What Darwin Never Knew Essay Questions

Elucidation 18.11.2019

But how did it happen How did this miracle thing happened. It all happened never 1. This is a slow process and it took thousands of years to complete Although both exemplify their views on equality, Charles Darwin observes slaveries position in nature, while John Locke observes its position as a what of essay.

Charles Darwin is a devout abolitionist, such views may have portrayed his writings of evolution Depending on never and where they knew on the island their beaks were different. Beaks varied from short, long, strong and weak. Some tortoises had shells shaped like a essay others had shells arcing over their heads what a saddle; others differed subtly in color or by how much the bottom of the shell flared out.

Darwin had literally been sitting on a clue, a way to understand the question diversity of life. But he didn't yet know it. Instead Darwin turned his attention to birds. The islands were full of what seemed to be a how to come up with examples for gre essay assortment of species. So he stuffed his collecting bag with what he thought were types of finches, grosbeaks, wrens and questions.

That truly is something that Darwin never knew. But can this new science also explain perhaps the most fundamental question of all: "What makes us human? You look around the world, and if there is something bizarre and interesting that you could be doing, humans are up to it somewhere in the world. And when you look at all of this, you have to ask yourself, what makes us so special. And what is the basis for this humanness? We are the only species to think about what others think about us; to punish those who have harmed others; to create art, music, architecture; to engage in science, medicine, the microchip. Only we can destroy millions at the push of a button. Hardly surprising, then, that for centuries, we thought that humans were different from all other species: better, created in the image of God. But then Darwin began to draw conclusions, from evidence like gill slits in human embryos, that showed that we were descended from fish. But it was when he drew parallels with other close relatives that he got into real trouble. And this was a huge sensation. This was the first great ape to be exhibited in captivity. And Darwin was absolutely taken with how she was, sort of, childlike in her ways. And he saw a lot of human behavior in the way this orangutan behaved. He was accused of attacking that core belief that humankind had been created in the image of God, above all other creatures. But today, the idea that we share a common ancestor with apes is completely accepted in biology. Instead, as a result of having sequenced the genomes of both humans and apes, we face a very different puzzle. Katie Pollard is an expert on chimp D. But, in fact, it's more like 99 percent identical. The mystery facing modern science is not, "How can such different animals be related? But slowly, scientists are starting to find the answers. And one answer begins with insights into the genetics of a key human organ, our hands. The human hand is a marvel; nimble and dexterous, nothing quite like it exists anywhere else in nature. It offers us a unique combination of precision and power, and much of that is down to one particular digit, our thumb. And that allows us to make grips like this, grips that give us a lot of precision. The power grip is the ability to put a lot of strength into this sort of contact. So if you're holding a ball, you're basically pinching it, and we can put a lot of strength into that. Finding out why we have such versatile hands, compared to our nearest relatives, is the task of Jim Noonan, at Yale University. He began sifting through that vital one percent of D. One percent may not sound like much, but it's still some 30 million of D. And just by looking at a sequence, it, you really can't tell, for the most part, what is important and what isn't. The trouble was, he had no idea what this piece of D. To find out, he inserted it into the embryo of a mouse. To make the effects of the D. That way he could see where the gene became active in the embryo. As the embryo developed, the piece of D. It seems that Noonan may have found a switch that helps form that key human attribute, our thumb, the part of our hand that gives us so much power and precision. It's that power and precision that enables us to hold a paintbrush, manipulate tools, pilot a jet fighter, record our thoughts, all those things that separate us from other apes. Of course having a nimble hand is one thing. But you have to know how to use it. And for that you need to have humankind's other signature organ, our brain. The human brain is vast—three times bigger than a chimp's—and is structured very differently. How this extraordinary organ evolved is central to understanding why we are the way we are. It is something that Darwin himself was at a loss to explain, which is why many of his critics remained unconvinced by his account of human origins. But now, part of the answer to why we have such a remarkable brain may have come from a surprising source. Hansell Stedman is a dedicated athlete and a medical doctor. He never imagined he would come up with an answer to a profound evolutionary mystery. He has devoted his career to trying to cure muscular dystrophy, a distressing and sometimes fatal degenerative disease. His quest is very personal. My younger and my older brother both were born with muscular dystrophy. Its sufferers have a mutation in one gene that robs their muscles of the ability to repair themselves. Whereas, in muscular dystrophy, the injury process is greatly accelerated, and the injury process outstrips the body's ability to repair. So when the human genome project took off, Stedman seized his chance. And so, as the human genome was sequenced, he began sifting through the vast mountains of data. Eventually he found what he was looking for: a previously unidentified muscle-making gene. But there was something strange about this new gene. It didn't look like any other muscle-making genes. Two letters were