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Credit: Photo courtesy of San Diego Zoo Wildlife Alliance
Despite having been driven nearly to extinction, the California condor has a high degree of genetic diversity that bodes well for its long-term survival, according to a new analysis by University of California researchers.
Nearly 40 years ago, the state s wild condor population was down to a perilous 22. That led to inbreeding that could have jeopardized the population s health and narrowed the bird s genetic diversity, which can reduce its ability to adapt to changing environmental conditions.
In comparing the complete genomes of two California condors with those of an Andean condor and a turkey vulture, UC San Francisco and UC Berkeley scientists did find genetic evidence of inbreeding over the past few centuries, but, overall, a wealth of diversity across most of the genome.
See millions of years of history while beachcombing in San Francisco
Sand dollar skeletons and fossils turn Ocean Beach into a living lab perfect for a family day trip.
Sand dollar skeletons, or “tests,” wash up in great numbers on San Francisco’s Ocean Beach. Examining these and other ephemera from the sea makes for a great science day trip for the whole family.Photograph by Robert C. Paulson Jr., Alamy
ByJordan Kushins
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When walking along San Francisco’s Ocean Beach, it’s nearly impossible to miss the sand dollars that dot the shoreline. At almost any time of day and tide, any season of the year, these white discs stretch as far as the eye can see: some cracked underfoot or broken in the Pacific waves, others still full and flawless with a flower-like pattern on top.
Billions and billions of tyrannosaurs walked the Earth
Scientists arrived at the estimate by using calculations based on size, metabolism, and the populations of animals today.
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Posted: Apr 23, 2021 5:17 PM ET | Last Updated: April 23
Over approximately 2.5 million years, North America was likely home to 2.5 billion Tyrannosaurus rexes. Less than 100 have been dug up and studied by paleontologists, according to a UC Berkeley study( Image by Julius Csotonyi, courtesy of Science magazine)
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2.5 Billion Tyrannosaurus Rexes Roamed North America over a Period of 2.5 Million Years Over approximately 2.5 million years, North America likely hosted 2.5 billion Tyrannosaurus rexes, a minuscule proportion of which have been dug up and studied by paleontologists, according to a UC Berkeley study.
Image by Julius Csotonyi, courtesy of Science magazine
How many Tyrannosaurus rexes roamed North America during the Cretaceous period?
That’s a question Charles Marshall pestered his paleontologist colleagues with for years until he finally teamed up with his students to find an answer.
What the team found, to be published this week in the journal Science, is that about 20,000 adult T. rexes probably lived at any one time, give or take a factor of 10, which is in the ballpark of what most of his colleagues guessed.