Transcript of The Extended Phenotype by Richard Dawkins Free Summary

Richard Dawkins the extended phenotype The Long Reach of the gene you no doubt know about Darwinism and the concept behind the survival of the fittest but when you consider who was actually doing the surviving there's a good chance that you may have only been thinking about humans or animals as it turns out there's more than one way to consider Darwin's theories and when we only pay attention to what's going on with the big organisms like monkeys and humans we miss out on a major player in the survival game genes when we zoom in down to the cellular level we can see how genes are really the ones actively trying to survive after all it's genes that are attempting to survive by supplying you with the ideal hair color facial features and personality for passing those very same genes On to the Next Generation as the author Richard Dawkins explains we should really be looking through the microscope and taking note of how competitive genes are since this is where all the adaptation mutation and replication is really taking place blink number one when considering Evolution we should think of genes as well as organisms ever since Charles Darwin's theory of evolution was published back in the mid 19th century his observations have often been summarized with the popular concept of the survival of the fittest when we imagine how this survival takes place place we take a very specific biological perspective on which organisms are fighting for survival when we think of life we think of the large organisms Darwin wrote about like birds and orchids or humans and we picture these plants and animals as being the selfish ones fighting for their survival so even though we recognize larger units such as societies populations and ecosystems as well as smaller units such as cells and genes when it comes to the biological evolution we almost always talk about selfish organisms most evolutionary biologists Focus their study on the individual body so for them it's organisms not populations or genes that compete and evolve but an interesting thing happens when we shift our Focus away from the individual bodies toward the genes and we start thinking about selfish genes rather than selfish organisms making this shift in perspective is a lot like adjusting the way we look at a Necker Cube which is the name of the typical 3D cube you've probably drawn on a piece of paper numerous times it's just two overlapping squares one slightly above the other with four diagonal lines connecting the corners when you look at a Necker Cube you can see it in two different ways with either the lower square or the upper Square making up the front of the cube but there's no one correct way of seeing it both perspectives are equally valid and accurate and it's the same for our biological perspective on what's fighting for survival both the organism Centric View and the gene Centric view are valid so when we shift to the genetic point of view we're not looking at things from a single correct perspective instead we're opening the door to new questions that go beyond why are certain genes useful to an organism now we can ask why are certain genes often grouped together in organisms in the ahead will further explore these questions and much more plink number two genes can only influence our lives they can't determine our futures we'd love a good myth whether it's the legend of the Yeti Bigfoot or accounts of Elvis Presley being alive and working at a gas station people cling to such stories and keep them alive for Generations the field of biology isn't immune to myths either and one of them could be called the gene myth this is the misconception which suggests that having certain genes means we're doomed to live out a specific fate for example if a child was struggling to get a passing grade in algebra her parents might think that getting a tutor would help but if the parents were then told that their child had a bad math gene they might just give up and think there's nothing we can do we can't fight science the truth is even though specific genes can suggest that a person is inclined or disinclined for something it doesn't mean anything is predetermined part of the problem is that people tend to misunderstand biology lingo when a biologist says something like the fruit fly has the red eye Gene what they really mean is that the fly with this Gene is more likely to have red eyes it's the many other genes that are also present that determine the ultimate influence of a gene otherwise known as the genetic environment that's why if you put that redey Gene from the fruit fly into the genetic environment of an elephant it doesn't mean that the elephant is guaranteed to have red eyes any more than the student with the bad math Gene is guaranteed to fail her algebra class another important factor is the organism's natural or social environment for example if a child does have a mathematical deficiency rooted in her genes it could very well be compensated for by an especially effective math tutor terms like genetic codes or genetically programmed can also make it sound like our genes are as deterministic as a piece of computer software but again this is just popular jargon among scientists and shouldn't be misconstrued our genes do of course influence us in many ways and certain genes will influence our capacity for mathematics but they cannot determine our Fates consider the books and movies we consume they can influence our decisions