Tag Archives: Eye

Are human bodies poorly designed? Is the human retina a bad design?

Christianity and the progress of science
Christianity and the progress of science

I think this “sub-optimal” argument against a Designer is stupid, because designs are always trade-offs between different quality goals, but just to put this one to bed, here is Evolution News.

Excerpt:

Now a new paper in Nature Communications, “Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision,” has expanded upon this research, further showing the eye’s optimal design. According to the paper, Müller cells not only act as optical fibers to direct incoming light through the optic nerve, but are fine-tuned to specific wavelengths to ensure that light reaches the proper retinal cells. From the Abstract:

Vision starts with the absorption of light by the retinal photoreceptors — cones and rods. However, due to the ‘inverted’ structure of the retina, the incident light must propagate through reflecting and scattering cellular layers before reaching the photoreceptors. It has been recently suggested that Müller cells function as optical fibres in the retina, transferring light illuminating the retinal surface onto the cone photoreceptors. Here we show that Müller cells are wavelength-dependent wave-guides, concentrating the green-red part of the visible spectrum onto cones and allowing the blue-purple part to leak onto nearby rods. This phenomenon is observed in the isolated retina and explained by a computational model, for the guinea pig and the human parafoveal retina. Therefore, light propagation by Müller cells through the retina can be considered as an integral part of the first step in the visual process, increasing photon absorption by cones while minimally affecting rod-mediated vision.

(Amichai M. Labin, Shadi K. Safuri, Erez N. Ribak, and Ido Perlman, “Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision,” Nature Communications, DOI: 10.1038/ncomms5319 (July 8, 2014).)

The paper presents Müller cells as a direct answer to the view that the vertebrate eye has a suboptimal wiring:

[T]he mammalian retina and the peripheral retina of humans and primates are organized in a seemingly reverse order with respect to the light path. This arrangement places the photoreceptors, responsible for light absorption, as the last cells in the path of light, rather than the first. Therefore, the incident light must propagate through five reflecting and scattering layers of cell bodies and neural processes before reaching the photoreceptors. This ‘inverted’ retinal structure is expected to cause blurring of the image and reduction in the photon flux reaching the photoreceptors, thus reducing their sensitivity. It has been recently reported that retinal Müller cells act as light guides serving to transfer light across the retina, from the vitreo-retinal border towards the photoreceptors.

I just had someone push this idea that human beings are badly designed as a response to the cosmic fine-tuning argument of all things. Her list of objections was all speculations (multiverse, aliense, design of humans could be better).

This argument that humans are poorly designed strikes me as literally insane. But since this argument is still in use, I guess I had better say something.

First, the argument assumes that the designer of human beings has to design for our comfort and pleasure. Apparently, God – if he were to exist – would be obligated to design creatures who never got sick, never grew old, and never suffered at all. This makes sense to atheists, for some reason – that the God of the universe has to create creatures that last forever and never suffer. There is this perception out there among atheists and very small narcissistic children (but I repeat myself) that God should be our cosmic butler, waiting at our beck and call to do whatever makes us happiest. From the Christian perspective, this is nonsense. Human beings only think about ultimate questions because, as C.S. Lewis wrote, we suffer pain and have limited lifespans. If were designed to be happy and live forever, we would never think about a relationship with God. By nature, humans want to avoid God, because we don’t want to be accountable to him for our rebellion against him and the harm we cause by disobeying the moral law.

The second problem with the argument from imperfection is that it has no understanding of how engineers work in practice. Engineers are used to trading off non-functional requirements against each other. If the laptop has a fast processor, then it runs hotter. If the laptop has great battery life, it’s heavier because of the larger battery. If the laptop has lots of memory, it costs more to buy. There is no way to get every design goal met because they conflict with each other.

Sometimes, I think that atheists are just little children who have stopped growing in maturity and wisdom. I once heard one particularly stupid atheist in a debate claim that his belief in God had ended when he asked God to help him find his cricket bat, and God had not cosmic butlered to his satisfaction. This happened when the atheist was a child, of course. And this is when most atheists become atheists. It’s not a conclusion that is reached for intellectual reasons. It’s just multiverse, aliens, science fiction, and sexual immorality all the way down. Give me what I want when I want it, and don’t judge me for being self-centered and immoral.

Convergence detected in the genetic structure of bats and dolphins

Apologetics and the progress of science
Apologetics and the progress of science

We have to start this post with the definition of convergence in biology.

In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.

It is the opposite of divergent evolution, where related species evolve different traits.

On a molecular level, this can happen due to random mutation unrelated to adaptive changes; see long branch attraction. In cultural evolution, convergent evolution is the development of similar cultural adaptations to similar environmental conditions by different peoples with different ancestral cultures. An example of convergent evolution is the similar nature of the flight/wings of insects, birds, pterosaurs, and bats.

