Books, Brochures, and Chapters>Book:  Coyne , Jerry A. (January 22, 2009), Why Evolution Is True, Penguin (Non-Classics), Retrieved on 2011-09-15
Folksonomies: evolution evidence creationism

Memes

15 SEP 2011

 Evolution is Personal

Among the wonders that science has uncovered about the universe in which we dwell, no subject has caused more fascination and fury than evolution. That is probably because no majestic galaxy or fleeting neutrino has implications that are as personal. Learning about evolution can transform us in a deep way. It shows us our place in the whole splendid and extraordinary panoply of life. It unites us with every living thing on the Earth today and with myriads of creatures long dead. Evolution giv...
Folksonomies: evolution
Folksonomies: evolution
  1  notes

The story of evolution is captivating precisely because it is so connected to us.

16 SEP 2011

 DNA as Evidence of Common Ancestry

By sequencing the DNA of various species and measuring how similar these sequences are, we can reconstruct their evolutionary relationships. This is done by making the entirely reasonable assumption that species having more similar DNA are more closely related—that is, their common ancestors lived more recently. These molecular methods have not produced much change in the pre-DNA-era trees of life: both the visible traits of organisms and their DNA sequences usually give the same informatio...
Folksonomies: evolution evidence
Folksonomies: evolution evidence
  1  notes

The idea of common ancestry leads naturally to powerful and testable predictions about evolution.

16 SEP 2011

 Design As Evidence of Evolution or Creation

It’s important to realize, though, that there’s a real difference in what you expect to see if organisms were consciously designed rather than if they evolved by natural selection. Natural selection is not a master engineer, but a tinkerer. It doesn’t produce the absolute perfection achievable by a designer starting from scratch, but merely the best it can do with what it has to work with. Mutations for a perfect design may not arise because they are simply too rare. The African rhinoce...
  1  notes

There's a big difference between how species would look if they were designed or engineered versus how they would look if they evolved. Evolution works with pre-existing traits, and engineer works from scratch.

16 SEP 2011

 Big History: A Summary of Evolution of Life on Earth

The first organisms, simple photosynthetic bacteria, appear in sediments about 3.5 billion years old, only about a billion years after the planet was formed. These single cells were all that occupied the Earth for the next two billion years, after which we see the first simple “eukaryotes”: organisms having true cells with nuclei and chromosomes. Then, around 600 million years ago, a whole gamut of relatively simple but multicelled organisms arise, including worms, jellyfish, and sponges....
Folksonomies: evolution big history
Folksonomies: evolution big history
  1  notes

A good summary of the origin of life on Earth evolving all the way up to human beings.

16 SEP 2011

 Birds to Reptiles

Because reptiles appear in the fossil record before birds, we can guess that the common ancestor of birds and reptiles was an ancient reptile, and would have looked like one. We now know that this common ancestor was a dinosaur. Its overall appearance would give few clues that it was indeed a “missing link”—that one lineage of descendants would later give rise to all modern birds, and the other to more dinosaurs. Truly birdlike traits, such as wings and a large breastbone for anchoring ...
Folksonomies: evolution
Folksonomies: evolution
  1  notes

Birds and reptiles share many resemblances, meaning they have a common ancestor, which is dinosaurs.

16 SEP 2011

 Evolutionary Theory Prediction Comes True in Walking Fish

This is where the prediction comes in. If there were lobe-finned fishes but no terrestrial vertebrates 390 million years ago, and clearly terrestrial vertebrates 360 million years ago, where would you expect to find the transitional forms? Somewhere in between. Following this logic, Shubin predicted that if transitional forms existed, their fossils would be found in strata around 375 million years old. Moreover, the rocks would have to be from freshwater rather than marine sediments, because ...
Folksonomies: evolution prediction
Folksonomies: evolution prediction
  1  notes

Tiktaalik was discovered right where evolution predicted it should exist, with traits that brought it closer to land without making it onto land, creating another fossil prediction for the future.

