Part 9: The unbelievability of change
Take a look at the diagram below and ask yourself the question: can something so small as a fertilized egg transform itself into something as incredibly large and complex as a fully functional human being? Well, of course – you might say – we have observed, within our lifetimes, people being born, growing up, and changing as they age.
But just for a moment, imagine that you have never observed birth or growth, and know nothing about how humans are conceived. Wouldn't the above diagram seem outlandishly incredible to you? You might scoff at it with incredulity, finding it unbelievable that such a small and simple object can transform itself into something so radically different.
I once scoffed at macroevolution for the same reason. It was difficult for me to imagine how birds evolved from dinosaurs, or how humans evolved from small, hairy mammals. But at the time I didn't consider an important fact: that in nature, small changes (micro-changes) often result in large changes (macro-changes) over a period of time.
Look again at the diagram above. It seems to represent an incredible macro-change (i.e., zygote to human), but this only seems incredible because the diagram doesn't show all the millions of tiny changes that take place in between. After conception, hundreds of cellular and genetic changes take place over a period of nine months to transform this little pack of cells into a human baby. And after birth thousands of changes occur to eventually transform the baby into an adult. In other words, the macro-change in the diagram is simply a result of a whole lot of micro-changes taking place over a period of time.
Richard Dawkins, in the preface of his book The Blind Watchmaker, argues that we battle to grasp macroevolution because our brains are built to deal with changes that occur in time-scales represented by days, months and years – not millions of years. Large macroevolutionary changes seem incredible, but if we consider thousands upon thousands of natural micro-changes guided by natural selection, then macroevolution doesn't seem that unbelievable at all. In fact, it seems perfectly logical.
I know, as Lui mentioned in an earlier post, that I have to do more than simply show that macroevolution is logical. So in the remaining posts I will argue that there are observable facts in nature that suggest that macroevolution has indeed occurred.
And I will start by exploring the layers of my mom's trifle . . .
Next post: Layers in a trifle
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