The evolutionary process consists of adaptations in different phases. For example, irregularities in the topology of a morphology might develop into fins; fins may develop into limbs; limbs may develop into wings, etc.
I was always bothered by this because it seemed that there would be no way for an animal to bridge from one useful configuration to another. For example: flight. How could there be a stage in between limbs and fully functional fully developed wings? How in the world could a freak mutation that brings an animal one tiny step closer to true wings become favored in an environment?
One could almost personify evolution as encouraging progress: “I know it doesn’t make sense now, but trust me, it would be very wise to grow some feathers on this appendage and develop lighter bones.”
The truth is, adaptations have to be useful all of the time throughout the intermediary stages between major equilibriums in adaptations. I read about it a little bit and my curiosity was partially satisfied. For example, it makes sense that the intermediary stages that led to flight went something like this:
http://www.ucmp.berkeley.edu/vertebrates/flight/evolve.html
1. Wings evolved from arms used to capture small prey. (This seems rational, so we can ask whether the ancestral forms were actually doing this.)
2. Wings evolved because bipedal animals were leaping into the air; large wings assisted leaping. (This is possible; any amount of wing could assist leaping. Remember that we first need phylogenetic evidence for a bipedal running or leaping origin.)
3. Wings were used as sexual display structures; bigger wings were preferred by potential mates. (This is a non-falsifiable evolutionary hypothesis — we cannot test it.)
4. Wings evolved from gliding ancestors who began to flap their gliding structures in order to produce thrust. (This is reasonable and possible, but only with phylogenetic evidence for an arboreal gliding origin.)
It’s pretty amazing when you consider how fine-tuned our universe is; it allows for the evolution of carbon chemistry needed for the basic component molecules of life; and it allows for the evolution of extremely advanced and crafty replicators—genes. The anthropic principle satisfies me in this regard. But the extent of the role of middle-stages in evolution and the fact that they, time and time again, never cease to disappoint in creating larger and greater adaptations, baffles me.
I mean, how easy could it be in another universe for life to evolve to a point and get stuck? There would suddenly be a point where there’d be no immediate advantage to a replicator to evolve in a way that would in some arbitrary future time become something greater and more complex. The fact that in our universe, historically there has always been an immediate advantage to a middle-step, amazes me, considering how long the process has gone on and considering how complex we have gotten. It seems entirely possible that we may get stuck like we should have a long time ago, but I doubt it with our luck!
I was always bothered by this because it seemed that there would be no way for an animal to bridge from one useful configuration to another. For example: flight. How could there be a stage in between limbs and fully functional fully developed wings? How in the world could a freak mutation that brings an animal one tiny step closer to true wings become favored in an environment?
One could almost personify evolution as encouraging progress: “I know it doesn’t make sense now, but trust me, it would be very wise to grow some feathers on this appendage and develop lighter bones.”
The truth is, adaptations have to be useful all of the time throughout the intermediary stages between major equilibriums in adaptations. I read about it a little bit and my curiosity was partially satisfied. For example, it makes sense that the intermediary stages that led to flight went something like this:
http://www.ucmp.berkeley.edu/vertebrates/flight/evolve.html
1. Wings evolved from arms used to capture small prey. (This seems rational, so we can ask whether the ancestral forms were actually doing this.)
2. Wings evolved because bipedal animals were leaping into the air; large wings assisted leaping. (This is possible; any amount of wing could assist leaping. Remember that we first need phylogenetic evidence for a bipedal running or leaping origin.)
3. Wings were used as sexual display structures; bigger wings were preferred by potential mates. (This is a non-falsifiable evolutionary hypothesis — we cannot test it.)
4. Wings evolved from gliding ancestors who began to flap their gliding structures in order to produce thrust. (This is reasonable and possible, but only with phylogenetic evidence for an arboreal gliding origin.)
It’s pretty amazing when you consider how fine-tuned our universe is; it allows for the evolution of carbon chemistry needed for the basic component molecules of life; and it allows for the evolution of extremely advanced and crafty replicators—genes. The anthropic principle satisfies me in this regard. But the extent of the role of middle-stages in evolution and the fact that they, time and time again, never cease to disappoint in creating larger and greater adaptations, baffles me.
I mean, how easy could it be in another universe for life to evolve to a point and get stuck? There would suddenly be a point where there’d be no immediate advantage to a replicator to evolve in a way that would in some arbitrary future time become something greater and more complex. The fact that in our universe, historically there has always been an immediate advantage to a middle-step, amazes me, considering how long the process has gone on and considering how complex we have gotten. It seems entirely possible that we may get stuck like we should have a long time ago, but I doubt it with our luck!