16 SEP 2011

 Hippopotamus as Closest Relative to the Whale

good candidate is the hippopotamus, which, although closely related to terrestrial mammals, is about as aquatic as a land mammal can get. (There are two species, the pygmy hippo and the “regular” hippo, whose scientific name is, appropriately, Hippopotamus amphibius.) Hippos spend most of their time submerged in tropical rivers and swamps, surveying their domain with eyes, noses, and ears that sit atop their head, all of which can be tightly closed underwater. Hippos mate in the water, an...
Folksonomies: evolution transition
Folksonomies: evolution transition
  1  notes

A list of the traits hippos exhibit that make the land mammal a likely candidate for being related to the whale.

16 SEP 2011

 Evolution of the Whale

Indohyus was not the ancestor of whales, but was almost certainly its cousin. But if we go back four million more years, to fifty-two million years ago, we see what might well be that ancestor. It is a fossil skull from a wolf-sized creature called Pakicetus, which is a bit more whale-like than Indohyus, having simpler teeth and more whale-like ears. Pakicetus still looked nothing like a modern whale, so if you had been around to see it, you wouldn’t have guessed that it or its close relati...
  1  notes

Species by species list of the links from ancient land mammals to the whale.

16 SEP 2011

 Clarification of the Term "Vestigial"

Opponents of evolution always raise the same argument when vestigial traits are cited as evidence for evolution. “The features are not useless,” they say. “They are either useful for something, or we haven’t yet discovered what they’re for.” They claim, in other words, that a trait can’t be vestigial if it still has a function, or a function yet to be found. But this rejoinder misses the point. Evolutionary theory doesn’t say that vestigial characters have no function. A trai...
Folksonomies: evolution vestigial traits
Folksonomies: evolution vestigial traits
  1  notes

A trait is vestigial not because it no longer serves a purpose, but because it no longer serves its original purpose.

16 SEP 2011

 Vestigial Traits in Humans

Our bodies teem with other remnants of primate ancestry. We have a vestigial tail: the coccyx, or the triangular end of our spine, that’s made of several fused vertebrae hanging below our pelvis. It’s what remains of the long, useful tail of our ancestors. It still has a function (some useful muscles attach to it), but remember that its vestigiality is diagnosed not by its usefulness but because it no longer has the function for which it originally evolved. Tellingly, some humans have a r...
Folksonomies: evolution vestigial
Folksonomies: evolution vestigial
  1  notes

Remnants of a tail, muscles that serve no purpose, etc.

16 SEP 2011

 Atavism In Modern Horses

Modern horses, which descend from smaller, five-toed ancestors, show similar atavisms. The fossil record documents the gradual loss of toes over time, so that in modern horses only the middle one—the hoof—remains. It turns out that horse embryos begin development with three toes, which grow at equal rates. Later, however, the middle toe begins to grow faster than the other two, which at birth are left as thin “splint bones” along either side of the leg. (Splint bones are true vestigia...
Folksonomies: evolution atavism
Folksonomies: evolution atavism
  1  notes

Modern horses have a common birth defect of growing extra toes from when their ancestors had them.

16 SEP 2011

 Hen's Teeth

Some atavisms can be produced in the laboratory. The most amazing of these is that paragon of rarity, hen’s teeth. In 1980, E. J. Kollar and C. Fisher at the University of Connecticut combined the tissues of two species, grafting the tissue lining the mouth of a chicken embryo on top of tissue from the jaw of a developing mouse. Amazingly, the chicken tissue eventually produced tooth-like structures, some with distinct roots and crowns! Since the underlying mouse tissue alone could not prod...
Folksonomies: evolution vestigial atavism
Folksonomies: evolution vestigial atavism
  1  notes

An experiment from 1980 that stimulated hens to grow teeth by triggering a gene holdover from their ancient reptilian ancestors.

