Hi all! If you have ever discussed evolution with someone trained to deny it, then you know how frustrating it can be. They will be dropping bits and pieces of info that they picked up on slightly but don't understand, and sometimes so will evolution defenders. I think one of the worst assaults on evolution isn't from active deniers. It's from supporters not being able to properly defend it. After all, this is a science based in, and supported by mounds of data. There is no "debate" over the basic facts. But, every now and again I see people throwing around the term "missing link" which I thought was known to be outdated and kind of meaningless, but it just goes to show how misinformed even well meaning people can be. So I'll let this blog explain the misconception:
Charles Sullivan and Cameron Mcpherson Smith go on to explain in the May 2005 issue ofSkeptical Inquirer that while the metaphor is seductive, it's mistaken:
But the metaphor is as misleading as it is attractive. The concept that each species is a link in a great chain of life forms was largely developed in the typological age of biology, when species “fixity” (the idea that species were unchanging) was the dominant paradigm. Both John Ray (1627-1705) and Carolus Linnaeus (1707-1797), the architects of biological classification (neither of whom believed in evolution), were concerned with describing the order of living species, an order they each believed was laid out by God (Ray suggested that the divinely specified function of biting insects was to plague the wicked).
But while the links of a chain are discrete, unchanging, and easily defined, groups of life forms are not. We generally define a species as some interbreeding group that cannot, or does not, productively breed with another group. But since species are not fixed (they change through time), it can be difficult to be sure where one species ends and another begins. For these reasons, many modern biologists prefer a continuum metaphor, in which shades of one life form grade into another. Life is not arranged as links, but as shades. The metaphorical chain is far less substantial than it sounds.
Thus the chain metaphor is wrong. It doesn’t accurately represent biology as we know it today, but as it was understood over four centuries ago. The myth persists because of convenience; it is easier to think of species as types, with discrete qualities, than as grades between one species and another. In school, we learn the specific characteristics of plants and animals; this alone is not a problem, except that we are not often exposed to the main ramification of evolution: that those characteristics will change through time.