[Music] it is a matter of survival as basic as breathing the ability to deliver to mobilize muscle and nerve allows us to confront a world full of deadly challenges but how did animals first evolve the splendid machinery for motion what creatures gave rise to life's glorious dance although movement and behavior is quite complex in the animal kingdom we really can see the roots of movement in a very simpler primitive group they are creatures so simple that scientists once considered them plants but now we know they revolutionized they invented wiring they invented cabling that's what who
knows I this was an amazing leap for the animal world join us as we trace the path in sedentary life - glorious movement the trail blazed by some unlikely huge their legacy forever transformed the shape of life [Music] [Applause] [Music] [Music] motion is very beautiful thing movement is so much a part of our lives it's like breathing we don't think about it biologist Jack Costello is awed by the graceful ballet of life one of the defining characters are what we usually think of a trait of animals that sets them aside from example plants fungi is
the ability to move racing through life in an awesome display of speed agility and power animals certainly seem to be in constant motion often to rest is to invite attack animals sense the world around them and react ceaselessly pushing striking sparring [Music] but what did it take to bring this fast-paced drama to life off the rocky coast of Rhode Island lies a watery world that may hold the answer [Applause] Costello is on the trail of an ancient mystery if we could travel back hundreds of millions of years he believes we would find the Pioneers that
introduced movement and behavior to the animal kingdom but he doesn't need a time machine in these cold murky waters Costello thinks he can find a creature very similar to those ancient trailblazers in fact his quarry is easily found and just as easily overlooked although movement and behavior is quite complex in the animal kingdom we really can see the roots of movement in a very simpler primitive group this flower like creature is an anemone one of an ancient group of animals called cnidarians how could such simple creatures have given rise to life's diverse ballet at first
glance some cnidarians don't even look like animals [Music] cnidarians with their tentacles spread out growing on the bottom really don't look very different frequently from the algae that surround them so in fact the early scientists classified them as plants these organisms perplex scientists for centuries early naturalist wonder were they plants animals or something in between [Music] the scientists to solve the mystery was a keen observer of the natural world a Swiss naturalist named Abraham Trombley [Music] probably lived in Holland during the 18th century working as a tutor he introduced his students to the subtle wonders
of nature while investigating life in a pond he stumbled on a tiny green plant like organism at first Trombley thought they were mere Tufts of grass then to his astonishment he observed something completely unexpected he observed them moving [Music] the first movement that I noticed was in their arms which bent and twisted slowly in all directions thinking that they were plants I could scarcely imagine that this movement was their own [Music] after weeks of painstaking observation Trombley began to suspect that these were not plants after all but animals it was an audacious hypothesis in its
day but testing it was easy Trombley offered his subjects food and noted their voracious attacks I saw them digest animals as long and even longer than themselves [Music] thus I had hardly any further reason to doubt that they were carnivorous animals trombley's discovery that cnidarians were active predatory animals was a revelation for 18th century science in the centuries that followed it would lead to even more profound conclusions about animal life [Music] today Castello believes that the appearance of early cnidarians was the pivotal event that triggered a revolution there are certainly a critical group to study
in fact they are quite important if you want to understand motion and behavior hundreds of millions of years ago before animals swam the oceans waters or scurried along the sea floor one group of animals existed they were sponges unable to actively move on their own they lacked all but the most rudimentary senses sponges filter tiny food particles from the water by pumping the ocean through their bodies they were simple little more than a loose collection of cells then creatures far more complex sprang into being and change the world these first cnidarians they may not look
like pioneers but cnidarians marked a turning point for animal behavior these creatures were the first to wield sensitive tentacles that could actually reach out and perceive the world more than 500 million years ago cnidarians invented other features we take for granted today here was an animal with a mouth and connected to that mouth a stomach to digest food it was a brilliant innovation that would spread throughout the animal kingdom [Music] but cnidarians brought even greater inventions these deceptively simple creatures invented movement [Music] the very first animal movements may have looked much like these subtle stirrings
[Music] past the filly tentacles of this cnidarian inside its throat thousands of tiny hairs pour water into its body [Music] scene in time-lapse the animal seems to sprout and grow as water fills its body to create a liquid skeleton it can now stand erect poised for action with two sets of muscles cnidarians can bend in any direction to control their muscles they rely on another cnidarian invention special cells cells called nerves through a set of these nerves electrical impulses trigger one set of muscles to contract pushing the animal higher by contracting the other set of
muscles the animal can flex itself into the perfect pose for snagging food it looks so simple but all creatures that crawl soar or swim today rely on muscle and nerve their ancient inheritance from cnidarians appearances can be deceiving creatures that look slow and simple actually started the nimble dance of life cnidarians made that huge jump that jumped to nerve and muscle tissue that made possible all kinds of motions it's incredibly simple but very effective system that's a beautiful system the California coast is home to some of the most spectacular cnidarians on earth attracting scientists the
