If Evolution Is In Progress, Why Fight Extinction?

If Evolution Is In Progress, Why Fight Extinction?

We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

Natural selection is a central tenet of evolution. However, most biologists seem determined to prevent the extinction of the species that have been selected against. Why is this? Preservation of genetic diversity?

I thought evolution was supposed to create diversity not destroy it. What am I missing?

First, a shorthand definition of Evolution is heritable change and not 'progress' (which is a rather loaded word). Also, evolution is not 'supposed' to do anything, and can lead to both an increase or a decrease in diversity, since (local) diversity is simply the net result of speciation rate and extinction rate (if we exclude colonization of new species from other areas). Therefore, I think the question is framed in the wrong way.

Second, there are many reasons why biologists might want to halt species extinctions, as hinted in the other comments and answers. Most obviously, conservation biologists want to prevent man-made extinctions which are due to how we have influenced/modified/destroyed the natural environments. I don't think conservation biologists in general are determined to halt all 'natural' extinction. However, most of the time it is really hard to pinpoint what would be a 'natural' extinction. Either way, the current rates of extinction, which have been estimated to lie 100-1000 times (IUCN, 2007) above background rates (some say it's closer to 10000 times higher), indicate that most extinctions are man-made.

The rationales people use for preserving biodiversity can however differ. Three distinct categories are:

1) For human survival and/or economy, e.g. through ecosystem services or resources we rely on.

2) For human welfare, e.g. recreation or esthetical reasons.

3) Ethical considerations, e.g. inherent value of species or to preserve the unique evolutionary history of the system.

Another way to structure these is to label 1) & 2) as instrumental values and 3) as inherent values. The instrumental values can then be subcategorized as services, goods/resources, information (e.g. genetic to be used in medical research), and esthetical/spiritual values.

Since the direct value of individual species are often (usually) uncertain (irrespectivly of the direct rationales used) the precautionary principle is often invoked to justify species conservation. Also, numerous examples exist of how aspects of biodiversity are related to human values (some recent examples are Garibaldi et al. 2013 and Gamfeldt et al. 2013), such as production or services, which can also be used to justify both conserving biodiversity or individual species. However, other aspects of biodiversity are functional diversity, which focus on preserving functional groups of species, or phylogenetic diversity, focusing on taxonomic coverage and uniqueness (evolutionary history), instead of 'overall' biodiversity (see e.g. Flynn et al, 2011 for a discussion of these concepts). Under these perspectives less focus is placed on individual species.

Evolution is simply a change in the allele frequency of a population over time. It is not progressive nor does it have to create diversity. Some of the mechanisms of evolution such as genetic drift and stabilizing selection tend to reduce the genetic diversity of populations.

Furthermore evolution and extinction are two independent processes. Extinction is the complete loss of a unit of genetic diversity (e.g., a species) from the planet. Evolution and extinction are linked because extinction eliminates a particular evolutionary history that cannot be recovered, but the two processes are affected by different factors within the environment.

Clarifying these definitions we can see that both evolution and extinction are value neutral from the perspective of the biosphere.

Humans tend to ascribe value to biodiversity based on aesthetics, ecosystem services, ethics, etc… and thus we may strive to preserve it for these reasons but this is unrelated to the biological function of evolution and extinction.

Good question. Evolution will and does continue. Mass extinctions have happened in the past and in fact we are the product and beneficiaries of that process; when niches open up from extinctions, other species just move in and take over, eventually they will adapt to take the place of those who have left. Of course that's a useful perspective since it will happen. A large number of animals and plants are endangered and while the impact overall can't be estimated since we have never counted all the animals and plants, much less microscopic species, an example of our dire straits can be gleaned from the fact that perhaps half of amphibians are endangered,

There are various arguments that there is lost knowledge - when these animals and plants we have never even cataloged disappear we will lose hundreds of millions of years of biological 'experience', of lost knowledge as well as an aesthetic/ethical argument that this is clearly wrong somehow; like a mass murder of animals and plants.

I think that most people who have never seen these animals and plants, understood how wonderful and awe-inspiring they are, how many odd abilities that evolution has gifted them. It seems like a nearly universal experience that those who have seen this are pretty strongly in favor of efforts to save them.

But that's not the question at hand; really won't the ecosphere heal and eventually be okay? Now that we have discovered life so far under the ocean and in the depths of the earth that even nuclear holocaust would probably not touch them. The answer is yes. The ecosphere and life will go on. There are two other useful questions though:

1) will we go on with it? Mass extinctions are the result of changes in the environment - all living things in that environment will sink or swim as it were and humans should not exclude ourselves. Will the future human race deal with loss of oxygen content, the loss of fresh water and the misery of population explosion? If the environment just keeps getting worse, will we do well? We're all assuming that we will figure out how to feed ourselves, find drinking water when both food and water are not really growing to meet our growing population, not to mention the desertification of arable land and the rise in temperature that will impact human geography and economics over the next 100 years or so. If the environment were to stabilize at least we would not be standing on shifting ground. If you are familiar with Malthus' argument, when there is no food or land left to exploit nature will take its course with us - war, famine etc etc. That is also a natural state, which we've managed to slowly eliminate. We may be bringing it back in.

2) How long do we want to wait for the ecosystem to heal? After the mass extinctions of the past, hundreds of millions of years were needed for the species around to re-establish themselves as they are now. Is that really a good trade off for a few decades of industrial-economic expansion?

Until then, the survivors are not necessarily the ones we'd prefer.

I volunteered at a survey of shellfish in the San Franscisco Bay. At one time the shellfish here were so plentiful that the natives piled giant shellmounds the size of small hills from their regular diets. Now because of fertilizer runoff and pollution these shellfish are nearly gone - we didn't see one the entire day looking around the survey area. Instead they nesting shells were covered with a slimy bunch of sea squirts - plant-like animals which can grow quickly enough to absorb the nutrients and robust enough to ignore the pollution and chemicals. I'd probably rather have a bay scallops on my plate rather than a salad of seq squirts. The Bay is swimmable, but is plenty slimy.

Got to sign off now, but that's the outline of an answer…

Simply put, evolution through natural selection is a process which occurs naturally. It will occur to any self-duplicating organism with: variations, hereditary traits and threats to propagation (e.g. all life forms we are familiar with). Evolutionary biologists study this, the same way astrophysicists study space, and studying black holes or life forms doesn't indicate anything other then knowing how it works.

Actually, considering that most people in a certain field take interest in it (because logic), it is to be expected that biologists as a whole would rather see life doesn't go extinct then it does - again saying nothing about whether extinctions have or have not happened in the past.

