Download Chapter 13 How Ecosystems Change

Chapter 13
How Ecosystems Change
Section 2
Ecosystem Development and
Change
College Bound Biology
Mr. McCloskey
Ecosystem Lifestyles
• Niche = The sum of an organism’s
interactions with its physical environment
and with other organisms.
Job #1
Bring minerals to the surface
Job #2 Carry dead material underground
Job #3
Helps water and gases penetrate soil
Ecosystem Lifestyles
• Fundamental Niche = The total niche that
an organism could potentially use within
an ecosystem.
Competing Organisms Coevolve
• Competition = A situation in nature when
two or more organisms attempt to use the
same resource.
Shallow water and deep
water barnacles compete
to take hold of the rocks.
Competing Organisms Coevolve
• Realized Niche = The part of a
fundamental niche that an organism
actually occupies as a direct result of
competition.
Competition can cause changes in
an ecosystem
• Competitive exclusion = The process in
which two species fighting for the same
resource results in one species losing and
dying out within the ecosystem.
Competition and Ecosystem
Development
• Competition is often seen when a
disturbance creates new habitat.
Competition and Ecosystem
Development
• Glaciers recede
Competition and Ecosystem
Development
• Yosemite Fires
Competition and Ecosystem
Development
• Tornadoes
Competition Drives Change in a
Developing Ecosystem
• The first species to enter the new habitat
are small, fast growing plants. These are
known as the SETTLERS or PIONEERS.
Competition Drives Change in a
Developing Ecosystem
• These small plants (pioneers) help to
improve the soil ecosystem and allow
other plants to come in and grow.
Competition Drives Change in a
Developing Ecosystem
• Succession = The regular progression of
species replacement in a developing
ecosystem
Competition Drives Change in a
Developing Ecosystem
• Primary Succession
= When succession
takes place on land
where nothing has
ever grown before.
Competition Drives Change in a
Developing Ecosystem
• Secondary succession = Succession
taking place in areas where there has
been previous growth like an abandoned
farm filed or forest clearing.
Ecosystem Stability
• Stability = The ability of the later stages of
succession to resist disturbances.
• Early succession = low stability
• Later succession = more stability
• Final community = most stable
What factors promote stability?
Answer = Diversity!!!
More diverse
ecosystems are
more stable. The
web of interactions
makes them more
likely to handle
distrubances.
What factors promote stability?
• Keystone Species = A species whose
niche affects many others in the
ecosystem and that cannot be readily
replaced if lost.
Why are some Ecosystems More
Diverse Than Others?
Answer
= The size of the ecosystem
Reducing the size of an ecosystem reduces the variety
of physical habitats.
National Parks!!!!
Why are some Ecosystems More
Diverse Than Others?
• Answer = The latitude of the ecosystem
Latitude has a great influence on ecosystems because both
moisture and temperature vary with the distance from
the equator.
The tropics are warm and moist and have long growing
seasons with lost of rain.
There is also little variation in the temperature from day to
day and year to year. Therefore, there are lots of
species coevolving.