Mean atmospheric O2
Geologic Time Scale
385 million years ago, near the end of the Devonian period, the first trees began to populate the Earth. Considered the first modern trees, tall plants with fern-like leaves of the genus Archaeopteris were a part of the Earth's primitive forests for the next 60 million years.
Unlike the trees we know today, Archaeopteris was in fact a primitive fern that reproduced by means of spores instead of seeds. While terrestrial plants had been around for 130 million years prior to Archaeopteris, this was the first plant to solve the biomechanical challenges of supporting and nurturing ever larger sizes, enabling these Archaeopteris to grow to heights of 70 feet and more, over twice the height of the Calamites.
In this image, four stages of the life of the Archaeopteris are illustrated. On the far left nearest our vantage point is a young, 20-foot Archaeopteris, and in the center at twice that height is a medium-aged Archaeopteris, and on the right is a fully mature specimen. Furthest right is the collapsed and decaying trunk of a mature tree, a contribution the biomass that will eventually become the oil, coal and natural gas we exploit today.
Copyright © Walter B. Myers. All rights reserved.
[ Home | What's New | The Graphics | Information | Site Map | ]