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Origin of Species
I. General
A. Def: group
of organisms with same characteristics to breed fertile offspring
B. John
Ray
1. All
different organisms able to produce same looking organism
2. All dogs
are dogs
C. Urnst
Mayr
1. Modern
definition
2. Species
that are isolated can loose ability to interbreed
D. Sub-species
1. Groups
of same species, but have different characteristics
2. Intergrade
– mixing characteristics of s.s.
3. Hybridization
– two different species mate and make another
II. Speciation (development)
A. Allopatric
– geographically isolated populations into distinct species
B. Sympatric
– change in species within a common area splitting into new species
C. Niche
1. Where
a species exists
2. Adapt
or fend or die
D. Pre
– Zygotic
1. Geographical
– separated by a barrier
2. Ecological
– in a different habitat
3. Temporal
– difference in mating seasons
4. Behavioral
– different rituals
5. Mechanical
– if it doesn’t fit, it doesn’t work!! Duh!
6. Gamete
Fusion Prevention – sperm & egg can’t
come together
E. Post
– Zygotic
1. The
zygote may form and not develop (doesn’t have the right messages)
2. Sterile
hybrid
3. Hybrid
weak to survive
F. Adaptive
Radiation
1. Many
similar species is derived from a common ancestor due to the occupation
of different niches within a common habitat
2. Darwin’s
Finches
a) Founder principle
b) Beaks changed;
coloration
3. Hawaiian
Distrophola – 16 to 24 hundred species
G. Sexual Selection
– artificial breeding
H. Rapid
Evolution
1. Change
in environment
2. Islands
3. New unoccupied
niches
I. Hybridization
1. Creates
phenotypes that might not normally occur
2. Introduce
variation
3. Methods
a) Parthenogenesis
(1) Dandelions, bees
(2) Development of an egg without
sperm
b) Polyploid
(1) Plants (seedless oranges)
(2) Vegetative propagation
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