Alright [MENTION=2589]Clete[/MENTION], here is my guess.
Evolution works on an expressed phenotype, and expressed allele. The phenotype can either be beneficial or not. If it is beneficial, then it is passed to the next generation. If it is not then it may or may not be passed on depending on how non-beneficial it is.
Let us take a fish, a pre-mud skipper if you will. It is swimming in shallow pools and when they dry up and run out of food, the fish has a rather big problem. At some point, for some unknown reason, a mutation occurs in the genes that control the fin development such that the bones of the fin become stronger. The fish happens to discover that its fins are strong enough that it can pull itself across the ground mud to a different pool when his runs out of food. The phenotype of this fish conveys an enhanced ability to survive so it is based on to future generations.
Looking at other animals, crabs, insects, arthropods, we might have to go back farther in time to single cell animals. Single cell animals developed flagella to move because it gave them an advantage. It is possible that the different phylum's each developed from a different single cell animal. Some developed 6 legs that walk sideways (crabs) while others developed 6 legs that move forward (insects).
The idea is that small beneficial changes add up over time. It is a concept that is actually used quite frequently in engineering. But here is where my gap in understanding comes in. Evolution can only act on an expressed phenotype. A phenotype is an expressed allele in a gene. Gene mutations are random so we are counting on a random mutation to create an allele that does something good. It gets further complicated by the fact that the stronger bones in my mud skipper example above is grossly incomplete. We would require a series of mutations that makes the bones stronger and the muscles stronger as well. Plus we have to have mutations to the gills to allow the fish to survive as it moves between pools. So it is not just one gene that needs to mutate. It is not even the just the genes dealing with fins that must mutate, we have multiple gene mutations required. And at some point we have to figure out how all new chromosomes come into existence. I have a rather large gap in understanding the details of genetics. I call that gap the ignorance gap because I have not taken the time to study in years and years.
That said, when we look at the fossil record it is fairly easy to see that all vertebrate animals can trace back to some single point of origin. When we compare the bone structures of whales and elephants and bats and people we can see all of the same bones though they are significantly in shape in size. This speaks to a common ancestor. I digress.
Evolution works on an expressed phenotype, and expressed allele. The phenotype can either be beneficial or not. If it is beneficial, then it is passed to the next generation. If it is not then it may or may not be passed on depending on how non-beneficial it is.
Let us take a fish, a pre-mud skipper if you will. It is swimming in shallow pools and when they dry up and run out of food, the fish has a rather big problem. At some point, for some unknown reason, a mutation occurs in the genes that control the fin development such that the bones of the fin become stronger. The fish happens to discover that its fins are strong enough that it can pull itself across the ground mud to a different pool when his runs out of food. The phenotype of this fish conveys an enhanced ability to survive so it is based on to future generations.
Looking at other animals, crabs, insects, arthropods, we might have to go back farther in time to single cell animals. Single cell animals developed flagella to move because it gave them an advantage. It is possible that the different phylum's each developed from a different single cell animal. Some developed 6 legs that walk sideways (crabs) while others developed 6 legs that move forward (insects).
The idea is that small beneficial changes add up over time. It is a concept that is actually used quite frequently in engineering. But here is where my gap in understanding comes in. Evolution can only act on an expressed phenotype. A phenotype is an expressed allele in a gene. Gene mutations are random so we are counting on a random mutation to create an allele that does something good. It gets further complicated by the fact that the stronger bones in my mud skipper example above is grossly incomplete. We would require a series of mutations that makes the bones stronger and the muscles stronger as well. Plus we have to have mutations to the gills to allow the fish to survive as it moves between pools. So it is not just one gene that needs to mutate. It is not even the just the genes dealing with fins that must mutate, we have multiple gene mutations required. And at some point we have to figure out how all new chromosomes come into existence. I have a rather large gap in understanding the details of genetics. I call that gap the ignorance gap because I have not taken the time to study in years and years.
That said, when we look at the fossil record it is fairly easy to see that all vertebrate animals can trace back to some single point of origin. When we compare the bone structures of whales and elephants and bats and people we can see all of the same bones though they are significantly in shape in size. This speaks to a common ancestor. I digress.