Outside the Beltway

This 46% number has barely budged over the past three decades, and I’m willing to bet it was at least as high back in the 50s and early 60s, that supposed golden age of comity and bipartisanship. It simply has nothing to do with whether we can all get along and nothing to do with whether we can construct a civil discourse.

The fact is that belief in evolution has virtually no real-life impact on anything. That’s why 46% of the country can safely choose not to believe it: their lack of belief has precisely zero effect on their lives. Sure, it’s a handy way of saying that they’re God-fearing Christians — a “cultural signifier,” as Andrew puts it — but our lives are jam-packed with cultural signifiers. This is just one of thousands, one whose importance probably barely cracks America’s top 100 list.

Contra Sullivan, Drum also argues that one’s position on evolution doesn’t really tell us very much about the cultural divide that Sully laments:

I could spend an entire day arguing politics and economics and culture with a conservative and never so much as mention evolution. It’s just not that important, and it doesn’t tell us much of anything about our widening political polarization. We should keep up the fight, but at the same time we shouldn’t pretend it has an epic significance that it doesn’t. I’m not optimistic about anyone or anything “bringing the country together,” but not because lots of people choose to deny evolution. Frankly, that’s one of the least of our problems.

I tend to think Drum is largely correct here. In the end, evolution is not an issue that most people have to deal with even tangentially in their daily lives and it’s likely that much of this 46% doesn’t really have a good understanding of what Evolutionary Theory is really all about. Polls like the one from Gallup frustrate me intensely because it would be nice if we lived in a country where rational thought was more common, but then again I’m not sure how common reason actually is amongst humanity in general.

As Drum goes on to say, none of this means that we should give in to the creationists and remove evolution from High Schools, or allow pseudo-science like “intelligent design” to be treated as it if were as valid as actual science, those are fights worth fighting. However, in the end, this is hardly the most important issue in the country.

About Doug Mataconis


As an active participant in many activities at my Southern Baptist church, I realize it’s likely the majority of folks I spend my time with are “Creationists” (a term I dislike intensely, since I believe in Creation, I just believe that God also created Science, which is the vehicle He uses to accomplish a whole lot of stuff. Like creating the Universe, for example).

But like Kevin, I believe there’s not much point in having that discussion with them. What difference would it make, beyond potentially driving a wedge between us? Those who believe God used a miracle to create the Universe in seven days, and even went so far as to create evidence that it was done over a much longer timeframe, aren’t likely to be swayed by anything I have to offer, and they’re certainly not going to change my mind.

We have many more things worth discussing things that will actually make a difference somewhere. Why would I want to get in the way of that by arguing over something where neither of us is going to be convinced by the other?

Refusal to grasp evolution is really more of a signifier of intellectual failure than an actual deficit itself. Compare it to other academic concepts – let’s say: math. Do you really use anything beyond algebra in your typical day? Do you have conversations about finding the length of a right triangle’s hypotenuse or what sine & cosine tell you? Would not grasping the inner details of those things really lessen your ability to thrive in society? I’d wager not. But someone who described those concepts as unnecessary to teach – or better yet, completely wrong – should be laughed out of polite society.

Instead, we elect them to high office.

Evolution is just one aspect of the anti-science attitudes of the US and those anti-science beliefs do matter and are at least partially responsible for the US’s decline and potentially the end of civilization as we know it.

You’re actually contradicting yourself.

If you think, as I do, that fighting to keep creationism and “intelligent design” out of high schools is important, then you consider that the fight for evolution matters.

I agree with Drum in the hierarchy of importance in our society, which starts with the fine and liberal arts majors on top, the philosopher kings, if you will, and the plebeian fields of the math and sciences on the bottom all the important people one can know, know nothing about evolution other than what is fashionable to believe. Evolution, Scientology, phrenology, all can come and go without making any difference.

@PD Shaw: Yes,, because it’s all the liberal arts majors for whom you have so much contempt who are the ones denying evolution.

Because of course everyone you despise must contain every single aspect of humanity that you despise. That way you can stay safe in your bubble of smugness and never interact with a human being who isn’t exactly like you.

@WR: another humorless liberal? They used to have senses of humor, but I’m dating myself.

@WR: After reading your word salad there, the only thought I can have is “of course this guy believes in evolution. He’s living proof that it occasionally runs backwards.”

As Drum goes on to say, none of this means that we should give in to the creationists and remove evolution from High Schools, or allow pseudo-science like “intelligent design” to be treated as it if were as valid as actual science, those are fights worth fighting. However, in the end, this is hardly the most important issue in the country.

It does not matter if it’s not the most important issue in the country. Rather, it is just another important issue we need to deal with. It’s an important part of the culture wars, a part of the struggle to determine what is taught in public high schools.

I would like to see creation and evolution taught side by side.And as one of my favorite creation teachers is fond of saying

“I don’t care if they teach evolution, I just want the lies taken out of the text books”.

(a term I dislike intensely, since I believe in Creation, I just believe that God also created Science, which is the vehicle He uses to accomplish a whole lot of stuff. Like creating the Universe, for example).

I just picked up one of these. Good book.

@G.A.: I see you also commented on that amusing one-star review for the book, which was completely not one-star for the reason I thought it would be.

Evolution, Scientology, phrenology, all can come and go without making any difference.

Bull. Phrenology, far as I know, never sued anyone.

“I don’t care if they teach evolution, I just want the lies taken out of the text books”.

What are some of the lies?

@G.A.: I would also like to see Creationism taught in public high schools. In a Civics class. As an example of how a small number of dedicated, well funded nut jobs can push an agenda successfully despite the irrationality of their position.

Evolution pales in comparison to the revelation that your standard issue human is composed mostly of bacteria. “You” are outnumbered 1000:1 by species, and 100,000:1 by genome. Bacteria communicate much like the internet, but without addressing, with LANs and WANs. And they make up the vast majority of “me”.

Whatever “I” am. Be that as it may, for those retaining reticence regarding evolution, “germanity” is going to go over like a fart in church. Pick any church.

Tend to agree with Drum here. In my evolution is not even in the top 20, maybe 50.

Made me think of the neuroscientist who wrote a piece for Psychology Today saying that the question of whether human beings have free will is meaningless because either “yes” or “no” have exactly the same effect on human behavior, namely, none whatsoever. See here.

In the end, evolution is not an issue that most people have to deal with even tangentially in their daily lives

Hmm…..not sure I agree with that. Just off the top of my head, I can think of a few not-so-tangential things where an understanding (and acceptance) of evolution would be beneficial.

The overuse of antibiotics. Genetically modified food. (BT corn is great….until it kills off the susceptible leaving only the resistant to procreate.) Even releasing boa constrictors in the Everglades. Give me an hour and I’ll come up with a whole list.

After all, evolution isn’t only about the origin of species. It’s also about how species interact and adapt.

