Topic 5: Ecology and ecosystems

1. Evolution is the cumulative change in the heritable characteristics of a population.
2. If we accept not only that species can evolve, but that new species may also arise by evolution from
pre-existing ones, then all of life may be seen as unified by its common origins.
3. The variations that are seen within a species are due to different selection pressures operating in
different parts of the world. However, these variations are not such that a new species may be said to
have formed. Different races are an example of this.
4. Homologous structures amongst different species represent evidence for evolution.
5. Evolution of Homologous structures by adaptive radiation have developed from the same part of a
common ancestor but may have different functions today. They show similarity in structure but, not
necessarily, function.
6. Fossils also represent evidence for evolution. Fossils show similarities and differences to organisms
of the present. However, missing links are not present to show a definite change from the fossil to the
present organism.
7. Selective breeding of domesticated animals shows that artificial selection can cause evolution.
8. Another piece of evidence for evolution is that breeds of animals that are reared for human use are
clearly related to wild species and in many cases can still interbreed with them.
9. These domesticated breeds have been developed from wild species by selecting desirable traits, and
breeding from them. This is evidence that evolution can proceed rapidly.
10. Populations of a species can gradually diverge into separate species by evolution.
11. Greater survival and reproductive success of individuals with favorable inherited characteristics
may lead to change in the characteristics of a population.
Continuous variation across the geographical range of related populations matches the concept of
gradual divergence.
12. The Galapagos finches, pesticide resistance in bacteria, and coloration of moths all represent
examples of evolution and survival of the fittest.
Complete the following.
1. What does it mean when we say members of a species share a common gene pool?
2. Why is a mule not considered to be part of its own species?
3. Why is the fossil record, which is important to verifying evolution, incomplete?
4. Give an example of how artificial selection has been used in today’s agricultural industry.
5. Explain a homologous structure as it would occur in whales and humans.
6. Explain the evidence for evolution provided by the pentadactyl limb.
7. Describe the evidence for evolution as shown by the geographical distribution of living organisms.
8. State two ways in which past living organisms have been preserved
9. Explain the process of speciation.
10. Discuss why the fossil record of many species is incomplete
11. Explain how antibiotic resistance has developed in bacteria.