Speciation in Protea cynaroides

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Mefiante (June 10, 2010, 12:19:02 PM):
I get species each adapting to whichever habitat they find themselves in (adapt, move or die are oftentimes the only 3 options in nature, and, if you're a plant, moving can prove difficult)
The above phrasing, particularly that of the last part in parentheses, suggests that a common misconception about evolution is in play. This misconception, which hampers clear understanding, is that individual organisms evolve. They don’t. That is, individuals don’t change their biology to accommodate an external change; they either survive the change or they die. Instead, owing to existing genetic diversity (and to a much lesser extent mutations) within a species, some of its individuals will already be better adapted to an impending environmental change than others, and those individuals will survive and reproduce preferentially, resulting in a gradual modification of the species’ genome over time. Viewed in this way, plants very definitely do move by means of spreading their seeds using wind, water and/or other organisms such as birds or ruminants.



These Proteas you speak of, however remain stable when imported into different habitats. Should it not follow that, given enough time we can expect species x to become more like species y if species x is imported into the habitat in which species y came to be?
This would be hard to predict because it depends on many interplaying factors. If species x and y are proper species that are reproductively isolated from one another then it is unlikely that x and y will converge towards one another in the same habitat. If they compete for much the same resources then the better-adapted species will come to dominate, perhaps even driving the other to eventual extinction. If they exploit mostly different niches of the environment then they will probably coexist freely. If one of them has a more voracious natural enemy (predator or pathogen) in that environment than the other, then it will likely occur less frequently unless it also reproduces at a higher rate. And those are only the more obvious factors and dynamics. There are other, more subtle ones that will affect how things proceed.



Next question: is it far-fetched to assume that, since species can adapt to their habitat, habitats (ie the plant species, soil composition, air-moisture content, other species etc) will over time change if a specific new specie is introduced?
There very definitely is a reciprocal interaction between environment and the species that inhabit it simply because resources are limited. The environment is affected by the species, which in turn affects the species. For example, few bacilli and viruses can survive in the absence of a living host but many of them also induce fatal diseases in that host. When the host dies, so usually does the colony of pathogens as well. Similarly, a swarm of locusts can denude its habitat to the point where many species, including the locusts themselves, die due to starvation. The environment may in some cases remain permanently changed or sometimes recover a fair way towards its former state.

'Luthon64
Hermes (June 10, 2010, 12:41:00 PM):
it is important to note that those descendants must be biologically viable.
Thank you for clarifying that.
These Proteas you speak of, however remain stable when imported into different habitats. Should it not follow that, given enough time we can expect species x to become more like species y if species x is imported into the habitat in which species y came to be? Next question: is it far-fetched to assume that, since species can adapt to their habitat, habitats (ie the plant species, soil composition, air-moisture content, other species etc) will over time change if a specific new specie is introduced? :-\
The first point I want to make is that the timescales we are talking about here are millions of years' evolution compared to a few decades of artificial cultivation. Over these few decades the different variants remained true to form. Left to nature in the long term, the imported species is likely to evolve in the direction of the indigenous one, but the indigenous one has a headstart. This may well result in the imported species becoming extinct in that habitat.

If an exotic species is introduced into a habitat and is successful, it may become invasive and change the habitat. This would happen when the species is ideal for that habitat, but had been absent as a result of geographic separation.
Hermes (June 10, 2010, 12:44:43 PM):
Sorry, I see Mefiante has addressed your questions while I was preparing my answer.
Lilli (June 10, 2010, 12:46:47 PM):
Mefiante, regarding your first comment - yes you are right. As I re-read my question even I had trouble remembering what I meant by such a poorly constructed sentence. Sorry :-[ The interesting thing, to me, is the exceptional complexity of these natural systems, and the interaction betwee species, and the influence all these elements have on one another. Again, you explain it wonderfully. Thanks
This may well result in the imported species becoming extinct in that habitat.
If an exotic species is introduced into a habitat and is successful, it may become invasive and change the habitat. This would happen when the species is ideal for that habitat, but had been absent as a result of geographic separation.
Don't you mean that the habitat was ideal for the species? Generally, invasive species tend to alter habitats beyond recognition, which is why organizations like the Department of Water Affairs have conservation programmes they call 'alien invasive species eradication programmes'.
Sorry, I see Mefiante has addressed your questions while I was preparing my answer.
Nah - you answered my question too, but it was a pretty stupid question anyways.
Mefiante (June 10, 2010, 12:56:32 PM):
I don’t see any stupid questions here and team answers tend to cover more ground than individual ones. Thus, no apologies are in any sense necessary or even fitting. :)

'Luthon64

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