The mutation that famously turned moths black during Industrial Revolution

http://www.bbc.com/news/science-environment-36424768

by sohkamyung • 10 years ago

90 72 10 years ago

bbc.com

amelius• 10 years ago

... the science behind biology's most famous insect

Wouldn't that be Drosophila?

danieltillett5• 10 years ago

It is a really good question what is the most famous insect in biology. There is a good case to be made for Drosophila, but I would be inclined to select Anopheles first purely on the deaths it has caused [1].

1. https://en.m.wikipedia.org/wiki/Anopheles

Amygaz• 10 years ago

Depends on your angle:

In term impact to the field of biological science, definitely Drosophila melanogaster. Lots of genetics, and now even brain research.

In term of most beneficial to humans: bees (direct economical benefits) and ants (largest environmental benefits, so indirect benefit to human)

In term of biggest threat, the debate is open, and always changing: before mosquitoes (Anopheles and Aedes), houseflies can carry a lot of diseases of every kind (parasites, bacteria, viruses). At one point it was the flea (the Black Death). Grasshopper and crickets also caused a lot of people to die from hunger, and are still significant agricultural pests. Ants and termites (crops, food supplies, infrastructures, diseases...)

barking19• 10 years ago

The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution?

I am a layman but one criticism of the theory of evolution that seems sensible to me is the absence of intermediate forms.

For example types of ape that could mate with say gorillas and chimpanzees.

All the species seem very well defined when you'd expect a continuum.

danieltillett5• 10 years ago

The most charitable thing I can think to say is you would find studying evolutionary biology very enlighting.

barking19• 10 years ago

I don't think that being either helpful or charitable were motivations behind your comment.

Angostura• 10 years ago

The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution?

It absolutely is evolution, what it isn't is 'speciation'. For speciation to occur you would have to have enough reproductive isolation and enough time to allow for sufficient change - let's say in the range of thousands/millions of years, rather than a decade or two. Biologists will tell you anyway that the concept of a biological species is a bit hard to pin down anyway.

I don't quite understand your criticism regarding intermediate forms. There are many clusters of species where interbreeding is possible to some extent - Zeedonks, Ligers et all, not mention types of bluebell, dandelions etc. Moreover there are many many species where there are distinct varieties which are still similar enough to interbreed, but may be on their way to separating if given enough time and isolation.

lanna• 10 years ago

There are many clusters of species where interbreeding is possible to some extent

Do not forget that the offspring itself also has to be fertile. Most hybrids aren't.

roywiggins• 10 years ago

Speciation can occur more or less immediately if two species produce a successful hybrid. It's much more common in plants, but it happens in animals too. The idea is, you have two species that occasionally produce viable offspring, which are themselves reproductively isolated from their own parent species.

https://en.wikipedia.org/wiki/Hybrid_speciation

mikekchar• 10 years ago

When you have a continuum, species don't diverge. They interbreed. So the whole will just carry on. If a mutation occurs that stops interbreeding, then that line is likely to die out because of competition with the main line.

However, imagine rabbits on an island. There are zillions of them everywhere and there is a wide variety of mutations. Mostly it doesn't matter because most of them can interbreed, and the ones that don't die out. But one day the rabbits get a terrible disease and almost all of them die. The ones that don't die have a mutation that makes them resistant to the disease. Now you have a different kind of rabbit where they are all resistant to the disease.

This keeps happening. Not always disease. Sometimes their food source disappears. Sometimes a new preditor arrives. Sometimes the weather changes. Each time, they almost all die. Only the ones that could survive live.

After all of that, the island rabbits are very specialised. They might not even be specialised for the current conditions. For example the disease may no longer exist. The weather may have changed back. The predators may have died out. But it doesn't matter. They are very different than the original rabbits, and also very different from the rabbits on the mainland. So much so that the two can't interbreed.

There is no intermediate forms because they all died. If they had not died, the specialised form would not have developed.

We can observe this both in the wild and in laboratory conditions. Especially with short lived insects (usually fruit flies) we can actually see evolution happening in this way. But with rabbits... we tried to kill all the rabbits in Australia with a disease and ended up with lots and lots of rabbits who are resistant to the disease.