It only matters if you care about learning how things actually work in reality, and care about your kids being taught the same. It also matters if you want to design policies that will actually work in the real world. But sure, aside from that it doesn’t matter at all.

After all, evolution isn’t only about the origin of species.

In the face of systematic attempts to efface from public view, Darwin’s racism, a friend writes to offer quotes from Darwin’s Descent of Man:

Savages are intermediate states between people and apes:

“It has been asserted that the ear of man alone possesses a lobule but ‘a rudiment of it is found in the gorilla’ and, as I hear from Prof. Preyer, it is not rarely absent in the negro.

“The sense of smell is of the highest importance to the greater number of mammals–to some, as the ruminants, in warning them of danger to others, as the Carnivora, in finding their prey to others, again, as the wild boar, for both purposes combined. But the sense of smell is of extremely slight service, if any, even to the dark coloured races of men, in whom it is much more highly developed than in the white and civilised races.”

“The account given by Humboldt of the power of smell possessed by the natives of South America is well known, and has been confirmed by others. M. Houzeau asserts that he repeatedly made experiments, and proved that Negroes and Indians could recognise persons in the dark by their odour. Dr. W. Ogle has made some curious observations on the connection between the power of smell and the colouring matter of the mucous membrane of the olfactory region as well as of the skin of the body. I have, therefore, spoken in the text of the dark-coloured races having a finer sense of smell than the white races….Those who believe in the principle of gradual evolution, will not readily admit that the sense of smell in its present state was originally acquired by man, as he now exists. He inherits the power in an enfeebled and so far rudimentary condition, from some early progenitor, to whom it was highly serviceable, and by whom it was continually used.”

[From Denyse: Decades ago, I distinguished myself by an ability to smell sugar in coffee. It wasn’t very difficult, with a bit of practice, and it helped to sort out the office coffee orders handily. My best guess is that most people could learn the art if they wanted to. Most human beings don’t even try to develop their sense of smell – we are mostly occupied with avoiding distressing smells or eliminating or else covering them up. I don’t of course, say that we humans would ever have the sense of smell of a wolf, but only that Darwin’s idea here is basically wrong and best explained by racism. ]

“It appears as if the posterior molar or wisdom-teeth were tending to become rudimentary in the more civilised races of man. These teeth are rather smaller than the other molars, as is likewise the case with the corresponding teeth in the chimpanzee and orang and they have only two separate fangs. … In the Melanian races, on the other hand, the wisdom-teeth are usually furnished with three separate fangs, and are generally sound they also differ from the other molars in size, less than in the Caucasian races.

“It is an interesting fact that ancient races, in this and several other cases, more frequently present structures which resemble those of the lower animals than do the modern. One chief cause seems to be that the ancient races stand somewhat nearer in the long line of descent to their remote animal-like progenitors.”

[From Denyse: The nice thing about teeth is that, if they give trouble, they can simply be pulled. I would be reluctant to found a big theory on the size or convenience of teeth, given that this fact must have occurred to our ancestors many thousands of years ago.]

“It has often been said, as Mr. Macnamara remarks, that man can resist with impunity the greatest diversities of climate and other changes but this is true only of the civilised races. Man in his wild condition seems to be in this respect almost as susceptible as his nearest allies, the anthropoid apes, which have never yet survived long, when removed from their native country.”
[From Denyse: Native North Americans often perished from human diseases to which they had not become immune in childhood. That is probably unrelated to the inability of anthropoid apes to stand cold climates.]

This includes the degraded morals of lower races:

“The above view of the origin and nature of the moral sense, which tells us what we ought to do, and of the conscience which reproves us if we disobey it, accords well with what we see of the early and undeveloped condition of this faculty in mankind…. A North-American Indian is well pleased with himself, and is honoured by others, when he scalps a man of another tribe and a Dyak cuts off the head of an unoffending person, and dries it as a trophy. … With respect to savages, Mr. Winwood Reade informs me that the negroes of West Africa often commit suicide. It is well known how common it was amongst the miserable aborigines of South America after the Spanish conquest. … It has been recorded that an Indian Thug conscientiously regretted that he had not robbed and strangled as many travellers as did his father before him. In a rude state of civilisation the robbery of strangers is, indeed, generally considered as honourable.”

“As barbarians do not regard the opinion of their women, wives are commonly treated like slaves. Most savages are utterly indifferent to the sufferings of strangers, or even delight in witnessing them. It is well known that the women and children of the North-American Indians aided in torturing their enemies. Some savages take a horrid pleasure in cruelty to animals, and humanity is an unknown virtue….. Many instances could be given of the noble fidelity of savages towards each other, but not to strangers common experience justifies the maxim of the Spaniard, “Never, never trust an Indian.”

[From Denyse: If early modern Europeans in Canada had not trusted “Indians,” they would all have died off pretty quickly.]

“The other so-called self-regarding virtues, which do not obviously, though they may really, affect the welfare of the tribe, have never been esteemed by savages, though now highly appreciated by civilised nations. The greatest intemperance is no reproach with savages.”

“I have entered into the above details on the immorality of savages, because some authors have recently taken a high view of their moral nature, or have attributed most of their crimes to mistaken benevolence. These authors appear to rest their conclusion on savages possessing those virtues which are serviceable, or even necessary, for the existence of the family and of the tribe,–qualities which they undoubtedly do possess, and often in a high degree.”

[From Denyse: Charles Darwin, let me introduce you to Hollywood, before you say any more silly things about the supposed immorality of “savages.” ]

Making slavery understandable, though of course distasteful now:

“Slavery, although in some ways beneficial during ancient times, is a great crime yet it was not so regarded until quite recently, even by the most civilised nations. And this was especially the case, because the slaves belonged in general to a race different from that of their masters.”

[From Denyse: Not really. In ancient times, slaves were typically unransomed captives in war, convicted criminals, or people who had fallen into irrecoverable debt. In Roman times, there would be nothing unusual about being a slave to someone of the same race as oneself. Slavery based on race alone was an early modern legal invention, aimed against blacks.]

Mass killings of savages is understandable as a type of species extinction:

“At some future period, not very distant as measured by centuries, the civilised races of man will almost certainly exterminate, and replace, the savage races throughout the world. At the same time the anthropomorphous apes, as Professor Schaaffhausen has remarked will no doubt be exterminated. The break between man and his nearest allies will then be wider, for it will intervene between man in a more civilised state, as we may hope, even than the Caucasian, and some ape as low as a baboon, instead of as now between the negro or Australian and the gorilla.”

“The partial or complete extinction of many races and sub-races of man is historically known….When civilised nations come into contact with barbarians the struggle is short, except where a deadly climate gives its aid to the native race…. The grade of their civilisation seems to be a most important element in the success of competing nations. A few centuries ago Europe feared the inroads of Eastern barbarians now any such fear would be ridiculous.”

