Mutations, gene flow, genetic drift, and selective breeding

Slides:



Advertisements
Similar presentations
Do Now Come in quietly Copy the objective (To learn about Evolution)
Advertisements

1 Lesson 25 – Evolutionary Processes Life Science.
Punnett Square Demonstrates how alleles can be combined when the F1 plants are self-fertilized to produce an F2 generation. Shows that 1/4 of the F2 plants.
Summer 2006 Workshop in Biology and Multimedia for High School Teachers.
Population genetics. Vocabulary Find the definition for: Microevolution Average heterozygosity Geographic variation cline.
EVOLUTION. EVOLUTION The first living organisms were simple, single celled organisms. Through time more complex simple- celled creatures were created.
KEY CONCEPT A population shares a common gene pool.
Modern View of Evolution: Genetic Change. Genes and Variation.
Theory of Evolution Chapter 15.
Evolution Species Changing over time. Charles Darwin Evolution by Means of Natural Selection.
The plant of the day Welwitschia is a monotypic gymnosperm genus
Mechanisms of Change The following four processes are the basic mechanisms by which evolution occurs. Its not just one mechanism that Evolution thrives.
The Mechanics of Evolution Interaction of Natural Selection and Inheritance (Genetics)
AND ADAPTATIONS NATURAL SELECTION 1. CHARLES DARWIN His theory of evolution by natural selection explained: Where all of the astonishingly diverse kinds.
Sources of Inherited Variation Mutations & Sexual Reproduction.
Evolution The change in life forms over time
Evolution commons.wikimedia.org/wiki/Image:Charles_Darwin_1881.jpgcommons.wikimedia.org/wiki/Image:DNA_double_helix_vertikal.PNG.
EVOLUTION Other Mechanisms of Evolutionary Change.
Mechanisms of Evolution. There are several: 1.Natural Selection 2.Gene Flow 3.Genetic drift 4.Mutations 5.Non-random mating There are several: 1.Natural.
Mechanisms of Evolution. There are several: 1.Natural Selection 2.Gene Flow 3.Genetic drift 4.Mutations 5.Non-random mating There are several: 1.Natural.
 Evolution is the change in the inherited traits of a population of organisms through successive generations  Two factors at work:  Processes that.
Mutations What you need to know. Definition of Mutation 1. A random change in an organism’s DNA Can be inherited – passed down from a parent to their.
Natural Selection process by which of life having traits that better enable them to adapt to specific environmental pressures, as predators, changes in.
A B C D E F G. Charles Darwin Natural Selection.
Mechanisms of Evolution What causes organisms to change over time?
Warm Up Contrast homologous and analogous characteristics.
Lesson # 5: Evolution (Natural Selection vs. Artificial Selection)
THE DEFINITION Biological evolution, simply put, is descent with modification. This definition encompasses small-scale evolution (changes in gene frequency.
Natural Selection. A. Species overproduce offspring that may survive an environment. B. There is little variation among members of a population. C. Competition.
Mechanisms of Evolution
Evolution of Populations
The Theory of Evolution
Learning Targets Describe the factors that Darwin considered when developing his Theory of Evolution. Explain the process of natural selection and how.
What is Evolution??? Learning Target: I can explain Natural Selection and the 4 conditions that are required for Natural Selection to take place.
3. Genetic Drift The change in allele frequencies as a result of chance processes. Directly related to the population numbers. These changes are much more.
Evolution Part 2.
Section 2: Genetic Change
Evolution as Genetic Change
V. How Does Evolution Work?
Summer 2006 Workshop in Biology and Multimedia
Darwin &. Natural Selection youtube. com/watch
Evolution of Populations
Darwin and Natural Selection
Selection, Survival of the Fittest, Mutation, Genetic Drift and Gene Flow How Evolution Happens.
Unit 8 – Evolution Learning Activities
Agents for Evolutionary Change
Evolution of Populations
Biology Unit 7 Notes: Evolutionary Mechanisms
Mechanisms for Evolution
Natural Selection & other mechanisms in Populations
Introduction to Evolution
Natural Selection & Evolution
Section 2: Genetic Change
Evolutionary Mechanisms
CORNELL NOTES: Mechanisms of Evolution
Bellringer Are evolution and natural selection related to one another? Explain. Who is Charles Darwin?
Genetic Drift.
Mechanisms of Evolution
Selection and Adaptation Vocabulary
Bellringer Brainstorm about two examples of mutations.  One mutation would be useful and beneficial, while the other would be harmful.  Discuss how the.
Darwin's Theory of Evolution
What leads to variation among species?
Natural Selection Genetic Drift Gene Flow Mutation Recombination
Microevolution Change within a species, organisms adapt to survive in their environment Micro - evolution is "driven" by natural selection Natural selection.
Natural Selection & other mechanisms in Populations
MICROEVOLUTION Microevolution refers to changes in allele frequencies in a gene pool from generation to generation. Represents a gradual change in a population.
V. How Does Evolution Work?
First, let’s talk about the word THEORY…
Mechanisms of Evolution
-Patterns -Other Factors of Evolution
Presentation transcript:

Mutations, gene flow, genetic drift, and selective breeding Evolution Mutations, gene flow, genetic drift, and selective breeding

Mutations Mutation is a change in DNA, the hereditary material of life. An organism's DNA affects how it looks, how it behaves, and its physiology — all aspects of its life. So a change in an organism's DNA can cause changes in all aspects of its life. Mutations are random Mutations can be beneficial, neutral, or harmful for the organism, but mutations do not "try" to supply what the organism "needs." In this respect, mutations are random- whether a particular mutation happens or not is unrelated to how useful that mutation would be. Not all mutations matter to evolution Since all cells in our body contain DNA, there are lots of places for mutations to occur; however, not all mutations matter for evolution. Somatic mutations occur in non- reproductive cells and won't be passed onto offspring.

Causes of Mutation Mutations happen for a couple of reasons. DNA fails to copy accurately Most of the mutations that we think matter to evolution are "naturally-occurring." For example, when a cell divides, it makes a copy of its DNA — and sometimes the copy is not quite perfect. That small difference from the original DNA sequence is a mutation. External influences can create mutations Mutations can also be caused by exposure to specific chemicals or radiation. These agents cause the DNA to break down. This is not necessarily unnatural — even in the most isolated and pristine environments, DNA breaks down. Nevertheless, when the cell repairs the DNA, it might not do a perfect job of the repair. So the cell would end up with DNA slightly different than the original DNA and hence, a mutation.

Gene flow Gene flow — also called migration — is any movement of individuals, and/or the genetic material they carry, from one population to another. Gene flow includes lots of different kinds of events, such as pollen being blown to a new destination or people moving to new cities or countries. If gene versions are carried to a population where those gene versions previously did not exist, gene flow can be a very important source of genetic variation.

Genetic drift Genetic drift — along with natural selection, mutation, and migration — is one of the basic mechanisms of evolution. In each generation, some individuals may, just by chance, leave behind a few more descendants (and genes, of course!) than other individuals. The genes of the next generation will be the genes of the "lucky" individuals, not necessarily the healthier or "better" individuals. That, in a nutshell, is genetic drift. It happens to ALL populations — there's no avoiding the whims of chance.

Genetic drift Genetic drift affects the genetic makeup of the population but, unlike natural selection, through an entirely random process. So although genetic drift is a mechanism of evolution, it doesn't work to produce adaptations.

Natural Selection There is variation in traits. For example, some beetles are green and some are brown. There is differential reproduction. Since the environment can't support unlimited population growth, not all individuals get to reproduce to their full potential. In this example, green beetles tend to get eaten by birds and survive to reproduce less often than brown beetles do.

Natural Selection There is heredity. End result: The surviving brown beetles have brown baby beetles because this trait has a genetic basis. End result: The more advantageous trait, brown coloration, which allows the beetle to have more offspring, becomes more common in the population. If this process continues, eventually, all individuals in the population will be brown.

Artificial Selection / Selective Breeding Long before Darwin, farmers and breeders were using the idea of selection to cause major changes in the features of their plants and animals over the course of decades. Farmers and breeders allowed only the plants and animals with desirable characteristics to reproduce, causing the evolution of farm stock. This process is called artificial selection/selective breeding because people (instead of nature) select which organisms get to reproduce.

Artificial Selection / Selective Breeding Can you think of a common example of selective breeding?