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Introduction to Evolutionary Biology

Introduction to Evolutionary Biology
Introduction to Evolutionary Biology Version 2 Copyright © 1996-1997 by Chris Colby[Last Update: January 7, 1996] volution is the cornerstone of modern biology. It unites all the fields of biology under one theoretical umbrella. It is not a difficult concept, but very few people -- the majority of biologists included -- have a satisfactory grasp of it. One common mistake is believing that species can be arranged on an evolutionary ladder from bacteria through "lower" animals, to "higher" animals and, finally, up to man. Mistakes permeate popular science expositions of evolutionary biology. Misunderstandings about evolution are damaging to the study of evolution and biology as a whole. This is a brief introduction to evolutionary biology. What is Evolution? Evolution is a change in the gene pool of a population over time. The English moth, Biston betularia, is a frequently cited example of observed evolution. Populations evolve. The word evolution has a variety of meanings. Related:  Evolution

Top 10 Myths About Evolution – with Downloadable PDF | Atheism Resource Email If you have been looking for a simple, easy to follow quick guide to evolution… we’ve got it. Our friends at the Skeptics Society gave us permission to reprint this. Below is the text. Learn it. Original Text: 1 If Humans Came From Apes, Why Aren’t Apes Evolving Into Humans? Humans, apes, and monkeys are only distant evolutionary “cousins.” 2 There Are Too Many Gaps in the Fossil Record for Evolution to Be True In fact, there are lots of intermediate fossils. 3 If Evolution Happened Gradually Over Millions of Years Why Doesn’t the Fossil Record Show Gradual Change? Sudden changes in the fossil record are not missing evidence of gradualism; they are extant evidence of punctuation. 4 No One Has Ever Seen Evolution Happen Evolution is a historical science confirmed by the fact that so many independent lines of evidence converge to this single conclusion. 5 Science Claims That Evolution Happens by Random Chance Natural selection is not “random” nor does it operate by “chance.”

Scientists Uncover How Dainty Rhino Feet Support Huge Bodies | Despite Their Portliness, Rhinos' Feet Take It All in Stride | Rhinoceros Feet Explained How do rhinos' dainty little pigeon-toed feet support their portly bodies? A group of veterinary scientists in the United Kingdom are on the case. By coaxing three white rhinos to walk back and forth across a "pressure pad," a floor mat embedded with thousands of pressure sensors, the researchers are collecting data on how much force the beasts exert on different parts of their feet as they walk. A rhinoceros can weigh as much as 8,000 pounds (3,600 kilograms), yet somehow, their feet manage to take all those tons in stride. Initial results show that, with each step, their toes feel peak pressures of 75 pounds per square inch (psi), and the pads of their feet, 15 psi. That's not so much. White rhinos in Namibia.Credit: Ikiwaner | Creative Commons In addition to figuring out how rhino feet manage this feat, the scientists are investigating how the beasts' locomotion differs from that of other large land mammals — in particular, elephants. For that matter, should anyone?

Giles Fraser says scientists are replacing theologians. Some thoughts on that | Jon Butterworth | Science This transition can of course only be for the best. And this good-humoured article is definitely a step up from the "science is the new religion" trope I feared from the headline. Fraser talks about two desires that many (though perhaps not all) of us have. One is to understand the world we live in; the other is to find a meaning to it. I see these as quite distinct, though it's possible Fraser does not. On the first, the understanding front, physics – or science in general, I would say – does seem to have theology beaten, for the same reason that actually looking at the clues gives you a better chance of doing a crossword. When it comes to meaning, well, that’s different. The ability to juggle atoms, quarks or chromosomes may help you understand what life is, but that is different from telling you its meaning, or a moral code to live by. But none of that makes life meaningless. After Reinhold Niebuhr, attributed As Fraser says, theology has always dealt in metaphor, in picture-language.

