Download Mechanisms of Evolution

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Pharmacogenomics wikipedia, lookup

Gene therapy wikipedia, lookup

Nutriepigenomics wikipedia, lookup

Inbreeding wikipedia, lookup

Gene expression profiling wikipedia, lookup

Biology and consumer behaviour wikipedia, lookup

Dominance (genetics) wikipedia, lookup

Gene wikipedia, lookup

Quantitative trait locus wikipedia, lookup

Mutation wikipedia, lookup

Heritability of IQ wikipedia, lookup

Genome evolution wikipedia, lookup

Artificial gene synthesis wikipedia, lookup

Public health genomics wikipedia, lookup

Point mutation wikipedia, lookup

Epistasis wikipedia, lookup

Site-specific recombinase technology wikipedia, lookup

Polymorphism (biology) wikipedia, lookup

Gene expression programming wikipedia, lookup

Genetic engineering wikipedia, lookup

History of genetic engineering wikipedia, lookup

Human genetic variation wikipedia, lookup

Designer baby wikipedia, lookup

Genome (book) wikipedia, lookup

Koinophilia wikipedia, lookup

Genetic drift wikipedia, lookup

Population genetics wikipedia, lookup

Microevolution wikipedia, lookup

Transcript
The Genetic Basis of Evolution
Gene Pools
are all of the alleles (alternate forms of genes) in
all of the individuals that make up a population.
What Drives Evolution?
There are 5 forces of change.
Recombination
1. Mutations
One type of mutation at the
level of the gene.
One type of mutation at the
level of the chromosome.
Mutations
-occur randomly
- can be beneficial, neutral, or harmful in
their effects
Venom-like proteins
first appeared about 200 million years ago
2. Gene Flow or Migration
• is the transfer of alleles or genes from one
population to another.
• This makes separate populations more similar
genetically.
Ex. Gene flow in plants
– wind-dispersed pollen
Gene Flow or Migration
3. GENETIC DRIFT
• A change in the population because of a
random event, such as a catastrophe
• The smaller the population, the less
genetic variety it has.
• 2 Types:
a. Genetic Bottleneck –
allele frequency is altered due to
a population crash.
-Catastrophe
-Only the survivors will
reproduce offspring
.
b. The Founder
Effect
• occurs when a small number of individuals from one population found a
new population that is reproductively isolated from the original one.
Endangered Species Are in the Narrow Portion of a Genetic
Bottleneck and Have Reduced Genetic Variation
4. Natural Selection
Natural selection leads to adaptation – an
increase in the fitness of a population in a
particular environment.
• Successful (adaptive) genotypes
become more common in subsequent
generations,
• causing an alteration in allele
frequency over time
• leads to a consequent increase in
fitness.
• The production of healthy, fertile
offspring results in VARIATIONS in
the gene pool.
.
Darwin’s Finches and the Theory of Evolution of Natural Selection
Case Study
Peter and Mary
Grant and their
colleagues
observed how
beak depth, a
significant trait
for feeding
success, varied
in populations
experiencing
climactic
variations.
Beak depth is a genetically
determined trait.
5. Recombination
-Genetic material combined during
sexual intercourse
-Crossing over
-Enormous diversity in species
-recombination or shuffling of
genes
-creates new allele combinations
in the gametes (sex cells)
Crossing Over
Chromosomes