The selfish gene is a great meme. Too bad it’s so wrong | Aeon Essays
of the nature of these relationships and the mechanisms of integration .. for several species of the leaf cutter ants in the genus Atta. [16, 17, 26], for  A. N. Andersen and A. D. Patel, “Meat ants as dominant members of d'une esp`ece nouvelle (viennense) du même genre,” Annales de la Société. Example Of Mutualism Evolution, A Mutual Breakdown Mit News, Examples Of . Leaf-cutter ant. They use the leaves to cultivate their fungus food. Ant normally meat-ants are vicious and territorial, however they make exceptions for other creatures . Farm QuotesFamily QuotesSunflower QuotesSunflower ImagesFarm . Ants Tending Leafhoppers Leafhopper, Beetle Bug, Bugs And Insects, Ants, Nymphs Funny Video Memes, Videos Funny Sugar Ants, Ant Removal, Animal Wallpaper, Hd Wallpaper, Household Pests, Household Human Relationships.
Subtle camo colouring turns conspicuously garish. How does this happen?
Leaf Hopper and Meat Ant by aleigha anderson on Prezi
Does something happen to their genes? Even as one animal becomes the other, as Jekyll becomes Hyde, its genome stays unchanged. Same genome, same individual, but, I think we can all agree, quite a different beast. We humans, for instance, share more than half our genomes with flatworms; about 60 per cent with fruit flies and chickens; 80 per cent with cows; and 99 per cent with chimps.
This means that we are human, rather than wormlike, flylike, chickenlike, feline, bovine, or excessively simian, less because we carry different genes from those other species than because our cells read differently our remarkably similar genomes as we develop from zygote to adult.
The writing varies — but hardly as much as the reading. This raises a question: How vital, really, are actual changes in the genetic code? Do we always need DNA changes to adapt to new environments? Are there other ways to get the job done?
Is the importance of the gene as the driver of evolution being overplayed? Yet for more than two decades they have been stirring a heated argument among geneticists and other evolutionary theorists. Twenty years ago, phase changes such as those that turn grasshopper to locust were relatively unknown, and, outside of botany anyway, rarely viewed as changes in gene expression. They show up in gene-expression studies of plants, microbes, fish, wasps, bees, birds, and even people.
The genome is continually surprising biologists with how fast and fluidly it can change gene expression — and thus phenotype. These discoveries closely follow the recognition, during the s, that gene-expression changes during very early development — such as in embryos or sprouting plant seeds — help to create differences between species.
At around the same time, genome sequencing began to reveal the startling overlaps mentioned above between the genomes of starkly different creatures. You could even say flexibility is the essence of being a primate.
Thus, a genetic blueprint creates traits and drives evolution. This gene-centric view, as it is known, is the one you learnt in high school. It comes from Gregor Mendel and the work he did with peas in the s. Since then, and especially over the past 50 years, this notion has assumed the weight, solidity, and rootedness of an immovable object.
But a number of biologists argue that we need to replace this gene-centric view with one that more heavily emphasises the role of more fluid, environmentally dependent factors such as gene expression and intra-genome complexity — that we need to see the gene less as an architect and more as a member of a collaborative remodelling and maintenance crew. This revolt among historians recast leaders not as masters of history, as Tolstoy put it, but as servants.
Thus the Russian Revolution exploded not because Marx and Lenin were so clever, but because fed-up peasants created an impatience and an agenda that Marx articulated and Lenin ultimately hijacked. Likewise, D-Day succeeded not because Eisenhower was brilliant but because US and British soldiers repeatedly improvised their way out of disastrously fluid situations.
Wray, West-Eberhard and company want to depose genes likewise. They want to cast genes not as the instigators of change, but as agents that institutionalise change rising from more dispersed and fluid forces. This matters like hell to people like West-Eberhard and Wray. Need it concern the rest of us? We are rapidly entering a genomic age.
A couple of years ago, for instance, I became one of what is now almost a half-million 23andMe customers, paying the genetic-profiling company to identify hundreds of genetic variants that I carry. Do I know how to make sense of them?
Do they even make sense? Soon, it will be practical to buy my entire genome. Will it tell me more? Will it make sense?
Die, selfish gene, die
Millions of people will face this puzzle. Yet we enter this genomic age with a view of genetics that, were we to apply it, say, to basketball, would reduce that complicated team sport to a game of one-on-one. A view like that can be worse than no view. We need something more complex. We have a more complicated understanding of football than we do genetics and evolution. Nobody thinks just the quarterback wins the game. Mendel spent seven years breeding peas in a five-acre monastery garden in the town of Brno, now part of the Czech Republic.
He crossed plants bearing wrinkled peas with those bearing smooth peas, producing 29, plants altogether. When he was done and he had run the numbers, he had exposed the gene. This was the Holy Shit! And this conceptual gene, revealed in the tables and calculations of this math-friendly monk, seemed an agent of mathematical neatness.
