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Biology 20 Unit IV: VARIATION IN POPULATIONS
INTRODUCTION
In 1859 Charles Darwin published On the Origin of Species by Means of Natural Selection. His book
connected what had previously seemed a bewildering array of unrelated facts into a cohesive view of
life. Darwin addressed the issues of the great diversity of organisms, their origins and relationships,
their similarities and differences, their geographic distribution, and their adaptations to their surrounding
environment. This unit focuses mainly on the mechanisms by which life evolves.
In biology, evolution refers to the processes that have transformed life on Earth from its earliest
primitive forms to the great diversity that characterizes it today. Evolution is inextricably intertwined
with ecology. According to Darwin's concept of natural selection, a population changes over time as a
result of the environment acting on traits of individuals in the population.
Lesson 1 Diversity of Organisms
1.
Name the five biological kingdoms into which living things are classified.
2.
Describe the characteristics of organisms in each kingdom.
3.
Give at least two examples of organisms classified in each kingdom.
4.
Define the terms population and species.
5.
Distinguish between a species and a subspecies, using examples.
Lesson 2 Variation and Adaptation
6.
Define adaptation.
7.
Explain how some variation may be of adaptive value to a species.
8.
Distinguish between continuous and discontinuous variations.
a. Graph variations within a population and between populations.
9.
Distinguish between inherited and acquired variations.
10. Describe and give an example of each of the following three categories of adaptation:
a. structural adaptations
b. physiological adaptations
c. behavioral adaptations
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Lesson 3 Evidence of Evolutionary Change
11. Define evolution. (IB also)
12. Describe what a fossil is, and explain how they are dated.
13. Explain how fossils are evidence of evolution. (IB also)
14. Define embryology, and explain how embryos can be evidence of evolution.
15. Differentiate between homologous, analogous and vestigial structures. Give examples of each.
16. Explain how homologous and vestigial structures are evidence of evolution.
17. Define physiology, and explain how physiological similarities can be evidence of evolution.
18. Explain how biochemistry can provide evidence of evolution.
5.4.2
Outline the evidence for evolution provided by the fossil record, selective breeding of
domesticated animals and homologous structures.
Lesson 4 Theories and Mechanisms of Evolution
19. Explain Lamarck's hypothesis of how life evolved by describing his ideas of:
a. use and disuse
b. inheritance of acquired characteristics
20. List and describe the five main ideas that form the basis of Darwin's theory.
21. Summarize Darwin's theory of natural selection.
5.4.3
5.4.4
5.4.5
5.4.6
5.4.7
State that populations tend to produce more offspring than the environment can support.
Explain that the consequence of the potential overproduction of offspring is a struggle for
survival.
State that the members of a species show variation.
Explain how sexual reproduction promotes variation in a species.
Explain how natural selection leads to evolution.
Greater survival and reproductive success of individuals with favourable heritable variations
can lead to change in the characteristics of a population. Aim 7: Computer simulations can
be performed.
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5.4.8
Explain two examples of evolution in response to environmental change; one must be
antibiotic resistance in bacteria.
Other examples could include: the changes in size and shape of the beaks of Galapagos
finches; pesticide resistance, industrial melanism or heavy-metal tolerance in plants.
22. Describe Devries' contribution to the modern view of natural selection.
23. Explain how isolation and migration can affect evolution of a species.
24. Differentiate between adaptive radiation and convergent evolution.
25. Define speciation.
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