Week 10 CHP 15-17 Task JWT 315

Chapter 16-17
Introduction
Microevolution pertains to changes in gene pool within a population. The gene pool
of a population can be described in terms of genotype frequencies and allele
frequencies various alleles at all the gene loci in all individuals make up the gene
pool of the population. Gene pool in a population can be changed mutations, gene
flow, non-random mating, genetic drift and natural selection.
If microevolution persists over a very long period, species that were referred to as
one may become two different species. Therefore, macroevolution is being able to
distinguish between two species that are very similar and therefore splitting one
species into two distinct species. There are 4 ways to distinguish between two
species, this is what we refer to as a species concept, morphological, evolutionary,
phylogenetic and biological species concept. The one species concept is we focus
mostly on in this chapter is biological that says two organisms that are of different
species will not mate (prezygotic isolation) or will produce a sterile offspring (post-
zygotic isolation).
Chapter 16
1. Define: population, Population genetics, allele differences,
Microevolution, gene pool, Allele frequencies
2. Explain the five causes of microevolution.

3. What are the four factors of natural selection that allow for adaptation of a
population to the biotic and abiotic environment
4. What are the three types of natural selection and their outcome? Give one
example of each
5. Why are recessive alleles important?
6. The gene pool of a population (i.e., allele frequencies in a population) may change
due to
A. migration.
B. a bottleneck.
C. genetic drift.
D. disruptive selection.
E. all of the above are correct.
7. Micro-evolution is a term that describes …

A the process by which new genera and families of organisms are formed.
B small changes that occur in the genotypes of organisms within the same species.
C changes that can be seen without a microscope.
D an increase in the size of individuals of a population over a long period of time.
8. If the frequency of a particular allele that is present in a small, isolated

population of alpine plants decreases due to a landslide that leaves an even
smaller remnant of surviving plants bearing this allele, then what has
occurred?
a. a bottleneck
b. genetic drift
c. microevolution
d. A and B only
e. A, B, and C
9. A bacterial infection was treated with a new drug and all the treated patients
recovered. One week later the infection returned in some patients.
From these observations one can reasonably conclude that …
A the patients developed resistance to the drug.
B the bacteria developed resistance to the drug through natural selection and their
numbers increased.
C the decrease in the infection allowed the bacteria to develop resistance to the
drug.
D a few of the resistant bacteria were present at the start of treatment and that
natural selection increased their numbers.
10. In a very large population, a quantitative trait has the following distribution
pattern:
If the curve shifts to the left or to the right, there is no gene flow, and the population
size consequently increases over successive generations, then which of these is
(are) probably occurring?
1. immigration or emigration
2. directional selection
3. adaptation
4. genetic drift
5. disruptive selection
A. 1 only
B. 4 only
C. 2 and 3
D. 4 and 5
E. 1, 2, and 3
11. Which of these evolutionary agents is most consistent at causing populations

to become better suited to their environments over the course of generations?
A. Mutation
B. Non-random mating
C. Gene flow
D. Natural selection
E. Genetic drift
Chapter 17
12. Explain the four ways species are defined.
13. Define two modes of speciation and what are the other two modes?
14. What is the biological species concept and what prezygotic isolating
mechanisms prevent reproductive attempts?
15. Explain how gene expression can influence speciation.
16. Macroevolution is a term that describes …

A an increase in the size of individuals of a population over a long period of time.
B the process leading to the formation of new genera and families of organisms.
C a gradual change in the number of species found in the fossil record.
D changes that can be seen without the need of a microscope.
17. Which ONE of the following is the best definition of a species?

A A population of similar animals which can interbreed
B A population of organisms which breed to produce fertile offspring
C A community of organisms which can interbreed
D A population of organisms with similar characteristics
18. Because of difference in peak breeding time, 5 species of frogs rarely produce
interspecific
hybrids. The isolating mechanism is
A. behavioral
B. ecological
C. geographical
D. mechanical
E. temporal
19. Suppose a species of grasshopper normally breeds in June and lays its eggs
on the young shoots of an annual grass that comes up in June. A mutant
female grasshopper in the population produces a batch of eggs that carry a
new allele that delays sexual development until August. Her offspring feed on
the young shoots of another grass, in the very same habitat, that comes up in
August. Her offspring mate successfully with one another producing a new
generation of August-mating grasshoppers. The August-mating subpopulation
of grasshoppers is a good candidate for:
A. allopatric speciation
B. stabilizing selection
C. sympatric speciation
D. directional selection
E. disruptive speciation
20. The shell of the banded snail, Cepaea nemoralis, displays a wide variety of
both colour and banding (rings). Birds, such as thrushes, eat these snails. The
birds break open the shells by striking the snails against a stone.
It was found that there were equal numbers of light- and dark-banded snails in a
specific grassland habitat where no thrushes were found. A population of thrushes
was then introduced to this grassland habitat.
An investigation was done to determine which colour snails (dark-banded or light-

banded) were eaten most by the thrushes.
The results are shown below:
Time (days) Number of dark-banded Number of light-banded

shells found around stone shells found around stone
Day 1 2 1
Day 2 3 0
Day 3 5 1
Day 4 7 0
Day 5 8 1
- Write a possible hypothesis for this investigation. (3)
- What phenomenon does this investigation illustrate? (1)
- Which snails were better adapted to prevent them from being eaten by the
thrushes? (1)
- Explain your answer to QUESTION above (2)
- Why can the number of snails at the start of the investigation be considered a
controlled variable? (1)

Week 10 CHP 15-17 Task JWT 315

Uploaded by

Copyright:

Available Formats

Week 10 CHP 15-17 Task JWT 315

Uploaded by

Document Information

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Week 10 CHP 15-17 Task JWT 315

Uploaded by

Copyright:

Available Formats

Chapter 16-17

2. Explain the five causes of microevolution.

7. Micro-evolution is a term that describes …

8. If the frequency of a particular allele that is present in a small, isolated

11. Which of these evolutionary agents is most consistent at causing populations

15. Explain how gene expression can influence speciation.

16. Macroevolution is a term that describes …

17. Which ONE of the following is the best definition of a species?

An investigation was done to determine which colour snails (dark-banded or light-

The results are shown below:

Time (days) Number of dark-banded Number of light-banded

- Write a possible hypothesis for this investigation. (3)

- What phenomenon does this investigation illustrate? (1)

You might also like