Download Assignment 10 Evolution

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Working in groups of two to four and armed with a textbook or some other reliable source answer the
following questions molecular biology (Chapters 14, 15, & 16). This assignment is worth 35 points with the
possible point for each question in parenthesis.
http://evolution.berkeley.edu/evolibrary/article/evo_01; http://www.pbs.org/wgbh/evolution/;
http://www.tiem.utk.edu/~gross/bioed/bealsmodules/hardy-weinberg.html;
http://anthro.palomar.edu/synthetic/synth_2.htm
1. (5) In your own words, describe how the fossil record, taxonomy, comparative anatomy,
comparative embryology, and comparative molecular biology studies are used to support
evolutionary ideas?
Evolutionists have long pointed to the data from the above categories to support the ideas of
the existence of an evolutionary process. The fossil record has revealed the interrelationship of
structure between extinct (gone) and extant (current or living) species by using radioisotope decay
(remember from chemistry) measurements and stratification (layers) studies. Bone and teeth
structure of fossils from the past are visible in related species of today and therefore lends
credence to the evolutionary process. Taxonomic studies are used to classify various fossils by
comparing them to extant organisms in an attempt to organize the volume of fossils in today’s
classification schemes. Comparative anatomy looks specifically at relatedness of body structures of
fossils and compares them to extant organisms and also compares extant species for similar
structures related to function. For example how does the arm of a bat, human, cat, and whale
relate to one another? Bone wise they are essentially the same but functionally they are quite
different. Comparative embryology is based on the premise that if species show similar patterns
during their embryonic development then they must be related evolutionarily. Comparative
molecular biology looks at the similarities between the DNA, RNA, and proteins of varied species to
support the idea that if these molecules are similar between various species then they must have
come from a common ancestor.
2. (5) Describe the differences between the ideas of macroevolution versus microevolution?
In general terms, macroevolutionary (basically looking at how species change over time)
scientists attempt to explain extinct and extant species change by looking at the entire geological
time frame as one picture in an attempt to explain the variety of species that are or have been on
the earth. Understanding and defining speciation is the cornerstone of this evolutionary idea.
They examine prezygotic (issues that prevent fertilization like mating behavior differences or
compatibility of sex cells being able to combine plus others) and postzygotic (issues faced by the
organism after fertilization like a sexual union producing an infertile offspring or doesn’t develop
beyond the zygote) barriers to speciation. They propose mechanisms of allopatric (geological
separation) and sympatric (reproductive timing separation) forces to potentially cause speciation.
Microevolutionary (basically looking at how populations change over time) scientists attempt
to explain population changes due to natural selection of individuals within a set population and
then to use this data to explain the bio-geological record. These people tend to look at current
events or events which have caused populations to adapt that are written or observed and then
applying these ideas to the entire time of evolution on earth. The understanding of specie
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Class Assignment 10
population pressures and adjustments is the cornerstone. They point to mechanisms such as
genetic drift (bottleneck and founder effects), gene flow (immigration vs. emigration of genes),
mutation (change in DNA structure), and natural selection (stabilizing, directional, or diversifying
effects on gene pools) as the driving forces for change.
3. (5) Describe the Hardy-Weinberg principles or guidelines and explain how these principles agree
or disagree with the ideas of evolution?
The Hardy-Weinberg equilibrium proposes that if a sexually reproducing population is very
large, with no gene flow, practices random mating, no mutations within the genome, no genetic
drift, and no natural selection occurring within the population then the genetic frequencies within
the population should stay constant. If the gene frequencies change from generation to generation
then microevolution (population evolution) could have occurred.
4. (5) How does an allopatric mode of macroevolution differ from a sympatric mode?
An allopatric mode on a population is when some major geological event separates one
population into two splinter groups that then become reproductively isolated, whereas a sympatric
mode occurs due to the reproductive isolation, such as the timing of reproductive cycles, of two
groups within one population that splinters it into two reproductively isolated groups.
5. (5) How do mutations, genetic drift, gene flow, or natural selection affect the process of
microevolution?
Mutations are changes in the DNA of an organism and if this occurs in the reproductive cells
the new information can be passed to subsequent generations. Genetic drift is based on the
random flow of genes within a population by the random elimination of breeders that can affect
the frequency of the genes showing in a population (bottleneck or founder) effect. Gene flow
involves the emigration and/or immigration of genes into or out of a population by the addition or
subtraction of members into the population. Natural selection involves how nature can change
over time and forces organisms to adapt to the change and reproduce or go extinct. All of these
change the frequencies of genes or alleles within a population.
6. (5) Draw a graph that would demonstrate a directional, a disruptive, and a stabilizing selection on
a population’s microevolution? This figure is a variation of Figure 15.9 in your text.
In a normal population the expressed phenotype ranges over a set range, say animal coat color
ranging from light to dark, but if the environment changes to become darker in color then those
animals with a darker cost would be favored over the lighter coated animals. This change will push
the population towards having a darker coat. This is termed a directional effect. If the
environment favors the two extremes in coat color (light and dark) then the population could
separate into two groups by what is termed a diversifying or disruptional effect. This effect could
lead to speciation if the resulting changes cause changes in preferential and isolational breeding. If
the population diversity in coat color diminishes due to some environmental constraint then it is
termed stabilizing effect. A good example of a stabilizing effect is birth weight of human babies. If
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Class Assignment 10
babies are around 7lbs. they tend to survive with an increased frequency and mom tends to survive
as well, so human birth weights have tended to stabilize around 6 to 8 lbs. in developed societies.
7. (5) Match the following rock groups in column A with the songs in column B?
I N Eagles
A J
Grand Funk Railroad
B H America
C L
Santana
E O Eric Clapton
F M Who
D G
K
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Jimi Hendrix
Steve Miller Band
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Closer to Home
Horse with no Name
Samba Pati
Foxy Lady
Signe
Getting In Tune
Stone Free
Sandman
Take it Easy
Feeling Alright
Swingtown
Black Magic Woman
Goin’ Mobile
The Last Resort
Tears in Heaven
Class Assignment 10