Does stamping on the ground really bring worms to the surface? And if so, why? What's the evolutionary impulse?
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Footfall triggered earthworms
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Footfall triggered earthworms
WornOldMotorbike wrote:
I wonder what happened in the evolutionary communication chain that allowed them to learn from the drowning of others but not from the blackbirds' sucker move.
If they stay below ground they all run the risk of drowning, where as if they go to the surface worst case scenario is that some of them will get eaten by blackbirds?
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Footfall triggered earthworms
I wonder what happened in the evolutionary communication chain that allowed them to learn from the drowning of others but not from the blackbirds' sucker move.
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Footfall triggered earthworms
Yeah, and the answer is probably that threats from the inanimate environment are stable over time, whereas those from predators form part of an "arms race" that never stands still. So typically organisms will do better against the former than they do against the latter.
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Footfall triggered earthworms
It's a lot easier and more energy efficient to evolve simple behaviour than a dual-purpose respiratory system. I'm not even sure it would be feasible for them to breathe underwater - fish need flowing water to ensure they get enough oxygen.
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Footfall triggered earthworms
Ginger Yellow wrote:
It's a lot easier and more energy efficient to evolve simple behaviour than a dual-purpose respiratory system. I'm not even sure it would be feasible for them to breathe underwater - fish need flowing water to ensure they get enough oxygen.
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Footfall triggered earthworms
That's not really the point. If the competitive advantages of being able to breathe underwater are outweighed by the associated energy costs, then the trait, even if it evolved, wouldn't spread throughout the population. There were some interesting results highlighting this in the recent Lenski paper on evolution of citrate metabolism (technically it was transporatation). Basically, even though the populations were immersed in a glucose poor, citrate rich medium, a mutation which allowed limited transportation and hence metabolism of citrate did not result in rapid population growth until a further mutation made the transportation much more efficient. Until then, the glucose-only bacteria competed just fine.
It's a really fascinating and powerful study demonstrating the effect of historical contingency on evolution, by the way. Anyone in the least bit interested in evolution should follow the link.
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