“[Flinders Island], situated between Tasmania and Australia, is forty miles long, and from twelve to eighteen miles broad: it seems healthy, and the natives were well treated. Nevertheless, they suffered greatly in health….With respect to the cause of this extraordinary state of things, Dr. Story remarks that death followed the attempts to civilise the natives.” [–Obviously the problem was trying to civilize these barbarians!]

“Finally, although the gradual decrease and ultimate extinction of the races of man is a highly complex problem, depending on many causes which differ in different places and at different times it is the same problem as that presented by the extinction of one of the higher animals.”

Of course the degradation extends to the intellectual:

“There is, however, no doubt that the various races, when carefully compared and measured, differ much from each other,–as in the texture of the hair, the relative proportions of all parts of the body …Their mental characteristics are likewise very distinct chiefly as it would appear in their emotional, but partly in their intellectual faculties. Every one who has had the opportunity of comparison, must have been struck with the contrast between the taciturn, even morose, aborigines of S. America and the light-hearted, talkative negroes. There is a nearly similar contrast between the Malays and the Papuans who live under the same physical conditions, and are separated from each other only by a narrow space of sea.”

[From Denyse: I would imagine that the aborigines of South America felt some resentment over the loss of their continent to invaders from Europe … ]

” A certain amount of absorption of mulattoes into negroes must always be in progress and this would lead to an apparent diminution of the former. The inferior vitality of mulattoes is spoken of in a trustworthy work as a well-known phenomenon and this, although a different consideration from their lessened fertility, may perhaps be advanced as a proof of the specific distinctness of the parent races.”

“So far as we are enabled to judge, although always liable to err on this head, none of the differences between the races of man are of any direct or special service to him. The intellectual and moral or social faculties must of course be excepted from this remark.”

And… drum roll. the main conclusion:

“The main conclusion arrived at in this work, namely, that man is descended from some lowly organised form, will, I regret to think, be highly distasteful to many. But there can hardly be a doubt that we are descended from barbarians. The astonishment which I felt on first seeing a party of Fuegians on a wild and broken shore will never be forgotten by me, for the reflection at once rushed into my mind-such were our ancestors. These men were absolutely naked and bedaubed with paint, their long hair was tangled, their mouths frothed with excitement, and their expression was wild, startled, and distrustful. … He who has seen a savage in his native land will not feel much shame, if forced to acknowledge that the blood of some more humble creature flows in his veins.”

[From Denyse: Sounds like a local rave to me. Not my ancestors (who were, as it happens, rigidly correct people, but my 2009 fellow Torontonians.)]

“For my own part I would as soon be descended from …[a] monkey, or from that old baboon… –as from a savage who delights to torture his enemies, offers up bloody sacrifices, practices infanticide without remorse, treats his wives like slaves, knows no decency, and is haunted by the grossest superstitions.

[From Denyse: Yuh, I know. I know women who have divorced guys like that too … but, when founding a theory in science, it strikes me that … ]

And let’s not forget sexism!

“The chief distinction in the intellectual powers of the two sexes is shewn by man’s attaining to a higher eminence, in whatever he takes up, than can woman–whether requiring deep thought, reason, or imagination, or merely the use of the senses and hands…We may also infer, from the law of the deviation from averages, so well illustrated by Mr. Galton, in his work on ‘Hereditary Genius,’ that if men are capable of a decided pre-eminence over women in many subjects, the average of mental power in man must be above that of woman.”

“The greater intellectual vigour and power of invention in man is probably due to natural selection, combined with the inherited effects of habit, for the most able men will have succeeded best in defending and providing for themselves and for their wives and offspring.”

[From Denyse: Re women vs. men: Actually, if we leave Darwin’s obsession with natural selection out of the matter for a moment, we can come up with a simple explanation for the difference between men’s and women’s achievements. Men are far more likely to win Nobel Prizes than women – but also far more likely to sit on Death Row.

For most normal achievements, women will do as well as men, given a chance. Women do just as well as men at being, say, a family doctor, an accountant, a real estate agent, a high school teacher, etc.

It’s only in outstanding achievements – either for good OR for ill – that men tend to dominate. One way of seeing this is that the curve of women’s achievements fits inside the curve of men’s achievements, either way.

Natural selection does not explain this because most men who have outstanding achievements do not contribute a great deal to the gene pool as a consequence.

Either they produce few or no children, or their children do nothing outstanding. So Darwin did not really have a good explanation for this fact.

What should we do? Breeding of people and letting the weak die off:

“The advancement of the welfare of mankind is a most intricate problem: all ought to refrain from marriage who cannot avoid abject poverty for their children for poverty is not only a great evil, but tends to its own increase by leading to recklessness in marriage. On the other hand, as Mr. Galton has remarked, if the prudent avoid marriage, whilst the reckless marry, the inferior members tend to supplant the better members of society. Man, like every other animal, has no doubt advanced to his present high condition through a struggle for existence consequent on his rapid multiplication and if he is to advance still higher, it is to be feared that he must remain subject to a severe struggle. Otherwise he would sink into indolence, and the more gifted men would not be more successful in the battle of life than the less gifted. Hence our natural rate of increase, though leading to many and obvious evils, must not be greatly diminished by any means. There should be open competition for all men and the most able should not be prevented by laws or customs from succeeding best and rearing the largest number of offspring.”

“We civilized men, on the other hand, do our utmost to check the process of elimination we build asylums for the imbecile, the maimed, and the sick we institute poor-laws and our medical men exert their utmost skill to save the life of every one to the last moment. There is reason to believe that vaccination has preserved thousands, who from a weak constitution would formerly have succumbed to small-pox. Thus the weak members of civilized societies propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man. It is surprising how soon a want of care, or care wrongly directed, leads to the degeneration of a domestic race but excepting in the case of man himself, hardly any one is so ignorant as to allow his worst animals to breed.”

[From Denyse: But how would anyone know who the “worst animals” are among people?]

@G.A.: I guess since Darwin was a racist, he was wrong about everything else?

Modern science pretty much rejects the idea of race entirely. It’s a social construct based on mostly superficial differences. White, black, European, Asian…we all have the same common ancestors.

I forgive Darwin his ignorance on these matters. We didn’t really start to understand genetics until the 1950s.

We didn’t really start to understand genetics until the 1950s.

And when we did, it did nothing but support evolutionary theory. This was far from a foregone conclusion. Understanding genetics and DNA could have led us in an entirely different direction. It could even have supported “intelligent design.”

But it didn’t–indeed, it was found to support evolutionary theory. A body of science created nearly 100 years after Darwin, science about which he could have known nothing, supports his theory. It’s amazing.

