Species, is it a limiting label? Do we use this term to a fault? I think so. What is a new or different species? Something completely different right? I think not.
This blog came to me after something I was listening to yesterday while driving home from work. I had a news radio show on when I heard a statement that began "Modern humans first appeared approximately...." It seems like such an odd statement to make. I can envision the mother ship in orbit beaming these first modern humans onto the surface of the Earth to perform this appearance. These so called modern humans are considered apart from everything that has walked the planet before. The discussion around Neanderthals and Cromagnon humans invokes the term species to deal with the problem of finding fossil remains of both from estimated similar geologic time.
Given recent news of flu virus evolving to infect people from pigs on a 10 year time scale and not so recent human changes enabling digestion of lactose in milk developing on a 10,000 year time scale, what changes might be possible in 50,000 years or 100,000 years. Significant changes in physical and physiological attributes of living things can happen well within the time gaps in fossil evidence. Samples of fossilized life or life evidence are rare and represent spotty evidence at best along a continuous time line into the past. Most of the time it is sudden, infrequent events that trap remains in a manner that results in fossils. Can we say that we have complete visibility of how a living thing has changed over time. No, we have snap shots, some of which show things we recognize as similar to others and sometimes do not. Does that mean that a continuous set of minor changes did not occur leading from one fossil to the next. No. But we do not have the evidence to show this gradual evolution from one to the next. In reality there are no actual divisions. This includes in the evolution of humans. The terminology generated by humans to assist with the description of the observed variety in the world of living entities has divided life into species, phylums and so on for convenience.
So what do we really have. We have a continuum of life all representing variations on a theme. A spectrum of possible variations of common ingredients. Nothing just springs into being. Cromagnon and Neanderthal came from a common ancestor and represent subsequent waves of migration from a common source. Variations in life build up with time due to environment and pressure of interaction with that environment. Our scientists look back across the abyss of time and see millions of years condensed into a scale too dense to show transitions that occur over tens or hundreds of thousands of years, as other than instantaneous. This is our failure to see and comprehend the granularity on that scale. All life on earth has a common origin and in a sense represents one family. The appearance of modern humans, or the fossil evidence of these humans, is sudden in our condensed view if history but in fact occurred over hundreds of thousands of years. When Cromagnon ventured out of Africa were the Neanderthal long dead or did they mingle with their own ancestors who had become isolated in the northern colder regions so long they developed unique physical attributes. But calling them a different species is more like an effort to deny our heritage than a scientific fact.
When we meet life on or from another planet will we then truly see another species of life? If all life evolves from common ingredients we may eventually recognize in a sense all life in our galaxy or even universe is related and species is no more than tabbed pages in a book denoting chapters.
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