All four serve the same function and are similar in structure, but each evolved independently.

Jonathan Wells explains the problem that convergence poses for naturalistic evolution:

Human designers reuse designs that work well. Life forms also reuse certain structures (the camera eye, for example, appears in humans and octopuses). How well does this evidence support Darwinian evolution? Does it support intelligent design more strongly?

Evolutionary biologists attribute similar biological structures to either common descent or convergence. Structures are said to result from convergence if they evolved independently from distinct lines of organisms. Darwinian explanations of convergence strain credulity because they must account for how trial-and-error tinkering (natural selection acting on random variations) could produce strikingly similar structures in widely different organisms and environments. It’s one thing for evolution to explain similarity by common descent—the same structure is then just carried along in different lineages. It’s another to explain it as the result of blind tinkering that happened to hit on the same structure multiple times. Design proponents attribute such similar structures to common design (just as an engineer may use the same parts in different machines). If human designers frequently reuse successful designs, the designer of nature can surely do the same.

I’m a software engineer, and we re-use components all the time for different programs that have no “common ancestor”. E.g. – I can develop my String function library and use it in my web application and my Eclipse IDE plug-in, and those two Java programs have nothing in common. So you find the same bits in two different programs because I am the developer of both programs. But the two programs don’t extend from a common program that was used for some other purpose – they have no “common ancestor” program.

Now with that in mind, take a look at this recent article from Science Daily, which Mysterious Micah sent me.

Excerpt:

The evolution of similar traits in different species, a process known as convergent evolution, is widespread not only at the physical level, but also at the genetic level, according to new research led by scientists at Queen Mary University of London and published in Nature this week.

The scientists investigated the genomic basis for echolocation, one of the most well-known examples of convergent evolution to examine the frequency of the process at a genomic level.

Echolocation is a complex physical trait that involves the production, reception and auditory processing of ultrasonic pulses for detecting unseen obstacles or tracking down prey, and has evolved separately in different groups of bats and cetaceans (including dolphins).

The scientists carried out one of the largest genome-wide surveys of its type to discover the extent to which convergent evolution of a physical feature involves the same genes.

They compared genomic sequences of 22 mammals, including the genomes of bats and dolphins, which independently evolved echolocation, and found genetic signatures consistent with convergence in nearly 200 different genomic regions concentrated in several ‘hearing genes’.

[…]Consistent with an involvement in echolocation, signs of convergence among bats and the bottlenose dolphin were seen in many genes previously implicated in hearing or deafness.

“We had expected to find identical changes in maybe a dozen or so genes but to see nearly 200 is incredible,” explains Dr Joe Parker, from Queen Mary’s School of Biological and Chemical Sciences and first author on the paper.

“We know natural selection is a potent driver of gene sequence evolution, but identifying so many examples where it produces nearly identical results in the genetic sequences of totally unrelated animals is astonishing.”

Nature is the most prestigious peer-reviewed science journal. This is solid material.

There is an earlier article from 2010 in New Scientist that talked about one of the previous genes that matched for hearing capability.

Excerpt:

Bats and dolphins trod an identical genetic path to evolve a vital component of the complex sonar systems they use to pursue and catch prey.

The finding is unusual, because although many creatures have independently evolved characteristics such as eyes, tusks or wings, they usually took diverse genetic routes to get there.

Analysis of a specific gene has now demonstrated that although bats live in air and dolphins in water, where sound travels five times faster, they independently evolved a near-identical gene that allows them to accept high-frequency sound in the ear – vital for sonar.

The gene makes prestin, a protein in hair cells of the cochlea, which is the organ in the inner ear where sonar signals are accepted and amplified. Prestin changes shape when exposed to high-frequency sound, and this in turn deforms the fine hair cells, setting off an electrical impulse to the brain. So the protein has the important jobs of detecting and selecting high-frequency sounds for amplification.

When researchers examined the molecular structure of the prestin gene from a range of animals, they found that the variants in echolocating bats and dolphins were virtually indistinguishable.

Indistinguishable genes in animals that don’t share a common ancestor? Maybe a better explanation for the evidence we have is – common designer.

New study: sub-optimal / poor design of the eye / retina isn’t really

I think this “sub-optimal” argument against a Designer is stupid, because designs are always trade-offs between different quality goals, but just to put this one to bed, here is Evolution News.

