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Formation of species
CHAPTER 16 SECTION 3
The process of species formation is called?
Speciation
Scientists use internal and external structures and appearances ( morphology )as the criteria for classifying a species
This is the morphological species concept
Because morphological characteristics are easy to observe, makes species designations based on morphology becomes convenient
THE CONCEPT OF SPECIES
This concept states
A species is a population of organisms that can successfully interbreed but cannot breed with other groups
What happens if species reproduce asexually?
How do we define a species that is extinct then?
BIOLOGICAL SPECIES CONCEPT
We have to use both concepts!
They must be isolated from other species.
2 forms of isolation exist
Geographic Reproductive
HOW DO YOU MAKE A SPECIES?
The physical separation of members of a population
Can you think of species that are geographically isolated that may have similar species in other areas?
GEOGRAPHIC ISOLATION
Results from barriers to successfully breeding between population groups in the same areas.
This can occur in two ways; before fertilization and after
REPRODUCTIVE ISOLATION
Before fertilization occurs when fertilization cannot occur.
Mating calls not recognized by certain frogs, differences in mating periods
REPRODUCTIVE ISOLATION
After fertilization barriers occur usually with the offspring.
Mostly involve offspring that are sterile
REPRODUCTIVE ISOLATION
2 different rates
Gradualism Punctuated Equilibrium
RATES OF SPECIATION
Rapid Change
Slow, gradual change
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