Biol 11
Evolution Review
Vocabulary:
Evolution
gene-pool
allele
natural selection
species
genotype
DNA
mutation
gradualism
Relative frequency
analogous
homologous
Differential migration (gene flow)
adaptation
Fossil
geological time
genetic drift
phenotype
punctuated equilibrium
fitness
common descent
vestigial organ
Fill in the blanks:
1. A common descent hypothesis offers a plausible explanation for
homology
among organisms.
Homologous
structures are similar in structure (not
function) because they were inherited from a common ancestor, such as the forelimbs in
birds, whales, horses and monkeys. The wing of a bird and insect are
analogous
structures; they are all adaptations for flying that are structurally unrelated.
2. Almost all living organisms use the same basic biochemical molecules, including
DNA, ATP, amino acid sequences of proteins, etc. Their similarity can be explained by
descent from a common ancestor.
3. In science, the word theory is reserved for conceptual schemes that are supported by
a large number of observations and have not yet been found lacking. A population is all
members of a single species occupying a particular area at the same time. The various
alleles of all the gene loci in all the members make up a gene pool for the population.
4. Sexual reproduction in and of itself cannot bring about a change in the relative
frequencies of a gene pool.
5. Mutations can cause evolutionary change by providing a
basis?
,
which underlie all the mechanisms that produce variation. Genetic drift
refers to
changes in allele frequencies of a gene pool due to chance. It occurs when, by chance
only, certain members of a population reproduce and pass on their genes to the next
generation.
6.
Gene Flow
is the movement of alleles between populations by migration.
Gene flow between two populations keeps their gene pools
mixed
and
prevents close adaptation to a local environment. Inbreeding
decreases
the
proportion of heterozygotes and increases the proportion of homozygotes and recessive
abnormalities.
7. A species
is defined as a group of interbreeding sub-populations that share
a gene pool and are isolated reproductively from other species. Speciation occurs after
a geographic barrier prevents gene flow between populations that originally belonged to
a single species.
8. Adaptive radiation refers to the proliferation of a species by adaptation to different
ways of life, as seen by the finches on the Galapagos Islands. A time of limited change
in a lineage is called equilibria . According to the gradualism model of evolution,
change is very slow but steady within a lineage with few transitional links. The
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punctuated equilibria model of evolution states that there is a stasis (period of
equilibrium) punctuated by speciation that occurs relatively rapidly with few transitional
links as fossils.
9. Charles Darwin’s most significant contribution to evolution was his theory of
evolution . according to Darwin, individual members of a species vary in physical
characteristics that could be passed from one generation to the next. The members of all
species completed with each other for limited resources. The ones that survive and
contribute to the evolutionary future of the species are better fit (the so-called survival of
the fittest). Such a process is said to be
selective because the organisms do not strive to adapt themselves to the environment
but the environment acts on them to select those individuals that are best adapted.
10. Teleological statements simply imply that evolution is pre-directed or that a species
shapes its own future rather than the environment acting on them to select those
individuals that are best adapted. Correct each of the teleological statements below.
Teleological Statements:
a. Birds have beaks so that they can eat seeds.
b. Plants have solved the problems of land existence.
c. Pesticides cause bacteria to become resistant.
Correct Scientific Statements:
a.
birds can eat seeds better because they have beaks (so they will be
stronger and have more babies…)
b.
plants are able to live on land because there was natural variation in the
species which solved the problems of living on land
c.
Some bacteria are resistant to pesticides because of natural variation in the
species
True or False Questions:
If you believe the statement to be false, rewrite the statement as a true one.
1. Sexual reproduction, by itself, can alter the allele frequencies of a gene pool.
Answer:F Restatement:
Sexual reproduction mixes up the gene pool but the
allelic frequencies are changed by (most commonly) and environmental pressure
that allows natural selection to take place.
2. Random gene mutations are the ultimate source of variation because they provide
new alleles.