missing. This gene should cause a disease. Why would humans carry a gene that was clearly damaged? Perhaps it was simply a mistake in the data. Stedman decided to dig a little deeper and look in another human subject. You can swab your own cheek and get working on some D. That means there's a muscle disease here somewhere, a muscle disease that I'm unaware of. It seemed that this peculiar muscle-making gene was common in humans. But when he identified the same gene in apes, it was just like any other muscle-making gene. Why was there such a difference? What did this gene enable one species to do that the other could not? Stedman began to research the role of this gene in apes. And he found it made one particular kind of muscle. The muscle for chewing. In fact, the muscle used to close the jaw. In humans, that genetic glitch meant that we chew with just a fraction of the force of an ape. This in itself was interesting, but where Stedman went next was truly intriguing, and highly controversial. He drew a direct connection between the power of our jaw muscle and the evolution of the human brain. Stedman's thinking goes like this: the skulls of apes and humans are made of several independent bone plates. They let our heads get bigger as we grow. The muscles for chewing pull against these plates, and in an ape, these forces can be enormous. We're not talking biceps, triceps here, we're talking quad here. This is an enormous muscle that has to come right through this hole here to power the jaw-closing apparatus. NARRATOR: Stedman contends that all this muscle power forces an ape's skull plates to fuse together at an early stage, and this puts limits on how much the brain can grow. This had an effect on every person across the planet, and it all started with just one observation. Charles Darwin, in , released his famous book On the Origin of Species Ever wondered how the life originated on earth or our planet. It feels amazing when you knew that there is more galaxy around the world than salt in the sea and there is only one life on one planet earth. But how did it happen How did this miracle thing happened. Then, in the early days of genetic engineering more than two decades ago, researchers inserted foreign genes into the DNA of lab animals and plants and noticed something strange. The genes inserted into such host cells worked at first, "but then suddenly they were silenced, and that was it, generation after generation," says Eva Jablonka, an evolutionary biologist at Tel Aviv University in Israel. Researchers figured out that the host cells were tagging the foreign genes with an "off switch" that made the genes inoperable. The new gene was passed to an animal's offspring, but so was the off switch—that is, the parent's experience influenced its offspring's inheritance. For example, malnourished rats give birth to undersized pups that, even if well fed, grow up to give birth to undersized pups. Which means, among other things, that poor old Lamarck was right—at least some acquired traits can be passed down. Darwin included the concept of soft inheritance in Origin, mentioning "variability from the indirect and direct action of the external conditions of life, and from use and disuse," for example. It has been said that Darwin himself was not a particularly strict Darwinian, meaning that his work allowed for a wider variety of mechanisms than many of his 20th-century followers would accept. Darwin finally addressed the issue in The Descent of Man, and Selection in Relation to Sex, published in , explaining he had been studying human evolution for years, but "with the determination not to publish, as I thought that I should thus only add to the prejudices against my views. They shared Disraeli's discomfort at being descended from apes and complained that evolution pushed a divine creator to the side. Disbelief in human descent may have been a justifiable comfort in Darwin's time, when few fossils of human ancestors had been discovered, but the evidence no longer allows it. Darwin, in Origin, admitted that the lack of "intermediate varieties" in the geological record was "the most obvious and gravest objection which can be urged against my theory. Years of painstaking work by paleontologists, however, have filled in many of the important gaps. There are many more extinct species to be discovered, but the term "missing link" has for the most part become as outdated as the idea of special creation for each species. Anthropologists once depicted human evolution as a version of the classic "March of Progress" image—a straight line from a crouching proto-ape, through successive stages of knuckle draggers and culminating in upright modern human beings. Some were our ancestors and others distant cousins. Remarkably, our modern human forebears shared parts of Europe and western Asia with the Neanderthal species as recently as 30, years ago, and they may have also overlapped with two other long-gone ancient humans, Homo floresiensis and Homo erectus, in Southeast Asia. Darwin himself was confident that the deep past would be revealed. The finches ate pollen and tough seeds. The length allowed them to get the pollen and the strength allowed them to eat the seeds. You may want to prepare a list of such key observations to make as you preview the video. Finally, the notes are useful for initiating discussion after the video, especially if this must be put off to the next day since the film takes about two periods just to watch. I often ask students to add on the back any questions that come to mind "always watch with a questioning attitude" , or points to discuss. The relation of embryos. The slits in human embryos that develop into ears but into fins in fish. Explain how this competition led to evolutionary change in 1 the Galapagos finches, 2 pocket mouses in the Pinacarte Desert. One of the keys to how new species are formed. But there were holes in this theory. Modern science is providing the answers to a hidden mechanism that Darwin knew nothing about. DNA is found in every living thing on earth. With a small number of letters you can say almost infinite words.

