disperbal and...
Post on 01-Nov-2019
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Process whereby an organism is able to
spread from its plate of original to
another locality
Dispersal
Barriers
Physical Barriers ☻ Water
☻ Topography (Mountain, Cliffs, valley)
☻ Desert
Ecological Barriers ☻ Climate zones
☻ Living environment
☻ Cultural desert
☻ Ecological “desert” (Salinity, Soil type, etc)
Passive Dispersal
Anemochore dispersal
(wind and air current)
Hydrochore dispersal (water)
Anemohydrochore dispersal
Biochore dispersal (other organism)
Anthropochore dispersal (by human)
Good Colonizers
Able to with stand extreme
condition (? Of food and water)
Good ability to reproduce good
Good competitor, if necessary
“pioneer” species
DISPERSAL AND COLONIZATION
1. Start with
one continuous
population.
Then, a colonist
floats to an
island on a raft.
2. Finish with
two populations
isolated from
one another.
Island
Continent
Why would these
populations
diverge into
separate
populations?
DISPERSAL AND COLONIZATION
1. Start with
one continuous
population.
Then, a colonist
floats to an
island on a raft.
2. Finish with
two populations
isolated from
one another.
Island
Continent
- genetic drift -
colonists are few and
likely to be non-
random sample of
original population
- natural selection -
selection pressures in
new environment are
unlikely to be the
same as in old
environment
- leads to different
species on islands vs.
mainland
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