http://www.pbs.org/wgbh/nova/labs/lab/evolution/
Related: Natural Selection and AdaptationThe mutation that helped ancient humans survive frostbite probably gave us arthritis When humans began their slow migration out of Africa some 100,000 years ago, they carried with them the genetic seeds necessary to help survive the bitter chill of Europe and Asia. But, unknowingly, in the same genes lurked a painful burden that afflicts millions today – with a new study finding that a gene variant that helped our ancestors survive extreme climates and frostbite also increases the likelihood of developing arthritis. According to researchers at Stanford and Harvard universities, a variant of the GDF5 gene – which is associated with bone growth and joint formation – has two effects on those that carry mutations of the gene: it reduces bone length (and, subsequently, height), and it can almost double the chance of osteoarthritis. "It's clear that the genetic machinery around a gene can have a dramatic impact on how it works," says one of the researchers, human evolutionary biologist Terence Capellini, now at Harvard University.
The tree of life gets a makeover The tree of life might seem like a stable design, appropriate for indelible ink. Plenty of people think so. An Internet search for “phylogenetic tattoos” turns up some showy skin art. But the branches are shifting. Since a radial diagram based on 1990s genetics inspired a rush for tree-of-life tattoos, technical diagrams of life’s ancestral connections have been redrawn. Case Study: How Did the Guppy Get His Color? This case study examines evolution in guppies as evidenced by color variation in populations. It is based on an iconic study performed by John Endler where he collected data on guppies by scoring the size, number, and brightness of spots. Students progress though the slides (lecture and discussion), and examine details of Endler’s study, such as where the pools were located and why natural barriers created different environments for the native guppies. The case also examine two predatory fish found in Trinidad, the killifish (Rivulus hartii) and the pike (Crenichichla alta).
Earth - Chicken grows face of dinosaur Sixty-five million years ago, an asteroid is believed to have crashed into Earth. The impact wiped out huge numbers of species, including almost all of the dinosaurs. One group of dinosaurs managed to survive the disaster. Today, we know them as birds. The idea that birds evolved from dinosaurs has been around since the 19th century, when scientists discovered the fossil of an early bird called Archaeopteryx. It had wings and feathers, but it also looked a lot like a dinosaur.
Lice Out!! I awakened one morning with such a feeling of my hair being on fire. The flames seemed to burn from the nape of my neck to my ears. I spent all day scratching and, that night, asked my daughter to look at my scalp for a rash. "I don't see a rash, but I think I see things moving." Tree of Life : Exhibits : Yale Peabody Museum of Natural History Phylogenetic trees predict the characteristics of species that have not yet been carefully studied. This can guide the search for useful natural products, including “bioprospecting” for new drugs. For example, the drug “taxol,” which is used to treat breast cancer, was first isolated from the Pacific yew plant. A focus on related plants turned up a similar chemical in a more widespread species, which greatly enabled the production of the drug. Treating Snake Bites In Australia, which has more poisonous snakes than any other continent, phylogenetic analysis is used to help identify antivenins.
Pink grasshopper found in marshes An "unusual" pink grasshopper has been discovered during a wildlife event at a Devon nature reserve. The insect was found by 11-year-old Daniel Tate at Seaton Marshes near Sidmouth. He said he thought it was a flower until he saw it jump and then he realised it was a grasshopper. The insect was later identified by wildlife officers as a young adult meadow grasshopper, which has been born pink through genetic mutation. Daniel, who attended the "mini-beasts" event with his great grandfather, said: "I was looking for grasshoppers when I saw something pink. "I thought it was a flower but I saw it moving, so I tried to catch it.
Why do leaves have such different shapes? There’s one thing about leaves that science has long agreed upon: They only grow so big as available water allows — but not so big that the whole plant overheats. The water part makes sense. We all need water to grow. And the sun? Leaves collect those rays and, through photosynthesis, convert them into food. Lesson: evolution mini-lesson: A Step in Speciation Time: Two 50-minute periods Preparation: 1. Make color copies of the salamander sheets (one per team of 2-4); place these in non-glare transparent plastic notebook sleeves to protect from wear and tear as they are re-used every period and year. 2. Make copies of Grid Map of California. Enlarged copies would work best (one per team).
All 2.3 Million Species Are Mapped into a Single Circle of Life Since Charles Darwin's day, biologists have depicted how new organisms evolve from old ones by adding branches to numerous trees that represent portions of the animal, plant and microbial kingdoms. Researchers from a dozen institutions recently completed a three-year effort to combine tens of thousands of trees into one diagram, most readable as a circle (below). The lines inside the circle represent all 2.3 million species that have been named. Biologists have genetic sequences for only about 5 percent of them, however; as more are finished, the relationships within and across groups of species may change. Experts estimate that up to 8.7 million species may inhabit the planet (about 15,000 are discovered every year). “We expect the circle to broaden,” says Karen Cranston, a computational evolutionary biologist at Duke University.
Genetic Science Learning Center Launch Tool The Genetic Science Learning Center is a great place to visit to explore and learn about cells, heredity, DNA, genes, natural selection, etc. The Learn.Genetics part of the site is geared to students, teachers, and the general public. It delivers educational materials on genetics, bioscience, and health topics. The homepage is divided into three main sections: Basics, New & Popular, and a section that highlights a variety of topics, from genetic technology to the new science of addiction. The site uses videos, animations, and interactives to help you explore the different topics.