What will happen to the theory of evolution now that it's been discovered that 90% of all animal life appeared at the same time as humans did some 100,000 to 200,000 years ago?
Charles Darwin's Theory of Evolution claims that the evolution of all life is a slow gradual process. Darwin wrote, “…Natural selection acts only by taking advantage of slight successive variations; she can never take a great and sudden leap, but must advance by short and sure, though slow steps.” Darwin conceded that, “If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.”
Looks like Darwin's theory has just been set for extinction.
A massive genetic study carried out by senior research associate at the Program for the Human Environment at Rockefeller University Mark Stoeckle and University of Basel geneticist David Thaler reveals that virtually 90 percent of all animals on Earth appeared at right around the same time.
It is textbook biology, for example, that species with large, far-flung populations — think ants, rats, humans — will become more genetically diverse over time.
But is that true?
“The answer is no,” said Stoeckle, lead author of the study, published in the journal Human Evolution.
For the planet's 7.6 billion people, 500 million house sparrows, or 100,000 sandpipers, genetic diversity “is about the same,” he told AFP.
The study's most startling result, perhaps, is that nine out of 10 species on Earth today, including humans, came into being 100,000 to 200,000 years ago.
“This conclusion is very surprising, and I fought against it as hard as I could,” Thaler told AFP.
That reaction is understandable: How does one explain the fact that 90 percent of animal life, genetically speaking, is roughly the same age?
Was there some catastrophic event 200,000 years ago that nearly wiped the slate clean?
– Simpler, cheaper –
To understand the answer, one has to understand DNA barcoding. Animals have two kinds of DNA.
Let's take a look at what DNA barcoding is:
What Is DNA Barcoding?
Over the last decade, hundreds of scientists collected around 5 million DNA barcodes from 100,000 animal species in different parts of the globe. Stoeckle and Thaler looked through these 5 million genetic imprints to find one of the most surprising discoveries about evolution to date.
There are two types of DNA. Most people know nuclear DNA. This is the DNA containing the genetic blueprint for each single individual. It is passed down from the parents to the offspring. The genome is made from kinds types of molecules arranged in pairs. There are 3 billion of these pairs, which are then used to form thousands of genes.
The other, less familiar type of DNA is one found in the mitochondria of cells. The mitochondria generate energy for the cell and contains 37 genes. One of these is the COI gene, which is used to create DNA barcodes. All species have a very similar mitochondrial DNA, but their DNA is also different enough so we can distinguish between species.
Paul Hebert, biologist and director of the Biodiversity Institute of Ontario, developed a new way to identify species by studying the COI gene.
Born Around The Same Time
In analyzing the COI of 100,000 species, Stoeckle and Thaler arrived at the conclusion that most animals appeared simultaneously. They found that the neutral mutation across species were not as varied as expected. Neutral mutation refers to the slight DNA changes that occur across generations. They can be compared to tree rings because they can tell how old a certain specie or individual is.
As to how that could have happened, it's unclear. A likely possibility is the occurrence of a sudden event that caused large-scale environmental trauma and wiped out majority of the Earth's species.