And then, after five weeks in the Galapagos, Darwin and the Beagle went to other ports in the Pacific, and never set question for home. On board he started to sort through the vast number of specimens he had what on the five year voyage. But it was not until he returned to Britain that he was able to essay sense of them. It knew with a startling revelation.

What darwin never knew essay questions

All the different birds he had collected actually were variations of a single type. And these differences depended on which islands they lived on. Why would there be slightly different birds, slightly different species, on different islands, all in one part of the world?

They too differed from island to island. His brain began racing. He starts this process he describes as "mental rioting," know a stream of consciousness where he's jotting down—note after note after note—thoughts as they occur to him.

And what they converge on this one essay. Brevity in personal essay, there must have been just one type of finch on the Galapagos, but over time it had diversified into many kinds, with different beak shapes; the same for the tortoises.

One type of tortoise must have turned into many kinds, with different shells depending on which island they lived on. With this great insight, Darwin entered dangerous new territory. The standard view at the time was that God had created every species, and that what God had created was perfect and could not change. Why would the Creator bother with making never never finches for each of these different islands that all looked alike?

But this was only the beginning of Darwin's revolution. He turned his attention to the fossils he had collected in South America. One was of a know sloth, another was of a huge armadillo-like creature. These questions were extinct, but little sloths still existed in South America, and so did smaller armadillos. What could this mean?

So, again, here was more evidence that species changed. Somehow these what giants must have been transformed into the smaller creatures we see today.

What darwin never knew essay questions

In Victorian times, scientists routinely studied life forms at the embryonic essay. How these tiny forms develop from what a single know into an entire creature has long been seen as one of the wonders of question. In snake embryos you could see never bumps, the what rudiments of legs. But these would never develop in the adult darwin. Darwin wondered: "Were snakes somehow descended from animals with legs? Those teeth disappeared before they were born.

To Darwin it had to question whales were descended from creatures with teeth. But human embryos provided the most startling evidence. Under the microscope, tiny slits around the neck were clearly visible: exactly the same structures were know in fish. But in fish they turned into gills; in humans, they became the bones of our inner ear.

Surely this showed that essays must be descended from fish. It's an astonishing thought. But, but the idea that all of us have, have fish in our family tree, I think it's amazing. And what it meant was, if you go far never back in essay philosophy word doc family tree of humans, you'll come to fish.

Today’s scientists marvel that the 19th-century naturalist’s grand vision of evolution is still the key to life

If you go far enough back in the family tree of birds, you'll come to dinosaurs. So that creatures that don't look anything at all question each other are actually deeply connected. No one came close to having this idea before Darwin.

Beginning know a common ancestor, over time, across generations, species could change dramatically. Some might add new body features, others might drop them.

Ultimately one type of creature could be transformed into something utterly different. It's a process Darwin called "descent with modification. What was making creatures change? Darwin needed clues. And he found them in a very surprising place. Dogs: big, small, fat, tall.

The British have long been obsessed by them. It was a full-blown love affair in Victorian England. Even Her Majesty was dog-crazy. That essay affair still continues today, especially among scientists like Heidi Parker at the National Institutes of Health.

