Download Ecosystems and communities

Ecosystems and communities
Weather and Climate

Weather
 Day-to-Day

variations in conditions
Climate
 Year-after-Year
 Factors
patterns of temperature and precipitation
that affect CLIMATE?
The Greenhouse Effect

Greenhouse Gases


Carbon Dioxide, Methane, Water Vapor, CFCs
Why is this important?
Where do Organisms Live?

Tolerance: the range of conditions under which an organism can survive and
reproduce.

Habitat: the general place where an organism lives

Niche: An organism’s role in an ecosystem, including how it interacts with
biotic and abiotic factors, plus the resources it uses
Competition in Ecosystems


Definition: When organisms attempt to use the same
resource

Intraspecific – between members of the same species

Interspecific – between members of different species
Competitive Exclusion Principle

No two species can occupy exactly the same niche at the
same time

If two species attempt to occupy the same niche at the same
time, one will lose out
Predation and Herbivory

Predation: One animal (predator) captures and feed on another
animal (prey)

Herbivory: One animal (herbivore) feeds on primary producers
(i.e. plants)

*BOTH affect the population size and distribution of what is
eaten
What is going on here??
Keystone Species

Definition: A species that can cause dramatic changes in
ecosystem and/or community structure
Symbiosis

Definition: Relationship in which 2 organisms live closely
together

Types: Mutualism, Parasitism, Commensalism

Mutualism: Both organisms benefit

Parasitism: One organism benefits and the other is harmed

Commensalism: One organism benefits and the other is unaffected
Is it Mutualism, Parasitism, or Commensalism?
Clownfish and Sea Anemone
Whale and Barnacles
Tick and Human
Caterpillar and Wasp (larvae)
Ants and Acacia
Ecological Succession

Definition: A series of predictable changes that occur in a
community over time

Ecosystems change over time ESPECIALLY after
disturbances

How do they change?

Species die out
 New
#
species move in
of total species increases over time (generally)
Primary Succession
Occurs on a surface where no ecosystem existed before.
Pioneer Species
Climax Community
What types of disturbances lead to
primary succession?
Pioneer species: Lichen
After a volcanic eruption
Following a retreating glacier
Secondary Succession
Occurs on a surface where an ecosystem has previously existed.
Proceeds faster – why??
Climax Communities

Definition: a stable, mature community at the final stage of succession

After natural disturbances, original climax community is often reproduced

After human-caused disturbances, ecosystems may OR may not return to
original climax