Recently in class, we used a five meter long strip of paper to record significant events in Earth’s history. Call us self-centered, but we mainly focused in important developments of life on Earth. We divided the timeline into 5 billion-year long segments, and then plotted important events in Earth’s development using a scale of 1 cm to 10 million years.
The result was, however, a mostly blank roll of paper. Though the last few hundred million years were packed full of important events, before that, there were huge gaps between notable changes. This served to remind us that, even if life has been around on Earth for most of this planet’s lifetime, life as we know it is an incredibly recent development. After all, even smallest gaps in our timeline spanned millions of years.
As life on Earth has diversified, it has become more difficult to fully comprehend all living organisms’ shared ancestry. And yet, while plotting back all the way to the first life on Earth, it became that most of our diversification has occurred in the (relatively) recent past. The billions of years separating all organisms from one common ancestor seem endless, and yet through all those years, similar traits have remained.