16 SEP 2011

 Vestigial GLO Pseudogene

And the evolutionary prediction that we’ll find pseudogenes has been fulfilled—amply. Virtually every species harbors dead genes, many of them still active in its relatives. This implies that those genes were also active in a common ancestor, and were killed off in some descendants but not in others. Out of about 30,000 genes, for example, we humans carry more than 2,000 pseudogenes. Our genome—and that of other species— are truly well populated graveyards of dead genes. The most fam...
  1  notes

Used to produce Vitamin C, alive in most mammals, but dead in humans, primates, and others.

16 SEP 2011

 Dolphins have Genes for Smelling

Another curious tale of dead genes involves our sense of smell, or rather our poor sense of smell, for humans are truly bad sniffers among land mammals. Nevertheless, we can still recognize over 10,000 different odors. How can we accomplish such a feat? Until recently, this was a completely mystery. The answer lies in our DNA—in our many olfactory receptor (OR) genes. [...] Our own sense of smell comes nowhere close to that of mice. One reason is that we express fewer OR genes—only abou...
  1  notes

Yet, as aquatic mammals, they have no need to smell anything.

16 SEP 2011

 Ontogeny Recapitulates Phylogeny

Now, we’re not absolutely sure why some species retain much of their evolutionary history during development. The “adding new stuff onto old” principle is just a hypothesis—an explanation for the facts of embryology. It’s hard to prove that it was easier for a developmental program to evolve one way rather than another. But the facts of embryology remain, and make sense only in light of evolution. All vertebrates begin development looking like embryonic fish because we all descended...
  1  notes

Embryos go through the stages of the evolution of their ancestors as they develop.

16 SEP 2011

 Human Fetuses Develop Useless Hair

One of my favorite cases of embryological evidence for evolution is the furry human fetus. We are famously known as “naked apes” because, unlike other primates, we don’t have a thick coat of hair. But in fact for one brief period we do—as embryos. Around sixth months after conception, we become completely covered with a fine, downy coat of hair called lanugo. Lanugo is usually shed about a month before birth, when it’s replaced by the more sparsely distributed hair with which we’r...
  1  notes

That appears at the same time in development as it does in Chimpanzees, but then vanishes.

16 SEP 2011

 The Flounder's Eye

A good example of bad design is the flounder, whose popularity as an eating fish (Dover sole, for instance) comes partly from its flatness, which makes it easy to bone. There are actually about 500 species of flatfish— halibut, turbot, flounders, and their kin—all placed in the order Pleuronectiformes. The word means “side-swimmers,” a description that’s the key to their poor design. Flatfish are born as normal-looking fish that swim vertically, with one eye placed on each side of a...
Folksonomies: evolution design
Folksonomies: evolution design
  1  notes

A fantastic example of bad design as it moves from one side of the fish's head to the other.

16 SEP 2011

 Convergent Evolution in Cacti and Succulents

Let’s begin with one observation that strikes anyone who travels widely. If you go to two distant areas that have similar climate and terrain, you find different types of life. Take deserts. Many desert plants are succulents: they show an adaptive combination of traits that include large fleshy stems to store water, spines to deter predators, and small or missing leaves to reduce water loss. But different deserts have different types of succulents. In North and South America, the succulents...
  1  notes

The two groups of species share many many traits, but they exist in completely different parts of the world, evolving separately, but converging to be almost interchangeable.

20 SEP 2011

 The Asian Giant Hornet

One of the marvels of evolution is the Asian giant hornet, a predatory wasp especially common in Japan. It’s hard to imagine a more frightening insect. The world’s largest hornet, it is as long as your thumb, with a two-inch body bedecked with menacing orange and black stripes. It’s armed with fearsome jaws to clasp and kill its insect prey, and also a quarter-inch stinger that proves lethal to several dozen Asians a year. And with a 3-inch wingspan, it can fly 25 miles per hour (far fa...
Folksonomies: evolution hornet bee
Folksonomies: evolution hornet bee
  1  notes

European honeybees are defenseless against this predator, but Asian honeybees have evolved an amazing counter attack.

