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Target acquisition and interception in dragonflies

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

Here is a fascinating post about some of the capabilities of dragonflies from Evolution News.

Selective attention

First, dragonflies have “selective attention” – the ability to focus on a single prey and ignore other distractions:

Dragonflies are among the best flyers in the insect world. Their twin pairs of paper-thin wings allow them to hover and move in all directions, even in mating. When the time comes to dart after prey at high speed, they rarely miss.

What’s their secret? One is “selective attention” — a trait previously known only in primates, according to new research from the University of Adelaide, Australia. Selective attention is the ability to focus on one object and exclude others. Just as a tennis player must focus on the ball and ignore the cheers of the crowd, a dragonfly must pick out one target from a swarm of insects and avoid being distracted by all the others.

Here’s a snip from the research paper:

Our data make a compelling case that CSTMD1 reflects competitive selection of one target. We emphasize “competitive,” because the attended target is not always the same between trials or even within a trial, as seen in strikingly perfect switches from one to the other…. Competition is further suggested by rare examples where the activity observed under Pair stimulation initially lags both T1and T2 responses… suggesting initial conflict in the underlying neural network before resolution of competition by a “winning” target.

We previously showed that CSTMD1 still responds robustly to a target even when it is embedded within a high-contrast natural scene containing numerous potential distracters. Taken together with recent evidence that the behavioral state of insects strongly modulates responses of neurons involved in visuomotor control, our new data thus suggest a hitherto unexpected sophistication in higher-order control of insect visual processing, akin to selective attention in primates.Perhaps the most remarkable feature of our data is that once the response “locks” onto a target (or following a switch), the second target exerts no influence on the neuron’s response: the distracter is ignored completely.

In order to succeed at the task of catching its prey, the dragonfly has to tune out all other distractions.

Target selection

In addition, dragonflies have the ability to intercept a target in mid-air – similar missile defense systems on AEGIS cruisers and destroyers.

The Evolution News article explains:

Another paper on dragonflies shows that these marvels of the insect world are equipped with navigational equipment that can do vector calculus. In the Proceedings of the National Academy of Sciences, Gonzalez-Bellido and a team at the Howard Hughes Medical Institute discerned “Eight pairs of descending visual neurons in the dragonfly [that] give wing motor centers accurate population vector of prey direction.”

Intercepting a moving object requires prediction of its future location. This complex task has been solved by dragonflies, who intercept their prey in midair with a 95% success rate. In this study, we show that a group of 16 neurons, called target-selective descending neurons (TSDNs), code a population vector that reflects the direction of the target with high accuracy and reliability across 360°. The TSDN spatial (receptive field) and temporal (latency) properties matched the area of the retina where the prey is focused and the reaction time, respectively, during predatory flights. The directional tuning curves and morphological traits (3D tracings) for each TSDN type were consistent among animals, but spike rates were not. Our results emphasize that a successful neural circuit for target tracking and interception can be achieved with few neurons and that in dragonflies this information is relayed from the brain to the wing motor centers in population vector form.

What did I make of this? Well, evidence like this always causes me to think aboutthe reality of God, and the disturbing thought that we do not live in an accidental universe where I can do whatever I want and be accountable to no one. It’s easier to believe that – it requires less work and it frees us to be our own boss and make our happiness the first priority. As individuals, it’s very tempting for us to think that we are number one, and to resent our obligations to anyone else. The problem is that the scientific data doesn’t support that worldview. The facts are what they are and it is up to us, now, to try to find out who the designer is and what he wants from us.

Polemics

John C. Sanford’s genetic entropy hypothesis

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

JoeCoder sent me a recent peer-reviewed paper by John C. Sanford, so I’ve been trying to find something written by him at a layman’s level so I could understand what he is talking about. (I am just a software engineer, not an expert in genetics). His CV is posted at the Cornell University web page.

I found this 20-minute video of an interview with him, in which he explains his thesis:

The most important part of that video is Sanford’s assertion that natural selection cannot remove deleterious mutations from a population faster than they arrive.

And I also found a review of a book that he wrote that explains his ideas at the layman level.

It says:

Dr. John Sanford is a plant geneticist and inventor who conducted research at Cornell University for more than 25 years. He is best known for significant contributions to the field of transgenic crops, including the invention of the biolistic process (“gene gun”).

[…]Sanford argues that, based upon modern scientific evidence and the calculations of population geneticists (who are almost exclusively evolutionists), mutations are occurring at an alarmingly high rate in our genome and that the vast majority of all mutations are either harmful or “nearly-neutral” (meaning a loss for the organism or having no discernible fitness gain). Importantly, Sanford also establishes the extreme rarity of any type of beneficial mutations in comparison with harmful or “nearly-neutral” mutations. Indeed, “beneficial” mutations are so exceedingly rare as to not contribute in any meaningful way. [NOTE: “Beneficial” mutations do not necessarily result from a gain in information, but instead, these changes predominantly involve a net loss of function to the organism, which is also not helpful to [Darwinism]; see Behe, 2010, pp. 419-445.] Sanford concludes that the frequency and generally harmful or neutral nature of mutations prevents them from being useful to any scheme of random evolution.

