Classifying Critters

This diagram is based on the visible similarities between different creatures. It was produced many years ago.

Today we know that it is DNA that maintains the identity of each and every species. But you can't see DNA.

From the dawn of life, DNA was recording the process. Like a tape recording, information accumulated, bit by bit.

The better we become at reading the DNA code, the more we will learn about this mysterious period in the history of our planet.

Through each individual, the DNA code is passed from one generation to the next. DNA is transmitted through mating.

If the DNA of the Egg and Sperm are not an exact match, gene for gene, triplet for triplet, atom for atom then a union is not possible. 

 There is NO homosexuality in nature.

If "individuals" of a species fail to mate, that species is doomed.

In order to grow and develop, the cell needs food.

But feeding means taking in protein. Foreign substances are taken into the body.

Two problems arise:

• The danger of infection could destroy the cell.

• The cell cannot use protein.

 The only kind of food cells can eat are "amino acids".

Click on the Egg to see how cells get their diet of amino acids and avoid invasion by foreign proteins.