4.2 Energy Flow

1.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?

2. What is lost between trophic levels in ecosystems and cannot be recycled?

3. 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?

4. What restricts the length of a food chain?

5. Which category of organisms is correctly described by its method of nutrition and site of digestion?

6. What limits the length of food chains in an ecosystem?

7. The statement is about the role of some bacteria in ecosystems. What is the mode of nutrition of these bacteria?

8. The diagram represents a pyramid of energy. What level does the letter X represent?

9. The following statements refer to a pyramid of energy. I.  Some material is not assimilated by each trophic level. II. Energy transformations are never 100 % efficient. III. Heat is lost during photosynthesis. Which of the statements give the reason why a pyramid of energy is narrower at the top than at the bottom?

10. The following shows an energy pyramid. How is energy lost between the trophic levels?

11. At each trophic level energy is lost. How is this energy regained by the ecosystem?

12. The diagram shows a pyramid of energy for a wetland environment. What units would be appropriate for the values shown?

13. What is recycled in an ecosystem?

14. The energy passing from the detritivores to the predatory invertebrates in this food web is 14 000 kJ m–2 year–1. Approximately how much energy (in kJ m–2 year–1) passes from the predatory invertebrates to the carnivores?

15. This question refers to the following food web. The energy passing from the detritivores to the predatory invertebrates in this food web is 14 000 kJ m–2 year–1. Approximately how much energy (in kJ m–2 year–1) passes from the predatory invertebrates to the carnivores?

16. To which trophic level do the butterflies belong?  

17. What are the units of a pyramid of energy?

18. What will happen to the food web above if the sea otter disappears?

19. Which organism in this food web is both a secondary and tertiary consumer?

20. What are the units of a pyramid of energy?  

21. How is energy passed from one trophic level to the next? I.  Food II. Light III. Heat

22. The following diagram shows part of a food web from Yellowstone Park. What would be the short-term effects on the populations of the other species if the gray wolf were exterminated?  

23. Why do food chains in an ecosystem rarely contain more than five organisms?

24. The scarlet cup fungus (Sarcoscypha coccinea) obtains its nutrition from decaying wood by releasing digestive enzymes into the wood and absorbing the digested products. Which of the following terms describe(s) the fungus? I.  Autotroph II. Heterotroph III. Saprotroph