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How does this behavior evolve? Shrinking your internal organs and going into a zombie state for a 9-day flight seems like it would require the coordination of

How does this behavior evolve? Shrinking your internal organs and going into a zombie state for a 9-day flight seems like it would require the coordination of dozens of separate processes, and making it only 95% of the way means drowning in the ocean. Evolution works through tiny incremental changes, but this flight sounds like an all-or-nothing scenario.

nerdponx 4y ago
I wonder if this evolved while ocean levels were lower, and the physical distances between chunks of land were shorter. And what if there were more islands along the way at some point? Also I wonder what % of godwits do actually fail along the way. I suspect that many "elderly" birds aren't able to make the trip.
- WalterBright 4y ago
  Nomadic tribes would just leave behind the elderly who could no longer keep up.
  - deleted 4y ago
    [deleted]
- 7952 4y ago
  I guess that death along the way is a very strong influence on their evolution. The ones that reproduce are the ones that did make the journey and have adapted to it.
- Infernal 4y ago
  The article mentions that survival of the trip is “above 90%”. I assumed that was one direction, but I suppose it could be round trip.
- stubish 4y ago
  I'm also curious as to when this behavior evolved. Did the distance become longer over time, as the continents moved apart?
setr 4y ago
>Evolution works through tiny incremental changes, but this flight sounds like an all-or-nothing scenario. I never confirmed one way or the other, but I'm fairly positive evolution operates by large sudden changes followed by incremental improvements/optimizations -- it's difficult to explain many "weird" traits through incremental improvements, because most of them would get stuck in local maxima's before achieving any real benefit over the prior state. Like you can't evolve a third arm by slowly iterating towards it, from a lump to a stump to a limb to a functional limb; it'd be entirely a loss until it becomes fully functional. You have to grow a shitty yet complete third arm first, but not so shitty that it doesn't offer benefit, and then iteratively improve it into a pretty nice arm
- 7952 4y ago
  I think that some traits have an unreasonably large effect on the species. And we attach greater significance to them after the fact which makes it seem like a big jump. For example some fish evolved to have stubby lobed fins. That gave them some local advantage. It is just coincidental that the same change lead to arms, legs and wings. And these kind of big visible features need more than a few changes in DNA to happen. An arm needs to attach to something, have muscles and arteries and nerves. That can only evolve iteratively from something else. There is a reason that elephant trunks are also a nose.
- robga 4y ago
  > I never confirmed one way or the other, but I'm fairly positive evolution operates by large sudden changes followed by incremental improvements/optimizations This is basically the theory of punctuated equilibrium as proposed by Stephen Jay Gould to the commonly held thought at the time of gradualism.
7952 4y ago
Not sure about migratory birds in particular. But being able to survive without food for long periods is clearly a good trait. It has evolved across plants and animals to a lesser or greater degree. That trait can team up with another. For example an animal that can dig can hybernate underground. An animal that can fly can journey to find food or a mate. It may start by flying a short distance across land and slowly build up the distance over successive generations. Then it could learn to follow the coast to find better food. Or develop abilities for navigation. Or an instinct to fly when the days get short and be less distracted by food. Slowly but surely the benefit of flying outweighs the benefit of staying at a food source. The travel gets longer and longer until it is crossing thousands of miles.

nerdponx 4y ago

I wonder if this evolved while ocean levels were lower, and the physical distances between chunks of land were shorter. And what if there were more islands along the way at some point? Also I wonder what % of godwits do actually fail along the way. I suspect that many "elderly" birds aren't able to make the trip.

WalterBright 4y ago
Nomadic tribes would just leave behind the elderly who could no longer keep up.
- deleted 4y ago
  [deleted]
7952 4y ago
I guess that death along the way is a very strong influence on their evolution. The ones that reproduce are the ones that did make the journey and have adapted to it.
Infernal 4y ago
The article mentions that survival of the trip is “above 90%”. I assumed that was one direction, but I suppose it could be round trip.
stubish 4y ago
I'm also curious as to when this behavior evolved. Did the distance become longer over time, as the continents moved apart?

setr 4y ago

>Evolution works through tiny incremental changes, but this flight sounds like an all-or-nothing scenario. I never confirmed one way or the other, but I'm fairly positive evolution operates by large sudden changes followed by incremental improvements/optimizations -- it's difficult to explain many "weird" traits through incremental improvements, because most of them would get stuck in local maxima's before achieving any real benefit over the prior state. Like you can't evolve a third arm by slowly iterating towards it, from a lump to a stump to a limb to a functional limb; it'd be entirely a loss until it becomes fully functional. You have to grow a shitty yet complete third arm first, but not so shitty that it doesn't offer benefit, and then iteratively improve it into a pretty nice arm

7952 4y ago
I think that some traits have an unreasonably large effect on the species. And we attach greater significance to them after the fact which makes it seem like a big jump. For example some fish evolved to have stubby lobed fins. That gave them some local advantage. It is just coincidental that the same change lead to arms, legs and wings. And these kind of big visible features need more than a few changes in DNA to happen. An arm needs to attach to something, have muscles and arteries and nerves. That can only evolve iteratively from something else. There is a reason that elephant trunks are also a nose.
robga 4y ago
> I never confirmed one way or the other, but I'm fairly positive evolution operates by large sudden changes followed by incremental improvements/optimizations This is basically the theory of punctuated equilibrium as proposed by Stephen Jay Gould to the commonly held thought at the time of gradualism.

7952 4y ago

Not sure about migratory birds in particular. But being able to survive without food for long periods is clearly a good trait. It has evolved across plants and animals to a lesser or greater degree. That trait can team up with another. For example an animal that can dig can hybernate underground. An animal that can fly can journey to find food or a mate. It may start by flying a short distance across land and slowly build up the distance over successive generations. Then it could learn to follow the coast to find better food. Or develop abilities for navigation. Or an instinct to fly when the days get short and be less distracted by food. Slowly but surely the benefit of flying outweighs the benefit of staying at a food source. The travel gets longer and longer until it is crossing thousands of miles.