How To Study Living Animals


5. THE CONNECTION BETWEEN STRUCTURE AND FUNCTION

A Review of the Work done on the First Four Groups of Animals

Review all your studies on the protozoa, sponges, cœlenterates, and worms herunterladen. Write the results in the following summary:—

1. What work, i.e. labor, must an animal do to live?

2. How many cells are necessary to do this work herunterladen?

3. When this work is divided among a number of cells, what is the effect upon the quantity and quality of work accomplished?

4. When this work is divided among a number of cells, how does the structure of the cells show it microsoft office kostenlos downloaden vollversion deutsch chip? How does the arrangement of the cells also show it? Give examples.

5. The technical expression for this specialization of cells, giving them different functions, is “division of labor.” Formulate a clear definition for this expression, giving an example to illustrate it.

6. Is division of labor a good thing for an animal body, or is it not? Give reasons for your opinion, with examples for illustration.


CHAPTER IV
ADAPTATION TO SURROUNDINGS

A Study of Crustacea

To Show the General Adaptation of an Invertebrate to its Surroundings

1. A STUDY OF CRAYFISHES
Materials.

Crayfishes, living and preserved. Some of the living crayfishes should be established in conditions as natural as possible i.e. in an inch or so of fresh water, with rocks, weeds, etc., and left undisturbed. Small crayfishes are desirable to show locomotion in water.