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vertebrates get a lot of credit for
being able to fly birds bats and
pterosaurs all took to the skies with
the help of modified forelimbs that
served as wings but spare a thought for
the insects who have all flight only
once and never looked back
they were the first animals to ever
develop the ability to fly and arguably
they did it the best
that's because evolution usually works
with what it has new body structures
don't crop up very often but in the case
of insects they didn't use modified
limbs to fly their wings were a brand
new innovation in their physiology and
in fact this development was so unusual
that scientists are still working on and
arguing about how and when insect wings
first came about so I'll tell you
upfront there's a lot we don't know but
one thing that experts do agree on is
that the ability to fly was something
totally completely new when insects
acquired it and it allowed them to take
over the world
I'd like to show you the very first
known insect as well as the first flying
insect but I'm afraid I'd start a brawl
among the paleontologists who study
these things because the fact is almost
every early insect fossil has been
disputed or has been accused of being a
different type of arthropod or even an
artifact of modern contamination one
contender for the first insect ever is
known as ray neo neethu Hearst II
discovered almost a hundred years ago in
Scotland this little guy is more than
400 million years old and it looks like
just an ink blot to somebody who doesn't
know what they're looking at in 2004
some American researchers interpreted
ray neo neethu as a flying insect even
though the fossil didn't have any wings
instead they looked at its mouth parts
and decided they resembled those of a
mayfly but this conclusion was
challenged in 2017 by another team that
used high-tech photography and decided
that Rhynie own atha was more likely a
kind of centipede not an insect at all
much less a flying one if Frannie onesa
isn't an insect then the contender that
everyone seems to accept is the earliest
known insect are some very fragmentary
pieces of EXO skeleton found in Gilboa
New York these little fragments are
about 380 million years old and are
thought to have belonged to insects from
the order arkeo Natha a group that
includes some of the most primitive
insects still alive today now the
earliest fossil evidence of a flying
insect seems to be the mayfly light
critter called della shala bitter fel
dances from 325 million years ago and
you'll notice there's quite a big gap
between the probably earliest insect and
the appearance of winged insects in the
fossil record paleontologists have
noticed this too where fossils of
insects are few and far between they
call it the hexa poda gap for roughly 65
million years basically the second half
of the Devonian period and the first
half of the Carboniferous insects
existed and continued to evolve but for
some reason they weren't preserved very
often in the fossil record this gap
complicates the issue of when flying
insects first appeared right now there
are two main competing theories one
theory holds that if ray neo neethu was
a flying insect that would
that the Terra goats the taxonomic group
that includes flying insects first came
about in the early devonian say more
than four hundred million years ago but
they didn't become very numerous or
diverse which would explain why they're
not represented well for those 65
million years until they suddenly
exploded in diversity in the late
carboniferous the other theory assumes
that rainy onesa was not a flying insect
so della kala is the earliest one we
know about which appeared tens of
millions of years later in this case
flying insects would have evolved before
delit shala but not as early as rainey
own atha and we just don't know when
thanks to the gap and sure enough
there's some evidence to support both of
these theories on one hand molecular
data for the origin of flying insects
line up with the age of radio Neethu
suggesting it or something that lived
during the same time might have been the
first a big ambitious study published in
2014
used genetic data to estimate the age of
the entire insect class they sequence
DNA from a hundred and three species of
insects representing every order known
to science and then they use this
massive amount of data to construct an
insect tree of life estimating when each
group of insects diverged from their
common ancestors studies like this are
based on the idea of the molecular clock
which hypothesizes that mutations build
up at a certain rate when that rate of
change is compared to what we see in the
fossil record it can be used to estimate
when a certain group first evolved and
the results suggested that flying
insects could have originated four
hundred and six million years ago in the
early devonian and that the common
ancestor of all insects lived a whopping
440 million years ago in the Silurian
period so the study didn't weigh in on
whether Ronnie Onassis specifically was
a flying insect but it said the timing
makes it at least plausible
now the competing theory relies more on
hard fossil evidence to determine when
insects first took flight of course
insects are small and fragile so they
don't make for great fossils but insect
wings fossilized pretty well and some
scientists argue that when we start
seeing wings 325 million years ago like
in Dulwich shala it's safe to conclude
that the wings evolved not long before
but one thing that most paleontologists
agree
and yes they do agree on something is
that when wings finally appeared they
changed everything the ability to fly
allowed insects to escape predators and
forage for food in ways and in places
that no other creature could before
winged insects represent the vast
majority of insects today and that
diversity may be the result of the
success that the power of flight gave
them but because wings appear to show up
so suddenly in the fossil record we
don't really know how this evolutionary
breakthrough came about
there aren't a lot of transitional
fossils to work with so how did Wings
evolve in the first place for a long
time it's been an open question as to
whether insect wings evolved as brand
new structures or were adapted from some
pre-existing body part the way bird
wings evolved from four limbs some
genetic and fossil evidence supports the
idea that wings started out as skill
structures many species of aquatic
insects have flat extensions on the
thorax and abdomen when they're in their
nip phase they sometimes have patterns
that look like the veins of wings and
they can even flap but while the gill
origin theory has received a good deal
of support more scientists now seem to
lean towards the wings being a brand new
kind of structure in recent years
scientists have hotly debated whether
the body tissue came from the top of the
insect known as the NOTAM or the side of
the body known as the pleura and again
there are good arguments on both sides
the NOTAM would have provided the stiff
rigid structure that wings need to
create lift and support the insect in
the air but having them develop on the
sides of the body would have offered
maneuverability and in fact research has
found that the genes that create movable
joints and insects activate on the sides
of the body since an insect's legs
develop from its sides and they
obviously move then possibly those same
genes or similar ones would be needed to
give the wings their ability to flap a
study of ancient insects conducted in
2017 said why not both it provided
support for the hypothesis that wings
could have come from both the top and
the sides this research looked at
insects from the late carboniferous like
IDO T lists in its nymphal form it had
two pairs of wing like structures plus a
third pair of stiff lobes extending from
the
sighs that might have been used for
thermoregulation the authors believe
these lobes represent what the earliest
form of insect wings were like most of
the structure came from the top
providing rigidity while the flexible
wing joint came from the side of the
body and even though these young insects
probably couldn't fly those lobes could
have been used to glide so it could be
that the ancestor of Altair goats had
three pairs of lobes to which could have
been used to glide from the tops of same
scale trees and then those lobes were
adapted for use as wings as insects
developed the musculature needed for
powered flight in the end we don't know
for sure when insects first flew or
where their wings even came from
for now the origins of insect flight
remain one of paleontologists great
mysteries but we do know that the
evolution of flight played a key role in
helping insects thrive as they do today
living on every continent and in nearly
every ecosystem as one of natural
history's greatest success stories
thanks for joining me today and thanks
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Duncan Miller and David Rasmussen thank
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