Snakes in the Plains
Starting from Ontario and going through the islands and mainlands therein, there's obviously very little change in the phenotype between Ontario and the Peninsular mainland, as there was likely little to no need for it. The snakes in those locations maintained their stripes as it was ideal for the camouflage of these locations. Kelleys Island, Bass complex islands, and the Middle and Pelee island all show greater variation.
These distributions of variation in phenotype are likely due to the migrations of snakes from different islands going around to one another, as well as a need to maintain their phenotypic appearance in order to protect themselves. Since the animals are always moving about, whether for the food, curiosity, breeding, weather, or something else, there will likely always be variation and - equally likely - there won't be a phenotype that gets wiped out by selection or adaptation, since they probably won't stick around long enough for it to impact all of them.
Consequences of migration for populations can be few or many depending on the organism and location. In general, I think resources, potential mates, predator/prey balance/imbalance, evolutionary disadvantage/loss, and space could all be consequences of migration.
(As always: M E M E S)
Why do you think the Middle and Pelee islands have such a high proportion of snakes with phenotype A even when compared to the other islands?
ReplyDeleteHi Litsa! I think the reason for their higher proportion of phenotype A snakes has a lot to do with the environment and how adaptive their phenotype is for environments. Since they lack stripes and have such a flat grey color, they can blend in well with the rocks. If they're migrating around a lot, then they still have the advantage of staying concealed fairly well on other islands as well, since they're considered the most adaptive phenotype.
DeleteYessss, I'm SO glad I'm not the only one who made a "Snakes on a Plane" reference! And memes...how did I not find this blog earlier....
ReplyDeleteAnywho. Similarities aside, Litsa asks a good question. The graphs for the islands all look slightly different; think there's a reason for that? And the consequences of migration - are those going to be the same on the islands as they are on the mainlands?
Once again, I must reiterate...SNEK MEMES
I want you to know how much I appreciate your blog, also that hissing "yessss" you did to start out your comment. 10/10.
DeleteI think the reason for the variation has to do with the natural adaptation aspect of their migration to those islands. Since they might stick out like sore thumbs in certain areas, they would need to have those adaptations to blend in better, assuming they stick around long enough for those changes to occur. If they're going around all willy-nilly and not staying in one place long enough, then they could lose those long-term advantages. HOWEVER, if they're not going to stick around in that location, then it's only a short-term problem (assuming they don't die before they leave again).
On the mainland front, I think the consequences could be similar, but not exactly the same. I think resource competition and predators are going to be the main issues that are unique to migration, and mating could also be an issue if they migrate and stay in one spot.
Sneks.
In really general terms though, what does migration really do? Assume you have two genetically differentiated populations and migration between them, what does eventually happen to those populations?
ReplyDeleteVery generally speaking, I think it's going to do a few things:
Delete1.) expand the populations, assuming that the offspring are healthy and the organisms have a high fitness;
2.) create genetic variation among the organisms by the sharing/exchanging of genetic material; and
3.) following 2, it's going to (eventually, hopefully) lead to evolutionary changes in those populations over time.
Cristina, I love your blog! I agree that it seems that there will always be variance, and that migration helps spread this. Why do you think frequency of 'A' was higher on some islands than on others? Could the size of 'N' have skewed our perception? Also, I LOVE the memes! :)
ReplyDeleteHi Benjamin! Thank you for the love! :)
DeleteI think phenotype A was higher because of its high adaptability to the environments. They were such a flat, monotonous grey color that they could blend in easily with rocks (and maybe look like a rock in the right setting?). They lacked any stripes, so it was probably easy for them to conceal themselves.
Loved the memes. A question that I had while writing this blog post was if the size of islands also plays a role in determining the type of snake able to thrive there. Smaller islands might have more erosion from the water, producing a more rocky environment. I think that knowing a bit more information may have helped in determining why the proportion of snakes presents this way.
ReplyDeleteThank you for the love, Mary! :)
DeleteThat's a really good point, I hadn't considered erosion as a possibility or even a player in this scenario. Not knowing a lot about these islands leaves a lot of room for speculation.
Hey there Cristina,
ReplyDeleteI also love the memes that you added in! Do you think there was any reason why the islands had varying phenotypic ratios among each other?
Hi Jade! Thank you for the love! :) Glad you like the memes.
DeleteI think the variation would have to do with the migration of phenotypes and the environments in which those phenotypes resided. They'd need to adapt to their environments, since not all colors or stripes will survive in one area as well as another. The migration part can impact because of different phenotypes coming across and staying to breed and live there, or staying long enough to breed and dip out again (if they do that, I'm assuming they don't stick around, since... well... snakes aren't known to be monogamous, more of a "hit it and quit it" species),