Scribd
Upload
30 views18 pages

Genetics & Evolution Basics

This document discusses population genetics and evolution. It covers key topics like gene pools, factors that affect allele frequencies like mutation, migration, genetic drift and selection. It also discusses speciation, the evolution of new species over time through mechanisms like geographical isolation of small populations, behavioral isolation, seasonal isolation and mechanical isolation as observed in the fossil record. Evolution occurs through changes in allele frequencies in a population over generations rather than in individuals.

Uploaded by

Tintin Brusola Salen
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPSX, PDF, TXT or read online on Scribd
30 views18 pages

Genetics & Evolution Basics

This document discusses population genetics and evolution. It covers key topics like gene pools, factors that affect allele frequencies like mutation, migration, genetic drift and selection. It also discusses speciation, the evolution of new species over time through mechanisms like geographical isolation of small populations, behavioral isolation, seasonal isolation and mechanical isolation as observed in the fossil record. Evolution occurs through changes in allele frequencies in a population over generations rather than in individuals.

Uploaded by

Tintin Brusola Salen
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPSX, PDF, TXT or read online on Scribd
You are on page 1/ 18

Population Genetics

The study of allele


frequencies within a
population
Gene Pool
All of the genes of a population of
organisms
Organisms that are the most
successful at reproducing contribute
most to the gene pool
Evolution
Any change in the frequency of
any allele within a gene pool
Populations undergo evolution
Individuals do not undergo
evolution
Factors Affecting the Allele
Frequency
Mutation
Especially important for
organisms with short generation
times
Factors Affecting the Allele
Frequency
Migration
Movement of organisms into or
out of the population
Factors Affecting the Allele
Frequency
Genetic Drift
Random change in allele
frequencies
Occurs mostly in small, isolated
populations
Factors Affecting the Allele
Frequency
Selection
Environmental pressures
Competition
Climate change
Factors Affecting the Allele
Frequency
Nonrandom mating
Preferences in selection of a
mating partner
SPECIES
Species: A group Kingdom
of organisms so Phylum
similar to one Class
another that they Order
can interbreed and Family
produce fertile Genus
offspring Species
Speciation
Speciation is the evolution of
new species through time
Speciation occurs most rapidly
in a small population
Mechanisms of Speciation
Artificial Speciation
New species have been developed
by man
Intentional mutations
Cross breeding
Genetic engineering
Mechanisms of Speciation
Natural Speciation by Isolation of
Small Populations
Geographical Isolation
Geographical barriers separate two
populations
Mountain ranges
Deep canyons
Bodies of water
Ecological Isolation
Organisms of two populations require
different habitats
Mechanisms of Speciation
Behavioral Isolation
Changes in habits that identify one
population with another
Mating rituals
Methods of communication
Mechanisms of Speciation
Seasonal Isolation
Reproductive cycles do not
coincide
Plants that flower at different
times
Animals that mate or nest build at
different times
Mechanisms of Speciation
Mechanical Isolation
Physical characteristics that keep
organisms from interbreeding
Difference in size
Difference in reproductive anatomy
Inability of sperm to penetrate the
egg
Observations From the Fossil
Record
Species often remain stable for
millions of years with little or no
noticeable change
Species may disappear rapidly and
new species may appear just as fast
Population Evolution
Punctuated
Equilibrium
Long periods of
stability followed
by short periods
of rapid change

You might also like