Why understanding evolution in action is important

by tanakawho

Malaria-transmitting mosquito evolving, NIH grantees find
[Via EurekAlert! - Infectious and Emerging Diseases]

(NIH/National Institute of Allergy and Infectious Diseases) Researchers funded by NIH have found that the major malaria-transmitting mosquito species, Anopheles gambiae, is evolving into two separate species with different traits, a development that could both complicate malaria control efforts and potentially require new disease prevention methods. Their findings were published in back-to-back articles in the Oct. 22 issue of the journal Science.

A. gambiae is the most common vector of human malaria in sub-Saharan Africa, where rates of the disease are highest. The researchers compared the genomes of two emerging species, dubbed M and S. Given that M and S appear to be physically indistinguishable and interbreed often, they were unexpectedly different at the DNA level. They also were found to behave differently and thrive in different habitats. For example, in the absence of predators, S mosquitoes outcompeted M mosquitoes, but the outcome was reversed when predators were present.

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I wrote earlier about recent work on the evolution of the Cane Toad. Creationists postulate a model which does not require firmly understanding the process of evolution in any detail. Gaining greater understanding of what is happening is not much of a goal for them.

This story demonstrates why having a good scientific model for understanding a process in the natural world can have real ramifications on human health. First off, an understanding of evolution underpins the research tools they use, such as the DNA sequence data they generated. we really only discovered the changes that are happening because of the tools of molecular biology.

While there appears to still be a lot of interbreeding between the two, the DNA suggests that not many genes flow between the two forms. Mating does not yet result in infertile hybrids. But if they are mating a lot, there should be lots of gene flow. What is going on? How can they be in the process of speciation?

It turns out that the different forms are being selected at the larval stage. The S-form is found in natural, ephemeral and predator-free pools of water. The M-form is found in water pools created by man and that often have predators. This is where the selection is taking place to create two species.

And this is what is happening throughout the genome, suggesting that speciation is actually fairly well advanced.. One region is know to be important for resistance to insecticides. The two forms carry two different mutations in this region, each of which confers resistance.

So, these two forms have not advanced far enough to the pint where they can no longer interbreed. And they can still produce offspring. But the specific form is selected at the larval stage, negating any interbreeding going on and restricting gene flow.

Now, for them to continue separating, they need to stop wasting their time interbreeding since it wastes their genes – the hybrid offspring get driven towards one form of the other. Well, it turns out that another area where there are genomic changed encompass odorant receptors – used to smell – that are involved in female sexual receptivity. They are starting to distinguish the right mate by smell.

These two types of mosquitoes are being selected via two different environments. Targeting human created pools of water would only affect one form. Since one likes human-created pools, this very speciation event may be driven by humans.The same might be seen with insecticide resistance.

Because we have the tools for understanding it and the scientific model to explain it, the importance of evolution for helping us work towards control of a disease carrying pest is pretty easy to see. Creationism provides no valid scientific model and would not provide us with any understanding of what was happening with these mosquitoes.

UPDATED: Proof of evoluton proves creationism

[UPDATE: I have another post that demonstrates why evolution in action can be important – mosquitoes caught in the act of forming two new species.]

by Sam Fraser-Smith

Australian Toads: Evidence of Creationism?
[Via The Sensuous Curmudgeon]

Let us consider the Cane toad, or Bufo marinus. This handsome creature is equipped with glands that secrete poison, known to kill animals unfortunate enough to bite one.

These intelligently designed, sprightly little fellows, averaging 4 to 6 inches in length, although much larger specimens have been observed, are invading Australia. The BBC has an article about their unwanted presence Down Under: Cane toads are evolving into super-invaders. They say, with bold font added by us:

Scientists have demonstrated a “runaway evolutionary effect” that is speeding up Australia’s cane toad invasion.

This explains why the invasive toads have increased their rate of spread so dramatically, the researchers say. They found that toads living at the very edge of their range were “super-invaders” – able to move beyond the boundaries of this existing habitat. And when toads at the frontiers bred, their offspring inherited this ability to move quickly into new territory.

Aha! A neat little example of evolution in action. Let’s read on:

This phenomenon, which scientists have termed the Olympic Village Effect, has been proposed before, since these same scientists observed that the toads at the edge of the range had bigger front legs and stronger back legs – all the better to jump and to invade new areas.

This is hopping-good stuff! We continue:

To confirm that this increased strength and speed had a genetic basis and could be inherited, Dr Phillips [Dr Ben Phillips from James Cook University in Queensland] studied a generation further.

He allowed toads from the same population to breed. Then he set up another radio-tagged toad race, this time between these captive-bred offspring. Toads that had parents from the edge of the range won the dispersal race, revealing that they inherited their speed and strength from their parents.

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So, they showed that bigger and stronger legs, which provided a selective advantage, were inherited. Sounds like a nice example of evolution. But then the creationists say:

Nicely done. But as you’ve probably guessed, creationists aren’t exactly, ah … jumping with joy to see this sort of thing. In fact, they seem to be hopping mad.

The fast-moving toads have larger and stronger legs, enabling them to jump farther and faster, and hence invade the continent more quickly. But they remain cane toads; even if, at some point, these fast-moving cane toads are unable to breed with the slow-moving toads and they become separate species, the toads are not evolving into a “higher” species with increased genetic information.

They say that there is actually loss of genetic information in each population, which goes demonstrates the opposite of evolution:

Far from a case of evolution in action, the great toad race shows how selective forces run the opposite direction from the speculations of molecules-to-man evolution.

That is why it is pretty much impossible to engage these people in meaningful conversations. They have no other scientific model, they twist the facts, move the goalposts and say ‘ nope, no evolution here.’

This rope-a-dope gets done all the time. Try and demonstrate small scale evolution in action and they say “Where is the transition species?” Demonstrate transition species and they say “Where is the cat-dog?”

There really is no engaging people who do not legitimately want to understand the world. They want to inhabit their Cargo Cult World and refrain from understanding anything that might alter that world.

CFLs are the best choiuce right now

by Bludgeoner86

Energy saving lamp is eco-winner
[Via EurekAlert! - Biology]

(Swiss Federal Laboratories for Materials Science and Technology (EMPA)) In a new study, Empa researchers have investigated the ecobalances of various household light sources. In doing so not only did they take into account energy consumption, but also the manufacture and disposal processes. They also evaluated usage with different electrical power mixes. The clear winner is the compact fluorescent lamp, commonly known as the energy saving lamp.

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They looked at incandescent, fluorescent, halogen and CFLs. They examined environmental costs to produce and dispose of as well as use.

CFLs won, partly, I think, because we would use 1/10 the number of bulbs as with incandescent . And, depending on how the energy is generated, they can result in much less carbon, mercury and other pollutants entering the environment.

I wonder how LEDs will turn out. Probably a little better than CFLs, I think.