ARCH 131 Lecture Notes - Microsoft Powerpoint, Unit, Ploidy

• School: Simon Fraser University
• Department: Archaeology
• Course: ARCH 131
• Professor: Dennis Sandgathe

Document Summary

This powerpoint and lecture will be a review of cell biology and. Genetics these things are responsible for the underlying mechanics of evolution. First, let"s take a quick, brief step backward: The earliest life on earth began as prokaryotic cells these are single-celled organisms and survive today as blue-green algae and, more commonly, as bacteria. They first appeared about 3. 8 billion years ago and were the only life on earth until about 1. 5 billion years ago when eukaryotic cells appeared. Eukaryotic cells began as single-celled organisms and there are countless examples of such organisms still alive today, but eukaryotes are the type of cell that multi-cellular organisms are composed of and multi-cellular life appeared about 600 million years ago. The main difference between prokaryotes and eukaryotes is that in prokaryotes the genetic material is not segregated from the rest of the cell by a nucleus it floats around among the other components of the cell.