Examples of Darwinist thinking (Introduction)
by David Turell 
, Wednesday, July 28, 2021, 19:46 (1212 days ago)
This paper conjures up a purposeful theory for early evolution of larger forms:
https://phys.org/news/2021-07-icy-snowball-earth-spurred-early.html
"A new study from CU Boulder finds that hundreds of millions of years ago, small single-celled organisms may have evolved into larger multicellular life forms to better propel themselves through icy waters.
"The research was led by paleobiologist Carl Simpson and appears today in the journal The American Naturalist. It hones in on a question that's central to the history of the planet: How did life on Earth, which started off teeny-tiny, get so big?
"'Once organisms get big, they have a clear ecological advantage because the physics around how they capture food become totally different," said Simpson, assistant professor in the Department of Geological Sciences and the CU Museum of Natural History. "But the hard part for researchers has been explaining how they got big in the first place."
"In his latest study, Simpson draws on a series of mathematical equations to argue that this all-important shift may have come down to hydrodynamics—or the pursuit of a more efficient backstroke.
"Roughly 750 million years ago, and for reasons that scientists are still debating, the planet became suddenly and dramatically colder—a period of time called "Snowball Earth." To adapt to these frigid conditions, which can make swimming more difficult, small organisms like bacteria may have begun to glom together to form larger and more complex life.
***
"During "Snowball Earth," the globe may have been all but recognizable. Ice sheets a half-mile thick or more may have blanketed the planet for as much as 70 million years, while temperatures in the oceans plummeted to less than 32 degrees Fahrenheit.
"But even amid those frigid conditions, something spectacular happened: The first organisms made up of many different cells, not just one, began to emerge around the planet. Scientists still aren't sure what those ancient multicellular organisms might have looked like. One theory suggests that they resembled Volvox, a type of algae that are common in oceans today and are shaped like a hollow sphere or snow globe.
"'That's something that has lodged in my mind for years," Simpson said. "How do Snowball Earth and the rise of multicellular organisms go together?"
"The answer to that counterintuitive problem may hinge on a little-known property of water.
"Simpson explained that when saltwater gets colder, it also becomes several times thicker, or more viscous. Humans are too big to notice the change. But for organisms the size of modern-day bacteria, the difference can be huge.
"'When you're small, you're stuck," he said. "The water moves you."
***
"If individual cells joined forces to make a bigger organism, in contrast, they could produce a lot more swimming power while keeping the energy needs of each cell low.
"'The advantage of the multicellular strategy is that each cell stays small and has low metabolic requirements, but these cells can swim together," Simpson said.
"He's currently testing the theory using experiments with modern algae in a lab and by digging deeper into Earth's fossil record. One thing is clear, Simpson said: Once life forms got big, a whole new world of possibilities became available to them. Primitive animals like sponges, for example, survive not by floating in the ocean but by actively pumping water through their bodies.
"'When you're big, you now can move the water rather than the other way around," Simpson said."
Comment: so the cells knew to join forces. Darwinist magical thinking.
Examples of Darwinist thinking: insect adaptations
by David Turell , Sunday, June 02, 2024, 16:27 (172 days ago) @ David Turell
One study with one insect in California, not evolution:
https://www.sciencealert.com/astonishing-study-shows-evolution-really-does-repeat-itsel...
"Astonishing Study Shows Evolution Really Does Repeat Itself
"Evolution is often thought of as a haphazard process acting on an assortment of traits that randomly appear through genetic variation.
"So much so that if we were to wind back the clock on evolution and "replay the tape of life," the late paleontologist Stephen Jay Gould said, he doubts "anything like Homo sapiens would ever evolve again."
"But a new study of stick insects suggests that evolution may sometimes repeat itself in a predictable manner, which could help our understanding of how organisms may change in response to selection pressures.
***
"Since the 1990s, Nosil and colleagues have been netting the flightless insects from along roadsides in the mountains near Santa Barbara, California.
"Three distinct varieties of T. cristinae camouflage themselves, either with white stripes or a plain green color to match their favored host plants, or a rarer darker shade. The stick insects only lay eggs once a year, so each year in the study represented a new generation of stick insects, without overlap.
"With more than 32,000 insects netted and cataloged, the team could tease apart the trends – finding that in all 10 of the geographically separated populations, the frequency of green and striped stick insects cycled year to year in a predictable way. If stripes became less common one year, they increased the next, and vice versa.
"However, the proportion of rarer, dark-toned insects, which blend into the forest floor, stayed fairly low and stable over time.
"Our results imply that evolution is both repeatable and complex for the same trait," Nosil and colleagues write in their published paper. (my bold)
"The findings are reminiscent of past studies trying to understand why evolution keeps making (and unmaking) crabs, with their side-scuttling body plans, hardy shells, and outsized claws. Research has also shown that other organisms, such as stickleback fish, have a similar tendency to evolve the same traits again and again.
"However, most of those findings are from studies of one or a few populations, or short lab experiments that aren't long enough to capture the emergence of genetic mutations that might give rise to useful traits.
"This new study harks back to decades-old questions of determinism and chance in the history of life, but it could have future implications too. Scientists not involved in the work think that understanding that evolution sometimes works in predictable ways could help researchers predict how organisms change and therefore manage populations.
"But since Nosil and colleagues only looked at T. cristinae and its relatives, they can only speculate how the results may differ in other taxa or if evolution is similarly predictable in other parts of the animal kingdom and plant world, too.
"There certainly seems to be a stack of examples now, from moths and butterflies to fish, finches, sheep, and deer, of species following predictable evolutionary paths, returning to tested traits that help them survive."
Comment: this is the usual Dawin-speak propaganda. The bold is absolutely on point. The insects have a built-in set of adaptions to fit the circumstances of their environment. The headline calling it evolution is totally overblown. Science writers Have this slant built into their thought patterns. Why? Current science is tearing down pure Darwinism.