and behavior but just like genes they won't determine our Fates blink number three organisms don't always have optimal traits which is a sign that Darwin didn't have the full picture the gecko is a fantastic example of the use of evolutionary development for protection having gained the ability to change the color of its skin so it can hide in plain sight where sharks on the other hand are a good example of predatory development their skin having become so smooth that it cuts through the water at lightning speed but are these traits always the best if you're an adaptationist someone who's taken Darwin's ideas to mean that all organisms evolve to gain traits that are optimal for the problems they face you'd answer yes however if we look around we can see that many traits are in fact not optimal at all one of the reasons for adaptation being suboptimal is a time lag which is the fact that time can present any number of changes to an environment or an organism circum ances so a trait that was once optimal can quickly become obsolete take an armadillo a slow creature that can roll up into an armored ball when danger strikes this could be a great defense to many predators but it's far from optimal when your environment becomes inundated with automobiles another cause for suboptimal traits is available genetic variation which means that often the optimal scenario just isn't in the cards any trait that can can be developed as a result of the existing gene pool and in many cases that pool is too shallow for the optimal trait to be developed this is why some vertebrates evolve to have wings instead of arms yet no vertebrate has ever evolved to have six or eight arms even though this could very well be an optimal trait for some the other thing to consider is that an optimal trait might be ideal for the individual but not ideal for the group or vice versa this is why ego is and altruistic behaviors are at odds with each other in many cases the egoistic approach could very well be the optimal one for an individual such as when a bison wounds another male bison to attract a mate but this approach backfires when faced with the outside thread of a pack of wolves without the altruistic behavior of working together to defend the herd the Bison that are left to lag behind or defend themselves are picked off by the Wolves as we can see there are many holes in the adaptationist approach to understanding Evolution so while Darwin may have had revolutionary thoughts these don't provide the full picture blink number four organisms will sometimes work against their own interest along with the adaptation of optimal traits there is another belief surrounding Evolution that may not be so accurate this one is about organisms maximizing their own Fitness in other words this is the central theory that every every plant animal and human will instinctively act in its own best interest to make sure it passes on its genes to the Next Generation once again however we can look around us and see many cases where an organism is actually acting in the best interest of another organism one that is manipulating it for its own benefit one such manipulator is the angler fish you may have seen pictures of this creepy deep water fish as it is a long and unique protrusion extending from its head is quite like a fishing rod in fact complete with a lure at the end which resembles a piece of food so the angler fish effectively manipulates the small fish that are attracted to its deceptive lure coaxing them to swim close to its mouth this works because the small fish have bad eyesight and are unable to discern The anger's Lure from dinner therefore these half blind fish have evolved to work in the angler fish's best interest not their own in a relationship like this we can see how changes in the manipulated organism lead to changes in the manipulator in this case the small fish will develop traits to avoid the lure while the angler fish will make its own subtle adaptations to ensure it continues manipulating the small fish in this way the manipulator could successfully continue its methods for as long as both organisms exist after all the angler fish faces the greater pressure to adapt while the small fishes have a variety of food options the angler fish will starve if it doesn't successfully lure in its prey so it's under pressure to adapt in this relationship changes in the manipulated will continue to maximize the fitness of the manipulator rather than its own Fitness in the next blink we'll take a closer look at what's Behind These evolutionary adaptations blink number five genes are the real replicators not organisms so let's return to the main question what's behind an organism's evolutionary drive to compete and Thrive to get to the bottom of this we need to First understand what a replicator is a replicator is anything that lasts because copies are made of it so a page that has repeatedly been xeroxed is a replicator as our DNA molecules and therefore the genes within those molecules in fact our genes are replicated all the time since this is a regular part of the cell division that goes on within our bodies now to truly understand replicators you should know that there are two different kinds active and passive an active replicator Works toward increasing the likelihood of being copied therefore DNA molecules are active replicators since they influence the organism's traits and behaviors otherwise known as the organism's phenotype in an effort to increase its chances of