What Is Genetic Drift? Genetic drift definition: A random change in the frequency of alleles in a gene pool, usually due to small population size.

Slides:

Advertisements

Similar presentations

The Five Factors of Evolution

Advertisements

How do we know if a population is evolving?

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

Population Genetics & Evolution. Individuals do not evolve but populations do.

Gene flow is the movement of alleles between populations.

The Genetics of Evolution What is the relationship between the genes of a population and evolution?

Genetic Drift Random change in allele frequency –Just by chance or chance events (migrations, natural disasters, etc) Most effect on smaller populations.

The Evolution of Populations Chapter 23 Biology – Campbell Reece.

How do we know if a population is evolving?

Changing Allele Frequency Chapter 23. What you need to know! The conditions for Hardy-Weinberg Equilibrium How to use the Hardy-Weinberg equation to calculate.

Population Genetics The Study of how Populations change over time.

 A llele frequencies will remain constant unless one or more factors cause the frequencies to change.  If there is no change, there is no evolving.

11.3 Other Mechanisms of Evolution KEY CONCEPT Natural selection is not the only mechanism through which populations evolve.

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

11.3 Other Mechanisms of Evolution KEY CONCEPT Natural selection is not the only mechanism through which populations evolve.

Chi square and Hardy-Weinberg

Genetic Drift What IS Genetic Drift?. Read the snip-it provided. In the space below, write a response to the information presented in the text. Formulate.

Put these events in order. A new selective pressure occurs. A pop. contains genetic variation as a result of mutation. Allele (gene) frequencies within.

The Chi Square Test A statistical method used to determine goodness of fit Chi-square requires no assumptions about the shape of the population distribution.

OUTLINE 22 Forces that disrupt HW equilibrium

Evolution The two most important mechanisms of evolution are

Populations, Gene Pools, & Microevolution

Definition: Movement of alleles from one population to another

The Genetics of Evolution

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

Measuring Evolution of Populations

Measuring Evolution of Populations

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

Genetic Drift: Chance Change A common misconception about evolution is that the features of organisms have evolved due to random chance alone Random cause.

The Chi Square Test A statistical method used to determine goodness of fit Goodness of fit refers to how close the observed data are to those predicted.

Hardy-Weinberg Genetic Equilibrium

The Chi Square Test A statistical method used to determine goodness of fit Goodness of fit refers to how close the observed data are to those predicted.

Daily Warm-up February 3rd

Population Genetics.

To be successful today…

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

Other Mechanisms of Evolution

Introduction to the Lab & Evolution

March 26th and 27th , 2018.

When Genes Flow… Gene flow= the movement of alleles between populations. Occurs when individuals join new populations and reproduce. Lots of gene flow.

Gene flow is the movement of alleles between populations.

CORNELL NOTES: Mechanisms of Evolution

Mechanisms of Evolution

Describe how evolution can be thought of as both a fact and a theory.

Evolution Evolution is driven by natural selection favoring phenotypes (expressed traits) that are better suited for the environment. Better suited individuals.

The Chi Square Test A statistical method used to determine goodness of fit Goodness of fit refers to how close the observed data are to those predicted.

Lecture: Natural Selection and Genetic Drift and Genetic Equilibrium

Mechanisms of Evolutionary Change

Genetic Equilibrium Population genetics looks at evolution at the genetic level Types of Evolution: Convergent Evolution Different species evolve similar.

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

Mechanisms of Evolution

Measuring Evolution of Populations

MECHANISMS OF EVOLUTION

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

LEARNING OBJECTIVE 3. Differentiate between different types of Natural Selection and how they impact Evolution.

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

Agenda 10/3 Hardy-Weinberg Introduction

What evidence do we have for evolution? (5)

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

Hardy Weinberg.

Natural Selection Microevolution.

Genetic Equilibrium Hardy - Weinberg.

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.

4-Population Genetics Notes

Evolution of Populations

Hardy-Weinberg Lab Data

Mechanisms of Evolutionary Change

Presentation transcript:

What Is Genetic Drift? Genetic drift definition: A random change in the frequency of alleles in a gene pool, usually due to small population size.

Genetic Drift: Chance Change A common misconception about evolution is that the features of organisms have evolved due to random chance alone Random cause Non-Random cause of change Mutations Non-random mating Genetic Drift (small pops) Natural Selection Gene flow** ** Migration can be random or non - random

Genetic Drift: Changes due to chance events Small populations are more prone to chance events causing change in allele frequencies The creation of small populations from large ones can therefore increase likelihood of change 2 examples of events that make populations vulnerable to genetic drift are Founder effect Bottleneck effect Berkeley – Understanding Evolution Bottlenecks and founder effects

Founder Effect

Bottleneck Effect

7 scenarios Population at equilibrium Population where mutations have occurred Population experiencing gene flow Population that has experienced the founder effect Population that has experienced the bottleneck effect Population that has experienced natural selection Population that has experienced non-random mating

Design your experiment! Consider the Strawfish and Population Genetics labs as a template Using the beads provided, design a lab that would simulate your lab groups’ assigned condition and its effect over time Determine logical number of generations (pop size is 10) Set up a control (Round 1) and figure out what your H-W Equilibrium allele frequencies should be (How does this correspond to a null hypothesis?) Check with me to make sure your design is appropriate before proceeding! Run your experiment and collect data When you collect data, only pull 10 individuals per round. The rest die. Create your new population based on the frequencies of each allele Run a chi-square analysis and determine whether or not to reject your null hypothesis Be able to explain your results to the class!

Sample Table X2 = sum Possible Outcomes Expected (e) Observed (o) o-e

Chi Square Formula and Table