It's no secret that greenhouse gases warm the planet and that this has dire consequences for the environment whole islands swallowed up by rising seas, animal and plant species stressed by higher temperatures, and upsets in ecological interactions as populations move to cooler areas. However, carbon dioxide has another, less familiar environmental repercussion: making the Earth's oceans more acidic. Higher levels of carbon dioxide in the atmosphere mean that more carbon dioxide dissolves in the ocean. This dissolved carbon dioxide forms carbonic acid the same substance that helps give carbonated beverages their acidic kick. While this process isn't going to make the ocean fizzy anytime soon, it is introducing its own set of challenges for marine organisms like plankton and coral.

This research profile follows Dr. Rosemary Gillespie to Hawaii as she evaluates hypotheses about the evolution of the colorful happy-face spider.

Wondering how global warming will affect our planet? Scientist Jennifer McElwain studies the fossil record in order to learn more about how global warming has affected life on Earth in the past and how it might affect life on Earth in the future.

Human activity has certainly affected our physical environment - but it is also changing the course of evolution. This research profile follows scientist David O. Conover as he investigates the impact of our fishing practices on fish evolution and discovers what happened to the big ones that got away.

The pork chops you buy in the supermarket neatly packaged in plastic and styrofoam may look completely sterile, but are, in fact, likely to be contaminated with disease-causing bacteria - and not with just any old bugs, but with hard-to-treat, antibiotic resistant strains. In a recently published study, researchers with the National Antimicrobial Resistance Monitoring System bought meat from a wide sampling of chain grocery stores across the country and analyzed the bacteria on the meat. Resistant microbes were found in 81% of ground turkey samples, 69% of pork chops, 55% of ground beef samples, and 39% of chicken parts.

The next time you are in the kitchen, try this experiment: pick up a box of butter (four sticks) in one hand and a box of saltines (four packets) in the other. Which is heavier? If you said the butter, you are not alone. Most people would identify the box of butter as the heavier object even though, if you look at the labels, you'll see that they both weigh exactly one pound! This is an example of the size-weight illusion, and it is incredibly common. Read more to see the evolution (and baseball) connection ...

This research profile examines how the scientist Carl Bergstrom uses computer modeling to understand and control the evolution of antibiotic resistant bacteria in hospitals.

This research profile follows paleoanthropologist Jackson Njau as he investigates ancient predators, like crocodiles and large cats, in an effort to understand how these organisms shaped the evolution of our human ancestors.

If you'd visited Tuolumne Meadows in Yosemite National Park 100 years ago, you probably would have encountered the alpine chipmunk, Tamias alpinus. Today, however, park visitors will have to hike up a nearby mountain to see one of these critters. That's because this species is sensitive to temperature and over the last hundred years of global climate change, Yosemite has warmed by about 5.5 degrees Fahrenheit. As the temperature increased, the chipmunks retreated to higher and higher elevations where it was cooler. Today, they occupy a fraction of their original range. If climate change continues, they could be squeezed right off the tops of their mountains and out of existence.

The Ensatina salamander has been extensively investigated because it is a ring species Ń a species that demonstrates how geography and the gradual accumulation of genetic differences factor into the process of speciation. Biologist Tom Devitt continues the more than 50 years of Ensatina research by applying new genetic techniques and asking new questions about this classic evolutionary example.

Swarms of tiny robots have given up their selfish ways and started sharing resources for the greater good. Though this might sound like the plot of a bad summer blockbuster, it is real news. This month, a team of Swiss researchers announced that they've used robots to simulate biological evolution. The simple, mobile robots - each a little larger than a sugar cube - began their lives directionless, meandering aimlessly into walls. But after a few generations of natural selection, their computer programs evolved so that they became efficient foragers, purposefully collecting disks that represent food. None of that is particularly surprising. Scientists have long been able to simulate evolution through computer programs that mimic the processes of genetic inheritance, mutation, recombination, and reproduction. What is noteworthy is that many of these robots eventually evolved to help one another, sacrificing personal success to aid other robots in their group.

Back in the Jurassic, dinosaurs may have dominated terrestrial ecosystems, but they were not alone. Scurrying around their feet and clinging to the trees above them were the fuzzy ancestors of their successors. When most of the dinosaurs perished, the surviving mammals diversified into the dinosaurs' niches, where they remain today. Last month, scientists reported on the discovery of a fossil mammal from China that would have lived alongside the dinosaurs and that, at 160 million years old, represents one of the earliest mammals known.

This short slide set explains the fidelity of DNA replication in evolutionary terms. Save the slide set to your computer to view the explanation and notes that go along with each slide.

This short slide set explains the existence of photorespiration using evolutionary history. Save the slide set to your computer to view the explanation and notes that go along with each slide.

This short slide set explains uniformity and variation in the process of photosynthesis across all life using evolutionary history. Save the slide set to your computer to view the explanation and notes that go along with each slide.

This short slide set weaves basic information about carbohydrates, proteins, and nucleic acids into one evolutionary story regarding the evolution of lactose tolerance, which relates to students' everyday lives. Save the slide set to your computer to view the explanation and notes that go along with each slide.

This short slide set explains the uniformity of the Krebs cycle across all life using evolutionary theory. Save the slide set to your computer to view the explanation and notes that go along with each slide.

This short slide set relates the role of RNA in the processes of transcription and translation to RNA's evolutionary history and the remnants of the RNA world. Save the slide set to your computer to view the explanation and notes that go along with each slide.

Scientists discover new species all the time, but usually these new species are microbes, plants, insects, and other forms of non-vertebrate life. Few vertebrate species have thus far evaded the curious gaze of biologists intent on understanding the diversity of life on Earth - that is, unless the vertebrate in question happens to be very, very tiny. Last month, scientists announced the discovery of not one, but four miniscule lizard species. The smallest of these new chameleons, which live in the far north of the African island of Madagascar and inhabit leaf litter, reaches an adult body size of just two centimeters.

The evolutionary tree presented focuses on relationships among the ray-finned fishes (Actinopterygii). You can click on the colored logos to read about evolutionary innovations and see lists of characteristics that evolved in different lineages. Note that this tree has been pruned to focus on certain groups of interest.