world over [Music] four biologist Ian long this rocky shoreline is a paradise by studying sea anemones long can imagine what the first animal behaviour may have actually looked like for me the really fascinating questions in biology all about origins where have we come from what sort of things started off the evolution of behavior and you've got to go back to a group like the cnidarians in order to study this question probably the most important thing that movement has provide the anemone is this ability to capture food [Music] cnidarians were the first active predators on the
planet like its ancestors this anemone may seem docile but it has tricks for snaring fast-moving flesh the goby is a swift swimmer with eyes and senses attuned to any sign of danger and a brain able to process complex signals it seems better equipped for survival [Music] [Music] the anemone however has developed weapons of its own [Music] lining its tentacles are millions of special capsules called nematocysts [Music] inside the capsules life thread-like projectors loaded with deadly poisons when unleashed these weapons fire with the acceleration of a rifle bullet they pierced their target and pump it full
of paralyzing toxins the tentacles must be touched before the weapons can discharge and for that the prey must come to the anemone it splat like appearance perfectly conceals its very deadly intent in silent ambush the anemone awaits its prey for the goby one unguarded moment could be fatal [Music] dragging the fish into its mouth the anemone devours it with tools invented by its ancient ancestors the goby will be slowly digested alive [Music] for more than half a billion years cnidarians have been honing and adapting their new mat assists and they've developed a stunning array of
weapons some are even laced with toxins that can be fatal to humans [Music] but these barbed projectiles are used for more than capturing food they are also weapons deployed against their own kind cnidarians like these may have been among the first animals to wage savage battles for turf these anemones appear to be peacefully coexisting in a tide pool on the surface all seems serene [Music] but trouble is brewing a struggle over a patch of rock [Music] splaying their tentacles the animals detect each other now there's no turning back [Music] each animal prepares for battle inflating
a series of sacs special tools for compound inside each sack are hundreds of thousands of weapons it is a veritable silo of warheads loaded with toxins [Music] but in order to deploy its weapons each combatant must reach out and strike its enemy [Music] and the fight begins in slow motion they deliver their devastating blows [Music] [Music] anemone battles can last for hours even days the fighting is brutal and can even lead to death [Music] with each strike thousands of poisonous weapons are unleashed penetrating flesh pumping soft bodies full of toxins [Music] as the arsenal is
used up the weapon sacks are left empty and tattered triumphant one anemone spreads its tentacles as though flaunting its victory the vanquished retreats within itself and will eventually move away [Music] animals have waged battles for dominance over hundreds of millions of years frenzy brawls for territory deadly battles for the right to mate these behaviors may have started with unassuming creatures while cnidarians may have sown the seeds of warfare and strife they also pioneered a more harmonious way of life cooperation these tiny coral polyps are also cnidarians and like their cousins they are predators dining on
plankton but these polyps forsake individual combat instead they are joined together in vast colonies [Music] instead of warring they build working together they create one of the greatest wonders of the natural world a spectacle of colors and formations like no other coral reefs [Music] off the northeast coast of Australia the Great Barrier Reef stretches for more than a thousand miles an unrivaled treasure teeming with a bounty of life all of it dependent on the labour of tiny cnidarians [Music] the reef is a marvel of cnidarian cooperation and productivity [Music] through the millennia this magical structure
the work of coral polyps has become so vast that it is visible from outer space [Music] to create such a magnificent structure corals ceaselessly grow and expand each species of coral synchronizes its spawning it is one of nature's most prolific spectacles and it happens on the same few nights each year no one fully understands what signals the millions of coral polyps to spew their eggs and sperm into the currents in a single swirling display by working together on an epic scale these cnidarians have found a way to guarantee their own rebirth cnidarians capture prey wage
battle and build great structures and they do it all with only basic nerves and muscles how they accomplish so much as long intrigued biologist ian long the reason that anemones hold a fascination for me it is that they have this seemingly very simply organized body plan and very simply organized nervous system and yet capable of fairly complex behavior patterns I was curious to see how they managed to do this lon decided to focus his research on the silent language of the cnidarians nervous system for his subject he picked one of the more unusual of all
anemones a solitary cnidarian called spawn fear anchored to a rock on the ocean floor it looks Valle neural but looks can be deceiving spam fear would seem to make an easy meal for any determined predator today it's being stalked by a stealthy foe the sea star derp mysterious sampling the water with its sensory tentacles a seastar inches toward its prey [Music] with legions of tube feet used in capturing and grasping its victims it is a well-armed hunter stop fear remains unaware of the approaching danger but Wender mysterious comes close enough to touch it ston feeis
springs into action [Music] in a stunning defensive maneuver ston via frees itself from the rock and screws away [Music] this is one of just a few anemones that can actually swim [Music] [Music] I was fascinated to see Houston fear was capable of actually producing this very complex behavior pattern when I brought it has a very simple nervous system I [Music] wanted to find out how it used that nervous system to produce such a complex behavior pattern in the laboratory lon attaches electrodes to stamfa to measure the frequency of its nerve impulses [Music] first he lightly
strokes Tom via with a paintbrush and the animal closes stampy is reaction to the paintbrush registers on the computer screen as pulses [Music] next lawn offers some fear food [Music] as expected it's nerves fire and the animal proceeds to eat finally laun uses a sea star to trigger ston fia's escape response all it takes is a single touch [Music] as nerve cells fire a rapid series of pulses appears on the screen Stan fiha makes its escape [Music] now let's just see how stumpy is able to perform this amazing swimming behavior look at the top here
