BMEN 515 Lecture Notes - Cambrian Explosion, Lycopodiopsida, Evolutionary Radiation

• School: University of Calgary
• Department: Biomedical Engineering
• Course: BMEN 515
• Professor: William Huddleston

Document Summary

Cambrian period (452-488 mya) marks the beginning of the palaeozoic era. The o2 concentration was approaching its current level; the continents had come together to form several large land masses. A rapid diversification of life took place cambrian explosion. Most of the major groups of animals that have species living today appeared during this period. Insects evolved wings (first animals to fly) and gained access to tall plants. the amniotes, vertebrates with well-protected eggs that can be laid in dry places. In seas, crinoids reached their greatest diversity, forming meadows on the sea floor. Few organisms that survived found themselves in a relatively empty world at the start of the mesozoic era (251 mya). Pangaea slowly separated into individual continents; oceans rose and reflooded continent shelves, forming huge, shallow inland seas. Atmospheric oxygen concentrations gradually rose to their former levels.