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Most species, as their numbers increase, would naturally expand their territory. Areas where others of their species (they are still the same species) are able to live would be a natural fit. So actually the tendency would be for them to come together.
Not sure what type of eruption you postulate that would drive animals several thousand miles apart. Do you understand how far that is? Maybe you could expand on what you are proposing here.
And if it were 'several generations' before they came back together, that is a very short time. Not nearly enough time for supposed speciation which takes lllllllllllllllooooooooooonnnnnnnnnnggggggg ages, as we've all been taught.
You're still assuming that there is only one factor to isolate a species. Species are like a web and you are thinking too linear about this. The planet is like a huge living organism one change in one place can lead to differences all over the board. I think you underestimate the power that yellowstone beholds. If it blew, it would cover most of North America in a cloud of ash and smoke. It would change rivers and weather patterns, burn entire mountains, melt snowpack and flash flood a few hundred thousand acres and some even speculate that it could wipe out most of the life in North America.
It would most likely cause extinction or clost to it for several species. Seeing as how species are like an interdependant chain; if one goes, it will have drastic effects on one or several other species. Plus, several generations can happen faster than you think. Nature doesn't subscribe to the same drive through mentality that you are trying to apply here. Not everything in nature has a 70+ year lifespan like we do. Some insects can have a number of generations in a month. After say, 15 or so years, that makes a big difference. If they change, they might not be food for the same group of species, likewise if they go extinct, they will no longer be able to feed another species. So what of this insect is the staple diet for another species? If a species has to adapt to a different food, some of the species may not be able to survive the new diet and would be forced to move on or die off. If the ones who can handle the new diet want to stay, then well... they divide...
And just because a mountain takes a looooooooooooooooooooooooooooong time to rise, doesn't mean that a species won't know the difference. Every day more and more of the mountain would become inhospitable to more and more species. In other words their territories may be able to expand, but they'll have to expand in another direction if they can't live on the slowly growing divider wall. It doesn't matter how slow a mountain grows, at some point, some species will no longer be able to cross it. Another way to look at it would be a piece of land breaking away into the water. It may take it 100,000 years to get far enough, but eventually there will be some native species that would not be able to cross the gap any longer. And they would... C'mon, it starts with a D...
It would of necessity completely separate the groups so that no interaction could take place. This would take a catastrophe of major proportions. The ordinary 'river flooding' , 'forest fire' scenes that are generally proposed simply wouldn't separate them except temporarily. And the type of separation needed for speciation would have to be very long in duration.
I think the most common reason for allopatric speciation is migraption which is rather common in the animal kingdom. Over where i live we are having a horrible wasp outbreak from the recent warm summers
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Originally Posted by c'est la vie
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inbreeding is also a very real problem since many of the separated groups would likely be small. At least we know they would be smallER than the groups that were able to survive previously. Inbreeding could weaken the populations instead of strengthening them.
You are thinking too small. We usually deall with multiples of 1000 when talking about populations. Inbreeding is not a problem.
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Originally Posted by c'est la vie
would not necessarily affect the member's ability to interbreed with other of his species (they are still the same species). So assuming that change (even if it did occur) would produce a distinct new species are more wishful thinking than anything.
You dont have to take our word for it. If you wanna see allopathic speciation in action and have 38 weeks to spare then you can do a very simple experiment involving fruit flies.
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Originally Posted by c'est la vie
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Since at point of separation both groups are the same species, loss of ability to breed with one group could very possibly be loss of ability to breed with BOTH groups. So where does that leave the first member of the 'new species'?
you've lost me here. Can you be more clear please?
I think you underestimate the power that yellowstone beholds. If it blew, it would cover most of North America in a cloud of ash and smoke. It would change rivers and weather patterns, burn entire mountains, melt snowpack and flash flood a few hundred thousand acres and some even speculate that it could wipe out most of the life in North America.
So how many speciation events (out of the billions that evolutionists must account for) are the result of a catastrophe of this magnitude?
How many times in earth's history has an eruption wiped out most of the life on a continent?
Seems like you are talking mostly about extinction of the whole species, not simply groups that had formerly lived together as a single species being separated.
What is required for geographic separation is for a group of critters to be divided into two or more groups AND SURVIVE , and eventually (so the story goes) one of the groups turns into a different animal (I can't even write it without laughing, sorry)
'One day, a group of critters found that a mountain separated them from the rest of the herd........' lol
I'm beginning to think you're deliberately ignoring my posts.
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Originally Posted by c'est la vie
It would of necessity completely separate the groups so that no interaction could take place.
Actually no. There must be some amount of separation, but complete separation is not required (it only speeds up the process). See ring species etc.
Quote:
Originally Posted by c'est la vie
Since at point of separation both groups are the same species, loss of ability to breed with one group could very possibly be loss of ability to breed with BOTH groups. So where does that leave the first member of the 'new species'?
*sigh*
You still don't get it. I thought the analogies with language would be intuitive enough.
Take two groups of the same species. Separate them (with a natural obstacle, distance, whatever) into group A and group B. No interbreeding can take place - but if you were to take an animal from group A and a mate from group B, they'd breed just fine.
Now wait. With each generation, random mutations appear and spread (as can be documented in laboratory conditions). Most of them are neutral, but many of these still spread throughout the population, a process called "genetic drift". The two groups start to have notable differences. Enough, eventually, that they wouldn't choose to mate even if they met (increasing, in fact, their separation). But if you force them, mixed couples are still mostly fertile.
