Download Homework one

Homework one: 2017 Week one-two: Review of important terms and principles.
Homework for Wednesday. Jan 18th. Due at 1:30. Bring two copies of Homework to class.
One copy has to be turned into Dr. Feaver at the beginning of class. Late copies are not
accepted. Lined paper must be used and writing must be legible. If I have trouble reading
your paper, your grade on those question affected will be 0. You are highly encouraged to
draft your homework assignments in Word or some other text editor and bring these to class.
Introduction
Darwin’s theory had two major tenets, one was that all living things (organisms) are related
through common descent and the other was that natural selection was the main mechanism by
which diversity in form and function among organisms although related, occurred.
In Darwin’s own words from the Origin of the species, published in 1859
“No one ought to feel surprise at much remaining as yet unexplained in regard to the origin of
species and varieties, if he makes due allowance for our profound ignorance in regard to the
mutual relations of all the beings which live around us. Who can explain why one species
ranges widely and is very numerous, and why another allied species has a narrow range and
is rare? Yet these relations are of the highest importance, for they determine the present
welfare, and, as I believe, the future success and modification of every inhabitant of this world.
Still less do we know of the mutual relations of the innumerable inhabitants of the world during
the many past geological epochs in its history. Although much remains obscure, and will long
remain obscure, I can entertain no doubt, after the most deliberate study and dispassionate
judgment of which I am capable, that the view which most naturalists entertain, and which I
formerly entertained -- namely, that each species has been independently created -- is
erroneous. I am fully convinced that species are not immutable; but that those belonging
to what are called the same genera are lineal descendants of some other and generally
extinct species, in the same manner as the acknowledged varieties of any one species
are the descendants of that species. Furthermore, I am convinced that Natural Selection
has been the main but not exclusive means of modification.”
We will deal in the next few lectures with the mechanisms of evolution, focusing of course on the
major mechanism of evolution as proposed by Darwin, natural selection.
You can see the importance Darwin placed on this mechanism by noting that the extended title of the
Origin of Species includes this mechanism.
The Origin of species by Means of Natural Selection of The Preservation of Favoured Races
in the Struggle for Life First edition. Charles Darwin.
http://www.talkorigins.org/faqs/origin.html
Darwin recognized genetic drift as a valid mechanism but did not think it was a major mechanism of
change. A growing appreciation for a larger relative role of genetic drift in generating diversity
is one of the major refinements by today’s evolutionists to Darwin’s theory. What the role is of
genetic drift in adaptation is still being debated today.
1. Explore the web pages that cover the basic mechanisms of evolution (up to including
misconceptions about natural selection—17 pages).
http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_14
Supply a definition from your readings for the following terms.
Evolution
Natural selection
Fitness
Sexual selection
Artificial selection
Gene or allele frequency
Mutation
Genetic recombination (sexual reproduction)
Genetic drift
Adaptation
Species
Again, please turn in one copy of the definitions above in at the beginning of class. You should place
the definitions next to the definitions you wrote down the second day of class. You may simply
xerox this documents to turn in for homework. Make sure your name is on the document.
For class
You should also be able to apply these terms. Application demands understanding and not simple
memorization. Think about the following questions as you move through the section on
mechanisms. Before class on Wednesday, you should visit the websites associated with the
questions we will discuss. Make no attempt to memorize the material on the website. We will revisit
them in class when we talk about the questions. We may get to questions 2- 5 on Wednesday, the
others on Friday.
Come prepared to discuss the following questions in class. The answers to these questions
will be the focus of class discussion and not part of your homework assignment that needs to
be turned in at the beginning, of class.
2. Popular literature often defines natural selection as survival of the fittest. Is this a more accurate
definition than differential reproduction?
3. What are the necessary conditions for natural selection?
http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_32
https://www.blackwellpublishing.com/ridley/tutorials/Natural_selection_and_variation5.asp to
https://www.blackwellpublishing.com/ridley/tutorials/Natural_selection_and_variation6.asp
What would happen [Would for example, the population evolve?], if each of these conditions were not
met to a population facing environmental change?
4. The connection between evolution and natural selection.
https://www.blackwellpublishing.com/ridley/tutorials/Natural_selection_and_variation7.asp to
https://www.blackwellpublishing.com/ridley/tutorials/Natural_selection_and_variation11.asp
a. Directional selection is seen as a force for evolution, stabilizing as a force against. Why?
b. Would it make a difference if you saw evolution as simple change in biology over time or a change
in gene frequency?
Adding definitions.
5. On fitness http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_27
a. One pair of birds fosters tender loving care on the two children they have every breeding season.
Unfortunately, despite their care only 4 children live to reproduce.
b. In another related species, pairs live only one season and have 12 -15 young. You follow two
pairs. One pair during their lifetime has 12 young but also leave 4 young that live to reproduce.
c. The other pair has 15 young, 7 survive, but only 5 so far have reproduced themselves
Which pair of the three would you judge most fit?
Which strategy, a or b, would you judge most fit?
How would you go about representing fitness mathematically?
6. (a) Sexual selection. http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_28
Is selection on reproductive structures, sexual selection?
(b) Go to the website http://evolution.berkeley.edu/evolibrary/article/sneakermales_01
How would you begin to evaluate the fitness of these two different types of males?
7. Artificial selection (goal oriented selection).
Insecticide resistance and antibiotic resistance, are these examples of artificial selection?
8. Gene frequency.
Much of detecting changes in evolution revolve around tracking gene frequency. You need then to
know now to calculate gene frequencies and monitor changes in such.
Try this problem
You sample a population of annual flower in 2002 and find the following phenotype frequencies:
Red Pink White
100 200 100
Color is a co dominant trait (i.e. the heterozygotes differ phenotypically from both homozygotes), and
the pink individuals are heterozygous.
You return to the population in 2003 and find the following phenotype frequencies:
Red Pink White
100 180 81
What changes have occurred in the population with respect to gene frequencies? What factors could
explain any differences noted?
9. Does recombination create new genetic variation?
10. A note on variation
http://evolution.berkeley.edu/evolibrary/news/060301_crime
What type of variation is used for DNA testing?
11. Working definitions for other terms.
Genetic drift
Adaptation
Species