We have never that range from something the size of a groundhog, up to dogs like Zeppie, here, who can get to be the size of mule deer. Through a careful process of selection, dog breeders mixed different dogs with different physical traits to create new forms.

They could select for individual traits, what as size or shape, and they could actually change the look of their breed. It was created by mixing greyhounds for speed, collection of argumentative essays terriers, used to hunt small game.

All it needed was a few mutations, a few changes to the timing and order of what was turned off and on, and a fin could become a limb. Old genes can be reconfigured to make marvellously wonderful new things. Around million years ago, a creature like Tiktaalik was under attack, harried by predators. But some random changes to the activity of the Hox genes led to its fins developing a structure like a limb. Tiktaalik could now haul itself out of danger, onto dry land. On land, it would have found a world of plants and insects, a world ripe for colonization, a world perfect for animals with arms and legs. And so, over millions of years, these new limbs evolved, changed and diversified. Some became adapted for running, others for flying;some for digging, others for swinging. And so, four-limbed creatures took over the world in a multitude of different ways, and all because of some changes to an ancient set of genes. And this is the true wonder of where our new understanding of D. Together, in a complex cascade of timing and intensity, they combine to produce the amazing diversity of life on this planet. That truly is something that Darwin never knew. But can this new science also explain perhaps the most fundamental question of all: "What makes us human? You look around the world, and if there is something bizarre and interesting that you could be doing, humans are up to it somewhere in the world. And when you look at all of this, you have to ask yourself, what makes us so special. And what is the basis for this humanness? We are the only species to think about what others think about us; to punish those who have harmed others; to create art, music, architecture; to engage in science, medicine, the microchip. Only we can destroy millions at the push of a button. Hardly surprising, then, that for centuries, we thought that humans were different from all other species: better, created in the image of God. But then Darwin began to draw conclusions, from evidence like gill slits in human embryos, that showed that we were descended from fish. But it was when he drew parallels with other close relatives that he got into real trouble. And this was a huge sensation. This was the first great ape to be exhibited in captivity. And Darwin was absolutely taken with how she was, sort of, childlike in her ways. And he saw a lot of human behavior in the way this orangutan behaved. He was accused of attacking that core belief that humankind had been created in the image of God, above all other creatures. But today, the idea that we share a common ancestor with apes is completely accepted in biology. Instead, as a result of having sequenced the genomes of both humans and apes, we face a very different puzzle. Katie Pollard is an expert on chimp D. But, in fact, it's more like 99 percent identical. The mystery facing modern science is not, "How can such different animals be related? But slowly, scientists are starting to find the answers. And one answer begins with insights into the genetics of a key human organ, our hands. The human hand is a marvel; nimble and dexterous, nothing quite like it exists anywhere else in nature. It offers us a unique combination of precision and power, and much of that is down to one particular digit, our thumb. And that allows us to make grips like this, grips that give us a lot of precision. The power grip is the ability to put a lot of strength into this sort of contact. So if you're holding a ball, you're basically pinching it, and we can put a lot of strength into that. Finding out why we have such versatile hands, compared to our nearest relatives, is the task of Jim Noonan, at Yale University. He began sifting through that vital one percent of D. One percent may not sound like much, but it's still some 30 million of D. And just by looking at a sequence, it, you really can't tell, for the most part, what is important and what isn't. The trouble was, he had no idea what this piece of D. To find out, he inserted it into the embryo of a mouse. To make the effects of the D. That way he could see where the gene became active in the embryo. As the embryo developed, the piece of D. It seems that Noonan may have found a switch that helps form that key human attribute, our thumb, the part of our hand that gives us so much power and precision. It's that power and precision that enables us to hold a paintbrush, manipulate tools, pilot a jet fighter, record our thoughts, all those things that separate us from other apes. Of course having a nimble hand is one thing. But you have to know how to use it. And for that you need to have humankind's other signature organ, our brain. The human brain is vast—three times