20 SEP 2011

 Dogs are Evolved from Wolves Through Artificial Selection

Take the domestic dog (Canis lupus familiaris), a single species that comes in all shapes, sizes, colors, and temperaments. Every single one, purebred or mutt, descends from a single ancestral species—most likely the Eurasian gray wolf—that humans began to select about 10,000 years ago. The American Kennel Club recognizes 150 different breeds, and you’ve seen many of them: the tiny, nervous Chihuahua, perhaps bred as a food animal by the Toltec of Mexico; the robust Saint Bernard, thick...
Folksonomies: evolution breeding dogs
Folksonomies: evolution breeding dogs
  1  notes

Breeders are able to sculpt dogs into whatever they desire. Experimental proof of evolution.

20 SEP 2011

 Examples of Species Evolved through Human Artificial Sele...

The dog can stand for the success of other breeding programs. As Darwin noted in The Origin, “Breeders habitually speak of an animal’s organization as something quite plastic, which they can model almost as they please.” Cows, sheep, pigs, flowers, vegetables, and so on—all came from humans choosing variants present in wild ancestors, or variants that arose by mutation during domestication. Through selection, the svelte wild turkey has become our docile, meaty, and virtually tasteless...
  1  notes

Turkeys, corn, broccoli, tomatoes, etc, etc, all bred from wild species into their modern domesticated forms.

20 SEP 2011

 Bacteria Evolve to Process Lactose in a Test Tube

But “laboratory” adaptations can also be more complex, involving the evolution of whole new biochemical systems. Perhaps the ultimate challenge is simply to take away a gene that a microbe needs to survive in a particular environment, and see how it responds. Can it evolve a way around this problem? The answer is usually yes. In a dramatic experiment, Barry Hall and his colleagues at the University of Rochester began a study by deleting a gene from E. coli. This gene produces an enzyme th...
Folksonomies: evolution experiment
Folksonomies: evolution experiment
  1  notes

Scientists blocked a gene for digesting lactose in bacteria, which then mutated to have the digestive function taken over by another gene producing an enzyme, which then got progressively selected for efficiency.

20 SEP 2011

 Speciesization in a Test Tube

We can even see the origin of new, ecologically diverse bacterial species, all within a single laboratory flask. Paul Rainey and his colleagues at Oxford University placed a strain of the bacteria Pseudomonas fluorescens in a small vessel containing nutrient broth, and simply watched it. (It’s surprising but true that such a vessel actually contains diverse environments. Oxygen concentration, for example, is highest on the top and lowest on the bottom.) Within ten days—no more than a few ...
Folksonomies: evolution experiment
Folksonomies: evolution experiment
  1  notes

Bacteria evolve into different species in order to adapt to the different environments at the bottom and top of a test tube.

20 SEP 2011

 Penicilin Resistant Staphylococcus

Another prime example of selection is resistance to penicillin. When it was introduced in the early 1940s, penicillin was a miracle drug, especially effective at curing infections caused by the bacteria Staphylococcus aureus (“staph”). In 1941, the drug could wipe out every strain of staph in the world. Now, seventy years later, more than 95 percent of staph strains are resistant to penicillin. What happened was that mutations occurred in individual bacteria that gave them the ability to ...
Folksonomies: evolution resistance
Folksonomies: evolution resistance
  1  notes

Evolution in action.

20 SEP 2011

 Resistance to Insecticides and Herbicides as Evolution

Still other species have adapted via selection to human-caused changes in their environment. Insects have become resistant to DDT and other pesticides, plants have adapted to herbicides, and fungi, worms, and algae have evolved resistance to heavy metals that have polluted their environment. There almost always seem to be a few individuals with lucky mutations that allow them to survive and reproduce, quickly evolving a sensitive population into a resistant one. We can then make a reasonable ...
Folksonomies: evolution resistance
Folksonomies: evolution resistance
  1  notes

If plants and insects can evolve resistance to these human-induced selective pressures, then we may assume they evolve to other natural environmental pressures as well.

