Topic 3 & 10
: Genetics
10.3 Gene Pools and Speciation
• Define the gene pool for humans living in
2015 compared to that in 1900.
1 – Gene Pools
Read & Consider Understandings 10.3.1-10.3.3



External and internal
structure (morphology
and anatomy)
Cell structure
Chemical composition
Species – a group of
organisms that
resemble on another
physically and may
reproduce viable
offspring.
Species

A population is a group of individuals of
a species, living together, and able to
interbreed. Populations are the venue for
evolution.
Population
A gene pool consists of all the genes and
their different alleles, present in an
interbreeding population.
 Allele frequency is the commonness of
the occurrence of any particular allele in a
population. Allele frequencies may be
static of changing in a population.

Genetic Dynamics
• How does one species diverge into multiple
species?
2 - Speciation
Read & Consider Understandings 10.3.4-10.3.5

Speciation is the evolution of new
species from existing species.
◦ Geographic Isolation & Genetic Drift
Speciation
Temporal Isolation – this may result
from members of a population getting on
slightly different timing for certain
behaviors or completion of cycles, namely
those involved in reproduction.
 Behavioral Isolation – this results when
members acquire distinct differences in
their growth and development and mating
practices.


In the case of asexual reproducers the
addition of a chromosome instantly
results in a new species.
Polyploidy
Allopatric speciation Sympatric
– isolating
speciation –
mechanisms that
involve physical
separation.
physical separation
that prevents gametes
of different demes
from ever meeting
mechanisms that
involve demes in the
same location.
isolating mechanism
prevents offspring
between members of
different demes
by geographic isolation by reproductive
isolation: temporal
mechanisms,
behavioral
mechanisms,
polyploidy
Allopatric vs. Sympatric


Gradualism – the
observation that
evolution by natural
selection is
exceedingly slow.
Punctuated
equilibria – the
theory that there may
have been several
abrupt steps to the
evolutionary process.
Evolutionary Process

Transient polymorphism is the process in
which one allele is progressively replaced
by another.
Transient Polymorphism

Balanced polymorphism – is the stable
coexistence of two or more distinct types
of individuals in a species. The proportion
of both alleles are maintained by natural
selection because both result in a
selective advantage.
Balanced Polymorphism
"Blue Jay." Western Iowa Watchable
Wildlife. N.p., n.d. Web. 19 Aug. 2015.
 Hermesh, Carol. "Stellar Jay - Spirit
Animal Totems." Spirit Animal Totems.
N.p., n.d. Web. 19 Aug. 2015.
 "Science Says Meditation Improves Gene
Pool." Silent Journey. N.p., 2013. Web. 19
Aug. 2015.

Works Cited