How To Study Living Animals


1. The Simple or Asexual Method of Reproduction
Materials.

Slides or diagrams, showing a dividing amœba, a dividing paramecium, a dividing vorticella, reproduction in some form of sporozoa, budding hydra, gemmules of spongilla, and some species of worm as Dero or Nereis in the process of dividing herunterladen.

Definitions.

Spore,

a cell capable of developing into a new organism.

Asexual reproduction,

reproduction by division of the cell or body herunterladen.

Sexual reproduction,

reproduction by means of the conjugation of two reproductive cells known as the egg and sperm cells.

Fertilization,

the fusion of the male or sperm cell with the egg or female cell microsoft office kostenlos downloaden vollversion deutsch chip.

Ovary,

an organ producing eggs.

Spermary,

an organ producing sperm cells.

Cross fertilization,

fertilization in which the sperm and egg cells are produced by different individuals.

Diœcious,

the different kinds of reproductive organs found in different individuals.

Monœcious,

the different kinds of reproductive organs found in the same individual.

Directions.

Note.—Refer to your notes, if the animals mentioned in these exercises have been already studied. This exercise may be largely review.

Study the methods of reproduction in the specimens or diagrams before you. Determine first, in what respects the methods of reproduction are similar in all; second, in what respects there is a variation.

Questions.

1. What has an amœba gained by dividing? What powers has each new cell that the original amœba had lost? What would have been the fate of the amœba if it had not divided into new cells?

2. What various forms of cell division did you find?

3. What is the simplest method of reproduction?