This is why acceptance of the fact of evolution is important: because, as the (very Christian) biologist Theodosius Dobzhansky wrote, “nothing in biology makes sense except in the light of evolution.” Rejection of evolution means rejection of the primary means of understanding nearly everything about us, and about the world around us, and how the myriad forms of life interact and propagate.

@Donald Sensing:
Sorry – meant to write, “in my church evolution is not even in the top 20.”

Evolution of crocodiles

Three feet long. 5-10lbs. Lived in the swamps of eastern Asia. Ate small animals. Sail on it's back. Split off into pre-historic crocodiles and early dinosaurs.


228,000,000 bc - 199,000,000 bc Most related to crocodilians. Were herbivores, however they demonstrate the skull structure and snout. They looked much like modern day crocodiles except their nostrils were located on the top of their head rather than the tops of their snout. They were alive during the early Jurassic period.



Middle Cretaceous period. 40ft long and 10-15 tons. Ate dinosaurs and fish. Lived in the rivers of Africa. Had an odd protrusion on it's snout. Looked and behaved like it's modern decedents, but it was twice as long and about 10 times as heavy. Bulla on it's snout. Also the media calls it super-croc.


100,000,000 bc - 95,000,000 bc

Really big 36 ft. long ten tons. Ate plankton and krill even though they had a hugh pelican like jaw.


Greek for terrible crocodile. Lived in the rivers of North America. About 33 ft long and 10 tons. They had a 6ft. long skull. Fed on fish, shell fish, and land creatures. Evidence in fossils suggests that they attacked large North American tyrannosaurs.


It is five feet long, 25-50 pounds, ate fish, and lived in the rivers of North America and western Europe. It had a long narrow profile and a tooth studded snout. It survived the K/T extinction.

Cretaceous-Paleogene Extinction Event

The K/T Extinction Event was an intense global mass extinction of Flora and Fauna which most notably included the dinosaurs. Strangely, many species of large crocodilians survived the event, evolving into the cute lovable creatures we know today.

Crocodylidae (Modern day crocodile)

The modern day crocodile, which includes the saltwater, Nile, and American variants, is spread throughout the world with various adaptions for specific climates and habitats. Though it looks prehistoric, it is a highly evolved and complex organism that is a successful predator.


This animal was nine feet long and 500 pounds, and they consume red meat who they hunted in the woodlands. These crocodiles have long curved teeth and long legs, that are unlike the modern croc's short legs. andThe crocodiles continuously get smaller because of environment changes.

Crocodylus thorbjarnarsoni

This is a very close relative of the modern day crocodile, it had a large scull and small raised rim in front of the eyes. It likely prayed on early humans. It lived in the Turkana basin in Kenya, and it could be the largest known true crocodile.

Wouldn’t it be great to have vast herds of mammoths roaming the Canadian tundra, or a thrill to see flocks of hundreds of millions of passenger pigeons settling in Michigan forests once again to gobble down vast amounts of beech mast and supply succulent squabs to Chicago restaurants? Or maybe enjoy watching flights of Carolina parakeets over southern farms, or at least observe a living pair of saber-toothed cats in a cage in a zoo. Of course, being able to rent a pair of velociraptors to add spice to the “reality” TV show you’re directing would be nice too.

An appealing picture to say the least: Jurassic Park in reality, bringing vanished animals back to life, made possible by spectacular progress in molecular biology.

After all, isn’t Homo sapiens destined to use its fine brains to engineer the entire planet (or universe)? But let’s restrict our dreaming to recreating organisms that Homo sapiens has itself exterminated. Surely, if that’s an achievable goal, and we want to do it, humanity should go full speed ahead and resurrect the creatures we have wiped from the earth.

Or should we? I’ll answer this question, but not before I briefly address another: Could we? Would it be possible? It seems likely that in some cases a simulacrum — perhaps a quite reasonable simulacrum — of an extinct organism can be produced. And one would be foolish to predict that even making a fully successful reconstruction of an extinct species is impossible. Science has come a long way in genetics, genomics, and development in a very short time much that can be done today seemed impossible when my wife, Anne, and I came to Stanford in 1959.

So, even though I suspect the resurrectionists generally underrate the genetic, epigenetic, and environmental dimensions of the problem they recommend tackling, for the purposes of this discussion let’s assume that reconstructing extinct species eventually will be practical at some level, behavioral traits and all. Yet I believe that the resurrectionists have been fooled by a cultural misrepresentation of nature and science — as in Jurassic Park, Avatar, X-men — traceable perhaps to Mary Shelley’s Frankenstein. As my colleague Chase Mendenhall put it, “We need more representations of the future, but we must live and act in the present, and there are far more urgent and tractable ways for creating imagined futures that don’t include bringing back a “pet” for humanity before you’ve had time to prepare its terrarium.”

Why We Should Bring
Back the Woolly Mammoth

Futurist Stewart Brand argues that with advances in genetic technology, we may someday be able to restore long-gone species like the woolly mammoth. It’s a goal worth pursuing, he says, with real benefits for conservation and biodiversity.
Read More

So what are the objections to an effort to start making amends for anthropogenic extinctions by trying to restore the victims to life? The soundest scientific reason, in my view, is misallocation of effort. It is much more sensible to put all the limited resources for science and conservation into preventing extinctions, by tackling the causes of demise: habitat destruction, climate disruption, pollution, overharvesting, and so on. Spending millions of dollars trying to de-extinct a few species will not compensate for the thousands of populations and species that have been lost due to human activities, to say nothing of restoring the natural functions of their former habitats.

Sadly, most non-scientists, and too many conservation biologists, who really care about the decay of biodiversity, are concerned about preventing the extinction of species, and the de-extinctionists thus naturally focus on resurrecting species. In part, this traces to a mistake my hero Charles Darwin made by mistitling what I consider the most important book ever written “On the Origin of Species” instead of “On the Differentiation of Populations.” Among other things, this has led to a century of pointless argument about how to define “species.” It’s as if geologists wasted their time in interminable ranting over how to define “mountain.” How high does it have to be? How isolated from other high points on a ridge? How steep the slopes? More important, this species-centric view also has led to the conservation focus being on species, even though right now the critical problem humanity faces is not species extinction but one of the extinction of populations. Populations are the entities that deliver crucial ecosystem services to society and the ecological engines that sustain and create species. Of course, when all populations of a species are gone, that species will be extinct, but there are orders of magnitude more populations than species disappearing today. And in most cases, as populations disappear and species extinction becomes more likely, the value of the organism as a service-provider approaches zero, including the aesthetic service of giving us the joy of watching or interacting with it.

