Biology 160
NAME: _______________________________________
Reading Guide 11: Population Dynamics, Humans, Part I
This is DUE: ________________
Come prepared to share your findings with your group.
*As before, please turn in only the Critical Thinking questions on a separate sheet of paper.
Critical Thinking questions: Section 1: 4, 17, 33, 34, 43EC, 44; Section 2: 4, 7, 36, 39, 44, 45, 47, 54, 55
What you’ll learn in this reading guide:
 Observations in the natural world that explain the Theory of Natural Selection:
o Overproduction with competition
o Individual variation
 Evidence for overproduction with competition in humans through population growth and apply it to
malaria resistance
 Evidence for individual variation in humans through sexual recombination and apply it to malaria
resistance
** Fill this reading guide out as you are reading the chapters. This will help you to pull out the important
information that will help us to understand how human resistance to malaria occurs.
Readings:  Essential Biology, 4th or 5th Ed. (Simon, Reece, & Dickey)
Ch 13, pg. 243-247; 252-253; 256-258 (How Populations Evolve)
Ch 19, pg 417-421 (Human Population Growth)
Ch 8, pg 130-140 (Meiosis)
While reading these chapters, constantly ask yourself, “How is this information helping me to understand
how human resistance to malaria occurs?”
Section 1
Chapter 13, pg 243-247; 252-253; 256-258
Now that you’ve seen evolution through natural selection in action during the development of HIV drug
resistance, let’s look more closely at the historical development of this idea and how it works in other
organisms.
1. What is the basic idea of natural selection?
2. What is the result of natural selection?
3. What is “one way of defining evolution” according to the text?
4. Critical Thinking: So does that mean that evolution can happen in a single individual? Explain your answer.
5. Summarize the idea of fixed species and its history.
6. Summarize Lamarck’s ideas about evolution.
7. What ship was Darwin on and when did it leave Great Britain?
8. Summarize how Charles Lyell’s book The Principles of Geology influenced Darwin’s thinking.
9. Who is Alfred Wallace?
10. Summarize and know the two main points that Darwin developed in his book On the Origin of Species.
A) First main point:
B) Second main point:
11. Make sure you can answer the Checkpoint questions. If not, write your questions here:
We’ll come back to the Evidence for Evolution when we study different species in our next unit. Right
now we want to focus in on populations of the same species (a population of HIV in one individual taking
anti-HIV drugs, a population of humans in areas with a high incidence of malaria, a population of insects
in a field sprayed with pesticide, etc…).
12. Overproduction with competition is one key observation made by Darwin. Explain what this is and what
happens to most of the offspring.
13. Individual variation in a population is another key observation made by Darwin. Explain whether these
traits must be heritable or not.
14. Define natural selection.
15. What are three key points about natural selection made by the text?
A)
B)
C)
16. Describe Figure 13.14, the evolution of pesticide resistance:
17. Critical Thinking: Is the gene conferring resistance to the pesticide a response to the pesticide or was it
already present in the insect population?
18. Make sure you can answer the Checkpoint questions. If not, write your questions here:
19. Define the “modern synthesis.”
20. Describe what a “population” is:
21. What is the smallest biological unit that can evolve?
22. Look up the term “allele” and write the definition here:
23. What is a “gene pool”?
24. According to the text, when is “evolution occurring on its smallest scale”?
25. Give examples of the types of individual variations that A) we can see and B) we can measure with
biochemistry.
26. Think Back: What is the difference between “genotype” and “phenotype”?
27. Is all variation in a population heritable? Explain why.
28. Look up the term “locus” and write the definition here:
29. What are two sources of genetic variation?
30. What are the possible effects of a random mutation?
31. How do random mutations affect the evolution of bacteria? Of plants and animals?
32. What process do plants and animals depend mostly upon for genetic variation?
33. Critical Thinking:
a) The processes that generate genetic variation are
CIRCLE ONE:
RANDOM
b) The process of natural selection is
CIRCLE ONE:
RANDOM
NOT RANDOM
NOT RANDOM
34. Critical Thinking: How can this information help to explain how malaria resistance in a population of
humans can occur? In your answer specifically refer to Darwin’s two key observations:
1) Overproduction with competition
2) Individual variation
**We will continue reading the rest of this chapter once we have learned about genetic variation and
inheritance.
Chapter 19, pg 417-421
Here we’ll look at evidence for how a human population can gain resistance to malaria according to Darwin’s
first observation that led to his theory of natural selection: Overproduction with competition
35. What population growth model does human population growth look like?
36. According to Figure 19.19 how large was the human population in
1600:
1800:
1900:
1950:
current population:
future projection for 2050:
37. What are some of the factors that allowed the human population to grow so rapidly?
38. What is age structure helpful for?
39. Describe how age structure is used to predict the future needs of an aging US population.
40. What are some of the predicted problems of such a high human population growth rate?
41. What is an “ecological footprint”?
42. Discuss why US population has such an enormous ecological deficit.
43. Extra credit: Search the web for site where you can calculate your ecological footprint. Write a two
sentence review of the site and provide its web address. Turn this in with your Critical Thinking questions.
44. Critical Thinking: How has this information about human population growth provided evidence for how
malaria resistance might occur in a human population?
Section 2
Chapter 8, pg 130-140
Now we’ll look at evidence for how a human population can gain resistance to malaria according to Darwin’s
second observation for his theory of natural selection: individual variation.