reproduction passive replicators on the other hand are like the Xerox sheet of paper they have no influence over their likelihood of being copied now within both of these kinds of replicators there are two subtypes germline replicators and deadend replicators germline replicators can be copied an infinite number of times while deadend replicators which includes the majority of our DNA can only be copied a finite number of times interestingly many other things can count as replicators including ideas and memes in scientific terms a meme is any piece of information that resides in our brains including words music or images a favorite joke or Melody can act as a replicator the funnier or catchier it is the better its chances of being copied or conversely a meme that makes people wish they had never heard it will quickly be forgotten or in other words leave the meme pool memes can also act like genes and that they get copied as they'll often go through some mutations and pick up bits of other memes when they're replicated and reintroduced blink number six organisms are vehicles that carry genes now that we've taken a closer look at genes and their role as replicators let's look more closely at organisms themselves rather than being replicators organisms are better defined as Vehicles you might look at the lineage of a mother daughter granddaughter great-granddaughter and so on and think that this is a sign of replication didn't the mother replicate to produce the a daughter however let's say the mother lost a finger a subsequent daughter wouldn't be born with a missing finger would she this is an example of what Darwinism calls the non- inheritance of acquired characteristics if we were true replicators the daughter would be born with the missing finger and any other acquired characteristics since this isn't the case humans and other organisms are not replicators instead organisms are Vehicles meaning they carry the replicators around and serve as their preservers and propagators so the daughter will be a vehicle for the mother's genes and she'll be the recipient of any mutations that may occur in the replication of those genes even though a traditional biology class May lump organisms and their genes together as interchangeable the more accurate picture is that genes and organisms are in completely different categories generally biologists will freely zoom in and out to show the same process of natural selection occurring at a genetic level at an organism level and at a group level with all the same rules applying but it's now clear that this old way of looking at things is inaccurate you can't just move freely between genes and organisms because genes are replicators and organisms are Vehicles however you can apply the same rules to organisms and communities or groups of organisms since they're both vehicles now let's look at an accurate theory of evolution that does acknowledge the difference between replicators and vehicles link number seven signs of how genes compete can be seen in the Outlaws and modifiers once we recognize the difference between vehicles and replicators we can start to see that the real active agents of evolution aren't the organisms but rather the genes a more accurate definition of the biological process of natural selection would be the process by which genetic replicators outcompete each other genetic replicators compete through phenotypic effects these are the different ways in which genes influence an organism's characteristics including their physical traits and behavior so in a human this would include hair and eye color and how timid his personality is since appearance and personality traits influence your chances of finding a partner and having children it's the genetic replicators with successful phenotypic effects that are going to survive in the gene pool however the traditional stance of biologists was that popular traits and behaviors were due to organisms maximizing their chances but we now know it's really the replicators that are actively competing interestingly enough the surviving replicators aren't always acting in the best interest of the larger genome there are genes known as Outlaws which promote their own Survival even when it's at the cost of most of the other genes good examples of Outlaws are the so-called segregation distorter genes which during sexual reproduction manage to increase their chances of replication to exceed their allotted 50% these genes have been well studied in fruit flies where they actively sabotage the sperm cells that contain the chromosomes with no segregation disorders to combat the damaging effect of Outlaws other genetic replicators can act as modifiers as we saw in the second blink no single Gene is responsible for a spefic specific trait or characteristic instead genes work together and in the case of an outlaw trying to corrupt The genome other genes can band together and come to the rescue these genes are called modifiers modifiers can fight back against Outlaws by outnumbering and essentially overruling them you can think of the scenario like a parliament or Congress of genes the more members that show up to vote against the outlaw the more likely the corruption will be fixed link number eight with genes at the center of our biological picture we can explain our Superfluous DNA one of The Oddities of human biology that has confounded biologists is the fact that we contain way more DNA than is necessary for our bodies to be built and to function properly in other