15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to...

35
15.3 NOTES

TAGS:

Transcript of 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to...

Page 1: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

15.3 NOTES

Page 2: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Genetic DriftA random change in the frequency of an allele in a population NOT due to natural selection.

More likely to occur in small populations.

Page 3: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Genetic DriftFounder effect: a small group separates from the population and lives somewhere elsethey carry a subset of the population’s gene

Ex: Amish community

Page 4: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Genetic DriftBottleneck: population declines to a very low number and then reboundsthe gene pool of the rebound population is similar to the original population

Page 5: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.
Page 6: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Ex: Northern Elephant SealsLarge population overhunting 20 Total

◦Population eventually recovered in size

◦Loss of genetic variationCould hurt long-term survival of species

Page 7: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.
Page 8: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Remember mutations? A random change in a sequence of DNA.

A small population with a lot of mutations has the greatest potential for evolution

Page 9: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Natural Selection

How does it alter phenotypes?

Page 10: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Stabilizing selection: selection against extreme expressions of a trait, selection for the average

Ex: birth weight in human babies

Page 11: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Directional selection: selection toward one extreme of a trait

Ex: Galapagos finches - large beaks during drought

Peppered moths - color

Page 12: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Disruptive selection: selection against the average, selection for both extremes

Ex: Cichlid fish size - males

Page 13: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Sexual selection: selection of a trait in males to attract a mate and intimidate other malesEx: peacocks

Page 14: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Reproductive Isolation

Some members of a population change so much that they can no longer produce offspring with members of the original population.

Page 15: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Eastern meadowlark and

Western meadowlarkDifferent mating

patterns LigerSterile

Page 16: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Geographic IsolationA separation of population by a barrierEx: mountains, rivers, the Grand Canyon

Page 17: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

For speciation to happen, a population has to move away and then be reproductively isolated.

Page 18: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Allopatric Speciation 

A physical barrier divides one population into 2 or more populations

Abert squirrelSouth Rim

Kaibab SquirrelNorth Rim

Page 19: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Sympatric Speciation A species evolves into a new species without a physical barrier

The old species and new species live side by side during speciation

Page 20: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Adaptive Radiation(Divergent Evolution)The evolution of a new species in a relatively short period of timeone species evolves into several different forms that live in different habitats

homologous structures

Page 21: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.
Page 22: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Coevolution

A close relationship between 2 species

The evolution of one species influences the evolution of the other

Page 23: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Datura Plant & Hawk Moth

Page 24: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Convergent EvolutionUnrelated species evolve similar traits even though they live in environments that are really far apartsimilar ecology and climateanalogous structures

Page 25: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

3. Convergent Evolution Unrelated species evolve

similar adaptations, due to environmental pressures (natural selection)

These adaptations may look similar from the outside, but actually evolve independently from each other Ex: sharks, dolphins, seals,

penguins

Page 26: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Analogous structures Similar in appearance and

function, but are developed from anatomically different parts

Evidence for convergent evolution

Ex: octopus eye versus vertebrate eye (both complex eyes

Page 27: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.
Page 28: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.
Page 29: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.
Page 30: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

South American North American Pliocene Pleistocene

Natural Selection Common Adaptation**But common adaptations do not necessarily

imply common ancestor!

Page 31: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.
Page 32: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Gradualism:

Evolutionary change occurs gradually, over long periods of time

Page 33: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Punctuated Equilibrium

Patterns of long periods of stability (no change) interrupted by episodes of rapid change

Page 34: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.
Page 35: 15.3 NOTES. Genetic Drift A random change in the frequency of an allele in a population NOT due to natural selection. More likely to occur in small populations.

Evolution can follow both patterns, depending on the situation and the time in evolutionary history


Golf Guide 15.3

Golf Guide 15.3

Changing Allele Frequencies. Allelic Frequencies Change When There Is: Non-random mating Gene flow/Migration Genetic drift Mutation Natural selection.

Changing Allele Frequencies. Allelic Frequencies Change When There Is: Non-random mating Gene flow/Migration Genetic drift Mutation Natural selection.