Human Evolution & Archaeology 100 Time-Saving Search Engines for Serious Scholars While burying yourself in the stacks at the library is one way to get some serious research done, with today’s technology you can do quite a bit of useful searching before you ever set foot inside a library. Undergraduates and grad students alike will appreciate the usefulness of these search engines that allow them to find books, journal articles and even primary source material for whatever kind of research they’re working on and that return only serious, academic results so time isn’t wasted on unprofessional resources. Note: Visit our updated list for the latest in academic search engines. General Start off your research with one of these more general academic search engines. Intute: Use this website’s search tools to find the best and most reliable sites to start your research. Meta Search Want to search it all at once? Dogpile: Search Google, Yahoo, Bing and more at once with this great search engine. Databases and Archives Books and Journals Science Math and Technology Social Science

The Brain—Information about the Brain 1 Introduction “I think, therefore I am.” —René Descartes, 17th-century philosopher Few of us question the crucial importance of the brain. It is vital to our existence. The brain makes up only 2 percent of our body weight, but it consumes 20 percent of the oxygen we breathe and 20 percent of the energy we consume. Scientists have worked for many years to unravel the complex workings of the brain. Despite these and other significant advances in the field of brain research, most of the processes responsible for the integrated functioning of billions of brain cells remain a mystery. An essential aspect of any scientific research is communicating results to the public in a way that is easily understood. To correctly interpret the information transmitted through these venues, we need a better understanding of basic concepts related to the brain. 2 Myths and Realities about the Brain Myth: The brain is separate from the nervous system. Myth: The brain is a uniform mass of tissue. Figure 1.

Your Inner Fish: Book and PBS documentary on Tiktaalik and Neil Shubin. Photo courtesy PBS We all know the Darwin fish, the car-bumper send-up of the Christian ichthys symbol, or Jesus fish. Unlike the Christian symbol, the Darwin fish has, you know, legs. But the Darwin fish isn't merely a clever joke; in effect, it contains a testable scientific prediction. If evolution is true, and if life on Earth originated in water, then there must have once been fish species possessing primitive limbs, which enabled them to spend some part of their lives on land. Sure enough, in 2004, scientists found one of those transitional species: Tiktaalik roseae, a 375-million-year-old Devonian period specimen discovered in the Canadian Arctic by paleontologist Neil Shubin and his colleagues. "It has a neck," says Shubin, a professor at the University of Chicago. "The genetic toolkit that builds their fins is very similar to the genetic toolkit that builds our limbs," Shubin says. Having the fossil to show, says Shubin, changes the entire nature of the discussion.

Human evolution Human evolution is the evolutionary process leading up to the appearance of modern humans. While it began with the last common ancestor of all life, the topic usually covers only the evolutionary history of primates, in particular the genus Homo, and the emergence of Homo sapiens as a distinct species of hominids (or "great apes"). The study of human evolution involves many scientific disciplines, including physical anthropology, primatology, archaeology, ethology, linguistics, evolutionary psychology, embryology and genetics.[1] The earliest documented members of the genus Homo are Homo habilis which evolved around 2.3 million years ago; the earliest species for which there is positive evidence of use of stone tools. History of study[edit] Before Darwin[edit] Darwin[edit] The first debates about the nature of human evolution arose between Thomas Huxley and Richard Owen. First fossils[edit] A major problem at that time was the lack of fossil intermediaries. The East African fossils[edit]

Brain's connective cells are much more than glue: Glia cells also regulate learning and memory Glia cells, named for the Greek word for "glue," hold the brain's neurons together and protect the cells that determine our thoughts and behaviors, but scientists have long puzzled over their prominence in the activities of the brain dedicated to learning and memory. Now Tel Aviv University researchers say that glia cells are central to the brain's plasticity -- how the brain adapts, learns, and stores information. According to Ph.D. student Maurizio De Pittà of TAU's Schools of Physics and Astronomy and Electrical Engineering, glia cells do much more than hold the brain together. De Pittà's research, led by his TAU supervisor Prof. Regulating the brain's "social network" The brain is constituted of two main types of cells: neurons and glia. But Ben-Jacob and colleagues suspected that glia cells were even more central to how the brain works. The brain is like a social network, says Prof. New brain-inspired technologies and therapies

