WHY IN OUR OPINION THE ANCIENTS BELIEVED IN SPONTANEOUS GENERATION OF BUGS AND FROGS

We have collected the opinions of our class; the signes + beside every affirmation indicate the number of pupils who share it.

  • Because frogs are not mammiferous ++++++++
  • Because it is  difficult to understand where they are from, their eggs are too small ++
  • It is difficult to observe these animals because they are very small ++++
  • These animals change their  shape during their life  +++++
  • The ancients  didn’t know very well these animals ++
  • It was difficult, at that time, to identify the sex of a bug or of a frog +
  • These  animals are wild and therefore it is difficult to observe their reproduction ++
  • The ancients were just a little interested about the life of these animals, so they paid little attention on them ++
  • The theory of spontaneous generation is true, in facy once I saw a woodworm coming out from a hole in a wood +

THE METAMORPHOSIS

Butterflies

Bees

Frogs

1st phase

The butterfly lays the eggs

1st phase

The queen bee lays a hundred of eggs.

1st phase

The eggs have a gelatinous covering whose volume increases with the water.

2nd phase

The grup get out of the egg and begins to eat the leaves.

2nd phase

After3 days  white grubs get out of the eggs .

2nd phase

After a week a tadpole develops. It doesn't have eyes and mouth .

3rd phase

The grub wraps up silk threads around the body, constructing a cocoon.

3rd phase

After 9 days the grubs begin to transform themselves in pupa

3rd phase

After two weeks the tadpole is equipped of mouth, of gills in order to breathe the air dissolved in the water and of tail in order to swim.

4th phase

The pupa develops iside the cocoon

4th phase

After3 weeks the bees develop completely.

4th phase

The front and posterior limbs develop, while the tail reverts.

5th phase

Finally the adult butterfly develops from the cocoon.

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5th phase

Finally the gills atrophy and the lungs develop. The frog leaves the water.

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School site Aristotle Redi Spallanzani Metamorphosis Microorganisms "The tiny animals"