Download How Evolution Works

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

Artificial gene synthesis wikipedia, lookup

Microevolution wikipedia, lookup

Dominance (genetics) wikipedia, lookup

Designer baby wikipedia, lookup

Gene expression programming wikipedia, lookup

Quantitative trait locus wikipedia, lookup

Gene wikipedia, lookup

Gene expression profiling wikipedia, lookup

Site-specific recombinase technology wikipedia, lookup

Population genetics wikipedia, lookup

Human genetic variation wikipedia, lookup

Genome evolution wikipedia, lookup

Epistasis wikipedia, lookup

Hardy–Weinberg principle wikipedia, lookup

Genetic drift wikipedia, lookup

Polymorphism (biology) wikipedia, lookup

Koinophilia wikipedia, lookup

The Selfish Gene wikipedia, lookup

Group selection wikipedia, lookup

Dual inheritance theory wikipedia, lookup

Transitional fossil wikipedia, lookup

Adaptive evolution in the human genome wikipedia, lookup

How Evolution Works
Genes, Geography and Sex
Early Idea: Lamarckian
Fossil record
indicated increasing
Reasoned traits are
passed via use and
e.g. the giraffe’s
Step 1: Raw Material
Genes are raw material
 Forms of genes = alleles
 Polygenic vs. Single gene trait
Selection on a Single Gene:
The Peppered Moth
Before Industrial
After Industrial
Single gene
controlling a trait
will have only a few
(usually 2 or 3
Variation and Selection
Variation from two sources
1) New mutations = new allele types
2) Gene shuffling = new allele
 Any change in allele frequency =
 Peppered Moth Simulation
Polygenic Traits
More than one gene controls a trait
Selection and Changing the
Most traits are polygenic
 The normal trait is the average or
mean in the population
 Selection changes the mean, usually
lowers variation
 Selection will adjust mean
Stabilizing Selection
Disruptive Selection
Can lead to new species
Does Evolution Ever Stop?
YES, but only if the following conditions
are met
1) Random mating
2) Large Population
3) No movement in or out of
4) No Mutations
5) No Natural Selection
 Hardy Weinberg Equilibrium
How New Species Are Formed
Two populations must become
reproductively isolated
Behavioral Isolation
Groups differ in mating, feeding,
sleep/awake cycles so members of
populations do not meet to mate
Rana aurora (Redlegged frog)
Breeds in fast moving
Rana catesbiana
(Common bullfrog)
Breeds in still ponds
Geographic Isolation
Geological Time and Evolution
First fossils 3.5 bya
550 mya =
Cambrian Explosion
(by fossil evidence)
Dating Fossil Age
Relative Dating
Radioisotope Dating
Known decay times
of isotopes can be
Extinction and Adaptive
Most species cannot
Those that can
radiate into open
Evolution Patterns
Convergent Evolution