5.2 Natural selection

1.What causes variation within a population?

2. A bacterial population with no resistance to an antibiotic may develop into a bacterial population with some resistance to an antibiotic. Which event could lead to this?

3. Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is based on DNA sequences and the cladogram on the right is based on comparing protein sequences. What is the reason that cladograms based on DNA sequences are more reliable predictors of the phylogenetic relationship of species than cladograms based on protein sequences?

4. What is a direct consequence of the overproduction of offspring?

5. The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system. The graph shows the percentage of samples in which this bacterium showed resistance to six antibiotics over a period of ten years. What is a possible explanation for the total percentage resistance being larger than 100% in 2010?

6. A bacterial population with no resistance to an antibiotic may develop into a bacterial population with some resistance to an antibiotic. Which event could lead to this?

7. The photograph shows vegetation in a rocky area. Which characteristic of the plants indicates that the area in which they are growing is probably dry?

8. Lichens are returning to the forests of the industrial areas of the United Kingdom due to strict pollution control. What is the expected outcome in the population of peppered moths (Biston betularia)?

9. What is the major contributor to the increase in antibiotic resistance in bacteria?

10. Which process promotes variation in a population?

11.How can species of bacteria evolve to be resistant to antibiotics? I.  A variation within one bacterium’s genome confers resistance. II. Antibiotics enable genes to become adapted through transcription and translation. III. An incomplete dose of antibiotics allows bacteria with a high resistance to survive and reproduce.

12. Darwin described evolution as “descent with modification”. What would make evolution less probable?

13. What promotes natural selection? I. Overpopulation II. Competition III. Variation

14. What causes heritable variation in a species? I. Muscle development through exercise II. Increased rainfall in the ecosystem III. Changes in the genome of the species

15. The long-term exposure of bacteria to antibiotics has led to the spread of resistant strains (for example, of Clostridium difficile). What is this an example of?

16. What type of process causes antibiotic resistance to develop in bacteria?

17. What type of process causes antibiotic resistance to develop in bacteria?  

18. Charles Darwin used domesticated animals to provide evidence for evolution by natural selection. What is this evidence?

19. Which process tends to reduce variety within a population?

20. What is the mechanism of natural selection?