20 SEP 2011

 Evolution Predicts the Flowering of Mustard Plants

Here’s another prediction: under prolonged drought, natural selection will lead to the evolution of plants that flower earlier than their ancestors. This is because, during a drought, soils dry out quickly after the rains. If you’re a plant that doesn’t flower and produce seeds quickly in a drought, you leave no descendants. Under normal weather conditions, on the other hand, it pays to delay flowering so that you can grow larger and produce even more seeds. This prediction was tested ...
Folksonomies: evolution predictions
Folksonomies: evolution predictions
  1  notes

Scientists predict how a drought will affect the flowering time of plants in California, and it comes true.

20 SEP 2011

 Evolution in the Laboratory Occurs Very Quickly

One approach is to compare the rates of evolution in the fossil record with those seen in laboratory experiments that used artificial selection, or with historical data on evolutionary change that occurred when species colonized new habitats in historical times. If evolution in the fossil record were much faster than in laboratory experiments or colonization events—both of which involve very strong selection—we might need to rethink whether selection could explain changes in fossils. But ...
Folksonomies: evolution experimentation
Folksonomies: evolution experimentation
  1  notes

So quickly in fact that scientists could turn an elephant into a mouse in just 10,000 years.

20 SEP 2011

 Evolution of the Eye

A possible sequence of such changes begins with simple eyespots made of light-sensitive pigment, as seen in flatworms. The skin then folds in, forming a cup that protects the eyespot and allows it to better localize the light source. Limpets have eyes like this. In the chambered nautilus, we see a further narrowing of the cup’s opening to produce an improved image, and in ragworms the cup is capped by a protective transparent cover to protect the opening. In abalones, part of the fluid in t...
Folksonomies: evolution links process
Folksonomies: evolution links process
  1  notes

A simple series of adaptive steps explain the evolution of eyes over time.

20 SEP 2011

 Evolution Takes Time

True, breeders haven’t turned a cat into a dog, and laboratory studies haven’t turned a bacterium into an amoeba (although, as we’ve seen, new bacterial species have arisen in the lab). But it is foolish to think that these are serious objections to natural selection. Big transformations take time—huge spans of it. To really see the power of selection, we must extrapolate the small changes that selection creates in our lifetime over the millions of years that it has really had to work...
Folksonomies: evolution time
Folksonomies: evolution time
  1  notes

A river formed the Grand Canyon, so we know that small processes can have huge effects given enough time.

20 SEP 2011

 Postmating Competition

Sexual selection doesn’t end with the sex act itself: males can continue to compete even after mating. In many species, females mate with more than one male over a short period of time. After a male inseminates a female, how can he prevent other males from fertilizing her and stealing his paternity? This postmating competition has produced some of the most intriguing features built by sexual selection. Sometimes a male hangs around after mating, guarding his female against other suitors. Wh...
  1  notes

Various evolutionary strategies males of different species keep a female from mating with other males after sex.

20 SEP 2011

 Mating Strategies of Males and Females

A vivid demonstration of this difference can be seen by looking up the record number of children sired by a human female versus a male. If you were to guess the maximum number of children that a woman could produce in a lifetime, you’d probably say around fifteen. Guess again. The Guinness Book of World Records gives the “official” record number of children for a woman as sixty-nine, produced by an eighteenth century Russian peasant. In twenty-seven pregnancies between 1725 and 1745, sh...
  1  notes

A Great summary of the differences between them evolutionarily.

20 SEP 2011

 Taxonomies are Not Arbitrary, but Factual

Mayr lived exactly 100 years, producing a stream of books and papers up to the day of his death. Among these was his 1963 classic, Animal Species and Evolution, the very book that made me want to study evolution. In it Mayr recounted a striking fact. When he totaled up the names that the natives of New Guinea’s Arfak Mountains applied to local birds, he found that they recognized 136 different types. Western zoologists, using traditional methods of taxonomy, recognized 137 species. In other...
Folksonomies: species taxonomy
Folksonomies: species taxonomy
  1  notes

Example of the natives of an island having nearly the same number of classifications of birds as the taxonomists who studies the species.

