Historically, Poland has been part of the barrier against the steppe invassions, first the Mongols, then the Russians themselves. From that point of view, it would be central Europe, as the steppe peoples would be eastern Europe. Poles often lived within the HRE, which would place them squarely in the Mittel-europa.
The Cambrian Explosion refers to the metaphorical explosion of life that began 542 million years ago and lasted for roughly 40 million years. This lesson will cover the events that occurred during this time period.
Cambrian Explosion. âCambrian explosionâ refers to the great quantity and diversity of life found in what is called the Cambrian layer of the geologic column. The Cambrian age in the geologic time scale is dated by scientists as being about 530 million years old. What is really interesting is not just what is found in this layer, but what is found in the layers above it, and what is not found in layers under it. The Cambrian layer has virtually every phyla known to man.