Resurrecting a population and then re-inserting it into habitats where it could supply the ecosystem services of its predecessor is a monumentally bigger project than recreating a couple of pseudomammoths to wander around in a zoo. The passenger pigeon is often mentioned as a target for de-extinction. Passenger pigeons once supplied people with abundant meat and likely helped to suppress Lyme disease. To create even a single viable population might well require fabricating a million birds or so, since the species apparently survived by a strategy of predator saturation.

And if the swarm were synthesized, where could it be introduced? The vast forests the pigeons required are partly gone and badly fragmented at best, and one of the birds’ food sources, the American chestnut, is functionally extinct. The passenger pigeon’s previous habitat is utterly transformed, and if humanity does not very quickly and substantially curb greenhouse gas releases, the pigeon’s old homeland will likely be completely unrecognizable in less than a century. In practical terms, in the near future in which action is required, extinction is certainly “forever.”

Reintroductions of surviving endangered species (which are vastly more important than attempted de-extinctions) illustrate the complexity and scale of the task. Culturing and reinserting animals into nature is already known often to require intense and expensive effort (consider the California condor), and even invasions of “natural” species (such as the first two introductions of starlings to North America) often fail to “take.” And as National Geographic photographer Joel Sartore has emphasized to me, zoos are already overwhelmed trying to breed endangered species for reintroduction and thus facing triage conundrums about which species to save and which to let go. Allocating more effort there is far more essential than research into restoring a few prominent elements of earth’s biodiversity with laboratory-created resurrections.

De-extinction thus seems far-fetched, financially problematic, and extremely unlikely to succeed on a planet continually being vastly transformed by human action. There are also risks beyond failure. Resurrected, previously benign organisms could become pests in new environments, might prove ideal reservoirs or vectors of nasty plagues, or might even harbor dangerous retroviruses in their genomes. But frankly, I think such problems will probably prove minor compared to the main problem, which is “moral hazard.”

Moral hazard is a term invented by economists for a situation where one becomes more willing to take a risk when the potential costs will be partly borne by others. For example, if a person can get government flood insurance, she is more likely to build a beachfront home, worrying less about the risks of sea level rise. The problem is that if people begin to take a “Jurassic Park” future seriously, they will do even less to stem the building sixth great mass extinction event. We are already seeing species extinctions occurring at a rate at least an order of magnitude above prehistoric “background” rates (those outside of the past five mass extinction events), and that gives weight to the extreme seriousness of the current population extinction crisis. And while the critical problem of climate disruption tends to engross the attention of environmentally concerned people, the erosion of biodiversity is potentially equally crucial. The disasters to be caused by climate disruption could be resolved in a few hundred thousand years recovery from a sixth mass extinction could easily take five or ten million years.

Right now the biggest moral hazard on the environmental front is created by the folly of “geoengineering” — the idea that, if humanity fails to limit the flux of greenhouse gases dramatically in the near future, overheating of the earth could be prevented by any one of a series of crackpot schemes. Biodiversity loss has not achieved the prominence of climate disruption, and it may not do so. But I’ve already had questions in classes and after speeches about the prospect of engineering biodiversity back into existence — always implying that “biodiversity” is giant ground sloths, ivory-billed woodpeckers, and the like. Moral hazard is already there, and if people ever wake up to their connections to the rest of the living world, it is sure to grow.

Scientists interested in trying to resurrect extinct species should surely be free to pursue their interests if they can get the needed support. Perhaps there will be some significant scientific positive fallout, and maybe, as my friend Stewart Brand suggests, we’ll be pleased to have some interesting results in a century (if civilization persists). But if de-extinction advocates are really concerned about the state of biodiversity, they should not be holding meetings or debates about de-extinction, or publicly dreaming about turning wood pigeons into replacement passenger pigeons in the foreseeable future. They should be putting much of their time into such efforts as keeping plastics and persistent organic pollutants out of the environment and reducing or eliminating the production of both, stopping mineral exploration in places like Yasuni National Park in Ecuador and Murchison Falls National Park in Uganda, trying to suppress the ivory trade, pushing reduction of meat eating, and educating decision-makers about the roles biodiversity plays in human lives. Above all, de-extinction scientists should be struggling to get a rapid transition to renewable energy, promote a stop-at-two goal for family planning, and generally seeking ways to reduce the scale of the human enterprise.

Failing in those areas will make all discussions of de-extinction moot, even in the long term. People crusading for women’s rights (which when achieved bring down birthrates) are doing a hell of a lot more for biodiversity than are biologists doing research on de-extinction.

President Trump has proposed shutting down both the NEA and the NEH. Are the arts essential to human society?

Without art, we’re not human. The ability to imagine and to take that imagination and make it into reality is one of the things that is really distinctive about humans. Whether it’s painting, building airplanes, or figuring out how to make a paycheck last to the end of the month, it all stems from the same creative capacity. And there is no better way to flex that creativity muscle than to do art, be exposed to art, and to think about art.

What President Trump will be doing by taking away the National Endowment for the Arts and the National Endowment for Humanities and cutting public access to art, is to rob humanity of imagination and creativity and hobble us in our capacity to get along and make a difference in the world.

Evolution, Explanation, Ethics and Aesthetics

Evolution, Explanation, Ethics and Aesthetics: Towards a Philosophy of Biology focuses on the dominant biological topic of evolution. It deals with the prevailing philosophical themes of how to explain the adaptation of organisms, the interplay of chance and necessity, and the recurrent topics of emergence, reductionism, and progress. In addition, the extensively treated topic of how to explain human nature as a result of natural processes and the encompassed issues of the foundations of morality and the brain-to-mind transformation is discussed.

The philosophy of biology is a rapidly expanding field, not more than half a century old at most, and to a large extent is replacing the interest in the philosophy of physics that prevailed in the first two-thirds of the twentieth century. Few texts available have the benefit of being written by an eminent biologist who happens to be also a philosopher, as in this work.

This book is a useful resource for seminar courses and college courses on the philosophy of biology. Researchers, academics, and students in evolutionary biology, behavior, genetics, and biodiversity will also be interested in this work, as will those in human biology and issues such as ethics, religion, and the human mind, along with professional philosophers of science and those concerned with such issues as whether evolution is compatible with religion and/or where morality comes from.

Evolution, Explanation, Ethics and Aesthetics: Towards a Philosophy of Biology focuses on the dominant biological topic of evolution. It deals with the prevailing philosophical themes of how to explain the adaptation of organisms, the interplay of chance and necessity, and the recurrent topics of emergence, reductionism, and progress. In addition, the extensively treated topic of how to explain human nature as a result of natural processes and the encompassed issues of the foundations of morality and the brain-to-mind transformation is discussed.

The philosophy of biology is a rapidly expanding field, not more than half a century old at most, and to a large extent is replacing the interest in the philosophy of physics that prevailed in the first two-thirds of the twentieth century. Few texts available have the benefit of being written by an eminent biologist who happens to be also a philosopher, as in this work.

