The History of Life on Earth in Three Minutes
Happy New Year, planet Earth!
According to the Anno Domini designation, the year is now 2014. But the Earth has been around a lot longer than that – about 4.567 billion years. The first evidence of life dates back to around 3.8 billion years ago. Homo sapiens first appeared on the planet around two hundred thousand years – or ten thousand generations – ago.
How’s that for perspective?
Kirk Johnson, director of the National Museum of Natural History, calls this perspective “deep time.” This is the story of our planet preserved in “the DNA of living things,” Johnson explains, as well as “in the fossils we find, in the geologic structures of our planet, in the meteorites we scavenge from the ice fields in Antarctica. Those things together give us an incredible manual for thinking about the planet.”
Why is this manual useful? We are facing a century that will be an incredibly challenging one for humanity. We now live on a planet with seven billion people, which is up from 1.7 billion people just three or four generations ago. So we have more people, and a greater need for resources.
Fortunately we have the bodies of extinct plants and animals that lived for the last three-and-a-half billion years. These fossils are not only a source of energy, but also a source of knowledge about how this planet works. Over its history the Earth has seen an incredible diversity of life – maybe as many as fifty million species. Johnson says we’re learning “as much about the evolution of life on Earth by looking at what happened in the past as we are at looking at the breakthroughs in genomics and DNA of living things.” Furthermore, Johnson sees the sequencing of the human genome as the vanguard for what will eventually be “the study of the genomics of all living things.”
We have the opportunity right now, Johnson says, to choose what our future will be. Our understanding of the diversity of life on this planet, he says, will be our guide. This story is being told at a current exhibition at the National Museum of Natural History called “Genome: Unlocking Life’s Code.”
In the video below, Johnson shares a unique perspective on deep time in the form of a timeline of life on this planet in just three minutes.
Image courtesy of Shutterstock