This is why it is important to teach evolution in school.

barking19• 10 years ago

That makes sense thanks. I'm not sure how a mutation that prevents breeding would be disseminated from the animal in which it occurred?

loudmax• 10 years ago

An even more impressive demonstration is the existence of ring species: https://en.wikipedia.org/wiki/Ring_species

Here, you have a population whose geographic range is in the shape of a ring. Say, around the base of a mountain range. Members of the species may display some regional variation, but they can interbreed with their nearby kin. At some point on the ring though, there is a break. Here, regional variations will have accumulated to the point where the members are not able to interbreed and you have what appears to be two distinct, if similar, species. Only by following the line of population the long way around the ring do you find that the populations are still connected and actually the same species.

marcosdumay• 10 years ago

Each time, they almost all die.

It's a detail, but I think it's an important one. Evolution drivers do not have to kill most individuals. In fact, it does not have to kill any single one. Just a small decrease in fertility is enough to extinguish a genetic trait.

Killing a huge number of individuals does make it act faster, but is by no means necessary.

fapjacks• 10 years ago

Right! It's about populations, not individuals.

dforrestwilson• 10 years ago

I'm scratching my head as to why you were down-voted. You may be wrong but you're not being rude or purposefully trolling.

danieltillett5• 10 years ago

I think the reason for the down votes is the post is kind of trollish. The points raised by the OP are the sort of spurious arguments that are brought up by the "intelligent design" promotors. Of course the OP could have just been innocently influenced by them, but it is always hard to know.

richmarr• 10 years ago

...criticism of the theory of evolution that seems sensible to me ...

Criticism of evolution isn't sensible, it's ignorant (which is fine). It's an observable phenomenon, each piece of which can be reasoned about without too much specialised knowledge.

Being ignorant about evolution is fine, and you asked politely and seem to have an open mind, so I don't think you should be downvoted. I think people are just a bit tired of creationists mis-using terms, lobbying, etc, so are sensitive on this topic.

barking19• 10 years ago

Criticism of evolution isn't sensible, it's ignorant

I am not criticising evolution. I'm not qualified to do that. It seems like it is the best explanation yet to explain the diversity of life on this planet.

Personally, I attach no credibility whatsoever to the creationists' explanations.

I do think that people, even those of us who do not know a lot about it, should be entitled to ask questions without having our motives questioned. Indeed I thought that scientific theories should always be open to criticism. To say that one theory should not be, would be to elevate it to the status of dogma.

And if people are 'very sensitive' to criticism about a particular theory, there is more than one possible explanation for that. Another might be a frustrating lack of evidence. For example, in this thread 2 posters mentioned the existence of ring species and linked to the wikipedia page for that. That page has four examples but then goes on to suggest that there is doubt as to whether these are actually examples of ring species.

To re-iterate, I would bet that evolution is probably correct, however a degree of humility, not always evident, from its adherents would do no harm. The sun, it turned out, didn't orbit the earth.

teekert• 10 years ago

I think it is a good question. But where does the definition of species go when A can produce offspring with B, B can produce offspring with C but A cannot produce offspring with C? Would you be willing to label B as an intermediate form?

Moreover, recognizing that the theory of evolution does not really speak of "intermediate forms" but of common ancestors, would you be willing to label an extinct (but well preserved in the fossil record, including its DNA) species that is the common ancestor of two species as an intermediate form?

In other words, what would be the evidence for evolution to convince you of the reality of the theory?

barking19• 10 years ago

I am fairly convinced of its veracity as it is.

I would just like to see more and more evidence as time goes by.

Physicists (and I'm not one of those either) seem to have a completely different attitude to evolution scientists.

Recently more evidence in support of einstein's relativity theory has been found, I believe. But they are still completely open to binning the theory if contradictory evidence appears.

There just seems to be an almost religious fervour around evolution that seems a bit unhealthy

mikeash6• 10 years ago

Continuous sorts of things exist:

https://en.m.wikipedia.org/wiki/Ring_species

Living things evolve in groups which is why it's more common to have clearer lines between them, but it's not always like that.

barking19• 10 years ago

There are no known examples of ring species it seems

https://whyevolutionistrue.wordpress.com/2014/07/16/there-ar...