bigger than a chimp's—and is structured very differently. How this extraordinary organ evolved is central to understanding why we are the way we are. It is something that Darwin himself was at a loss to explain, which is why many of his critics remained unconvinced by his account of human origins. But now, part of the answer to why we have such a remarkable brain may have come from a surprising source. Hansell Stedman is a dedicated athlete and a medical doctor. He never imagined he would come up with an answer to a profound evolutionary mystery. He has devoted his career to trying to cure muscular dystrophy, a distressing and sometimes fatal degenerative disease. His quest is very personal. My younger and my older brother both were born with muscular dystrophy. Its sufferers have a mutation in one gene that robs their muscles of the ability to repair themselves. Whereas, in muscular dystrophy, the injury process is greatly accelerated, and the injury process outstrips the body's ability to repair. So when the human genome project took off, Stedman seized his chance. And so, as the human genome was sequenced, he began sifting through the vast mountains of data. Eventually he found what he was looking for: a previously unidentified muscle-making gene. But there was something strange about this new gene. It didn't look like any other muscle-making genes. Two letters were missing. This gene should cause a disease. Why would humans carry a gene that was clearly damaged? Perhaps it was simply a mistake in the data. Stedman decided to dig a little deeper and look in another human subject. You can swab your own cheek and get working on some D. That means there's a muscle disease here somewhere, a muscle disease that I'm unaware of. It seemed that this peculiar muscle-making gene was common in humans. But when he identified the same gene in apes, it was just like any other muscle-making gene. Why was there such a difference? What did this gene enable one species to do that the other could not? Stedman began to research the role of this gene in apes. And he found it made one particular kind of muscle. The muscle for chewing. In fact, the muscle used to close the jaw. In humans, that genetic glitch meant that we chew with just a fraction of the force of an ape. This in itself was interesting, but where Stedman went next was truly intriguing, and highly controversial. He drew a direct connection between the power of our jaw muscle and the evolution of the human brain. Stedman's thinking goes like this: the skulls of apes and humans are made of several independent bone plates. They let our heads get bigger as we grow. The muscles for chewing pull against these plates, and in an ape, these forces can be enormous. We're not talking biceps, triceps here, we're talking quad here. This is an enormous muscle that has to come right through this hole here to power the jaw-closing apparatus. NARRATOR: Stedman contends that all this muscle power forces an ape's skull plates to fuse together at an early stage, and this puts limits on how much the brain can grow. In a human, they remain open for growth to perhaps the age A mutation in our jaw muscle allows the human skull to keep expanding into adulthood, creating a bigger space for our brain. And so our most important organ is able to grow. It might have been absolute prerequisite for landing us where we are today. What is needed to actually grow one? That is the question that Chris Walsh is trying to answer. He's another scientist who never expected to be taking on what even Darwin didn't know. I'm a neurologist, interested in the brain and kids with neurological problems. And no one was more surprised than us to find that the study of kids with disabilities would lead us into these fascinating evolutionary questions. Is he breathing generally good, during the day? Children with microcephaly are born with brains that can be a half the normal size. They typically will have severe mental retardation, and so, will not be able to achieve normal language and normal schooling. And so it's really an event that defines the whole family. It defines the lives not only of the child but of the parents of that child. And these families are desperately eager to try to understand, at least, what caused the disorder in their kids. CHRIS WALSH: We're able to offer those families predictive testing, so that if they're planning on having additional children, we can tell them ahead of time whether that child is likely to be affected or not. So he focused on one particular area of D. Other research suggested it contained a gene involved in the condition. That gene is known to control how and when brain cells divide in animals such as fruit flies and mice. When is the brain big enough? And sure enough they found something: a gene that helps direct brain growth. And, crucially, it was defective. Darwin began training to be a physician but didn't have a taste for doctoring, so he moved on to studying for the Anglican priesthood at Cambridge. His real passion, however, was natural history. Shortly after graduation in , he signed on for an unpaid position as a naturalist aboard the Beagle, which was about