Download Genes and Evolution - Mad River Local Schools

GENES AND
EVOLUTION
Unit Eight
Principles of Evolution
1) Genetic variety
◦ DNA mutations-adds new phenotypes to a population
◦ Genetic recombination (crossing over) allows for variety
2) Mutation and Environment
◦ New phenotype either “fits” or doesn’t “fit” with environment
◦ Those that fit best are more likely to reproduce and survive (natural selection)
3) New Species Evolve
◦ Mutations and natural selection result in a new species over millions of years
Difference between Natural Selection and
Evolution:
Natural selection drives evolution
Today’s Focus
◦DNA mutations:
◦ Brings in new alleles
◦ Adds new phenotypes to a population
◦ Allows organisms to adapt to their environment
Sequencing Neanderthal DNA
1. Why is comparing human DNA to Neanderthal DNA difficult in the lab?
2. How can the bases of DNA change overtime?
3. Where was the sample taken from Pääbo found and how old was it?
4. What did the lab results say about the population size of Neanderthals?
5. How many Neanderthals did Paabo sequence and where were they from?
6. Was the Neanderthal DNA genetically diverse?
7. How does the DNA differ between modern humans and Neanderthals?
8. What percent of DNA changed after humans split from Neanderthals?
Sequencing Neanderthal DNA
https://www.youtube.com/watch?v=-1Nrm-M-m14&feature=player_embedded
Thursday Assessment Question
How do DNA mutations give rise to new species over millions of years?
Notebook Checklist
Evolution foldable
Neanderthal questions
GENES AND
EVOLUTION
Unit Eight
Which of the following best describes
evolution?
a. Changing of organisms over time
b. The descent of an organism from a common ancestor
c. Phenotypes of an organism and how they fit with the
environment
d. Both a and b
Which of the following is the most necessary
in order for evolution to happen?
a.
b.
c.
d.
Organisms need to have selective pressure
There needs to be a common ancestor
Phenotypes need to be successful
There must be genetic mutations
What is the difference between a gene and
a phenotype?
a. A gene is a sequence of DNA and a phenotype is the gene
expression
b. A gene is a protein and a phenotype is DNA
c. A gene is a sequence of DNA and a phenotype is the
physical protein expression
d. I don’t know
Gene Frequency
◦Indicates which genotypes are most prevalent or least
prevalent in a population
◦Calculated as a percent
◦# in population/total
Gene Frequency
◦Brown- AA
◦White-aa
What is the genotypic
frequency for homozygous
recessive?
Beetle Genotypic Frequency Lab
Purpose
Explore the genotypic frequency in a beetle
population
Connection to Learning Objective
How does a changing in genotypic frequency
result in evolution?
Friday Assessment Question
How did a change in genotypic frequency
cause your beetle population to evolve?