But not entirely. Slightly more children that average will die at birth, or be crippled or infertile or something. And the more generations the two groups are appart, the less likely a (hypothetical) mixed couple could produce fertile children. Eventually, mixed breeding becomes completely impossible. You have two species (by the popular definition of species).
Let's recap. Initially, one species. Eventually, two species. In the middle? Something in-between. Where you place the line is entirely arbitrary. As counter-intuitive as it is, evolution isn't a discrete procees but a continuous one.
Now do you understand the language analogy? Each "generation", words change a little, accents creep in, neologisms appear, grammar evolves... You can find some text that's definitely in Latin, and another that's definitely in French. A Latin-speaker could not understand a French-speaker. But in between? Communication would be partial and imperfect. Precise boundaries cannot be found.
So how many speciation events (out of the billions that evolutionists must account for) are the result of a catastrophe of this magnitude?
How many times in earth's history has an eruption wiped out most of the life on a continent?
Seems like you are talking mostly about extinction of the whole species, not simply groups that had formerly lived together as a single species being separated.
What is required for geographic separation is for a group of critters to be divided into two or more groups AND SURVIVE , and eventually (so the story goes) one of the groups turns into a different animal (I can't even write it without laughing, sorry)
Huge events like that are not needed, I simply used that one to break the shell that it is at least possible. But since you askm Yellowstone for example goes off about every 600,000 years...
The Island that drifts away from the mainland isn't a catastrophy at all - just a little bit of drift. But as I already mentioned, this kind of catastrophy is not needed. Again, a mountain range can divide a species despite their slow growth as eventually the expanding species will find, at some point, that they can no longer cross the mountain.
I am not talking about extinction of the species in question, I was talking about things that make a species move on. Several things at once can force a species to do one thing or another. If species X lives primarily off of a certain insect for example, and that insect goes extinct in a given area, the species that eats it will have to adapt their diet. The ones who cannot handle the new diet will be forced to move on to an area where that insect can still be found. However, if some of the species have adapted their diet sucessfully and choose to stay - they just divided.
The species doesn't have to be 100% divided as a whole. Only a fraction needs to be splintered off from the rest.
Take two groups of the same species. Separate them (with a natural obstacle, distance, whatever) into group A and group B. No interbreeding can take place - but if you were to take an animal from group A and a mate from group B, they'd breed just fine.
Don't brush this off so lightly.
This type of separation can seldom happen.
Certainly not frequently enough to account for even a significant fraction of the billions of speciation events that evolutionists must account for.
Certainly not frequently enough to account for even a significant fraction of the billions of speciation events that evolutionists must account for.
But as has been said many times already, this is not the only way for speciation to occur, only the most intuitive (in my opinion). You visited the Wikipedia page, you should know.
(Anyway, I'm on shakier grounds here because I can't find a source that gives the % of speciation events attributed to each possible cause, but I still think it can account for a large proportion. A single geological event would separate not just one species, but all species living in that area.)
EDIT: I realize we've strayed rather far from topic. I'd like to know if *sherry* (or anyone else) still has questions or arguments against the evolutionary explanations of morality that were provided.
A single geological event would separate not just one species, but all species living in that area.
Not at all.
Let's take the 'flooded river' scenario.
It would not necessarily separate any groups of critters living in the river itself.
Birds would not have a problem with it. Same with many species of insects.
Many plants might still be able to continue as before given that wind would travel across a flooded river.
Larger animals might easily find a way to cross, just having to go farther to do it.
The same is true of many postulated 'separation' causes -- forest fires, volcanos, etc
They affect a relatively small area when you get down to it.
The really big events , a volcano that kills off half the continent, an island that breaks off the mainland, are so rare as to be an insignificant percentage.
Also, most of the supposed events do not last long enough to allow speciation to occur.
When was the last time you saw a river remain flooded for more than 1 year?
A forest fire burn in the same area for more than a few days (any given spot is burned and the fire moves on, animals started coming back into the burned area fairly quickly)?
A volcano that erupted for a year in duration?
It just doesn't add up. You need separations that last llllllllllllllllooooooooooonnnnnnnnnnggggggggggg ages.
Many of the speciation types listed rely on partial or total separation.
We've mostly been discussing total separation. Once you get down to partial separation, you're really talking about an arbitrary definition because anyone can say 'well I can imagine a scenario in which there'd be more interaction, so these groups are *partially* separated'
Everything becomes *partial separation* at that point. It is in the eye of the beholder.
At that point you've really given yourself an unfalsifiable theory. Which means it's not scientific.
The endemic species richness on Madagascar, relative to landmass area, is unparalleled in the world. Many organisms on the island have restricted geographical ranges. A comprehensive hypothesis explaining the evolution of this microendemism has yet to be developed. Using an analysis of watersheds in the context of Quaternary climatic shifts, we provide a new mechanistic model to explain the process of explosive speciation on the island. River catchments with sources at relatively low elevations were zones of isolation and hence led to the speciation of locally endemic taxa, whereas those at higher elevations were zones of retreat and dispersion and hence contain proportionately lower levels of microendemism. These results provide a framework for biogeographic and phylogeographic studies, as well as a basis for prioritizing conservation actions of the remaining natural forest habitats on the island.
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