UC Berkeley
2023 Stories
Familiar sparks for ancient extinctions
Around 10,000 years ago, two-thirds of Earth’s large mammals blipped out of existence. Mammoths, mastodons, sabertoothed cats, and many other species from all over the world went extinct. Despite investigating many possible causes, biologists have yet to find a smoking gun revealing the culprit behind the disappearances. But that doesn’t necessarily mean that we are missing something. Extinction can be, well … complicated. Perhaps we haven’t been able to identify a single main trigger for the extinctions because several causes acted together. A new study takes this possibility seriously and untangles the interacting factors behind large mammal extinctions in Southern California at the end of the last Ice Age.
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Meteorite impact no picnic for sharks either
Around 66 million years ago, a massive meteorite struck Earth, triggering a series of ecological disasters that wiped out T. rex along with all the other non-bird dinosaurs. For most of us, that’s old news – and might be as much as we know about this dramatic time. But scientists, of course, dig much deeper into the past, investigating exactly how mass extinctions played out and how they affected different groups of organisms. Now, new research explores this same extinction event from the view of another ancient and famously toothy group: sharks, skates, and rays.
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How did dinos get so big…and so little?
Dinosaurs come in all sizes. The lumbering Argentinosaurus probably reached 115 feet, the winged Microraptor less than 4 feet. And today, the sole surviving lineage of dinosaurs – modern birds – includes both miniscule hummingbirds and leggy ostriches. (Learn more about why birds are actually a type of dinosaur here.) Scientists have long been interested in how non-bird dinosaurs, which include the largest land-dwelling animals that ever lived, came to have such different body sizes. The answer, of course, is through evolution, but what evolutionary changes were involved? New research helps answer that question.
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Nature or nurture? In tiger snake evolution it’s complicated…
Seeing differences in the biological world often leads to questions about nature and nurture. Did I outperform my sibling in basketball because I inherited my mom’s quick reaction time (nature) or because I practiced more (nurture)? Is this golden delicious apple really old (nurture) or are they just a mealy apple type (nature)? Is our dog well behaved because she’s part golden retriever (nature) or because of all that puppy training (nurture)? Often the answers to such questions are not either/or. New research on venomous tiger snakes highlights just how intertwined nature and nurture can be – and how evolution has a hand in both!
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