By Becky Oskin
Starting out the size of a hippo some 50 million years ago, whales have since evolved into the largest animals on Earth. But their growth wasn’t steady over the millennia; instead, filter-feeding whales like the blue whale only ballooned in size starting about 2.5 million years ago. Whales’ grass-gobbling relatives, such as sea cows, also expanded in size during this time.
A blue whale off the coast of Southern California. Photo by D Ramey Logan, via Wikipedia.
By Betsy Towner Levine
A UC Davis Evolution and Ecology team has discovered that cichlid fishes in Africa’s Lake Victoria have suffered a unique and unexpected effect of evolutionary adaptation: mass extinction.
While a graduate student in Interim Dean Peter Wainwright’s lab, Ph.D. student Matthew McGee studied the die-off of cichlid species in Lake Victoria that occurred after Nile perch were introduced into the lake in the 1950s.
Since then the perch, Lates niloticus, have decimated the lake’s fish-eating cichlids, once the most species-rich group of cichlids in Lake Victoria. The native fish have essentially been removed and replaced by the invader.
By Kathleen Holder
Why do people ride horses but not their striped African cousins?
A few zebras have accepted a rider or pulled a cart, but zebras have never been truly domesticated — and for good reason: They can be aggressive, panicky and unpredictable, making them difficult to halter and saddle train. While smaller than horses, they have powerful legs that can carry them at speeds up to 35 mph, and with a kick, can break the jaw of a predator. Those Chuck Norris-like skills are useful when you have lions, cheetahs and hyenas chasing you down for lunch.
At the bottom of a frigid Antarctic lake, a thin layer of green slime is generating a little oasis of oxygen, a team including UC Davis researchers has found. It’s the first modern replica discovered of conditions on Earth two and a half billion years ago, before oxygen became common in the atmosphere. The discovery is reported in a paper in the journal Geology.
The switch from a planet with very little available oxygen to one with an atmosphere much like today’s was one of the major events in Earth’s history, and it was all because some bacteria evolved the ability to photosynthesize. By about 2.4 billion years ago, geochemical records show that oxygen was present all the way to the upper atmosphere, as ozone.
By Kat Kerlin
Marine “bugs and slugs” make ideal houseguests for valuable seagrass ecosystems. They gobble up algae that could smother the seagrass, keeping the habitat clean and healthy. That’s according to results from an unprecedented experiment spanning the Northern Hemisphere and led by an international team of scientists, including marine biologists from UC Davis.
The study, led by the Virginia Institute of Marine Science, was conducted simultaneously at 15 sites across seven countries through a project called the Zostera Experimental Network, or ZEN, after the seagrass species Zostera marina.
Santiago Ramirez, an assistant professor in the Department of Evolution and Ecology at the UC Davis College of Biological Sciences, has been awarded a Packard Fellowship in Science and Engineering from the David and Lucille Packard Foundation. Ramirez is one of 18 scientists nationwide to receive the prestigious fellowship, worth $875,000 over five years, this year.
The fellowships are intended to give early-career scientists the freedom and flexibility to “think big” and explore new ideas and approaches.
By Roger Chetelat
This week, an international team of researchers, led by the Chinese Academy of Agricultural Sciences in Beijing, is publishing in the journal Nature Genetics a brief genomic history of tomato breeding, based on sequencing of 360 varieties of the tomato plant.
The C.M. Rick Tomato Genetics Resource Center here at UC Davis played an important role in this study by providing seed of both cultivated tomato varieties and related wild species.
Domestic tomatoes (left) and three wild relatives.
Can plants and animals evolve to keep pace with climate change? A study published May 19 in the journal Proceedings of the National Academy of Sciences shows that for at least one widely-studied plant, the European climate is changing fast enough that strains from Southern Europe already grow better in the north than established local varieties.
Small and fast-growing, Arabidopsis thaliana is widely used as the “lab mouse” of plant biology. The plant grows in Europe from Spain to Scandinavia and because Arabidopsis is so well-studied, there is a reference collection of seeds derived from wild stocks across its native range. Originally collected from 20 to 50 years ago, these plants have since been maintained under controlled conditions in the seed bank.
Aquatic algae can sense an unexpectedly wide range of color, allowing them to sense and adapt to changing light conditions in lakes and oceans. The study by researchers at UC Davis was published earlier this year in the journal Proceedings of the National Academy of Sciences.
Phytochromes are the eyes of a plant, allowing it to detect changes in the color, intensity, and quality of light so that the plant can react and adapt. “They control all aspects of a plant’s life,” said Professor Clark Lagarias, senior author on the study. Typically about 20 percent of a plant’s genes are regulated by phytochromes, he said. Phytochromes use bilin pigments that are structurally related to chlorophyll, the molecule that plants use to harvest light and use it to turn carbon dioxide and water into food.
Full post: Algae “see” a wide spectrum of light
(578 words, 3 images, estimated 2:19 mins reading time)
Getting to name new species must be one of the small pleasures of being a biologist. And if you’ve spent much of your Ph.D. painstakingly breeding thousands of hybrids of tiny fish, then flown with them to the Bahamas, you might as well have some fun with the naming, too.
Chris Martin, a graduate student working with Peter Wainwright in the Department of Evolution and Ecology, has been studying species of pupfish in some small lakes on the island of San Salvador in the Bahamas. There are about 50 species of pupfish across the Americas, and they are all pretty much the same — except in these lakes, where Martin found some oddities including a pupfish that crushes snails in its jaws and a fish that eats scales off other fish.
Full post: Name that pupfish!
(281 words, 2 images, estimated 1:07 mins reading time)