words we have Superfluous DNA but remember one of the primary reasons biologists have been unable to figure this out is their organism Cent perspective of evolution from this point of view the sole purpose of DNA is to supervise the building of an organism's body and to make sure it functions properly and for this the mysterious leftover DNA is indeed Superfluous and purposeless if we put on our Gene Centric classes however and look at Evolution again we can see that this extra DNA isn't so purposeless after all in fact the purpose becomes clear and simple the DNA is there to ensure its own Survival in this light the Superfluous DNA in organisms is not unlike an extra passenger in the backseat of a car being driven by the essential DNA this freeloader might not be chipping in for gas money or providing directions but it's not causing any harm either so how is it that biologists can't recognize this well to put it in another way it's as though they're looking at our DNA like someone from an alien Utopia would imagine if all biologists came came from a planet called Utopia where everyone lived in harmony with complete trust in each other so you understand how a utopian biologist might be confused as to why humans would use locks fences and guard dogs to protect their belongings this would all seem completely pointless to the biologists but once the alien biologists learn that humans distrust and compete with one another the extra security measures would start to make sense similarly for our Earthling biology ologist to understand the reason behind Superfluous DNA they need to recognize that DNA is acting for its own Survival and replication not that of the vehicle blink number nine the various meanings of Fitness have confused the topic of evolution throughout these blinks we've talked about survival of the fittest and how genes and organisms can try to maximize their Fitness but what does Being Fit really mean ins scientific terms part of the confusion that has lingered around the field of evolution is that Fitness tends to be used by biologists in different ways In Darwin's original use of the term fit organisms were any with the capacity to survive therefore the fittest were the strongest with the best eyesight the sharpest hearing all characteristics that increase their chances of survival now what the survival of the fittest also implies is that as time goes on and multiple Generations are born Evolution will lead to organisms having stronger muscles sharper eyesight and even more sensitive hearing this leads us to the second way Fitness is used as a measure of how successful an organism is at reproducing and passing its genes to the Next Generation so if you were comparing a blackbird to a crow the fittest of the two would be the one that raises the most Offspring to reach reproductive age there's a third way of defining Fitness what's known as Inclusive fitness in this sense it's not just the individual organism that's being measured but also the fitness of its immediate family and close relatives those who are most likely to share the individual's genes so the Inclusive fitness of an individual wombat would also depend on its sisters and cousins and how high their chances of survival to reproductive age were with all these different meanings to the term Fitness it's little wonder that there's been confusion surround ing evolution in Darwinism and since it's key to the traditional organism Centric understanding of evolution when there is confusion around what Fitness means the whole perspective becomes fuzzy Fitness is the go-to term when biologists present their standard view of evolution which includes the erroneous notion that individual organisms are the primary beneficiaries of genetic adaptations so this is just one more reason to shift our perspective away from the selfish organism to a selfish Gene blink number 10 the influence of genes goes beyond the individual organism we've realigned our evolutionary perspective away from the organism and squarely onto the survival of genes so it's time to do the same with our understanding of the phenotype as we've explained in previous blinks the phenotype is what gives us all our observable characteristics including our physiological traits such as hair color and our behavioral traits and personalities but it's important to remember that genes combine with the organism's environment to make the phenotype but what if the phenotype goes beyond the individual organism as certain animal artifacts suggest for example imagine a species of ctis fly that has larvae that build nests out of stones taken from the bottom of a stream now picture two nests of distinct colors one made of dark stones and one made of light the choice of stones depends on the behavior of the larve that build each Nest so in this case since the behavior is a result of the genes that make up the phenotype the colors of the nests are also the result of the lar genes more precisely we could say the nest is a phenotypic expression of the lar genes what's more since this phenotypic expression extends beyond the bodies of the larve we could say that the color of the nest is an example of the extended phenotype of the Lar genes in fact an extended phenotype can include far more than that it can include everything the organism produces so a spider web is an expression of a spider's extended phenotype we can also look Beyond The Nest to include the immediate surroundings of an organism as an extension of its phenotype a good example