21 SEP 2011

 The Biological Species Concept (BSC)

And when we think of why we feel that brown-eyed and blue-eyed humans, or Inuit and !Kung, are members of the same species, we realize that it’s because they can mate with each other and produce offspring that contain combinations of their genes. In other words, they belong to the same gene pool. When you ponder cryptic species, and variation within humans, you arrive at the notion that species are distinct not merely because they look different, but because there are barriers between them ...
Folksonomies: biology definitions species
Folksonomies: biology definitions species
  1  notes

A species is defined by the fact that its members can breed with one another.

21 SEP 2011

 Barriers that Keep Different Species from Interbreeding

What keeps members of two related species from mating with each other? There are many different reproductive barriers. Species might not interbreed simply because their mating or flowering seasons don’t overlap. Some corals, for example, reproduce only one night a year, spewing out masses of eggs and sperm into the sea over a several-hour period. Closely related species living in the same area remain distinct because their peak spawning periods are several hours apart, preventing eggs of on...
Folksonomies: biology species breeding
Folksonomies: biology species breeding
  1  notes

Different pheremones, blooming times, geographical isolation can keep members of two different species from breeding.

21 SEP 2011

 Seeing How Species Arise is Similar to Understanding Star...

The way we discovered how species arise resembles the way astronomers discovered how stars “evolve” over time. Both processes occur too slowly for us to see them happening over our lifetime. But we can still understand how they work by finding snapshots of the process at different evolutionary stages and putting these snapshots together into a conceptual movie. For stars, astronomers saw dispersed clouds of matter (“star nurseries”) in galaxies. Elsewhere they saw those clouds condens...
  1  notes

Just as astronomers search the skies for stars in varying stages of life, biologists look for species in varying degrees development.

21 SEP 2011

 Lineaus Was Persecuted for Lumping Humans with Apes Taxon...

We’ve always perceived ourselves as somehow standing apart from the rest of nature. Encouraged by the religious belief that humans were the special object of creation, as well as by a natural solipsism that accompanies a self-conscious brain, we resist the evolutionary lesson that, like other animals, we are contingent products of the blind and mindless process of natural selection. [...] The idea that humans are part of nature has been anathema over most of the history of biology. In 173...
Folksonomies: evolution science religion
Folksonomies: evolution science religion
  1  notes

Although he thought he was merely seeing God's plan.

21 SEP 2011

 Australopithecus afarensis' Hip Bone Indicates She Could ...

When Lucy’s hundreds of fragments were assembled, she turned out to be a female of a new species, Australopithecus afarensis, dating back 3.2 million years. She was between 20 and 30 years old, 3.5feet tall, weighing a scant 60 pounds, and possibly afflicted with arthritis. But most important, she walked on two legs. How can we tell? From the way that the femur (thighbone) connects to the pelvis at one end and to the knee at its other. In a bipedally walking primate like ourselves, the fem...
Folksonomies: evolution bipedalism lucy
Folksonomies: evolution bipedalism lucy
  1  notes

The bone tilts to bring the knees inward, like it does in humans, but not in chimps, who waddle because they are bow-legged.

21 SEP 2011

 The Laetoli Footprints

team of paleoanthropologists led by Mary Leakey confirmed the bipedality of A. afarensis with another remarkable find in Tanzania: the famous “Laetoli footprints.” In 1976, Andrew Hill and another member of the team were taking a break by indulging in a favorite field pastime: pelting each other with chunks of dried elephant dung. Looking for ammunition in a dry stream bed, Hill stumbled upon a line of fossilized footprints. After careful excavation, the footprints turned out to be an ...
Folksonomies: evolution stories
Folksonomies: evolution stories
  1  notes

Not only do these prints demonstrate A. afarensis could walk upright, but the nature of their preservation, having been made in volcanic ash and their proximity to one another, paints a image of two ancestors huddling together in an ashen landscape.

