BIO152H5 Study Guide - Final Guide: Invertebrate, Red Algae, Arthropod

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Published on 28 May 2011
School
UTM
Department
Biology
Course
BIO152H5
Professor
BIO152 Exam prep (post-midterm content)
Dr. F. Rawle
Study Tables and Sample Questions
Sample Questions:
-Do the textbook questions (focus on the “Check Your Understandingquestions
throughout the text) in addition to the questions below to adequately prepare for the
final.
Chapter 24
1.Why do traits have to be heritable in order for evolution by natural selection to
occur?
2.Transitional forms and vestigial traits have both been used as evidence that
species change over time. Comment on the strengths and weaknesses of these
two types of evidence.
3.Why is genetic homology “the most fundamentallevel of homology?
4.List the traits that might help some individuals survive or reproduce better than
other individuals for each of these organisms: rabbit, turtle, oak tree, bacteria.
5.A pattern of repeated speciation events is often found in island chains. What
about islands promotes speciation?
6.Explain why individuals do not change when natural selection occurs.
………………………………………………………………………………………..………..
Answers:
Chapter 25
1.Practice doing calculations using the Hardy-Weinberg equation.
2.Can you think of a situation in which the Hardy-Weinberg expected genotypes
could be found even though the Hardy-Weinberg assumptions were not strictly
met?
3.Sometimes mate choice is nonrandom, such that genetically different individuals
are more likely to mate. This is called outbreeding. What would happen to allele
frequencies and genotype frequencies in a population experiencing an
outbreeding mating pattern?
Chapter 26
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BIO152 Exam prep (post-midterm content)
Dr. F. Rawle
1.Which species definition (i.e., biological, morphospecies, or phylogenetic) would
you use for (1) a new fossil species, (2) a well-studied bacterial species, and (3)
a well-studied mammalian species? Why?
2.Why does the fact that the seaside sparrow phylogeny shows only two distinct
groups suggest there may be more gene flow within those two groups than
previously thought?
3.Colonization followed by genetic drift and natural selection has also led to
speciation in aquatic organisms and organisms that live at the top of some
mountains. Explain how this could happen.
4.Why is genetic drift more likely to be an important evolutionary factor in
colonization events than in vicariance events?
5.Has natural selection caused speciation yet in the case of the two soapbug
populations? Why or why not?
6.Polyploid mutations are an important cause of speciation in plants but not in
animals. Why?
Chapter 27
1.Are bat wings and pterosaur wings an example of homology or homoplasy?
Why?
2.There are no known fossils o the very first living organisms. Give at least two
reasons to explain why this lack of fossil evidence for these first organisms is not
surprising.
3.Crustaceans and centipedes have fewer Hox genes than velvet worms or fruit
flies do. Based on the phylogeny shown in Figure 27.10, does it look like the Hox
genes found in fruit flies were secondarily lost in crustaceans, or were these
genes never present in crustacean ancestors? Explain your answer.
4.Why isnt the “new genes, new bodies” hypothesis sufficient to explain all animal
morphological diversity?
5.What might happen if the Earth were to be hit by another asteroid the size of the
one that struck 65 mya?
Study Tables: also review the tables shown in class and the tables from your textbook.
The essence of natural selection can be summarized with two statements
(1)NS occurs when individuals with certain alleles produce the most surviving
offspring in a population.
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BIO152 Exam prep (post-midterm content)
Dr. F. Rawle
(2)An adaptation is a genetically based trait that increases an individuals ability to
produce offspring in a particular environment.
Mechanisms that shift allele frequencies in populations
NameDescription Example
Natural selection Certain alleles are favored.
Types: balancing selection,
directional selection, stabilizing
selection, and disruptive
selection.
M. Tuberculosis bacteria
became resistant to
antibiotics b/c the resistant
bacteria was favored by
natural selection (selection
pressures).
Gene flowMovement of alleles between
populations. Reduces differences
between populations.
New Lupines (plants)
popns grow on slopes of
recently active volcanoes.
Gene flow (pollen carried
by bees) makes the popns
more alike over time.
Genetic drift Random changes in allele
frequencies (some alleles get
lucky). Most important in small
populations.
Occur by 2 methods in natural
popns: Founder effects (change
in allele freq. after a new popn
establishes), or genetic
bottleneck (sudden reduction in
alleles in a popn due to disease
or natural catastrophe).
British ship lands on island
with sailors and native
women children allele
frequencies change at
random (founder effect
like with green iguanas in
inland after hurricane). Fruit
flies with normal or forked
bristles (50% each at
beginning) but due to
genetic drift, by 16th
generation the forked
alleles was lost. In small
popn: freq. of ppl with
achromatopsia (vision
defect) increased after a
typhoon (bottleneck).
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Document Summary

Do the textbook questions (focus on the check your understanding questions throughout the text) in addition to the questions below to adequately prepare for the final. Chapter 24: why do traits have to be heritable in order for evolution by natural selection to occur, transitional forms and vestigial traits have both been used as evidence that species change over time. What about islands promotes speciation: explain why individuals do not change when natural selection occurs. Why or why not: polyploid mutations are an important cause of speciation in plants but not in animals. Why: there are no known fossils o the very first living organisms. Give at least two reasons to explain why this lack of fossil evidence for these first organisms is not surprising: crustaceans and centipedes have fewer hox genes than velvet worms or fruit flies do. Study tables: also review the tables shown in class and the tables from your textbook.