This book is a useful resource for seminar courses and college courses on the philosophy of biology. Researchers, academics, and students in evolutionary biology, behavior, genetics, and biodiversity will also be interested in this work, as will those in human biology and issues such as ethics, religion, and the human mind, along with professional philosophers of science and those concerned with such issues as whether evolution is compatible with religion and/or where morality comes from.

Aging is an inevitability, or so we have to assume: the processes of evolution blindly but efficiently explore the space of possible living creatures, and have been doing so for a very, very long time. We might think that surely a very long-lived or ageless species would have a great advantage in evolutionary competition, its individual members able to produce descendants for far longer than competitors in more short-lived species. Yet virtually all species - with only a very few exceptions - age in easily measured ways. The species that age are also the species that have won in evolutionary terms, and therefore prospered and spread. Why is this?

A recent open access paper (in PDF format) explores one of the approaches used to answer this question, and does so in a very readable fashion:

Living organisms shouldn't age, at least if that could be helped (many of use would certainly like that, but our wishes are not a valid argument). Evolution works in a way that any species whose representatives have any distinct disadvantage will be driven to extinction. It makes sense then to assume that, if aging could be avoided, species that showed senescence as the individuals grow older should be replaced by others where aging does not happen (or happens at a much slower rate). Senescence increases mortality and an individual who dies of old age will leave, in average, a smaller number of descendants than another individual that does not age and manages to live and reproduce for a longer time. And yet many known living organisms show senescence. The time it takes for an individual to show signs of old age varies greatly among species, but aging seems so natural that many people fail to realize there is an apparent contradiction between senescence and evolution.


Understanding why we age is a long-lived open problem in evolutionary biology. Aging is prejudicial to the individual and evolutionary forces should prevent it, but many species show signs of senescence as individuals age. Here, I will propose a model for aging based on assumptions that are compatible with evolutionary theory: i) competition is between individuals ii) there is some degree of locality, so quite often competition will between parents and their progeny iii) optimal conditions are not stationary, mutation helps each species to keep competitive.

When conditions change, a senescent species can drive immortal competitors to extinction. This counter-intuitive result arises from the pruning caused by the death of elder individuals. When there is change and mutation, each generation is slightly better adapted to the new conditions, but some older individuals survive by random chance. Senescence can eliminate those from the genetic pool. Even though individual selection forces always win over group selection ones, it is not exactly the individual that is selected, but its lineage. While senescence damages the individuals and has an evolutionary cost, it has a benefit of its own. It allows each lineage to adapt faster to changing conditions.

We age because the world changes.

And there is illustrated one of the present competing viewpoints on the origins of aging.

I posit that aging is unnatural, period. It serves no purpose, evolutionary or otherwise. It is nothing more than the consequence of living far beyond our "design specifications". Few will see a connection between teenage pregnancy and old age, but I posit that they are biologically linked. In the eyes of nature, we are "supposed" to reproduce in our teens, and die by predation, starvation, disease, trauma or hypothermia in our mid to late twenties. Indeed, studies have found that cognitive, immunological, and reproductive decline all begin at the same age. 27 years! Bear in mind that civilization as we know it has existed for only 10,000 years. That is 0.5% of the 2.5 million year existence of the genus Homo. In other words, for 99.5% of human history parenthood before age 20 and death before age 30 was the order of the day. We are cavedwellers living in the modern world, eight-tracks in the MP3 universe.

Right, the article: "Old age begins at 27: Scientists reveal new research into ageing" from 15th March 2009 informs: The research at the University of Virginia, reported in the academic journal Neurobiology Of Aging, found that the first age of humans at which performance was significantly lower than the peak scores was 27. Nevertheless, aging in plants and animals is not unnatural. Aging in the current population of humans, however, is not natural either. Humans are doing all sorts of unnatural stuff with their brains. Designing software and writing with computers, for instance, most of it is unnatural. Yet, any normal human being is doing much unnatural stuff, because of the larger human brain. Thus, an aging human being is unnatural, because of a larger brain size that demands too much time for the process of senescence until it has eliminated the outdated individual from the genetic pool. Someone should come and fix this.

Our species is the most adaptable form of macroscopic of life on Earth, through the employment of our very own engine of behavioural adaptation - the human brain. Even if this model of aging is correct, it shows that aging is little more than a redundant, inferior and outmoded feature that should be done away with as quickly as possible.

So the variables here are
- time (senescence)
- number of offspring
- mutation rate.

I guess as humans we can't complain, being on the leading edge of nature's exploration space with respect to time. Could an increased mutation rate offset its penalty?
It's all in the numbers - someone please post a Mathematica notebook.

So, as it is with humans, the time factor (short life) already won out over an increased mutation rate?

Principles of Evolution, Ecology and Behavior

This course presents the principles of evolution, ecology, and behavior for students beginning their study of biology and of the environment. It discusses major ideas and results in a manner accessible to all Yale College undergraduates. Recent advances have energized these fields with results that have implications well beyond their boundaries: ideas, mechanisms, and processes that should form part of the toolkit of all biologists and educated citizens.

This Yale College course, taught on campus three times per week for 50 minutes, was recorded for Open Yale Courses in Spring 2009.


This course presents the principles of evolution, ecology, and behavior for students beginning their study of biology and of the environment. It discusses major ideas and results in a manner accessible to all Yale College undergraduates. Recent advances have energized these fields with results that have implications well beyond their boundaries: ideas, mechanisms, and processes that should form part of the toolkit of all biologists and educated citizens.

Cotgreave, Peter and Irwin Forseth. Introductory Ecology. Oxford: Blackwell Science Ltd, 2002.

Krebs, John R. and Nicholas B. Davies. An Introduction to Behavioral Ecology, 3rd ed. Oxford: Blackwell Science Ltd, 1993.

Stearns, Stephen C. and Rolf Hoekstra. Evolution: An Introduction, 2nd ed. Oxford: Oxford University Press, 2005.

There are two midterms and a paper. The sections are Writing Intensive and require writing exercises culminating in one 15-20 page review paper or research proposal in which you utilize readings from the original scientific literature to address a question that you pose. The course grade consists of 25% from each midterm and 50% from the essay/section grade.

Special feature: The course is designed to elicit your own, original questions about evolution, ecology, and behavior through interactions with a website featuring video and still images from the Galapagos and issues and questions posed by recent papers from the primary literature. Your writing project and your take-home final will address questions you posed yourself, then refined in response to feedback from your TF.

Midterm examination 1: 25%
Midterm examination 2: 25%
Paper: 50%

Five Reasons Why Evolution Is Important

Today is the 201st birthday of Charles Darwin. It is worth celebrating this anniversary not only because of Darwin's great contributions to science, but also because of the practical ways his theory of evolution improves our lives today.