21 SEP 2011

 1.5 Percent Gene Difference Translates to Thousands of Pr...

But recent work shows that our genetic resemblance to our evolutionary cousins is not quite as close as we thought. Consider this. A 1.5 percent difference in protein sequence means that when we line up the same protein (say, hemoglobin) of humans and chimps, on average we’ll see a difference at just one out of every 100 amino acids. But proteins are typically composed of several hundred amino acids. So a 1.5 percent difference in a protein 300 amino acids long translates into about four di...
  1  notes

The analogy is made that if you change 1 percent of the words you change much more than 1 percent of the sentences, and the same applies to the genetic drift between humans and chimps.

21 SEP 2011

 There Are Human Races

In response to these distasteful episodes of racism, some scientists have overreacted, arguing that human races have no biological reality and are merely sociopolitical “constructs” that don’t merit scientific study. But to biologists, race—so long as it doesn’t apply to humans!— has always been a perfectly respectable term. Races (also called “subspecies” or “ecotypes”) are simply populations of a species that are both geographically separated and differ genetically in on...
  1  notes

It is wrong to pretend they do not exist, but we should remember that the differences between human races are minor compared to the genetic differences between individuals within a race.

21 SEP 2011

 Human Race Differences the Result of Sexual Selection

Most of the genetic differences between races are trivial. And yet others, those physical differences between a Japanese individual and a Finn, a Masai, and an Inuit, are striking. We have the interesting situation, then, that the overall differences in gene sequences between peoples are minor, yet those same groups show dramatic differences in a range of visually apparent traits, such as skin color, hair color, body form, and nose shape. These obvious physical differences are not characteris...
  1  notes

Cultural norms in different societies probably shaped many of the physical differences we see between races today, different definitions of beauty.

21 SEP 2011

 Evolution of Lactose Tolerance

One case involves our ability to digest lactose, a sugar found in milk. An enzyme called lactase breaks down this sugar into the more easily absorbed sugars glucose and galactose. We are born with the ability to digest milk, of course, for that’s always been the main food of infants. But after we’re weaned, we gradually stop producing lactase. Eventually, many of us entirely lose our ability to digest lactose, becoming “lactose intolerant” and prone to diarrhea, bloating, and cramps a...
  1  notes

Some groups of humans evolved the ability to digest milk beyond infancy as their societies domesticated cows.

21 SEP 2011

 Are Humans Still Evolving?

Anybody who teaches human evolution is inevitably asked: Are we still evolving? The examples of lactose tolerance and duplication of the amylase gene show that selection has certainly acted within the last few thousand years. But what about right now? It’s hard to give a good answer. Certainly many types of selection that challenged our ancestors no longer apply: improvements in nutrition, sanitation, and medical care have done away with many diseases and conditions that killed our ancestor...
  1  notes

Culture has removed many of the selective pressures from human survival, allowing harmful mutations to build up in the genepool; meanwhile, people living in third-world countries continue to experience selective pressures from droughts, famines, and disease.

21 SEP 2011

 Evolution Threatens Creationists Sense of Values

At this point I could simply say, “I’ve given the evidence, and it shows that evolution is true. Q.E.D.” But I’d be remiss if I did that, because, like the businessman I encountered after my lecture, many people require more than just evidence before they’ll accept evolution. To these folks, evolution raises such profound questions of purpose, morality, and meaning that they just can’t accept it no matter how much evidence they see. It’s not that we evolved from apes that bother...
  1  notes

Resistance to evolution is less about the theory and more about its moral implications.

