Go, go, Gadget Evolution!
Something that has been going through my mind for the last week or so...
Evolution is not perfect, at best it is "good enough." There are many examples of "acceptable" problems with natural selection, so long as an organism isn't affected to the point that it is unable to procreate. A quick example is intestine lenght--during a low food period, it's important to have a longer intestine to absorb as much nutrients from food as possible, but in high food availability periods, this unnecessarily long intestine is just extra weight being carried around (which incidentally is unnecessarily requiring extra nutrients to maintain)--big problem if weight really matters for you, such as if you are a bird.
Now for the weird stuff.
If an organism always produced viable offspring (let's quickly define that as offspring that can be expected to produce their own offspring, ad nauseum) on day 20 of its life, and always spontaneously combusted on day 21, there is no selective pressure against that spontaneous combustion. The organism has continued its line, and there will forever be another group of the same organism to create babies and afterward suffer a horrible flaming death.
If, however, that spontaneous combustion occured immediately after producing offspring, and injured or killed some of the offspring in the process, there would be selective pressure, and a change would be expected over time--perhaps, say, delaying that fiery death long enough to put the offspring out of harm's reach. But I digress...
The thought that occured to me was that there are no selective pressures against necessary or negligible "inconveniences" of essential life functions, so long as they do not affect the viability of the organism. For our example, we'll stay with the need to produce viable offspring. We'll also use some weird examples, just so you're warned.
Okay, let's say Organism A doesn't have a birth canal, but instead loses a limb during the birthing process, and that's where the offspring leaves the parent from (it's okay, Organism A has a lot of limbs, like an octopus). Organism A gives birth to its first litter of Baby A's, and must live the rest of its life with one less limb--perhaps slightly hindered in its day to day activities, but it survives, long enough to have a second litter. It loses another limb for this new litter, and so on, each time becoming slightly less effective on a day to day basis. There's a limit here, either 1: Organism A is unable to give birth to any further litters as it has exhausted its limbs, or 2: it is unable to survive the period of time between giving birth as it has an insufficient nuber of limbs to care for itself. However, if Organism A generally produces only one set of offspring during its lifetime, it doesn't matter how many limbs it loses to that initial litter--if they all fall off and Organism A is completely helpless after that first litter, there is no selective pressure against losing one or all limbs.
...Okay, I think that's the end of this post, for now, anyway. I'm getting tired, and I'm sure I'm rambling right now; perhaps I'll elaborate on this later--it also appears I may have repeated myself here.
Evolution is not perfect, at best it is "good enough." There are many examples of "acceptable" problems with natural selection, so long as an organism isn't affected to the point that it is unable to procreate. A quick example is intestine lenght--during a low food period, it's important to have a longer intestine to absorb as much nutrients from food as possible, but in high food availability periods, this unnecessarily long intestine is just extra weight being carried around (which incidentally is unnecessarily requiring extra nutrients to maintain)--big problem if weight really matters for you, such as if you are a bird.
Now for the weird stuff.
If an organism always produced viable offspring (let's quickly define that as offspring that can be expected to produce their own offspring, ad nauseum) on day 20 of its life, and always spontaneously combusted on day 21, there is no selective pressure against that spontaneous combustion. The organism has continued its line, and there will forever be another group of the same organism to create babies and afterward suffer a horrible flaming death.
If, however, that spontaneous combustion occured immediately after producing offspring, and injured or killed some of the offspring in the process, there would be selective pressure, and a change would be expected over time--perhaps, say, delaying that fiery death long enough to put the offspring out of harm's reach. But I digress...
The thought that occured to me was that there are no selective pressures against necessary or negligible "inconveniences" of essential life functions, so long as they do not affect the viability of the organism. For our example, we'll stay with the need to produce viable offspring. We'll also use some weird examples, just so you're warned.
Okay, let's say Organism A doesn't have a birth canal, but instead loses a limb during the birthing process, and that's where the offspring leaves the parent from (it's okay, Organism A has a lot of limbs, like an octopus). Organism A gives birth to its first litter of Baby A's, and must live the rest of its life with one less limb--perhaps slightly hindered in its day to day activities, but it survives, long enough to have a second litter. It loses another limb for this new litter, and so on, each time becoming slightly less effective on a day to day basis. There's a limit here, either 1: Organism A is unable to give birth to any further litters as it has exhausted its limbs, or 2: it is unable to survive the period of time between giving birth as it has an insufficient nuber of limbs to care for itself. However, if Organism A generally produces only one set of offspring during its lifetime, it doesn't matter how many limbs it loses to that initial litter--if they all fall off and Organism A is completely helpless after that first litter, there is no selective pressure against losing one or all limbs.
...Okay, I think that's the end of this post, for now, anyway. I'm getting tired, and I'm sure I'm rambling right now; perhaps I'll elaborate on this later--it also appears I may have repeated myself here.