Inheritance appeared to work like algebra. Anything so math-friendly had to be driven by discrete integers. It was beautiful work. This recognition was the Holy Shit! It seemed to explain everything. And it saved Darwin. Darwin had legitimised evolution by proposing for it a viable mechanism — natural selection, in which organisms with the most favourable traits survive and multiply at higher rates than do others.
But he could not explain what created or altered traits. Genes created traits, and both would spread through a population if a gene created a trait that survived selection. That much was clear by Naturally, some kinks remained, but more math-friendly biologists soon straightened those out. This took most of the middle part of the 20th century.
Biologists now call this decades-long project the modern evolutionary synthesis. And it was all about maths.
Fisher, Haldane and Wright, working the complicated maths of how multiple genes interacted through time in a large population, showed that significant evolutionary change often revealed itself as many small changes yielded a large effect, just as a series of small nested equations within a long algebra equation could. The second kink was tougher.
Meat ant - Wikipedia
If organisms prospered by out-competing others, why did humans and some other animals help one another? This might seem a non-mathy problem. Yet in the s, British biologist William Hamilton and American geneticist George Price, who was working in London at the time, solved it too with maths, devising formulas quantifying precisely how altruism could be selected for.
Some animals act generously, they explained, because doing so can aid others, such as their children, parents, siblings, cousins, grandchildren, or tribal mates, who share or might share some of their genes.
The closer the kin, the kinder the behaviour. With fancy maths, they argued that we should view any organism, including any human, as merely a sort of courier for genes and their traits.
This flipped the usual thinking. It made the gene vital and the organism expendable. Our genes did not exist for us. We existed for them. We served only to carry these chemical codes forward through time, like those messengers in old sword-and-sandal war movies who run non-stop for days to deliver data and then drop dead.
This notion of the gene as the unit selected, and the organism as a kludged-up cart for carrying it through time, placed the gene smack at the centre of things. It granted the gene something like agency. At first, not even many academics paid this any heed. This might be partly because people resist seeing themselves as donkey carts. Another reason was that neither Hamilton nor Williams were masterly communicators.
But 15 years after Hamilton and Williams kited this idea, it was embraced and polished into gleaming form by one of the best communicators science has ever produced: In his magnificent book The Selfish GeneDawkins gathered all the threads of the modern synthesis — Mendel, Fisher, Haldane, Wright, Watson, Crick, Hamilton, and Williams — into a single shimmering magic carpet.
These days, Dawkins makes the news so often for things like pointing out that a single college in Cambridge has won more Nobel Prizes than the entire Muslim world, that some might wonder how he ever became so celebrated. The Selfish Gene is how. To read The Selfish Gene is to be amazed, entertained, transported.
He replicates in prose the process he describes. He gives agency to chemical chains, logic to confounding behaviour. He takes an impossibly complex idea and makes it almost impossible to misunderstand. He reveals the gene as not just the centre of the cell but the centre of all life, agency, and behaviour. Along with its beauty and other advantageous traits, it is amenable to maths and, at its core, wonderfully simple.
As both conceptual framework and metaphor, the selfish-gene has helped us see the gene as it revealed itself over the 20th century. But as a new age and new tools reveal a more complicated genome, the selfish-gene is blinding us. They do so even though they agree with most of what Dawkins says a gene does. In many cases, the other cogs drive the gene. The gene, in short, just happens to be the biggest, most obvious part of the trait-making inheritance and evolutionary machine.
But not the driver. Another way to put it: Mendel stumbled over the wrong chunk of gold.
Mendel ran experiments that happened to reveal strong single-gene dynamics whose effects — flower colour, skin texture — can seem far more significant than they really are. As with grasshoppers, a new environment can quickly turn a plant into something almost unrecognisable from its original form. If Mendel had owned an RNA sequencing machine and was in the habit of tracking gene expression changes, he might have spotted these.
When something has so many parts, evolution will act on all of them. Other ways may actually do more. What significant and plausible evolutionary dynamics stand in tension with a single-gene-centred model?
Such epigenetic changes may provide a way to pass heritable traits down through at least a few generations without changing any actual genes. To be sure, this research is still unproven as a significant evolutionary force. But while it is clearly important enough to pursue, many defenders of the selfish-gene model dismiss it out of hand. Of these genomic dynamics, perhaps the most challenging to the selfish-gene story are epistatic or gene-gene interactions. Epistasis refers to the fact that the presence of some genes or their variants can have profound and unpredictable influences on the activity and effects generated by other genes.
Think Jerry Garcia playing with different musical partners. Epistasis is hardly a new concept. In fact, geneticists have been arguing about its importance ever since R. Fisher and Sewall Wright bickered about it in the s.
Individual bees morph from worker to guard to scout by gene expression alone, depending on the needs of the hive This is not merely a matter of one gene muffling or amplifying another, though both these things happen.
For example, colonies residing in Western Australia may have lighter heads whereas those living in the eastern states have darker heads. An unpublished study examining the mitochondrial DNA did not find any distinction between eastern and western populations of I.
The forms in Yorke Peninsula have also never been subject to study, so future research may shed light as to whether or not these ants are genetically different from the meat ant. It is a member of the family Formicidaebelonging to the order Hymenoptera an order of insects containing ants, beesand wasps.