1. What cellular processes does sexual reproduction depend upon?
2. What is a somatic cell and how many chromosomes does a human somatic cell have?
3. What is a karyotype?
4. Critical Thinking: Why do you have to break open a somatic cell during metaphase of mitosis to obtain a
karyotype?
5. What are homologous chromosomes? Redraw and label the upper left drawing of Figure 8.11 to help you
remember their structure.
6. How many pairs of homologous chromosomes do humans have?
7. Critical Thinking: If a cell were in G1 phase of the cell cycle, what would the chromosomes look like?
Would they have sister chromatids? Why?
8. What are the sex chromosomes?
9. What are the sex chromosomes in a human male?
10. What are the sex chromosomes in a human female?
11. What are autosomes?
12. How many autosomes does a human somatic cell have?
13. What is a life cycle?
14. What does diploid mean and how are the total number of chromosomes represented?
15. What are gametes?
16. What does haploid mean?
17. How is the haploid number represented and what is the haploid number for humans?
18. Why do sexually reproducing organisms need to produce haploid cells?
19. What is fertilization?
20. What is a zygote?
21. The zygote is (CIRCLE ONE)
HAPLOID
DIPLOID
22. What cell division process did every cell in your body use to develop from the zygote to produce diploid
cells?
23. What cellular process is used to produce haploid cells?
24. Redraw Figure 8.13 to help you remember how the chromosomes are divided up during the formation of
gametes.
25. What are the two special features of meiosis? What happens during these features?
A)
B)
26. What is the difference between homologous chromosomes and sister chromatids?
27. Vocabulary to know for understanding meiosis:
Diploid
Chromatin
Microtubules (pg 69)
Centrioles (glossary)
Centrosomes
Mitotic Spindle
Nuclear envelope
Plasma membrane
Chromosome
Sister chromatids
Centromere
Homologous chromosomes
Tetrad
Sites of crossing over
Haploid
Daughter chromosomes
Cleavage furrow
Cell plate
28. Draw a picture of each stage of meiosis in order to understand how DNA is divided into four haploid
daughter cells. Also describe in words what changes are happening to the chromosomes and nucleus and to the
spindle and cytoplasm during each phase. Remind yourself here about the difference between homologous
chromosomes and sister chromatids.
Draw a picture of a cell at this stage
Changes to the Chromosomes
Changes to the Spindle and
Stage of
and
the
Nucleus
the Cytoplasm
Meiosis
Interphase
Prophase I
Meiosis I
Metaphase
I
Anaphase I
Telophase I
and
Cytokinesis
Stage of
Meiosis
Prophase II
Draw a picture of a cell at this stage
Changes to the Chromosomes
and the Nucleus
Changes to the Spindle and
the Cytoplasm
Meiosis II
Metaphase
II
Anaphase
II
Telophase
II and
Cytokinesis
29. What separates during meiosis I?
30. What separates during meiosis II?
31. Make sure you can answer the Checkpoint questions. If not, write your questions here:
32. Redraw Figure 8.15 to help you understand how mitosis and meiosis compare.
The Origins of Genetic Variation
33. In Figure 8.16 do “Possibility 1” and “Possibility 2” happen by (CIRCLE ONE)
RANDOM CHANCE
or by a
SPECIFIC CELLULAR INSTRUCTION?
34. According to Figure 8.16, what determines which chromosomes will be packaged together in the haploid
gametes?
35. Describe what happens during the independent assortment of chromosomes.
36. Critical Thinking: How does the independent assortment of chromosomes contribute to genetic variability
in a population?
37. How many possible human chromosome combinations are there?
38. What is “random fertilization”?
39. Critical Thinking: How does random fertilization contribute to the genetic variability in a population?
40. What is “crossing over”?
41. Redraw Figure 8.18 to help you learn about crossing over, making sure to understand the following terms
Tetrad
Chiasma
Recombinant Chromosomes
42. In what phase does crossing over occur during meiosis?
43. Can multiple crossing over events happen in the same homologous pair?
44. Critical Thinking: How does crossing over contribute to the genetic variability in a population?
45. Critical Thinking: Mutations in the gametes of the parents also contribute to genetic variation. According
to current research published by Roach et al, (2010), they found that a child contains approximately 60
independent mutations that are not found in either parent! This is called the intergenerational mutation rate.
These mutations (or genetic variations) occurred during the formation of the gametes during meiosis. How does
the intergenerational mutation rate contribute to the genetic variability in a population?
46. Think Back: Review Figures 10.21 and 3.23 to understand how mutations in a gene can affect its protein
product. What type of mutation (silent, missense, nonsense, insertion, deletion) is the sickle cell mutation?
47. Critical Thinking: What do you think would happen if one of these intergenerational mutations happened
in a gene and caused one of the following types of mutations:
a) if it were a silent mutation
b) if it were a missense mutation
c) if it were a nonsense mutation
d) if it were an insertion or deletion mutation
48. What is “nondisjunction”?
49. During meiosis, when can nondisjunction occur?
50. What are the results of nondisjunction in both the gametes produced and the fertilized zygote?
51. Describe what trisomy 21 and Down syndrome are.
52. How does the age of the mother correlate with the incidence of Down syndrome?
53. Copy down Table 8.1 to help you understand what results from sex chromosome nondisjunction.
54. Critical Thinking: “The Advantages of Sex”
a) What are some advantages and disadvantages to reproducing asexually?
b) What are some of the hypotheses as to why all animals reproduce sexually?
55. Critical Thinking: How has this information about genetic variation in sexually reproducing organisms
provided evidence for how malaria resistance might occur in a human population?