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Like Escape Artists, Rotifers elude enemies
by drying up and –Poof!- they are gone with the wind. These tiny
animals have evolved a way to avoid parasites and pathogens by
drying up and blowing away.
A few genera of rotifers occur in the sea,
but most are freshwater species and over a 1000 species have
been reported from northwest Europe. Some are free swimming,
others may cling to plants or live in moist places like mosses
or lichen. I find them regularly in my bird bath and if the bird
bath dries out Bdelloid (the B is silent) rotifers can shrivel
to a cyst like form which can remain in a state of suspended
animation and withstand years of desiccation or extremes of
temperature (a state known as anabiosis).
Rotifers sometime become infected with a
deadly fungi, whereupon they dry out and become a cyst and get
blown away by the wind . The fungi is far more sensitive to
dehydration than the rotifer and the longer they remain dried
out the more successful they are at ridding themselves of fungi
and escaping death. Once they return to water they can
re-establish a
parasite free population.
 A
new study just published in the
Proceedings of the National Academy of Sciences
challenges the decades of
accepted theories about the evolution of flight. A new analysis
was done of an unusual fossil specimen discovered in 2003 called
“microraptor” in which three-dimensional models were used to
study its possible flight potential, and it concluded this
small, feathered species must have been a “glider” that came
down from trees.
The research is well done and consistent with a
string of studies in recent years that pose increasing challenge
to the birds-from-dinosaur theory. The weight of evidence is now
suggesting that not only did birds not descend from dinosaurs,
but that some species now believed to be dinosaurs, may have
descended from birds.
Small animals such as velociraptor that had
generally been thought to be dinosaurs are more likely
flightless birds. Raptors look quite a bit like dinosaurs but
they have much more in common with birds than they do with other
theropod dinosaurs such as Tyrannosaurus, and the evidence is
finally showing that these animals which are usually considered
to be dinosaurs were actually descended from birds, not the
other way round.
A new type of flying reptile has also been found
providing the first clear evidence of an unusual and
controversial type of evolution. Pterosaurs, flying reptiles,
also known as pterodactyls dominated the skies in the Mesozoic
Era, the age of the dinosaurs, 220—65 million years ago.
Scientists have long recognised two different groups of
pterosaurs, primitive long-tailed forms and advanced
short-tailed pterosaurs, some of which reached gigantic size.
These groups are separated by a large evolutionary gap ,
identified in Darwin’s time that looked as if it would never be
filled—until now.
This new pterosaur has been christened
Darwinopterus,
meaning Darwin’s wing honouring the 200th
anniversary of Charles Darwin’s birth and t he
150th anniversary of the publication of
On
the Origin of Species.
More than 20 fossil skeletons of
Darwinopterus,
some of them complete, were found early last year in north-east
China in rocks dated about 160 million years old. This is close
to the boundary between the Middle and Late Jurassic and at
least 10 million years older than the first bird,
Archaeopterus.
There were very few reported sightings during
February. A pod of 6 Bottlenose
Dolphins was seen
off St Ives on the 7th, and 10 dolphins seen off Carnello Long
Rock were probable also Bottlenose, as were 7 dolphins seen off
St Agnes Head on the 25th.
A pod of 10 Common
Dolphins was seen off Cape Cornwall on the 7th and a Grey Seal
was seen off St Ives on the 13th. There were 4 other reports of
Harbour Porpoises. One was seen north of the Runnelstone on the
12th, 3 adults and a baby were seen 1 Km southwest of Gwennap
Head on the 17th, An adult with a baby was seen right by the
Runnelstone on the 22nd. One was also seen travelling west off
Gwennap Head on the 25th.
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