Excerpt:

Now a new paper in Nature Communications, “Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision,” has expanded upon this research, further showing the eye’s optimal design. According to the paper, Müller cells not only act as optical fibers to direct incoming light through the optic nerve, but are fine-tuned to specific wavelengths to ensure that light reaches the proper retinal cells. From the Abstract:

Vision starts with the absorption of light by the retinal photoreceptors — cones and rods. However, due to the ‘inverted’ structure of the retina, the incident light must propagate through reflecting and scattering cellular layers before reaching the photoreceptors. It has been recently suggested that Müller cells function as optical fibres in the retina, transferring light illuminating the retinal surface onto the cone photoreceptors. Here we show that Müller cells are wavelength-dependent wave-guides, concentrating the green-red part of the visible spectrum onto cones and allowing the blue-purple part to leak onto nearby rods. This phenomenon is observed in the isolated retina and explained by a computational model, for the guinea pig and the human parafoveal retina. Therefore, light propagation by Müller cells through the retina can be considered as an integral part of the first step in the visual process, increasing photon absorption by cones while minimally affecting rod-mediated vision.

(Amichai M. Labin, Shadi K. Safuri, Erez N. Ribak, and Ido Perlman, “Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision,” Nature Communications, DOI: 10.1038/ncomms5319 (July 8, 2014).)

The paper presents Müller cells as a direct answer to the view that the vertebrate eye has a suboptimal wiring:

[T]he mammalian retina and the peripheral retina of humans and primates are organized in a seemingly reverse order with respect to the light path. This arrangement places the photoreceptors, responsible for light absorption, as the last cells in the path of light, rather than the first. Therefore, the incident light must propagate through five reflecting and scattering layers of cell bodies and neural processes before reaching the photoreceptors. This ‘inverted’ retinal structure is expected to cause blurring of the image and reduction in the photon flux reaching the photoreceptors, thus reducing their sensitivity. It has been recently reported that retinal Müller cells act as light guides serving to transfer light across the retina, from the vitreo-retinal border towards the photoreceptors.

Bookmark it because this is the kind of silly objection to design that they hear on the Discovery Channel, PBS, etc.

Convergence detected in the genetic structure of bats and dolphins

We have to start this post with the definition of convergence in biology.

In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.

It is the opposite of divergent evolution, where related species evolve different traits.

On a molecular level, this can happen due to random mutation unrelated to adaptive changes; see long branch attraction. In cultural evolution, convergent evolution is the development of similar cultural adaptations to similar environmental conditions by different peoples with different ancestral cultures. An example of convergent evolution is the similar nature of the flight/wings of insects, birds, pterosaurs, and bats.

All four serve the same function and are similar in structure, but each evolved independently.

Jonathan Wells explains the problem that convergence poses for naturalistic evolution:

Human designers reuse designs that work well. Life forms also reuse certain structures (the camera eye, for example, appears in humans and octopuses). How well does this evidence support Darwinian evolution? Does it support intelligent design more strongly?

Evolutionary biologists attribute similar biological structures to either common descent or convergence. Structures are said to result from convergence if they evolved independently from distinct lines of organisms. Darwinian explanations of convergence strain credulity because they must account for how trial-and-error tinkering (natural selection acting on random variations) could produce strikingly similar structures in widely different organisms and environments. It’s one thing for evolution to explain similarity by common descent—the same structure is then just carried along in different lineages. It’s another to explain it as the result of blind tinkering that happened to hit on the same structure multiple times. Design proponents attribute such similar structures to common design (just as an engineer may use the same parts in different machines). If human designers frequently reuse successful designs, the designer of nature can surely do the same.

I’m a software engineer, and we re-use components all the time for different programs that have no “common ancestor”. E.g. – I can develop my String function library and use it in my web application and my Eclipse IDE plug-in, and those two Java programs have nothing in common. So you find the same bits in two different programs because I am the developer of both programs. But the two programs don’t extend from a common program that was used for some other purpose – they have no “common ancestor” program.

Now with that in mind, take a look at this recent article from Science Daily, which Mysterious Micah sent me.

Excerpt:

The evolution of similar traits in different species, a process known as convergent evolution, is widespread not only at the physical level, but also at the genetic level, according to new research led by scientists at Queen Mary University of London and published in Nature this week.

The scientists investigated the genomic basis for echolocation, one of the most well-known examples of convergent evolution to examine the frequency of the process at a genomic level.

Echolocation is a complex physical trait that involves the production, reception and auditory processing of ultrasonic pulses for detecting unseen obstacles or tracking down prey, and has evolved separately in different groups of bats and cetaceans (including dolphins).

The scientists carried out one of the largest genome-wide surveys of its type to discover the extent to which convergent evolution of a physical feature involves the same genes.

They compared genomic sequences of 22 mammals, including the genomes of bats and dolphins, which independently evolved echolocation, and found genetic signatures consistent with convergence in nearly 200 different genomic regions concentrated in several ‘hearing genes’.

[…]Consistent with an involvement in echolocation, signs of convergence among bats and the bottlenose dolphin were seen in many genes previously implicated in hearing or deafness.

“We had expected to find identical changes in maybe a dozen or so genes but to see nearly 200 is incredible,” explains Dr Joe Parker, from Queen Mary’s School of Biological and Chemical Sciences and first author on the paper.