Here are five reasons--drawn from medicine--why evolution is important:

1. H1N1 & Emerging Diseases

The outbreak of the H1N1 "swine flu" in 2009 reminds us of our vulnerability to emerging diseases. Like SARS in 2002, H1N1's abrupt appearance emphasizes the fact that viruses evolve, producing new and potentially pandemic-causing contagions. In our highly mobile world, new viruses can jump continents in mere hours via planes. Rapid evolution combined with rapid travel mean that emerging diseases threaten human health as never before--and therefore, understanding how these diseases evolve is vital as never before.

2. HIV
One reason no vaccine against HIV has yet been found is that HIV is one of the fastest evolving entities known to science. HIV's rapid, "Borg"-like adaptability means that the key to defeating this scourge may lie in better understanding of how viruses evolve.

Evolution helps us understand HIV's origins. Because we know that HIV and SIV (simian immunodeficiency virus) share a common viral ancestor, this opens other avenues of research into ultimately defeating HIV.

The technique of applying drug cocktails to HIV-infected patients has proven remarkably successful. The evolutionary idea with drug cocktails is that because HIV evolves so quickly, one single drug will usually leave some surviving viruses a multi-drug approach has better success. Moreover, periodically switching the cocktail's components helps eliminate viruses which have evolved resistance. All of these techniques rest upon a scientific understanding of evolution.

3. Vaccines
With the exception of clean drinking water, few technologies have improved human health more than vaccines. While misinformed celebrities may peddle long-discredited superstitions about links between childhood vaccines and autism, the truth is that untold millions of adults are alive and healthy today because as children they received vaccines. Vaccines work so well, in fact, that today the horrors of smallpox and polio epidemics are fading memories.

Vaccines exploit the efficiency of our own immune system to recognize and eliminate microbial threats that have been previously introduced into our bodies. Because these threats evolve, vaccines must change too. The flu shot you received this year will not protect you against next year's bug because flu viruses evolve quickly. Evolution makes sense of the need for a new vaccine every year, and point the way toward developing it.

4. Antibiotic Resistance

Penicillin was once a "miracle" drug, but today medical professionals find a host of diseases--from staph infections to tuberculosis--evolving resistance to antibiotics.

The origin of antibiotic-resistant organisms is a textbook example of natural selection. Patients infected with a diverse population of bacteria are given an antibiotic that wipes out almost all the bacteria. If they start to feel better and do not finish the full course of antibiotics, what is left behind are those bacteria most resistant to the drug. Those survivors then become the nucleus of a new, resistant population. Understanding this evolutionary process is an important part of modern public health.

5. Drug Development
New drugs must be tested for a variety of safety factors, yet we cannot simply give unknown drugs to human test subjects and hope for the best. Because we know from evolution that we share a common ancestor with animals such as mice, dogs, and macaques, we can test drugs on these animals without endangering humans. The billions of dollars spent by pharmaceutical companies on animals testing depend on a practical application of evolution.

Evolution has also helped scientists identify sources of lifesaving drugs. The Pacific Yew tree, for example, was once the only source of Taxol, a remarkable drug used to fight ovarian, lung, and breast cancer. This endangered tree grows very slowly, however, and 4-6 trees would be destroyed to produce just one dose of Taxol.

Evolution came to rescue. Scientists used the evolutionary history of the Pacific Yew to trace back other trees in its family line, discovering Taxol-like compounds in more common trees. Evolution guided scientists in finding a replacement to the Pacific Yew, thus dramatically increasing the supply of Taxol available to cancer patients. Evolution saves lives.

These are only a handful of the reasons why evolution is important to medicine (and more information can be found here and here). There are a host of other applications of evolution--agriculture, forensics, bioengineering. But the importance of evolution extends beyond its practical side evolution explains the diversity of life on this planet, shows us our connection to other living things, and reveals profound insights into the processes of nature.

Today, on Darwin's 201st birthday, take a moment to reflect on the importance of evolution.

Rapid evolution and host immunity drive the rise and fall of antibiotic resistance during acute infection

Blue and pink coloured packets of antibiotics. Credit: Shutterstock

Antibiotic resistance poses a serious threat to human health. Resistant infections now cause more than 750,000 deaths per year and are predicted to increase to 10 million deaths per year by 2050. It is known that treating patients with antibiotics is associated with the emergence of resistance—and worse outcomes for patients. But how resistance emerges during infections remains poorly understood.

In a new study published in Nature Communications, an international team led by Oxford University scientists reports that rapid bacterial evolution interacts with host immunity to shape both the rise, and fall, of resistance during infection.

This study highlights the need to understand better how our immune system works with antibiotics to suppress bacterial infections.

Craig MacLean, co-author and Professor of Evolution and Microbiology at the University of Oxford, said: "Our study suggests that natural immunity can prevent resistance during infection and stop the transmission of resistant strains between patients. Exploiting this link could help us to develop new therapeutics to use against bacterial pathogens and to better use the antibiotics that we have now."

The research described in this article is part of a larger ASPIRE-ICU study, which stands for Advanced understanding of Staphylococcus aureus and Pseudomonas aeruginosa Infections in EuRopE—Intensive Care Units. The ASPIRE-ICU trial was conducted by the COMBACTE consortium and brought together multiple collaborators from leading academic research labs along with AstraZeneca scientists. The COMBACTE consortium is a major academia-industry collaboration exploring new approaches to antimicrobial resistance.

The collaborators discovered that antibiotic treatment killed the overwhelming majority of bacteria causing the infection, but bacteria with resistant mutations continued to grow and replicate during treatment. However, they also learned that the resistant mutants had low competitive ability, leading to the loss of resistance after treatment as resistant mutants were replaced by sensitive competitors that managed to escape antibiotic treatment.

Professor MacLean said: "Both the rise and fall of resistance during infection are simple and elegant examples of evolution by natural selection."

Host immunity helped to suppress the infection, probably removing >90% of resistant mutants that were present at the start of antibiotic treatment. Host immunity also eventually eliminated the resistant populations that were present after treatment.

The team was able to generate these insights by tracking changes in the bacterial population in a single subject at an unprecedented level of resolution, and combining this with data on patient health and immune function. The bacterial pathogen in this case was Pseudomonas aeruginosa, an opportunistic pathogen that mainly causes infections in hospitalized patients and in people with cystic fibrosis or bronchiectasis.

Professor MacLean said: "This is the kind of study that I could have only dreamed of 10 years ago. Technological progress was certainly important to this project, but the real key to our success was increased collaboration and cross-talk between medical researchers and evolutionary biologists."

Watch the video: How To Go Extinct (January 2023).