[…]In the next section of the book, Sanford examines natural selection and asks whether “nature” can “select” in favor of the exceedingly rare “beneficial” mutations and against the deleterious mutations. The concept of natural selection is generally that the organisms that are best adapted to their environment will survive and reproduce, while the less fit will not. Sanford points out that this may be the case with some organisms, but more commonly, selection involves chance and luck. But could this process select against harmful mutations and allow less harmful or even beneficial mutations to thrive? According to Sanford, there are significant challenges to this notion.

Stanford is a co-author of an academic book on these issues that has Dembski and Behe as co-authors.

Now, I do have to post something more complicated about this, which you can skip – it’s an abstract of a paper he co-authored from that book:

Most deleterious mutations have very slight effects on total fitness, and it has become clear that below a certain fitness effect threshold, such low-impact mutations fail to respond to natural selection. The existence of such a selection threshold suggests that many low-impact deleterious mutations should accumulate continuously, resulting in relentless erosion of genetic information. In this paper, we use numerical simulation to examine this problem of selection threshold.

The objective of this research was to investigate the effect of various biological factors individually and jointly on mutation accumulation in a model human population. For this purpose, we used a recently-developed, biologically-realistic numerical simulation program, Mendel’s Accountant. This program introduces new mutations into the population every generation and tracks each mutation through the processes of recombination, gamete formation, mating, and transmission to the new offspring. This method tracks which individuals survive to reproduce after selection, and records the transmission of each surviving mutation every generation. This allows a detailed mechanistic accounting of each mutation that enters and leaves the population over the course of many generations. We term this type of analysis genetic accounting.

Across all reasonable parameters settings, we observed that high impact mutations were selected away with very high efficiency, while very low impact mutations accumulated just as if there was no selection operating. There was always a large transitional zone, wherein mutations with intermediate fitness effects accumulated continuously, but at a lower rate than would occur in the absence of selection. To characterize the accumulation of mutations of different fitness effect we developed a new statistic, selection threshold (STd), which is an empirically determined value for a given population. A population’s selection threshold is defined as that fitness effect wherein deleterious mutations are accumulating at exactly half the rate expected in the absence of selection. This threshold is mid-way between entirely selectable, and entirely unselectable, mutation effects.

Our investigations reveal that under a very wide range of parameter values, selection thresholds for deleterious mutations are surprisingly high. Our analyses of the selection threshold problem indicate that given even modest levels of noise affecting either the genotype-phenotype relationship or the genotypic fitness-survival-reproduction relationship, accumulation of low-impact mutations continually degrades fitness, and this degradation is far more serious than has been previously acknowledged. Simulations based on recently published values for mutation rate and effect-distribution in humans show a steady decline in fitness that is not even halted by extremely intense selection pressure (12 offspring per female, 10 selectively removed). Indeed, we find that under most realistic circumstances, the large majority of harmful mutations are essentially unaffected by natural selection and continue to accumulate unhindered. This finding has major theoretical implications and raises the question, “What mechanism can preserve the many low-impact nucleotide positions that constitute most of the information within a genome?”

If you think all this is interesting, there is a much longer lecture here, which I have not watched. JoeCoder has watched it and he endorses it.

Now I have been told by JoeCoder that there are many critical responses to his hypothesis, most of which have to do with whether natural selection can overcome the difficulty he is laying out. But since this is not my area of expertise, there is not much I can say to adjudicate here, I won’t be able to respond to these. I hope that I will have time to come back to this and read about it at some point. I do have an e-book of the that collection of papers book I linked to above.

Positive arguments for Christian theism

Polemics

Is belief in God compatible with belief in evolution?

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Sherlock Holmes and John Watson: let's take a look at the facts
Sherlock Holmes and John Watson: let’s take a look at the facts

What should we make of theistic evolutionists telling us that you can believe in God, while still knowing that matter, law and chance fully explain the development of all of biological life?

Consider this quotation from Phillip E. Johnson.

Quote:

The National Academy’s way of dealing with the religious implications of evolution is akin to the two-platoon system in American football. When the leading figures of evolutionary science feel free to say what they really believe, writers such as Edward O. Wilson, Richard Dawkins, Daniel Dennett, Carl Sagan, Steven Pinker, Stephen Jay Gould, Richard Lewontin and others state the “God is dead” thesis aggressively, invoking the authority of science to silence any theistic protest. That is the offensive platoon, and the National Academy never raises any objection to its promoting this worldview.

At other times, however, the scientific elite has to protect the teaching of the “fact of evolution” from objections by religious conservatives who know what the offensive platoon is saying and who argue that the science educators are insinuating a worldview that goes far beyond the data. When the objectors are too numerous or influential to be ignored, the defensive platoon takes the field. That is when we read those spin-doctored reassurances saying that many scientists are religious (in some sense), that science does not claim to have proved that God does not exist (but merely that he does not affect the natural world), and that science and religion are separate realms which should never be mixed (unless it is the materialists who are doing the mixing). Once the defensive platoon has done its job it leaves the field, and the offensive platoon goes right back to telling the public that science has shown that “God” is permanently out of business.

