Download SPECIATION

How Do We
Get A New
Species?
SPECIATION
Is It This Easy?
NO!
The gene pools of two populations
must separate.
1
• Because members of a population
interbreed, they share a
common group of genes called a
GENE POOL
___________.
• A gene pool consists of
____________
ALL the genes present in a
population, including all the
alleles
different _________.
The ____________________
relative frequency is the
number of times that an allele occurs in
the gene pool compared to the
occurrence of other alleles in the gene
pool.
Sample Population
48%
heterozygous
black
Frequency of Alleles
allele for
brown fur
allele for
black fur
16%
homozygous
black
36%
homozygous
brown
RELATIVE FREQUENCY is often
expressed as a __________________.
percentage
EX: In this population
Dominant B allele (black) = 40%
Recessive b allele (brown) = 60%
2
NOTHING
RELATIVE FREQUENCY has _________
to do with whether an allele is
DOMINANT or _____________
RECESSIVE
______________
In this
population,
the
recessive
allele is
more
frequent.
_______________________IS
THE
SEXUAL
REPRODUCTION
MAJOR SOURCE OF VARIATION IN
NOT
POPULATIONS, but it does _______
change the __________________
of
relative frequency
alleles in population!
Shuffling a deck of cards
can shuffle to produce
many different hands,
but doesn’t change the
number of kings or
queens in the deck.
Interbreeding
Fertile Offspring
= Reproductive
Isolation
3
Reproductive
Isolation
• Behavioral Isolation
• Geographical Isolation
• Temporal Isolation
Behavioral Isolation
Two populations can mate, but mating rituals differ.
Geographic Isolation
Populations are separated by
geographic barriers.
4
Temporal Isolation
When two or more species
reproduce at different times.
5