How To Study Living Animals


3. REVIEW AND LIBRARY WORK ON CRUSTACEA

1. What are arthropods?

2. Give the classes of arthropods with an example of each herunterladen.

3. What are the distinguishing characteristics of the class crustacea?

4. In what respects are most of the appendages of the crayfish homologous, i.e herunterladen. alike in the plan of structure? Which do you consider the simplest, and why do you? Which do you consider the most specialized, and why?

5 microsoft office kostenlos downloaden vollversion deutsch chip. Which somite of the crayfish is without appendages? How many somites are there in a crayfish’s body, if each somite bears only one pair of appendages, as many scientists believe? How many of these are in the head; thorax; abdomen?

6. Compare the nervous system of the crayfish with that of the earthworm as regards efficiency. Upon what do you base your answer?

7. Name two points in which earthworms and crayfishes are alike. Name three in which they differ.

8. How are crayfishes caught for market? Where do those sold in Chicago usually come from? How are they shipped?

9. Compare the young forms of a crayfish and a crab.

10. Describe any five different crustacea.

11. Describe the work done by the United States government and by the state governments to protect and to perpetuate the lobster. Why is it thought necessary to do this?

12. Discuss the process and the advantages and disadvantages of molting, as seen in the crustacea.

13. Name two advantages in having such a shell as crustacea have. Name two disadvantages. On the whole, is such a shell favorable to an animal’s chances of success or is it not?

14. Give the curious myth about goose barnacles.

15. What crustacea are parasitic? Give an account of one.

16. Why are barnacles classed among crustacea? Where were they once classed? Why may they be considered degenerate, even though not parasitic? How do they manage to succeed? What is their economic importance? How are their effects checked or prevented?

17. Describe some of the odd means of self-protection shown among crustacea.

18. Describe a compound eye. Give two theories as to what can be seen with a compound eye. Why do we not know, instead of theorizing?

19. What is the economic value of the very small crustacea?

20. Discuss the value to man of the various forms of crustacea.


CHAPTER V
ADAPTATIONS FOR PROTECTION FROM ENEMIES

A. The Exoskeleton