Evolution - A-Z - Frequency-dependent selection Frequency-dependent selection occurs when the fitness of a genotype depends on its frequency. It is possible for the fitness of a genotype to increase (positively frequency-dependent) or decrease (negatively frequency-dependent) as the genotype frequency in the population increases. Examples of frequency dependence can arise in systems of mimicry: • Natural selection may favor non-poisonous butterflies that have the same color pattern as poisonous butterflies. This system is called Batesian mimicry. • In other butterflies, such as in central and south American Heliconius, there are several morphs within a species, each morph having a different color pattern. But with negatively frequency-dependent fitnesses (as in Batesian mimicry), it is possible for natural selection to maintain a polymorphism. The image opposite shows different forms of the species Heliconius erato.

Engineered stem cells seek out and kill HIV in living mice Expanding on previous research providing proof-of-principle that human stem cells can be genetically engineered into HIV-fighting cells, a team of UCLA researchers have now demonstrated that these cells can actually attack HIV-infected cells in a living organism. The study, published April 12 in the journal PLoS Pathogens, demonstrates for the first time that engineering stem cells to form immune cells that target HIV is effective in suppressing the virus in living tissues in an animal model, said lead investigator Scott G. Kitchen, an assistant professor of medicine in the division of hematology and oncology at the David Geffen School of Medicine at UCLA and a member of the UCLA AIDS Institute. "We believe that this study lays the groundwork for the potential use of this type of an approach in combating HIV infection in infected individuals, in hopes of eradicating the virus from the body," he said.

The "Johnny Depp Effect" - An evolutionary explanation for homosexuality Who is more attractive as a mate? A guy who is kind or a guy who is cruel? A guy who is sensitive or a guy who lacks empathy ? A guy who is physically attractive or a guy who is homely? A guy who can appreciate art or the guy who only appreciates ESPN? Now consider who is more likely to be gay. This exercise in mate preferences (and stereotypes , please excuse us) serves to illustrate a simple point: Gay men are attractive. Two recent articles suggest that these women are on to something. Again, scientists have known for some time that sexual orientation has a genetic component. It was once hypothesized that such a trait could be maintained via kin selection. Hypotheses demand empirical tests, and when the kin selection hypothesis of homosexuality was tested by David Bobrow and Michael Bailey of Northwestern University and later by Qazi Rahman and Matthew Hull of the University of East London, it was not supported. References

The Dramatic Evolution Of The Human Face Over 7 Million Years The Dramatic Evolution Of The Human Face Over 7 Million Years Scientists believe they've been able to successfully map the evolutionary changes to the human face over the past 7 million years. And whilst there's a certain amount of assumption and theory when you're dealing with such a ginormous timespan, much of the what you're about to see is based on hard evidence. Over the years tiny bones, skulls, teeth and fragments have been unearth and discovered across the globe. 27 profiles (or stages if you will) of the human face, based on the evidence of the past and the ability of technology today. Prepare to be amazed. Via Senckenberg Research Institute

Missing link found? Scientists unveil fossil of 47 million-year-old primate, Darwinius masillae Tama/Getty The 47 million year old fossilized remains of a primate is seen at the American Museum of Natural History in New York. Feast your eyes on what a group of scientists call the Holy Grail of human evolution. A team of researchers Tuesday unveiled an almost perfectly intact fossil of a 47 million-year-old primate they say represents the long-sought missing link between humans and apes. Officially known as Darwinius masillae, the fossil of the lemur-like creature dubbed Ida shows it had opposable thumbs like humans and fingernails instead of claws. Scientists say the cat-sized animal's hind legs offer evidence of evolutionary changes that led to primates standing upright - a breakthrough that could finally confirm Charles Darwin's theory of evolution. "This specimen is like finding the Lost Ark for archeologists," lead scientist Jorn Hurum said at a ceremony at the American Museum of Natural History. "It is the scientific equivalent of the Holy Grail.