of this is a beaver dam since these dams are generally an expression of not just an individual Beaver but rather an entire Beaver family they're a perfect examp example of a joint extended phenotype which recognizes Expressions made by multiple organisms blink number 11 the external influence of genes can result from multiple organisms joined together now you know how to recognize when the influence of an organism's phenotype extends Beyond its own body you might be wondering how do I know what is and isn't an expression of an organism's phenotype when considering what qualifies as an extended phenotype remember that an extended phenotype needs to be related to things that influence the organism's survival and chance of reproduction if we're looking at a pigeon its nest helps ensure the survival of its Offspring and should therefore be considered part of the pigeon's extended phenotype but what about when the pigeon is gathering sticks for the nest searching for materials it might push around leaves and make scratch marks in the dirt are these part of the pigeon's extended phenotype 2 no these foraging signs don't affect the pigeon survival so they don't qualify as expressions of the pigeon's phenotype as for the joint extended phenotype like the beaver's dam there are other shared Expressions to look out for and they can be rather surprising one interesting case is what happens when a snail is influenced by a parasitic flatworm known as a fluke researchers have found that when a snail is carrying a fluke its shell grows thicker than those of snail S without a parasite the question then becomes is the difference in Shell thickness a response to the environment and simply the presence of the fluke or has a genetic change taken place as it turns out studies show that the thickened shell is indeed a shared expression under normal circumstances the snail shell is an expression of its own phenotype as it helps keep it protected and therefore is crucial to its survival but only so much of a snail's genetic resources can go toward the shell so it's thick and strength are limited when genes from the fluke parasite are introduced these genes will quickly multiply and make the shell as thick as it can be so that the fluke in its Offspring can Thrive this is also an interesting example because it shows how an extended phenotype can in some cases be another organism's living tissue blink number 12 in the concept of the extended phenotype the necer cube flips in this final blink let's Circle back to where we started with the visual aid of the Necker Cube this was used to illustrate two equally valid views in biology the traditional view that emphasize the individual organism and the alternate view that emphasize the genes as the elements competing for survival by this point we've seen plenty of examples of The Selfish Gene and how these act in their own interest through their extended phenotype so it should be easier for you to see both sides of the necer cube with both both perspectives on Evolution but just in case let's look at one final example the Bruce effect which we'll see in both the traditional organism Centric View and the gene Centric view the Bruce effect was discovered in a study involving mice the researchers found that female mice would terminate their current pregnancies when exposed to the scent of an unknown male Mouse in the traditional view we would say that the organism of the male Mouse manipulates the female organisms to maximize its own Fitness by causing the female to terminate a pregnancy from another mouse so that she can bear the new male Mouse's Offspring in the confusing language of conventional biology we could also say that there's a gene for this scenario we could say that this Gene which causes the female Mouse to terminate a pregnancy upon smelling the male scent was serving the organism of the male Mouse and his survival but we can also describe the Bruce effect in another way we can say that determination of pregnancy is a result of a phenotype in the male mouse that is being expressed in the actions of the female Mouse the genes in the male Mouse cause them to produce a scent which then causes the termination of pregnancy in the female Mouse and these genes are serving themselves increasing the chances of their own replication Next Generation so the behavior of the mice serves the genes not the other way around in summary we can say the following is the central theorem of of the extended phenotype an organism's Behavior will maximize the survival of the genes that create the behavior even when those genes aren't part of the organism's genome as is the example of the female Mouse you've just heard our links to Richard Dawkins X book the extended phenotype thank you for listening Professor Dawkins contends that there are two equally valid views in biology there's the conventional darwinian view that emphasizes the importance of the individual organism and sees it as the focal unit of natural selection and then there's the more modern view of the extended phenotype which emphasizes the importance of genes not organisms as the focal units of natural selection by broadening our perspective and taking both views into account we can appreciate a more complete understanding of biology well before you leave don't forget to subscribe to books in blinks and leave your thoughts in the comment section below also check out the other titles in our [Music] playlist I'm Pedro from books in blinks and I hope to see you here again