The genus Froggattella is the sister group of Iridomyrmex, both of which are in a clade that is 23 million years old. These ants were classified as two subspecies of I. In the early s, scientists discovered several different forms of meats ants, forming the Iridomyrmex purpureus species group; three forms were identified the regular I. However, as there were no clear morphological differences among these variations, the taxonomic status and evolutionary relationship of these ants remained uncertain.
Others may be darker, appearing metallic-bluish to purplish-black. Some forms may be dominant in certain habitats; for example, one form may be widespread throughout moist environments in dry areas, and others in cool and dry areas.
He also recognised another form, an undescribed blue form that was first studied several years earlier. The blue form was found to be genetically isolated and its allele frequencies differed significantly from the forms purpureus and viridiaeneus, but the same study concluded that these latter two forms were similar. Instead, they were only recognised by their colour and the genitalia of the males. This, in particular, is due to its blue-green iridescence colour.
The mesosomal setae as in haur found on the mesosoma are dark and sometimes translucent. The iridescence between the compound eyes and the lateral portion of the head ranges from slightly purple to strong and dark purple.
The colour of the legs and coxae the basal segment of the insect leg, which attaches to the body are darker than the mesothorax, and the petiole narrow waist is reddish brown and also darker than the mesothorax. The soft hairs on the head are frequent around the occipital marginand around the mandibular insertion, three to eight pale setae are usually seen.
The soft hairs are also common around the first gastral tergite. Examined specimens show no known ocelli. Erect setae on the pronotum are abundant.
The anterodorsal meaning in front and toward the back portion of the propodeum is arched and flat. The gaster can be brown or black with blue or purple iridescence and the legs are either orange or brown.
The iridescence around the foreparts is blue, pink, pale greenish yellow and purple. The erect setae are brown. The head has a concave posterior margin as in the end of an organism from its head with erect setae abundant in front of the face.
The sides of the head are convex. The eyes are semicircular and positioned around the midpoint of the ants' head capsule. The frontal carinae a keel-shaped ridge or structure are convex and the antennal scapes extend beyond the head's posterior margin by two or three times the diameter. Erect setae are found all over the antennal scape and noticeably prominent on the clypeal margin a shield-like plate at the front of an insect.
The mandibles are elongated and triangular, with long curved setae around the head capsule. These setae are mostly short and bristly.
The mesonotum is sinuous meaning it has many curvesand, like the pronotum, has 12 or more mesonotal setae. The mesothoracic spiracles are very small and the propodeal dorsum is smooth or convex. There are also a number of propodeal setae. There are both non-marginal and marginal setae present on the first gastral tergite around the gaster.
Queens are easily distinguishable from workers by their black colour and larger size, measuring The antennae and legs are ferruginous rust-like colourthe head is fusco-ferruginous, and the sides beneath the face and mandibles are ferruginous.
The head is wider than the thorax and emarginate. There is an impressed line that runs from the anterior nearer to the front of the body stemma to the base of the clypeus. The wings are subhyalineexhibiting a glassy appearance. The wings are yellowish along the anterior margin of the superior pair and also around the base; the nervures the veins of the wings are rufo -fuscous. Males are bright violet, and the antennae except for the first joint and tarsi are ferruginous.
Like the queen, the wings are subhyaline imperfectly hyaline and the nervures are rufo-fuscous. The abdomen shows a bright green tinge when seen under certain light. The head and anus are ventral. The integument is covered in spinules that are either isolated from each other or in short rows on the posterior somite and on the ventral surface. The body hairs are very short, measuring 0.
These spinules are either isolated or seen in near parallel rows. Several head hairs are present but they are small at 0. Each lobe has spinules and three sensilla simple sensory receptors around the anterior surface. The ventral border only has two sensilla and a number of spinules, and on the posterior surface, there are several rows of spinules and three sensilla.
The mandibles have a central apical most distal plate or appendage from the body tooth which is clearly noticeable and sharp. The maxillae have lobes, and the labial palps sensory structures on the labium are knob-shaped.
Aside from colour differentiation that was a key morphological character to distinguish I.
Meat ant and Leaf Hopper
For example, those that are found in very hot regions tend to be larger, whereas those found in regions of high humidity tend to be smaller than average. For example, populations restricted to the coasts of Western Australia usually have pale setae, compared to most colonies throughout the country, which have the common blackish setae.
The variation of the iridescence is, however, a consistent pattern found in other Iridomyrmex species with little distinction, making it a subtle character. Shattuck further notes that populations found throughout the Northern Territory and South Australia have reduced pubescence on the first gastral tergite, but this is different elsewhere.
Its isolation has also allowed meat ants to form associations with neighbouring nests of the same species. In Queenslandthey are frequently encountered in the eastern regions, whereas their abundance is limited around the north and central parts.
In the Northern Territory, specimens have been collected in the north and south regions but compared to other jurisdictions the ant is uncommon. The meat ant shares its distribution with many other animals and insects, some of which may cause harm to the ant or rival it, such as the banded sugar ant Camponotus consobrinus.