Wednesday, 7 April 2021

How Science Works - Looking for Questions Requiring Answers

Top: Fifty-two-million-year-old fossil snakefly (Megaraphidia ootsa sp.nov) from Driftwood Canyon in British Columbia, Canada.
Bottom: Living snakefly.
Fossil image © Zootaxa.
Fossil discovery deepens snakefly mystery - University Communications - Simon Fraser University

A paper published in Zootaxa very recently, neatly illustrates how science works.

The paper concerns the discovery of four new (to science) extinct species of snakefly which pose something of a problem. They were found in western North America in an area which our understanding of their modern counterparts says they shouldn't have been in.

All know modern snakeflies live in habitats which experience winter frosts and it was assumed that their over-wintering eggs needed a period of freezing in order to develop. However, these extinct species are all from temperate regions which experience few if any winter frosts, so the question is, why did their modern descendant evolve to be dependent on these winter conditions?

Sadly, the paper is behind a paywall, however, the Simon Fraser University media release has the details:
Fossil discoveries often help answer long-standing questions about how our modern world came to be. However, sometimes they only deepen the mystery—as a recent discovery of four new species of ancient insects in British Columbia and Washington state is proving.

The fossil species, recently discovered by paleontologists Bruce Archibald of Simon Fraser University and Vladimir Makarkin of the Russian Academy of Sciences, are from a group of insects known as snakeflies, now shown to have lived in the region some 50 million years ago. The findings, published in Zootaxa, raise more questions about the evolutionary history of the distinctly elongated insects and why they live where they do today.

The average yearly climate was moderate like Vancouver or Seattle today, but importantly, with very mild winters of few or no frost days. We can see this by the presence of frost intolerant plants like palms living in these forests along with more northerly plants like spruce.

Now we know that earlier in their evolutionary history, snakeflies were living in climates with very mild winters and so the question becomes why didn’t they keep their ability to live in such regions? Why aren’t snakeflies found in the tropics today?

Such discoveries are coming out of these fossil sites all the time. They’re an important part of our heritage.

Bruce Archibald, Co-author
Palaeontologist
Simon Fraser University
Vancouver, BC, Canada
Snakeflies are slender, predatory insects that are native to the Northern Hemisphere and noticeably absent from tropical regions. Scientists have traditionally believed that they require cold winters to trigger development into adults, restricting them almost exclusively to regions that experience winter frost days or colder. However, the fossil sites where the ancient species were found experienced a climate that doesn’t fit with this explanation.

“The average yearly climate was moderate like Vancouver or Seattle today, but importantly, with very mild winters of few or no frost days,” says Archibald. “We can see this by the presence of frost intolerant plants like palms living in these forests along with more northerly plants like spruce.”

The fossil sites where the ancient species were discovered span 1,000 kilometers of an ancient upland from Driftwood Canyon in northwest B.C. to the McAbee fossil site in southern B.C., and all the way to the city of Republic in northern Washington.

According to Archibald, the paleontologists found species of two families of snakeflies in these fossil sites, both of which had previously been thought to require cold winters to survive. Each family appears to have independently adapted to cold winters after these fossil species lived.

“Now we know that earlier in their evolutionary history, snakeflies were living in climates with very mild winters and so the question becomes why didn’t they keep their ability to live in such regions? Why aren’t snakeflies found in the tropics today?”

Pervious [sic] fossil insect discoveries in these sites have shown connections with Europe, Pacific coastal Russia, and even Australia.

Archibald emphasizes that understanding how life adapts to climate by looking deep into the past helps explain why species are distributed across the globe today, and can perhaps help foresee how further change in climate may affect that pattern.

“Such discoveries are coming out of these fossil sites all the time,” says Archibald. “They’re an important part of our heritage.”
Of such things is science made. Answers identify more questions which require more answers, so the sum total of our knowledge and understanding increases. Unlike Creationism, where dogma dictates always the same answer and life is a fruitless process of careful self-deception and delusion and understanding is the same now as it was in the Bronze Age, science is an expanding wave-front of new knowledge and understanding and life is a stimulating voyage of discovery.

Reference:

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