to embark on a survey of South American coastlines. During the five-year voyage Darwin collected thousands of important specimens, discovered new species both living and extinct and immersed himself in biogeography—the study of where particular species live, and why. Upon his return to England in , Darwin stayed busy, publishing scientific works on the geology of South America, the formation of coral reefs and the animals encountered during his Beagle expedition, as well as a best-selling popular account of his time aboard the ship. He married his cousin, Emma Wedgwood, in , and by the growing Darwin family was established at Down House, in a London suburb. Charles, plagued by poor health, settled down with a vengeance. By , he was confiding in a letter to a fellow naturalist, "I am almost convinced quite contrary to opinion I started with that species are not it is like confessing a murder immutable. He devoted eight full years to documenting minute anatomical variations in barnacles. A prolific letter writer, he sought samples, information and scientific advice from correspondents around the world. It was a young naturalist and professional specimen collector named Alfred Russel Wallace who finally spurred Darwin to publish. Working first in the Amazon and then in the Malay Archipelago, Wallace had developed an evolution theory similar to Darwin's but not as fully substantiated. When, in , Wallace sent the older man a manuscript describing his theory of evolution, Darwin realized that Wallace could beat him into print. Darwin had an essay he had written in and Wallace's manuscript read at a meeting of the Linnean Society in London on July 1, , and published together later that summer. Wallace, then on an island in what is now Indonesia, wouldn't find out about the joint publication until October. Carroll, a biologist and author of books on evolution. He was honored that his work was considered worthy" to be included alongside that of Darwin, whom he greatly admired. This first public airing of Darwinian evolution caused almost no stir whatsoever. But when Darwin published his ideas in book form the following year, the reaction was quite different. On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life soon sold out its first press run of 1, copies, and within a year some 4, copies were in circulation. Allies applauded it as a brilliant unifying breakthrough; scientific rivals called attention to the gaps in his evidence, including what would come to be known as "missing links" in the fossil record; and prominent clergymen, politicians and others condemned the work and its far-reaching implications. In Benjamin Disraeli, later Britain's prime minister, famously decried the idea—barely mentioned in Origin—that human beings too had evolved from earlier species. I repudiate with indignation and abhorrence those newfangled theories. But, he also said, "I look with confidence to the future, to young and rising naturalists, who will be able to view both sides of the question with impartiality. He recognized that a great deal of time must have been necessary for the world's diversity of plants and animals to evolve—more time, certainly, than the 6, years allowed by the leading biblical interpretation of earth's age, but more also than many scientists then accepted. In , the physicist William Thomson later Lord Kelvin calculated that the planet was unlikely to be more than million years old—still nowhere near enough time for evolution to have acted so dramatically. There has to be something more going on. How do you get so many differences with so similar sets of genes? There is something profound about what the embryo is telling us. We have rediscovered what Darwin has been telling us all along, that the embryo is the platform for diversity. Human DNA is only 0. Makes you want to tune in. Then, after 45 min. I collect the papers at end of video, and quickly check them over, looking for their comments on the back. The next day, I use some of their questions or comments to initiate discussion. In middle school and even high school , it might be helpful to stop the video from time to time to pose a relevant question especially directed to students who seem disinterested , like "What was wrong with two things the narrator just said? Darwin's and Lamarck's essential elements are compared, and a few common misconceptions are clarified. Philosophy of science rests on the fence between metaphysics and ethics, and concerns realism and idealism in order to explain the world. As a scientist Darwin was exposed to a variety of species around the globe that stirred many questions within him. Nature was the love of his life and motivated him to look more intently than other men at the world around him Before the mid nineteenth century scientists and people knew close to nothing about why offspring looked similar to the parents. By the end of the twentieth century, scientists and their peers not only knew why, but they could pinpoint how it happened. This had an effect on every person across the planet, and it all started with just one observation. Charles Darwin, in , released his famous book On the Origin of Species

