Materials.

Books and diagrams showing as many methods for the care of young as possible.

Observations.
  1. To what extent is care given to the eggs and young in the case of fish? Is the number of eggs large or small? Contrast this condition with that of the robin. What general conclusion is suggested?
  2. Describe the egg-laying habits of five or more of the following: grasshopper, cecropia moth, tussock moth, leaf miner, case bearer, leaf roller, sphinx moth, gall insects, ichneumon flies, spiders, earthworm. How is the developing animal protected in each case? How is food assured?
  3. Contrast the method of the honeybee and the solitary wasp as to the method of caring for and feeding the young.
  4. Describe the nests of five or more of the following: spider, honeybee, bumblebee, paper wasp, mud dauber, digger wasp.
  5. Describe the nests of the following: stickleback fish, sunfish.
  6. Describe the nests of ten birds common to your neighborhood.
  7. Describe the homes of the following: woodchuck, mole, squirrel, rabbit, muskrat, prairie dog, beaver, bear.
  8. In case of birds which of the parent birds builds the nest and cares for the little birds?
  9. How are the young cared for in the following cases: crayfish, cyclops, pipefish, Surinam toad?
Summary.
  1. What general methods are there for protecting the young?
  2. What various devices for assuring plenty of food for the developing animal?
  3. What is the relation between the care given the young and the number of eggs produced?

D. Adaptations for the Preservation of the Species

Review Questions and Library Exercise
  1. Show how the sexual method of reproduction tends to produce variations.
  2. What is meant by the term heredity?
  3. What are chromosomes? What do some zoölogists believe to be the relation between these chromosomes and heredity?
  4. What are dominant and recessive characters? What is meant by "Mendel law of heredity"?
  5. What is meant by the term parthenogenesis? What are some of its advantages and under what conditions does it take place? Name some animal in which parthenogenesis commonly takes place.
  6. What is sex dimorphism? Give some examples.
  7. What were the experiments of Professor Loeb and others in connection with artificially fertilized eggs?
  8. How do eggs vary as to the kind of shell, amount of food, size, etc.? What is the effect of the amount of food upon the rate of development? On the stage of development at which the egg is hatched?
  9. Contrast præcocial and altricial birds.
  10. What is the effect of ground nesting and tree nesting upon the number of eggs and the care of the young?
  11. Describe the metamorphosis of grasshopper, June beetle, honeybee, dragon-fly, cicada, may-fly, ant-lion, caddis fly.
  12. Compare the development of the crayfish, crab, and lobster. What names are given to the larvæ? What is the significance in the fact that the lobster hatches in the "mysis stage"?
  13. What are some of the peculiar names given to the larvæ in the case of echinoderms, worms, and mollusks? Why should these have received special names?
  14. Name the three primitive germ layers. State the principal organs derived from each in the higher animals.
  15. What is ontogeny? phylogeny? What is the meaning of the law "The ontogeny is an epitome of the phylogeny"?
  16. Who was Weissman? What important contribution did he make to zoölogy?
  17. With what phase of zoölogy is the name of T. H. Morgan associated?