21 SEP 2011

 Humans Should be Proud

Evolution is neither moral nor immoral. It just is, and we make of it what we will. I have tried to show that two things we can make of it are that it’s simple and it’s marvelous. And far from constricting our actions, the study of evolution can liberate our minds. Human beings may be only one small twig on the vast branching tree of evolution, but we’re a very special animal. As natural selection forged our brains, it opened up for us whole new worlds. We have learned how to improve ou...
Folksonomies: evolution wonder vision
Folksonomies: evolution wonder vision
  1  notes

We are the one species of 3.5 billion years of evolution that has figured out how we got here.

20 SEP 2011

 The Species Missing from Islands

Native Missing Plants Land mammals Birds Reptiles Insects and other Amphibians arthropods (e.g., spiders)    Freshwater fish [...] Further, when you look at the type of insects and plants native to oceanic islands, they are from groups that are the best colonizers. Most of the insects are small, precisely those that would be easily picked up by wind. Compared to weedy plants, trees are relatively rare on oceanic islands, almost certainly because many trees have heavy seeds that neither fl...
Folksonomies: evolution species islands
Folksonomies: evolution species islands
  1  notes

The fact that the species that exist on islands could only have migrated there versus the ones that do not exist are evidence of evolution.

16 SEP 2011

 Evolution Remodels the Old into New

...evolutionary change, even of a major sort, nearly always involves remodeling the old into the new. The legs of land animals are variations on the stout limbs of ancestral fish. The tiny middle ear bones of mammals are remodeled jawbones of their reptilian ancestors. The wings of birds were fashioned from the legs of dinosaurs. And whales are stretched-out land animals whose forelimbs have become paddles and whose nostrils have moved atop their head.
Folksonomies: evolution kluge
Folksonomies: evolution kluge
  1  notes

Evolution modifies existing structures rather than creating new ones from scratch.

20 SEP 2011

 Research Conquers our Ignorance

Hard problems often yield before science, and though we still don’t understand how every complex biochemical system evolved, we are learning more every day. After all, biochemical evolution is a field in still its infancy. If the history of science teaches us anything, it is that what conquers our ignorance is research, not giving up and attributing our ignorance to the miraculous work of a creator. When you hear someone claim otherwise, just remember these words of Darwin: “Ignorance mor...
  1  notes

Science yields answers in time, ignorance begets confidence in the present.

16 SEP 2011

 Mammals Produce Useless Yolks

Vestigial genes can go hand in hand with vestigial structures. We mammals evolved from reptilian ancestors that laid eggs. With the exceptions of the “monotremes” (the order of mammals that includes the Australian spiny anteater and duck-billed platypus), mammals have dispensed with egg-laying, and mothers nourish their young directly through the placenta instead of by providing a storehouse of yolk. And mammals carry three genes that, in reptiles and birds, produce the nutritious protein...
  1  notes

Because they evolve from egg-laying reptiles, they have dead genes for producing yolks and even produce yolks in the placenta.

16 SEP 2011

 Convergent Evolution in Mammals and Marsupials

The most famous example of different species filling similar roles involves the marsupial mammals, now found mainly in Australia (the Virginia opossum is a familiar exception), and placental mammals, which predominate elsewhere in the world. The two groups show important anatomical differences, most notably in their reproductive systems (almost all marsupials have pouches and give birth to very undeveloped young, while placentals have placentas that enable young to be born at a more advanced ...
  1  notes

Although they have very different reproductive strategies, the two groups have many parallels in species adapted to the same environments.

16 SEP 2011

 "Natural" Classification of Species as Evidence for Evolu...

Actually, the nested arrangement of life was recognized long before Darwin. Starting with the Swedish botanist Carl Linnaeus in , biologists began classifying animals and plants, discovering that they consistently fell into what was called a “natural” classification. Strikingly, different biologists came up with nearly identical groupings. This means that these groupings are not subjective artifacts of a human need to classify, but that they tell us something real and fundamen...
Folksonomies: evolution species taxonomy
Folksonomies: evolution species taxonomy
  2  notes

Taxonomists working independently naturally "nest" species in the same groups.