1. (we’ll work as a class in 5 min.)
WELCOME BACK!!!
In Activity: Scent Lab
Pick up Scent Lab by door & Read the Directions
(we’ll work as a class in 5 min.)

2. Scent Lab
Pretend you are a wolf and must find your pack using your sense of smell.
Why is the adaptation of smell important to the survival and evolution of Wolf packs?

3. TEKS 7C
Analyze and evaluate how natural selection produces change in populations, not individuals

4. Population Genetics Lab
Clear your desk & Read the introduction
Use the materials to model populations in various scenarios:
Population, Natural Selection, Mutation, Reproductive Isolation, Gene Flow, Genetic Drift, Barrier Isolation
Answer all questions on the handout
Return the materials to your teacher
Class Debrief

5. Concept Map Notes: Speciation Mutations Gene Shuffling
Gene Flow (migrations)
Genetic Drift (bottle neck effect & founder effect)

6. Emergence of Evolutionary Thought
Galapagos Islands
Charles Darwin

7. Voyage of the H.M.S. Beagle
Darwin was 22
joined the crew of the
H. M. S. Beagle as naturalist
left England in 1831
arrived in the
Galapagos Islands in
1835
collected specimens & recorded observations

8. Darwin’s Galapagos Observations: 1835
Darwin’s hypothesis:
Perhaps all the species descended from the mainland finch, then changed slightly after becoming isolated on different islands.

9. Concept Map Notes: Speciation Mutations Gene Shuffling
Gene Flow (migrations)
Genetic Drift (bottle neck effect & founder effect)

10. Evolution: How It Works
Mechanisms of Evolution:
natural selection
Mutation
Non-random mating
Population Genetics:
Genetic drift
Migration (gene flow)

11. Mechanisms of Evolution: Natural Selection
V = Variation: All life forms vary genetically within a
population.
I = Inheritance: Genetic traits are inherited from
parents and passed on to offspring.
S = Selection: Organisms with traits that are
favorable for survival get to live and pass on
their genes to the next generation.
T = Time: Evolution can happen in a few
generations, but major change, such as
speciation, often takes long periods of time.

12. Mechanisms of Evolution: Natural Selection
Natural Selection is determined by the environment.

13. Mechanisms of Evolution: Nonrandom Mating
A preference by one sexual partner for a particular phenotype
The result of nonrandom mating is that some individuals have more opportunity to mate than others and thus produce more offspring

14. Mechanisms of Evolution: Causes of Mutations
1. DNA fails to copy accurately
2. Environmental influences can cause mutations.

15. Mechanisms of Evolution: Population Genetics
Important terms:
Gene Pool consists of all genes including all the different alleles in population
Relative Frequency of an allele is the number of times that the allele occurs in a gene pool.
Single Gene Traits are controlled by a single gene that has two alleles

16. Mechanisms of Evolution: Genetic Drift p.400
Genetic drift is a change in a population’s allele frequencies due to chance. The smaller the population, the larger the effect.
Bottleneck Effect
Founder Effect
Genetic Drift (2007) by Michael Dumas

17. Genetic Drift: Bottleneck Effect
Disease, starvation, or some other disaster can nearly wipe out large populations. Even though the population recovers, the relative abundance of alleles has been randomly altered.

18. Genetic Drift: Bottleneck Effect
Gene pool

19. Genetic Drift: Founder Effect p.400
A few individuals leave a population and establish a new one.
By chance the allele frequencies for many traits may not be the same as in the original population.

20. Mechanisms of Evolution: Migration (gene flow)
Movement of genes from one population to another. If genes are carried to a population where those genes previously did not exist, gene flow can be a very important source of genetic variation.

21. Evolution vs. Genetic Equilibrium
Hardy-Weinberg Principle: allele frequencies in a population remain constant unless one or more factors cause those frequencies to change. (p.402)
Genetic Equilibrium: allele frequencies remain constant (no change = no evolution).

22. Development of New Species: Speciation
Speciation is the development of one or more species from an existing species.
How does speciation occur? (p.404)

23. Speciation: How Does it Work? (p.404)
Sometimes barriers arise between parts of a population and create local breeding units. Then, two or more gene pools exist when there was only one.
Geographic isolation: populations can be separated by geographic barriers
Reproductive isolation: any aspect of structure or behavior that prevents breeding (breeding seasons, behavior, etc)

24. Evidence of Evolution 1. fossil record 2. homologous structures
3. vestigial organs
4. developmental embryology
5. biogeography – different species are
found in similar geographic regions
6. molecular (DNA) evidence – comparisons
can be made between organisms

25. Evolution Simplified selection time genetic variation in individuals +

26. “OUT” Exit Ticket
Explain 3 examples of how population genetics can affect the evolution of a population.

27. A Final Thought (read this quote & respond with your thoughts on paper)
Evolution is not merely an idea, a theory or a
concept, but it is the name of a process in nature,
the occurrence of which can be documented by
mountains of evidence that nobody has been able
to refute. It is now actually misleading to refer to
evolution as a theory, considering the massive
evidence that has been discovered over the last 140
years documenting its existence. Evolution is no
longer a theory, it is a fact.”
Ernst Mayr
Professor Emeritus
Harvard University