(Phillip E. Johnson: “The Wedge of Truth”, IVP 2000, pp. 88-89).

So what naturalistic scientists believe is that God didn’t do anything to create the diversity of life – that nature does all of its own creating without God. In fact, it doesn’t matter if the best naturalistic explanation is improbable or implausible – naturalists must bitterly cling to materialistic explanations of natural phenomena. Any doubts about the efficacy of naturalistic mechanisms get met by “theistic evolutionists” – scientists who think that science shows that God didn’t do anything in the history of life.

When it comes to discussing origins, you have to be very careful with theistic evolutionists. The one question they want to avoid is whether science, done in the ordinary naturalistic way, can discover evidence of intelligent agency in the history of the development of life. And that’s why you have to ask them that question first. “Is there any scientific evidence that intelligent causes were active during the history of the development of life on this planet?” Their answer to that is the same as atheists, namely: “there is no scientific evidence that intelligent causes are responsible for the effects we see in the history of life on Earth”. Theistic evolutionists and atheists agree on that: as far as pure scientific evidence is concerned, nature can do its own creating without any intelligence writing genetic code or engineering animal body plans.

Now, take a look at this article by Jay Richards. He cites some theistic evolutionists.

Excerpt:

Biologist Ken Miller:

For his part, [Ken] Miller, a biologist, has no qualms about telling us what God would do: “And in Catholicism, he said, God wouldn’t micromanage that way. ‘Surely he can set things up without having to violate his own laws.'”

I am unaware of any tenet of Catholic theology that requires God not to micromanage. It is, however, a tenet of deism.

Got that? What really happened is that God didn’t do anything. How does he know that? From the science? No. Because he assumes naturalism. Oh, it’s true that he says that God is lurking somewhere behind the material processes that created life. But God’s agency is undetectable by the methods of science. And he is hoping that you will accept his subjective pious God-talk as proof that a fundamentally atheistic reality is somehow reconcilable with a robust conception of theism.

More from Richards:

Then we get Stephen Barr offering his private definition of “chance.”

It is possible to believe simultaneously in a world that is shaped by chance and one following a divine plan. “God is in charge and there’s a lot of accident,” said Barr, also a Catholic. “It’s all part of a plan. . . . God may have known where every molecule was going to move.”

What does Barr really believe? He believes that what science shows is that nature created life without any interference by an intelligent agent. Barr then offers believers his subjective pious God-talk to reassure them that evolution is compatible with religion. He has a personal belief – NOT BASED ON SCIENCE – that the material processes that created all of life are “all part of a plan”. He cannot demonstrate that from science – it’s his faith commitment. And more speculations: “God may have known…”. He can’t demonstrate that God did know anything from science. He is just offering a personal opinion about what God “could have” done. The purpose of these subjective opinions is to appease those who ask questions about what natural mechanisms can really create. Can natural causes really account for the development of functional proteins? Never mind that – look at my shiny spiritual-sounding testimony!

That’s theistic evolution. What really happened is that no intelligent causes are needed to explain life. What they say is “God could” and “God might” and “I pray” and “I attend this church” and “I received a Christian award” and “I sing praise hymns in church”. None of these religious opinions and speculations are relevant to the science – they are just opinions, speculations and biographical trivia. Atheists and theistic evolutionists agree on what science shows about the diversity of life – intelligent causes didn’t do anything.

Front-loading?

One of the ways that theistic evolutionists try to affirm design is by insisting that the design is “front-loaded”. The design for all the information and body plans is somehow embedded in matter.

Here is Stephen C. Meyer to assess that:

It’s very important to understand that there is no scientific evidence for design (information) being front-loaded. So although the theistic evolutionists are talking about design, it’s still in the realm of faith – not detectable to scientific investigation. And as Dr. Meyer explained, it doesn’t work to explain design anyway.

I attended a Wheaton College philosophy conference where Dr. Michael Murray read a paper advocating for this front-loaded view of design. I raised my hand to ask him a question, “hey, philosophy guy, did God front-load the information in that paper you’re reading, or did you write it yourself?” But the philosophy moderators must have known that I was an engineer, and would talk sense into him, because they never called on me. However, I did e-mail him later and asked him if he had any evidence for this front-loading theory, and couldn’t God write sequence information in time the same way he had sequenced information in his essay. He replied and said that front-loading was more emotionally satisfying for him. That’s philosophy, I guess. Thank goodness an engineer wrote his e-mail program so that he could at least come clean about his silly view.

The quickest way to disarm a theistic evolutionist is to ask them for a naturalistic explanation of the origin of life. And for a naturalistic explanation of the Cambrian explosion. And so on. Focus on the science – don’t let them turn the conversation to their personal beliefs, or to the Bible, or to religion. No one cares about the psychology of the theistic evolutionist. We only care what science can show.