Name:
Mechanisms of Evolution
Go to: http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_15
Use a different color as you fill in the answers.
Read the first page and then click on NEXT at the bottom righthand side.
1. List the 4 basic mechanisms of evolutionary change?
Mutation, Migration, Genetic Drift, Natural Selection
2. Click on mutation. What is it?
A mutation is a change in the sequences of bases in the DNA, which code for genes. Instead of AGTCTTA, it becomes
ACTCTTA which would produce a different amino acid/protein. Mutations are different than the recombination of genes
produced in sexual reproduction because mutations are new to the individual/species.
3. Describe (NOT LIST!) 4 ways that the hypothetical brown beetles could have increased in numbers.
-A mutation could have caused the brown beetles to increase.
- A brown beetle could have joined a population of green beetles.
- Several of the green beetles may have been killed off prior to having offspring, the next generation
may have more brown beetles.
- The green beetles are easier to find for predators and therefore are less likely to reproduce.
4. The mechanisms you listed cause a change in the ___________ of genes. What does that term mean?
FREQUENCIES – The amount of that trait in the total population. 54% brown to 65% brown in the next
generation.
5. Natural selection and genetic drift can not occur unless their is_genetic diversity.
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6. List the 3 primary mechanisms of genetic variation.
Mutations, Gene Flow, Sex
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8. Mutations are always random.
9. Explain this cartoon with regards to the 2nd paragraph on this page:
Mutations do not ‘try’ to supply what an organism
needs because they are random. In the cartoon a
beaver would find a chainsaw arm to be very
beneficial but that wouldn’t happen just because a
beaver needs it.
Name:
10. Give a specific example, original example of a mutation that wouldn’t matter to evolution? (think!)
A form of cancer that develops late in life (not affecting reproductive cells) would not matter to evolution.
11. What does it mean when it says, mutations are “random”?
A mutation is a change in the base pair sequences, and it is never done “on purpose” by nature.
12. Explain why the seeds if the apple in the picture on this slide, would not carry the genes for ½ gold ½ red.
The mutation was not affecting the reproductive cells of the apple.
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13. Just for a refresher, what small components make up a protein?
Amino acids, (which comes from the mRNA code from the DNA).
14. When they say, “Some mutations don’t have any noticeable effect on the phenotype” what are they
saying?
There is ‘junk’ DNA and we don’t understand its purpose.
15. What is a lethal mutation?
A mutation that causes the death of an organism.
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16. List and explain the 2 causes of mutations.
DNA failing to copy correctly during cell division.
An external influence such as radiation or chemicals can cause the DNA to break down and replicate
incorrectly.
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17. What is gene flow AKA (also known as)?
Migration
18. Give 2 specific examples of how this process happens.
Pollen being blown to a new destination or people moving to new cities or countries
19. Gene flow adds genetic _variety to a population.
20. Think of your own, unique scenario where this would be an advantage. Explain it.
Answers vary
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21. Thinking back to our genetics chapter, how does sexually reproduction “shuffle” ones genes?
Genes recombine because ½ come from dad and ½ come from mom to make a new individual.
22. New combinations can be __good, bad, or neutral.
23. Explain how this “genetic shuffling” could be “a bad thing”.
It is possible for a new combination of less desirable traits to be passed on.
Name:
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24. Explain the statement, “organism's genotype is expressed as a phenotype”.
The letters (genetic composition) tell what the physical traits will show on the outside
25. What in the world is morphology?
The study of the form and structure of organisms. For example, comparing the shape of the femur in different
grazing mammals is a morphological study.
26. What are two morphologically changes that were shown on this slide with regards to the little, basic fruit
fly?
Two pairs of wings instead of one, or legs where the antennae are supposed to be.
27. Look at the fetal development of snake, chicken and opossum. Why might scientist look at this with
regards to evolution?
Characters displayed by embryos such as these may help untangle patterns of relationship among the lineages.
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28. Summarize genetic drift in your own words.
By chance, some organisms may be randomly eliminated from a population, thereby changing the gene
frequency within a population.
29. Is genetic drift a random process?
YES
30. What is an adaptation and why would this say that genetic drift does not work to produce them?
Adaptions are inherited characteristics that enable a greater fitness to an organism, but genetic drift
has no effect because it is a random process, separated from natural selection.
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31. Draw/explain your own hypothetical (made up) example of natural selection. (no birds no bugs!)
Answers vary
32. If you have variation, differential reproduction, and heredity, you will have evolution by natural selection
as an outcome.
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33. What are some “cool” examples adaptations produced by natural selection?
Leaf bugs = katydids.
Mimicry
Orchids fooling wasps.
34. What does the blue-footed booby (yes, a real bird!) have as an adaptation to attract a mate, reproduce
and thus pass on its genes?
BLUE FEET!
35. Give an example where we can literally “see” natural selection.
The moths in Europe before and during the Industrial Revolution.
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Name:
36. On this page, why is the brown beetle more “fit”?
They leave more offspring.
37. Is fitness constant? _no____ Why or why not? Sometimes an adaptation will help out in a certain
environment, but if the environment changes it may not always be a beneficial adaptation.
38. Is the fittest animal always the biggest, fastest, baddest (I know it’s not a word, but..) etc.?___NO____
Why or why not?
Overall it is more important to find a mate and reproduce than to just merely survive.
Summarize the Main Ideas from the Evidence for Evolution Packet. (3-4 Sentence summary)
You might want to check out this link - http://evolution.berkeley.edu/evolibrary/article/0_0_0/lines_01
Summarize the Main Ideas from this Mechanisms of Evolution Webquest. (3-4 Sentence summary)