Read Online Spirals in Time: The Secret Life and Curious Afterlife of Seashells by Helen Scales - Free Book Online Page A
Authors: Helen Scales
Tags: science, History, Non-Fiction, Nature, Life Sciences, Social History, Marine Biology, Seashells
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grows bigger, and bivalves in the real world don’t do this).
Other parts of the museum were empty, Raup suggested, simply because the process of natural selection hasn’t got around to filling them yet. He thought that as soon as a situation arises in which those theoretical shells become useful and confer an advantage on their owners, then, sure enough, they will evolve. Other researchers disagree. They think the vacant spaces of the museum will never be filled, because the necessary genetic mutations to make those shells haven’t happened and maybe never will. Their view is that natural selection doesn’t have at its disposal all the genetic variation that is necessary to fill every part of the imaginary museum. Debates still rage over who is right.
Following on from Raup’s original concept, many other museums of possible creatures have been built (they are now known technically as theoretical morphospaces). There are museums for beetles, aquarium tanks for fish, sea urchins and phytoplankton, even a herbarium for plants and aviaries for birds and pterosaurs. Just like the shell museum, theserambling spaces are filled with both real and imaginary beasts, and they are encouraging biologists to think about which forms and shapes in nature are possible and popular, and which are impossible or for some other reason have never occurred or will never occur.
Throughout his papers, Raup was always careful to point out that his model isn’t perfect, and it doesn’t account for all the things we see in the real world. For one thing, he confessed to being overly simplistic about fixing the various shell dimensions throughout a mollusc’s lifespan; there are real shells that seem to shift the values of T, D and W over time, so they hop around the imaginary museum as they get older. And, as Clements and Liew found with their strange microsnails, there are some molluscs that break all the rules. One of the tiny snail species from the limestone hills of Malaysia makes a shell that spins around not just a single axis but four: the most of any known shell.
For the sake of simplicity, other features seen on many real shells are also omitted from the museum of all possible shells. For example, Raup left out the ornaments – spikes, knobbles, ribs and spines – that molluscs use to decorate their shells.
Why shape matters
Geerat ‘Gary’ Vermeij has probably spent more time than anyone else thinking about the shapes of seashells. Born and raised in the Netherlands, the first shells he encountered were what he describes as ‘drab chalky clams’ on windswept North Sea beaches. Then, in 1955, his family moved to Dover, New Jersey, where Vermeij experienced something of an epiphany. His fourth-grade teacher, Mrs Colberg, decorated the classroom windowsills with dozens of shells she had gathered during holidays to southern Florida’s tropical shores. They were nothing like the shells Vermeij had got to know in Europe, being elegantly sculpted and covered in prickles and bumps. Her cowrie and olive shellswere so shiny he was sure someone had varnished them. When a classmate brought shells from the Philippines to ‘show and tell’, Vermeij saw these were even more exotic and enthralling. He resolved to begin collecting his own shells and to find out as much as he could about them.
A decade or so later, Vermeij graduated with a Ph.D from Yale University, and since the 1980s has been Professor of Paleoecology at the University of California, Davis. It became his lifelong passion to understand how and why shells grow in so many different forms throughout space and time. He has travelled the world exploring the coasts and seashells of nearly every continent, and published more than a hundred scientific papers and four books about shells and evolution. And, since the age of three, Gary Vermeij has been blind.
Using his finely tuned sense of touch, Vermeij studies shells by turning them over and over in his hands, feeling their
Other parts of the museum were empty, Raup suggested, simply because the process of natural selection hasn’t got around to filling them yet. He thought that as soon as a situation arises in which those theoretical shells become useful and confer an advantage on their owners, then, sure enough, they will evolve. Other researchers disagree. They think the vacant spaces of the museum will never be filled, because the necessary genetic mutations to make those shells haven’t happened and maybe never will. Their view is that natural selection doesn’t have at its disposal all the genetic variation that is necessary to fill every part of the imaginary museum. Debates still rage over who is right.
Following on from Raup’s original concept, many other museums of possible creatures have been built (they are now known technically as theoretical morphospaces). There are museums for beetles, aquarium tanks for fish, sea urchins and phytoplankton, even a herbarium for plants and aviaries for birds and pterosaurs. Just like the shell museum, theserambling spaces are filled with both real and imaginary beasts, and they are encouraging biologists to think about which forms and shapes in nature are possible and popular, and which are impossible or for some other reason have never occurred or will never occur.
Throughout his papers, Raup was always careful to point out that his model isn’t perfect, and it doesn’t account for all the things we see in the real world. For one thing, he confessed to being overly simplistic about fixing the various shell dimensions throughout a mollusc’s lifespan; there are real shells that seem to shift the values of T, D and W over time, so they hop around the imaginary museum as they get older. And, as Clements and Liew found with their strange microsnails, there are some molluscs that break all the rules. One of the tiny snail species from the limestone hills of Malaysia makes a shell that spins around not just a single axis but four: the most of any known shell.
For the sake of simplicity, other features seen on many real shells are also omitted from the museum of all possible shells. For example, Raup left out the ornaments – spikes, knobbles, ribs and spines – that molluscs use to decorate their shells.
Why shape matters
Geerat ‘Gary’ Vermeij has probably spent more time than anyone else thinking about the shapes of seashells. Born and raised in the Netherlands, the first shells he encountered were what he describes as ‘drab chalky clams’ on windswept North Sea beaches. Then, in 1955, his family moved to Dover, New Jersey, where Vermeij experienced something of an epiphany. His fourth-grade teacher, Mrs Colberg, decorated the classroom windowsills with dozens of shells she had gathered during holidays to southern Florida’s tropical shores. They were nothing like the shells Vermeij had got to know in Europe, being elegantly sculpted and covered in prickles and bumps. Her cowrie and olive shellswere so shiny he was sure someone had varnished them. When a classmate brought shells from the Philippines to ‘show and tell’, Vermeij saw these were even more exotic and enthralling. He resolved to begin collecting his own shells and to find out as much as he could about them.
A decade or so later, Vermeij graduated with a Ph.D from Yale University, and since the 1980s has been Professor of Paleoecology at the University of California, Davis. It became his lifelong passion to understand how and why shells grow in so many different forms throughout space and time. He has travelled the world exploring the coasts and seashells of nearly every continent, and published more than a hundred scientific papers and four books about shells and evolution. And, since the age of three, Gary Vermeij has been blind.
Using his finely tuned sense of touch, Vermeij studies shells by turning them over and over in his hands, feeling their
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