Answer:T Restatement:
3. Whenever reproductive isolation develops, speciation has occurred.
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Answer:
F Restatement:
When reproductive isolation develops,
speciation often occurs if the environments for the two populations are different
Matching:
Match the following terms to each of the statements below.
a. fitness
e. gene pool
i. mutation
b. homologous
f. phenotype
j. genetic drift
c. analogous
g. genotype
k. natural selection
d. population
h. alleles
l. evolution
i provides new alleles for variation
k. environmental pressure chooses which individuals will survive
j. populations evolve due to chance
l. change in relative allelic frequencies of a gene pool
f. What the genotype will look like
e. all the alleles in all members of a population
f. alternative forms of a gene
d. all members of a single species occupying a particular area at the same time
h. type of genes found in an organism for a trait
c. structures have the same function, different origin
b. structures have the same origin, different function
a. ability to be successful in a particular environment
1. Fossils can be dated by the radioactive dating method, which relies on radioactive
techniques to assign an actual date to a fossil.
2. Who is Darwin and what is he famous for?
Darwin was a wealthy English
man who is famous for publishing “The origin of the Species By Means of Natural
Selection” in 1859.
3. When Darwin traveled to South America, he was amazed at the variation he found in
forest. When he traveled further, he discovered that even more species had become
extinct from the earth. It is estimated that more than 99% of all the species that ever
existed are extinct .
4. Explain how polar bears are better “fit” to the Arctic environment than grizzly bears
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are.
Polar bears are camouflaged in snow, making them better predators. Also,
their fur is hollow, which telescopes the warmth of the sun to their skin, and adds
extra insulation from the cold. They are EXCELLENT swimmers and have some
special adaptations for that as well.
5. What evidence have you studied that supports the theory of “common descent”?
Homologous structures and vestigial structures
6. Describe a possible scenario to explain how penguins have adapted to their
environment.
7. List at least 3 difference types of evidence that support the theory of evolution.
8. Explain the difference between relative dating and absolute dating.
9. How old do they think the Earth is?
4.5 billion
10. Explain why sedimentary rock is the best place to find fossils.
Sedimentary rock is made from debris from that has been compressed over
millions of years, but there is some chance that the harder parts of the living
organisms can survive in VERY particular conditions. However, Igneous and
metamorphic are formed by intense heat that once living tissue cannot withstand.
11. Explain this quote: The fossil record shows that change (in organisms) followed
change on Earth.
12. Why do scientists use embryology as a piece of evidence for evolution?
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13. Analogous structures are structures that have the same function, but have a
different underlying structure. For example, butterfly wings and birds wings. How do
these compare to homologous structures?
14. Provide as many examples as you can think of for vestigial organs. What do all of
these structures have in common?
15. Why do scientists look to our chemical composition in an effort to support the theory
of evolution?
16. Evolution is just a theory. Why do we (as science educators) spend so much time
trying to explain it to our students?
17. Describe the difference between Lamark’s theory of how animals adapted, to
Darwin/Wallace’s theory of natural selection.
18. Compare artificial selection to natural selection. Why do scientists use artificial
selection as yet another piece of evidence for the theory of evolution?
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19. What is the “Mathusian Doctrine” and how does it relate to the theory of evolution?
20. Explain the phrase: survival of the fittest”
21. Why are the “peppered moths” another piece of evidence evolution?
22. What is the “raw material” for natural selection? Where does this “raw material”
originate? (how did it get there in the first place?)
23. “Translate” the textbook definition into commonly used words or phrases.
24. How do we define a species?
25. Why are microbiologists so concerned about the extensive use of antibiotics in
medicine today?
26. Why can’t more than one species occupy the same niche for a long period of time?
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27. Why is it necessary for isolation (or separation) of populations for speciation to
occur?
28. What is reproductive isolation?
29. Briefly summarize the 5 steps to Speciation using a different hypothetical scenario
than the one that they use in the book. (i.e) don’t use finches as the example.
30. Compare and contrast the terms “divergent and convergent evolution”. (divergent
evolution is also called
) Use a diagram to aid your
discussion.
31. What are analogous structures?
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32. Describe the differences between natural selection and genetic drift. Show how they
both can lead to evolution of a species.
33. How is mutation related to evolution?
34. Explain ”migration” in terms of evolution. How does “migration” lead to perpetuation
of the same species, while “differential migration” leads can lead to speciation.
35. Why is the horseshoe crab, Limulus called a ”living fossil”?
36. Compare and contrast gradualism and punctuated equilibrium. Use diagrams to
aid in your discussion. The other name for gradualism is
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