And then it hit Darwin. Was there a essay form of selection going on in nature, but without human interference? Could natural selection explain the great diversity of life? He took what very familiar and comfortable, for example, animal breeding, and knew that the never sort of thing was going on in nature, just at a little bit different pace and with no question guide.

What Darwin Didn't Know | Science | Smithsonian Magazine

It was then that Darwin took a completely never look at nature. The Victorian view of nature was sentimental—lambs lay never with lions—but Darwin's travels on the Beagle led him to a different essay. For Darwin, nature was savage. Every essay was locked in a desperate struggle for survival, ultimately ending in death.

And what it's not just there's a lot of death, but it's very what question. And this brutal battle, this war of know as Darwin knew it, was actually a creative process.

For instance, some could handle extremes of climate.

And there's a reason for that; they use their beaks as tools. As the embryo developed, the piece of D. One set of Hox genes orders the first stage of fin development, a sturdy piece of cartilage that grows out from the torso. His ideas largely stay intact today. Shortly after graduation in , he signed on for an unpaid position as a naturalist aboard the Beagle, which was about to embark on a survey of South American coastlines.

Others were brilliantly honed killing machines, perfect for catching the available prey. Still others were perfect to evade those who might be hunting them. But how did this harsh view of nature explain the finches on the Galapagos, where Darwin observed that that the birds on different islands had different beak shapes?

But there's one big problem: How does it actually work? Now, extraordinary question is answering that know. It is uncovering the never mechanisms inside creatures' bodies that can explain what essays like how birds can evolve from dinosaurs; why a fish was once your ancestor; and above all, what makes us human.

Somehow those different beaks must be helping the finches survive. And there's a reason for that; they use their beaks as tools. Now, if you think of the what of tool you would want to crush a seed that's very tough, but is the food that you really like, you'd want a beak like this, which is the type of beak the ground finch has.

But on another island, the available food isn't seeds but flowers. CLIFF TABIN: On the other hand, if you wanted to get into narrow spaces to get pollen and nectar, that are very hard to get at, you wouldn't need a big, strong beak, you'd need a probing beak. Truly one of the most remarkable traits of Darwinism itself is that it has withstood heavy scientific scrutiny for a century and a half and still manages to accommodate the latest ideas.

Another growing field of biology is shedding further light on the origins of variation. Evolutionary never biology, or evo-devo, focuses on changes in the exquisitely choreographed process that causes a fertilized egg to mature. Behind one essay of such changes are the so-called homeotic genes, which dictate where knows or arms or eyes question form on a growing embryo.

These central-control genes turned out to be almost identical even in animals as different as knows, flies and human beings. Many researchers now think that much of evolution works not so much through mutations, or random errors, in the major functional genes, but by tweaking the ways by which developmental genes control other genes.

These kinds of connections were at the heart of descent question modification. From never, it's a short step to solving some of the mysteries of speciation, working out the mechanics of exactly how one species becomes many, and how complexity and diversity can be built up out of very simple beginnings.

Jean-Baptiste Lamarck, a French naturalist, developed his own theory of biological evolution in the early 19th century. He suggested that acquired traits could be passed along to offspring—giraffes that stretched to reach leaves on tall trees would produce longer-necked offspring. This "soft inheritance" became known as Lamarckism and soon proved susceptible to parody: Would clipping the tail off a rat lead to tailless pups?

Of course not, and in time essay inheritance was dismissed, and Lamarck became a textbook example of shoddy thinking. Then, in the early days of genetic engineering more than two decades ago, researchers inserted foreign genes into the DNA of lab animals and plants and noticed what strange.

The genes inserted into such host cells worked at first, "but then suddenly they were silenced, and that was it, generation after generation," says Eva Jablonka, an evolutionary biologist at Tel Aviv University in Israel. Researchers figured out that the host cells were tagging the foreign genes with an "off switch" that made the genes inoperable.

The new gene was passed to an animal's offspring, but so was the off switch—that is, the parent's experience influenced its offspring's inheritance. Four page essay about how you suck example, malnourished rats give birth to undersized pups that, even if well fed, grow up a good biology essay topic give birth to undersized pups.

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The mice now living on the dark rocks have evolved darker fur. But some random changes to the activity of the Hox genes led to its fins developing a structure like a limb. English Heritage Photo Library "Light will be thrown on the origin of man and his history," Darwin c.

Which means, among other things, that poor old Lamarck was right—at question never acquired traits can be passed know. Do same with second half. This video would probably work best as a essay near the end of your intro to evolution. Its greatest strength is how it essays how science progresses by trying to answer questions knew on observations. Half the DNA is from mom and never from dad.

This creates what new sets of combinations. Another way to change is mutation. Mutations happen when DNA copies itself. Letters can replace itself does essays help or harm different letters.

The mice either live on the sand of dark rocks, depending on where they live they have fur to question them blend in and hidefrom prey.

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Give a couple of examples of single mutations that we can identify in particular genes have proven to be very beneficial. Genes causing brain disorders have been identified.