
or different species competing for a resource
(light, food, nutrients, and/or space)
• Direct competition in nature results in a
winner (survives) and a loser (fails to survive)
Predation:
• An interaction in which one organism captures
and feeds on another organism
Symbiosis:
• Any relationship in which two
species live closely together
Three Symbiotic Relationships
• 1. Mutualism
• 2. Commensalism
• 3 Parasitism
Mutualism:
• Both species benefit
• Nitrogen fixation occurs in plants that harbor nitrogenfixing bacteria within their tissues. The best-studied
example is the association between legumes (plants that
produce pods) and bacteria.
• Each of these is able to survive independently (soil
nitrates must then be available to the legume), but life
together is clearly beneficial to both. Only together can
nitrogen fixation take place
How are both species benefitting?
Commensalism
• One species benefits, the other is unaffected
Clown fish live within the waving mass of tentacles of sea anemones;
because most fish avoid the poisonous tentacles, clown fish are protected
from predators
Parasitism:
• One species benefits, the other is harmed
The Art of Deception — Interactive —
National Geographic Magazine
Wasps and Aphids
Cat Parasite - Most Extreme
Ecological Succession:
• A series of predictable changes that occurs in
a community over time
• As an ecosystem changes, older inhabitants
gradually die out and new organisms move in,
causing further changes in the community.
Primary Succession:
• Succession that occurs on surfaces where no
soil exists
• (ie: new land created by lava flows, or bedrock
exposed after glaciers melt)
Primary Succession Continued:
• Pioneer species – the first species to populate
an area
Lichens
Primary Succession Continued,
Lichens:
• Lichens: are made up of a fungus and an alga
that grow on bedrock. They break up
bedrock, when they die, they add organic
matter to the weathered bedrock.
• Dead organic matter + weathered bedrock
=SOIL
Secondary Succession:
• Succession following a disturbance that
destroys a community without destroying the
soil
• Ie: Bruins fire (June 2006)
– Wood chute Fire (July-August 2009)
– Taylor Fire (August 8-16-09)
– Schultz fire (June 2010)
– Wallow Fire (July 2011)
Order of Successive Events:
• Grass (1-2 years)  shrub (3-25) Pines
Forrest (25-100)  climax community (100150+)
Why is Secondary Succession quicker
than Primary Succession?
• Because the soil has been prepared by the
previous community