Biology 15.3

Biology 15.3

1 Random Genetic Drift : Chance as an Evolutionary Force Random Genetic Drift is the random change in allele frequencies from one generation to the next.

1 Random Genetic Drift : Chance as an Evolutionary Force Random Genetic Drift is the random change in allele frequencies from one generation to the next.

Chapter 15.3

Chapter 15.3

15.3 Mechanisms of EVOLUTION. The formation of a new species 15.3 Speciation.

15.3 Mechanisms of EVOLUTION. The formation of a new species 15.3 Speciation.

15.3 Optical Phenomena

15.3 Optical Phenomena

Evolution by genetic drift random fluctuation in allele frequencies allele loss or fixation allele frequency differences between populations.

Evolution by genetic drift random fluctuation in allele frequencies allele loss or fixation allele frequency differences between populations.

The SandBar 15.3

The SandBar 15.3

1 Review Define genetic drift Relate Cause and Effect How can the founder effect lead to changes in the allele pool 2 Infer Genetic equilibrium is uncommon.

1 Review Define genetic drift Relate Cause and Effect How can the founder effect lead to changes in the allele pool 2 Infer Genetic equilibrium is uncommon.

15.3: Human Evolution

15.3: Human Evolution

Migration and Drift - courses.pbsci.ucsc.edu · 1/6/2019  · 1 allele = w 1 = pw 11 + qw 12 The fitness of the A 2 allele = w 2 = qw 22 + pw 12 One final fitness to define…. Mean

Migration and Drift - courses.pbsci.ucsc.edu · 1/6/2019  · 1 allele = w 1 = pw 11 + qw 12 The fitness of the A 2 allele = w 2 = qw 22 + pw 12 One final fitness to define…. Mean

Allopatric Speciation—Drift Drift is important in evolution Just because an allele is common doesn’t mean selection favored it.

Allopatric Speciation—Drift Drift is important in evolution Just because an allele is common doesn’t mean selection favored it.

VOCABULARY EVOLUTION. GENETIC DRIFT RANDOM CHANGE IN ALLELE FREQUENCIES THAT OCCURS IN SMALL POPULATIONS.

VOCABULARY EVOLUTION. GENETIC DRIFT RANDOM CHANGE IN ALLELE FREQUENCIES THAT OCCURS IN SMALL POPULATIONS.

Three major factors alter allele frequencies and bring about most evolutionary change: –Natural selection –Genetic drift –Gene flow Concept 23.3: Natural.

Three major factors alter allele frequencies and bring about most evolutionary change: –Natural selection –Genetic drift –Gene flow Concept 23.3: Natural.

testbankgo.eu · Web viewANSWER: Genetic drift refers to chance fluctuations of allele frequencies of a population and can be seen in both founder’s effect and population bottlenecks

testbankgo.eu · Web viewANSWER: Genetic drift refers to chance fluctuations of allele frequencies of a population and can be seen in both founder’s effect and population bottlenecks

Population Genetics – Natural Selection€¦  · Web viewPopulation Genetics – Genetic Drift & the Bottleneck Effect . INTRODUCTION . Genetic drift is a change in allele frequencies

Population Genetics – Natural Selection€¦  · Web viewPopulation Genetics – Genetic Drift & the Bottleneck Effect . INTRODUCTION . Genetic drift is a change in allele frequencies

Populations microevolution - genetic drift - natural selection - migration allele frequencies How do _____ evolve?

Populations microevolution - genetic drift - natural selection - migration allele frequencies How do _____ evolve?

Three-Allele Selection Model - Worcester Polytechnic Institute...Three-Allele Selection Model A Major Qualifying Project submitted to the Faculty ... (no genetic drift), equal allele

Three-Allele Selection Model - Worcester Polytechnic Institute...Three-Allele Selection Model A Major Qualifying Project submitted to the Faculty ... (no genetic drift), equal allele

Selection versus drift The larger the population the longer it takes for an allele to become fixed. Note: Even though an allele conveys a strong selective.

Selection versus drift The larger the population the longer it takes for an allele to become fixed. Note: Even though an allele conveys a strong selective.