“We know natural selection is a potent driver of gene sequence evolution, but identifying so many examples where it produces nearly identical results in the genetic sequences of totally unrelated animals is astonishing.”

Nature is the most prestigious peer-reviewed science journal. This is solid material.

There is an earlier article from 2010 in New Scientist that talked about one of the previous genes that matched for hearing capability.

Excerpt:

Bats and dolphins trod an identical genetic path to evolve a vital component of the complex sonar systems they use to pursue and catch prey.

The finding is unusual, because although many creatures have independently evolved characteristics such as eyes, tusks or wings, they usually took diverse genetic routes to get there.

Analysis of a specific gene has now demonstrated that although bats live in air and dolphins in water, where sound travels five times faster, they independently evolved a near-identical gene that allows them to accept high-frequency sound in the ear – vital for sonar.

The gene makes prestin, a protein in hair cells of the cochlea, which is the organ in the inner ear where sonar signals are accepted and amplified. Prestin changes shape when exposed to high-frequency sound, and this in turn deforms the fine hair cells, setting off an electrical impulse to the brain. So the protein has the important jobs of detecting and selecting high-frequency sounds for amplification.

When researchers examined the molecular structure of the prestin gene from a range of animals, they found that the variants in echolocating bats and dolphins were virtually indistinguishable.

Indistinguishable genes in animals that don’t share a common ancestor? Maybe a better explanation for the evidence we have is – common designer.

Bad news for believers in naturalistic explanations of the Cambrian explosion

Before we see the new discovery, let’s review what the Cambrian explosion is all about.

Video 1:

Video 2:

Casey Luskin explains the new discovery at Evolution News.

Excerpt:

A recent article in Science begins by observing that the lack of evolutionary ancestors for the animal phyla that appear abruptly in the Cambrian explosion has been troubling to many evolutionary scientists:

Ever since Darwin there has been a disturbing void, both paleontological and psychological, at the base of the Phanerozoic eon. If his theory of gradualistic evolution be true, then surely the pre-Phanerozoic oceans must have swarmed with living animals — despite their conspicuous absence from the early fossil record.

(N. J. Butterfield, “Terminal Developments in Ediacaran Embryology,” Science, Vol. 334:1655-1656 (December 23, 2011).)

The articles goes on to explain that in 1998, tiny fossil animal embryos were reported that offered “palpable relief” to those evolutionary scientists worried about the lack of Precambrian ancestors.

However, new analyses of these microfossils now strongly suggest that they were not multicellular animals, and thus could not be Precambrian multicellular metazoa that have long been the holy grail for evolutionary paleontologists. Rather, they likely represent single-celled amoeba-like organisms.

[…]A Science Daily article on the study explains that many Darwinian scientists will be dismayed by the results of this study:

Professor Philip Donoghue said: “We were very surprised by our results — we’ve been convinced for so long that these fossils represented the embryos of the earliest animals — much of what has been written about the fossils for the last ten years is flat wrong. Our colleagues are not going to like the result.”

How did the investigators determine the nature of these ancient organisms? The fossils were exceptionally well preserved, such that, as the lead author on the paper stated, “the fossils are so amazing that even their nuclei have been preserved.” These allowed the authors to determine that these were in fact eukaryotic organisms, but not multicellular animals.

Casey goes on to answer the response by naturalists that “the fossil record is incomplete”.

I think it’s important, when deciding whether naturalistic evolution happened, to be aware of these problem areas. So often when discussing Darwinian evolution, people like journalists and philosophers and economists, etc. will just accept the theory because they trust in what experts tell them. There can be a lot of pressure in the university to not be seen as a dumb person, so that people will just go along with whatever their professor tells them to believe. And, that’s not necessarily a bad policy when time is short. However, that is taking evolution on blind faith. It’s a good thing, as we get older, to go back and revisit these things to see if they are really true.

For example, a really educated Darwinian should be able to finish a sentence like this: “People who doubt fully naturalistic evolution do so because of the following pieces of scientific evidence…” If you meet someone who cannot finish this statement, but who still espouses Darwinian evolution, then you know that you are dealing with someone who has jumped to the answer without really working through the problem by themselves. It can be very tempting, especially for artsy types, to just try to jump to the answer that all the smart people believe without really working through the problem. But that’s not a good way to decide what’s true. Everyone has to work through these problems themselves, and listening to the best people on both sides is the way to do that. People who question evolution nowadays don’t question that the universe is billions of years old or that scientific methods have to be used to answer scientific questions. By all means, let’s decide how we got here by appealing to science.

If you would like to see a nice hour-long video on the Cambrian explosion, then click here.

By the way, if you missed my previous post on the new discovery of oxygen in the early Earth’s environment, and the challenge it represents to naturalistic scenarios for the origin of life, then do check that out.