Friday Headlines, April 18, 2014
THE LATEST IN THE GEOSCIENCES
Earthquake near Acapulco!
This earthquake occurred where the Cocos plate is subducting (sliding beneath) the North American plate. Such earthquakes are very common along the western edges of North and South America (although the earthquakes in California are from a different but related mechanism).
This one was cool because it showed up on the seismometer that we have in our building.
All multi-cellular organisms on this planet under go a stage early in development where they are an embryo. The earliest part of embryology is a stage where there is merely a hollow ball of cells.
From time-to-time, these embryonic cell-balls get preserved in the fossil record.
Recently, some fossils were found in a Cambrian (540 million to 485 million years ago) aged limestone in China.
It’s difficult to know what animal these might have come from, given the age of the rocks as well as the fact that many animals go through this same embryonic stage. It is interesting, however, to realize that embryonic development is the same now as it was more than 400 million years ago!