0xcde4c3db• 10 years ago

There is a continuum, but it's primarily over time. Everything seems separate because you're not looking at the dimension over which it connects. If you only looked at the horizontal cross-section of a tree above the trunk, you might similarly ask "how can this be one plant when none of the parts are connected?". Well, they are. You just aren't going to see the connection in that slice.

0xfeba• 10 years ago

The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution?

Yes. Evolution is just change in phenotypes over time. Speciation is a whole other ballgame, and there's no definitive answer as to what delineates species from one another. Some different species of fish will interbreed when forced together.

That is: Species are not well defined. They are only defined for human convenience, for categorization. But in reality, it's all one continuum. Interbreeding is only one factor in categorizing it. The big thing about being able to interbreed is chromosonal alignment, not necessarily whether they are differing species.

The humans of today aren't the same as the humans from 500 or 1,000 years ago. Prevalence of sickle-cell disease, lactose intolerance, skin pigmentation all these little things add up. If your substantiation of evolution consists of when speciation occurs, you're limiting yourself.

Take dog breeds for example. The changes we've implemented using the tool of evolution are drastic. What's to prevent this process from continuing? From eventually causing 'speciation', in the sense that two dog breeds can no longer interbreed? There are already subtle differences between dog breeds that make producing offspring difficult, and in the wild this difference would be magnified greatly.

hayksaakian• 10 years ago

I thought it was pretty clearly defined: they product offspring which can reproduce and produce viable offspring among themselves but not with the original population

dragonwriter• 10 years ago

The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution?

Yes, not all evolutionary changes constitute changes of species.

I am a layman but one criticism of the theory of evolution that seems sensible to me is the absence of intermediate forms.

An incomplete fossil record (and, given what is known about how the fossil record is laid down, its obviously going to be extremely incomplete even before considering how little of it we've actually been able to access) combined with evolution that is continuous (even if punctuated rather than constant-pace) is naturally going to miss lots of things between many of the things it preserves. That isn't a criticism of evolution.

All the species seem very well defined when you'd expect a continuum.

There is a continuum; talking about it in any useful way, however, forces us to divide it up into discrete buckets -- taxonomic categories, whether "species" or higher- or lower-level categories -- and, where there are unclear cases, we end up arguing over which bucket they belong in, and how many buckets we should consider there to be.

Tloewald• 10 years ago

Species is not a well-defined term in the sense a mathematician understands well-defined. E.g. the usual "ability to breed and create fertile offspring" excludes all organisms that do not reproduce sexually, and does not account for fertile hybrids and "ring species".

quadrangle• 10 years ago

Actually, the world is full of high-resolution continua in species, it's just not always present. Divergence occurs due to isolation or some other factor.

Horses and Zebras are different species but can interbreed. Lions and Tigers can interbreed. https://en.wikipedia.org/wiki/Hybrid_(biology)

So the expected continuum you seek is totally there in tons of cases. It's just that there are cases where divergence gets too stark and intermediates die out.

When humans choose (for conceptual and communications' sake) to identify two very similar groups as different species versus different breeds, then we call mixes "hybrids" like this. When we think it's just a little too similar and we call them "breeds" of the same species, then we don't call mixes "hybrids" as often. This is just problems with the simiplisticness of language.

skepticarse• 10 years ago

If I recall the moths were glued to trees for photos.

http://hoaxes.org/photo_database/image/the_peppered_moth

This whole thing was BS, or at least a huge part of it.

splawn7• 10 years ago

You mean the picture was staged... which is a huge difference from saying the "whole thing" or even "a huge part of it". Do you also look at paper models of the solar system and go "Those aren't real planets... must be a bunch of BS"? It seems to me like you either didn't read the article or didn't understand it.

NickBusey• 10 years ago

From the link the parent commenter posted:

The staging was an issue, critics argued, because it over-simplified the peppered moth story and made it seem that the camouflage of the moths was a self-evident advantage. However, it wasn't clear that moths rested on tree trunks during the day, as the pictures implied. Some evidence suggested they preferred to remain higher in the tree canopy and beneath branches where their coloration would have been less of an advantage. Also, it wasn't clear that birds were the main predator of moths. Bats also ate moths, and since bats use echolocation to navigate, the coloration of the moths would not have made a difference. Critics also questioned the methodology of Kettlewell's experiments.

The mutation that famously turned moths black during Industrial Revolution

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