Tectonic plate movement, climate change etc. how does it effect a tortoise?

[FLINTUS]

This is something I've been thinking about for a long time. Over time, the tectonic plates of the world shift, and it's not just the main continental plates, you have all those small plate boundaries. So the plate boundaries are either constructive, destructive or conservative, and as we all know over millions of years the plates move by massive amounts. In 200-250 million years it is believed the plates will join up to form a super continent again, and Britain will be pretty close to where Antarctica is now. So how does this effect our shelled friends? When the more modern day versions of these creatures evolved, the Earth would've been a very different place, and they would've adapted to certain climates and diets-for instance, the dry Australian outback would've been a mild, tropical forest. Now, surely this means basically the animals are not living in the conditions they receive now. Perhaps, this is why it is hard to keep some species in a way we would consider natural in captivity. And in the wild now, we see a lot of tortoises pyramid. Take Indian Stars as an example, I have seen them pyramid a lot naturally in the wild, perhaps because it wasn't that long ago that it was near Madagascar, but the plate travelled at double the speed of most of the plates in the world, crashing into Asia with the environment changing very quickly. Now of course some of the habitat destruction will not help, but I would be interested if somebody kept them in the way that place would've been when the species was first formed. I am very interested to hear other peoples' opinions on this.

 

[tortadise]

Very interesting. My mom has a published theory on this in the Smithsonian actually. I get all sorts of talk about this from her the best way for me to describe what could possibly happen. Is the exact scenario of the Galapagos. Those island are on the largest hot spot in the world and have the most active volcanoes found internationally. The island move east bound a few inches a year. The farthest island is actually dying. The greenery is starting to die off. The further west you go towards the hot spot. The more life and sustained lush environment you get. But then once you get closer and just over the hot spot the islands are solid volcanic rock with very few greenery. Their are animals that have adapted to living on them though. So in retrospect, if a pangean affect were to occur it would likely be a slip over a large span of time. If the earth flipped (which it is slipping off its access slowly. Its at 30 degrees now instead of 23) I think the animals effected would slowly adapt and evolve to their surroundings over time.

 

[FLINTUS]

I'm sure they would adapt, but would they adapt fully? I mean red foots, a partial forest species, suffers shell rot easily, and before the plate movements it wouldn't be exposed to such humid and wet conditions due to the position of those plates. So they have adapted to the humidity, but maybe they haven't adapted to the wet conditions yet. The volcanology is interesting, as it carries on from plate movements. Are animals found nearer active volcanoes if they have the choice? Because once the ash has been established the soil will become fertile and offer plenty of vegetation for food, even though this is a very long process.

 

[tortadise]

Good questions. I really Dont know. I would assume it would take some sort of hypothetical scenario of just how the plates and continental land masses would assemble together. Mountains play a large roll in weather systems, desert or tropical environments. Also equator locations, tropic of cancer and Capricorn locations. Hourly sun and moon solstice. days of light during the day. Like if we tipped to 45 degrees what tortoise could live in daily temps of 98+ during day then drop to 30- at night. Not too many could handle those temps. Add rain and you have some serious issues. I guess its all scientific hypothetical scenarios. But take sea turtles for an example. They can actually regulate and keep warmth in due to evolved fat layers and thickened carapaces. So could this be a possibility of a red foot or Sulcata if presented over 1000s of years of land movement into different climactic scenarios. I think so. Would be interesting to see what sort of species could evolve into

 

[FLINTUS]

I'm wondering now whether I can get a map of the earth and what the climate was like for different areas when these species first evolved. I might do like a little trial period of care like that for about 2 months and see how they take to it. Anyone else got an opinion on this? If there are enough studies to show that some species haven't adapted, we might be able to keep some of the species that drop off and die more (truly) naturally, to what they evolved to, and maybe have more success.

 

[ascott]

Evolution; a perfect science we simple humans just simply are not qualified to monkey with....but one we always strive to replicate...fun thread

 

[FLINTUS]

Would they evolve fully? That is why so many species have been wiped out, failure to adapt to a new environment.

 

[ascott]

Evolve fully; wow, that would be so hard to know the answer to, I mean people will of course presume an outcome, but to truly know??--I mean an evolutionary change could take a multitude of years to fully establish...how awesome it would be to see such a change, but we just don't live nearly long enough, unfortunately...but such a fun wonderful thing to imagine, huh...

 

[turtlesteve]

This is a very interesting topic. From a geologic standpoint, I am inclined to think that tortoises would adapt to continental drift, as it occurs over hundreds of millions of years - as in, relatively slowly.

I would think faster changes are of much greater concern, such as cyclical ice ages, which are a "new" geologic phenomenon. These ice ages have occurred for only the most recent 2.5 million years of tortoises' 200 million years of existence.

Consider that giant tortoises existed all over the world but died off in the most recent ice ages, or were finished off by humans thereafter. For example, Florida had two known species of large tortoise other than gophers, at least one of which survived to be hunted by humans. Going a little further back, the ancestors of gopherus were about 36" in length and roamed the central US, but disappeared when the ice ages started. Then you also have the ancestors of galapagos torts in south america, and the giant horned tortoises in Australia.

On the flip side, that the diversity of map turtles along the gulf coast may be related to ice ages, which isolated river systems due to changes in sea level.

 

[Madkins007]

I do not remember where I read it, but both monkeys and tortoises are thought to have moved from Africa to South America about the same time, and then the two continents moved apart before too many of either group moved in too far which supposedly is why there are so few types of each group there. Combine that with the the similarity between red-foot and hingeback DNA, and it is very possible that the prototypes of the red-foot (probably more like a yellow-foot) came from the African forests and settled in the SA forests with similar habitats. Then, as climate changed, 'outlyers' probably became the red-foots, taking advantage of a wider range of climate.

Now, as far as the original question goes, I don't think continental drift is a concern for species. When continents A and B touched, the climate, soil, plants, etc. would have been nearly identical between them and animals colonizing as a response to population pressures, better food sources, etc. and they would have settled in familiar places. In the eons it would take the for the plates to move enough to make a difference, the climate would be changing due to natural causes.

For example, the 5 DNA types of red-foots seem to have developed at the same times and climate change reshaped the SA rainforests, cutting off different populations at different times.

 

[AnnV]

I love hanging out with smart ppl!

Ann from CT

 

[Yvonne G]

It happens so very slowly, that I believe it will have no effect that can be seen. All life on the planet will evolve to fit the circumstances.

 

[FLINTUS]

It happens so very slowly, that I believe it will have no effect that can be seen. All life on the planet will evolve to fit the circumstances.

Now, this is where I disagree with you and where the thread gets it's interest.
I'm going to use geochelone elegans as my example again. These guys often pyramid in the wild, something which I have seen when in India. Now, as I said before, the subcontinent of India travelled 2-3 times the speed of the other continents, from where Madagascar was to crashing into Asia.
FACT: Not all the species evolved-there are still species which are designed for the previous conditions, in particular aquatic species, so are now only find in very limited ranges of microclimates.
So, if some fish haven't had time to adapt, why should tortoises?