One of the roadblocks in discussing evolution with people is getting them to conceptualize the process. People are used to visualizing things relative to their own lives. It's easy to conceptualize how long a week or month or year is. But try imaging a thousand years. Or ten thousand. Or a million. It's pretty much impossible, because we're just no used to dealing with such vast periods of time in our own lives.
Likewise, the same problem occurs with evolution. People are used to seeing animals give birth to the same kinds of animals. Dogs give birth to dogs. Humans give birth to humans. Creationists seize on this to create misconceptions about evolution, like "monkeys give birth to monkeys, not humans" or "when has a dog ever given birth to a non-dog?". They are creating a misconception based on the way we see every thing today. We see modern dogs, modern apes, modern humans, and it's difficult to see how such species could be related by common ancestry.
The first thing to understand is that there is no magical process for change in biological evolution. The minor variations we see in organisms today is part of the same process that diversified all life. Sure, we see dogs giving birth to dogs, cats giving birth to cats. But dogs give birth to slightly different dogs, which then give birth to slightly different dogs, and so on and so on, until you wind up with something we might no longer call a "dog". But there is no magic moment when a dog suddenly gave birth to a non-dog in a single step. The actual change is relatively gradual.
Diagram 1: Microevolution and Macroevolution
To conceptualize this process of change, see the above diagram. In it, the color orange gradually becomes the colour yellow. The overall change is clearly visible. But if you zoom into a point along the bar, the change becomes much less apparent. The section I zoomed in on looks uniform orange, yet there is actually a tiny change from the left side to the right side (note: because it's a GIF file limited to 256 colors, the color might actually be uniform; but in the original Photoshop version there was a slight difference). The difference, of course, is almost imperceptible. It's like seeing dogs producing dogs. We just don't see the dramatic level of change the overall picture provides. And with respect to biological evolution, the overall picture is far greater than human lifespans or even human civilization.
Diagram 2: Rates of Change
The previous picture showed a pretty linear picture with a constant rate of change. The reality of biological evolution is that rates of change vary. In the above picture the gradation is more dynamic. But even during "rapid" periods of change, the changes are still difficult to detect when zoomed in to a specific spot.
Diagram 3: Branching Evolution
Another factor is that evolution is not a linear path from Species A --> Species B --> Species C --> etc. Evolution is a branching tree. Populations split and diversify, then those new populations further split and diversify, etc. The resulting picture is much more complex. But again, if you zoom into any point on the tree you wind up with the same barely perceptible rates of change. Dogs producing dogs, as it were.
Diagram 4: Discontinuity in the Fossil Record
The problem with historical development of species is we don't have an exact record of every single organism or even every single species that ever lived. Fossilization is an extremely rare process in itself, not mention actually finding the fossils. Yet, even with the fossils that are found it is possible to big putting together these branching patterns of the historical development of life. Granted, scientists doing this may make mistakes, but as more fossils are found, a clearer picture forms.
Diagram 5: Fossil Hominid Skulls
Even with the fragmentary picture formed from the fossil record, patterns do emerge. Pictured above are a series of fossil skulls (adapted from a picture at Talk.Origins). When arranged chronologically, there is a clear pattern of evolutionary development. Keep in mind that the actual evolutionary development was probably not linear, and followed a branching pattern similar to the previous two diagrams. This does not change the fact that there is a pattern of gradual evolutionary change with respect to the chronology of the fossils.
I hope that this might help some people who have trouble conceptualizing the process of biological evolution. It can be difficult to visualize, especially if one is just used to seeing everything as we see things today, relative to our own lives. But there is a bigger picture out there. It just takes a little work to see it.
(If anyone can see any points that need correction or things that should clarified or explained differently, let me know.)
Likewise, the same problem occurs with evolution. People are used to seeing animals give birth to the same kinds of animals. Dogs give birth to dogs. Humans give birth to humans. Creationists seize on this to create misconceptions about evolution, like "monkeys give birth to monkeys, not humans" or "when has a dog ever given birth to a non-dog?". They are creating a misconception based on the way we see every thing today. We see modern dogs, modern apes, modern humans, and it's difficult to see how such species could be related by common ancestry.
The first thing to understand is that there is no magical process for change in biological evolution. The minor variations we see in organisms today is part of the same process that diversified all life. Sure, we see dogs giving birth to dogs, cats giving birth to cats. But dogs give birth to slightly different dogs, which then give birth to slightly different dogs, and so on and so on, until you wind up with something we might no longer call a "dog". But there is no magic moment when a dog suddenly gave birth to a non-dog in a single step. The actual change is relatively gradual.
Diagram 1: Microevolution and Macroevolution
To conceptualize this process of change, see the above diagram. In it, the color orange gradually becomes the colour yellow. The overall change is clearly visible. But if you zoom into a point along the bar, the change becomes much less apparent. The section I zoomed in on looks uniform orange, yet there is actually a tiny change from the left side to the right side (note: because it's a GIF file limited to 256 colors, the color might actually be uniform; but in the original Photoshop version there was a slight difference). The difference, of course, is almost imperceptible. It's like seeing dogs producing dogs. We just don't see the dramatic level of change the overall picture provides. And with respect to biological evolution, the overall picture is far greater than human lifespans or even human civilization.
Diagram 2: Rates of Change
The previous picture showed a pretty linear picture with a constant rate of change. The reality of biological evolution is that rates of change vary. In the above picture the gradation is more dynamic. But even during "rapid" periods of change, the changes are still difficult to detect when zoomed in to a specific spot.
Diagram 3: Branching Evolution
Another factor is that evolution is not a linear path from Species A --> Species B --> Species C --> etc. Evolution is a branching tree. Populations split and diversify, then those new populations further split and diversify, etc. The resulting picture is much more complex. But again, if you zoom into any point on the tree you wind up with the same barely perceptible rates of change. Dogs producing dogs, as it were.
Diagram 4: Discontinuity in the Fossil Record
The problem with historical development of species is we don't have an exact record of every single organism or even every single species that ever lived. Fossilization is an extremely rare process in itself, not mention actually finding the fossils. Yet, even with the fossils that are found it is possible to big putting together these branching patterns of the historical development of life. Granted, scientists doing this may make mistakes, but as more fossils are found, a clearer picture forms.
Diagram 5: Fossil Hominid Skulls
Even with the fragmentary picture formed from the fossil record, patterns do emerge. Pictured above are a series of fossil skulls (adapted from a picture at Talk.Origins). When arranged chronologically, there is a clear pattern of evolutionary development. Keep in mind that the actual evolutionary development was probably not linear, and followed a branching pattern similar to the previous two diagrams. This does not change the fact that there is a pattern of gradual evolutionary change with respect to the chronology of the fossils.
I hope that this might help some people who have trouble conceptualizing the process of biological evolution. It can be difficult to visualize, especially if one is just used to seeing everything as we see things today, relative to our own lives. But there is a bigger picture out there. It just takes a little work to see it.
(If anyone can see any points that need correction or things that should clarified or explained differently, let me know.)