we've got the feeding response and on the bottom is the swimming response and I can see from the shape of the pulses here that these responses are using exactly the same nervous system for both behaviors the difference is that the swimming response is essentially just up the temple so that we're getting a lot more pulses being fired in a much shorter interval by upping the temple stone fear has actually been able to use the same system to produce a completely new behavior [Music] Lon discovered that behavior is determined by both the frequency and the number
of times the nerves fire this exquisite system first perfected by cnidarians would be passed on throughout the animal kingdom [Music] the cnidarians were really the first group to have perfected this they invented wiring they invented cabling that's what nerves are nerves are cables that pass electricity through them this was an amazing leap for the animal world animals have evolved an astounding array of ways to move to act and react and it all began with cnidarians so we have a bright fit owing to this humble primitive group despite their revolutionary accomplishments most ancient cnidarians were bound
to the seafloor but theirs was a body plan that could not be held down for long exactly when or how it happened remains a mystery but over millions of years some cnidarians evolved in a dramatically new direction the edges of their mouth extended and they developed arm like feeding structures their tentacles became thin strands their cylindrical stalk transformed to a gelatinous Bell and a familiar ghost-like animal took shape [Music] with the evolution of jellyfish cnidarians may well have been the first element to swim the world's oceans with a body plan that would endure the ages
they entered watery realms across the planet today these ocean drifters are prolific and they come in a stunning variety of shapes and sizes many jellyfish are food for other organisms like this young sea turtle [Music] but jellyfish are hardly passive victims in fact they are dominant predators in many of the world's oceans [Music] trailing their deadly tentacles jellyfish slowly trawl for prey [Music] how could such wispy creatures seemingly unable to get out of their own way be such rapacious predators could their hypnotic pulsing movements carry a deadly secret in 1990 Jack Costello began to investigate
the mystery of how jellyfish move and feed what he discovered would change the way we view these diaphanous killers at Greenwich Cove in Rhode Island Costello leads a group of students back to where he conducted his breakthrough research in search of new insights Costello used an underwater video camera by capturing hour upon hour of jellyfish movement on videotape he could meticulously examine how and why they swim the way they do one focus of his research was a group called noon jellies moon jellies begin their lives as tiny polyps anchored to the seafloor [Music] they are
ghostly forms of life no larger than the tip of a pencil [Music] like so many cnidarians they seem perfectly ordinary and perhaps unexcited until you look closely at their hidden lives in fact just a few times each year moon jellies undergo one of the most fantastic transformations in the animal kingdom at some point those polyps though begin to divide and it's almost like they form little plates one on top of each other [Music] each polyp performs dozens of Orange plates each plate in turn becomes a single animal called Ana fira the ephyra can be considered
the juvenile jellyfish stage each of which breaks off from the pulp stem and swims away [Music] millions of years ago ancient cnidarians may have freed themselves from the seafloor in just such a way [Music] over the course of a month the juvenile jellyfish feed on plankton as they develop into adults [Music] [Music] fully grown they can reach nearly two feet in width when they spawn these jellyfish gather in massive swarms near the coast [Music] males cast threads of sperm into the water [Music] collecting the threads with their frilly arms females capture and ingest the sperm
which then fertilize their eggs [Music] accustomed to open seas they're delicate bodies can be battered in these swarms as they join together many will succumb and die [Music] within days their flimsy bodies break down and disappear but their offspring will take root as tiny polyps and start the cycle anew [Music] [Laughter] moon jellies have a remarkable life cycle but castella was more intrigued by something they do every day he is fascinated by the way they move [Music] his hours of videotape reveal that jellyfish swim constantly but for all their movement they don't seem to be
getting anywhere they do spend all their time swimming and they really don't make much forward progress [Music] so really that leaves us asking why would they spend their time sorry what equally confounded Costello was that jellyfish are not designed for easy movement through the water in fact their body plan seems shaped to slow them down that round disc like shape it's probably one of the least effective shapes for forward progress that we can imagine now there is ambient flow so it is coming in the animals moving with the current a flattened shape moving through the
water presents the most resistance in what we call drag of any form that you can imagine to get a clearer view of jellyfish in motion Costello established a simple experiment was there some hidden purpose in the jellyfish design perched above the rugged Big Sur coastline in Northern California the laboratory has been established to explore and document animal behavior not only this needs to be locked off doesn't it with a crew of filmmakers Costello demonstrates his experiment their subject a jellyfish the size of a water drop what we wanted to do was look at the action
of swimming and look at how it did interact with the fluid around Costello adds tiny particles to the tank enabling him to see how the water flows around the jellyfish now as the jellyfish swims it creates a visible current suddenly the animals secret is revealed what we found through looking at it is that this very high drag body form is very good at creating vortices and flow around the Bell margin so that the flow goes right through those tentacles and enables the jellyfish to capture its prey [Music] if it's swimming along here and actually it's
the swimming motion and the flow created by swimming that's bringing all the prey into the capture surfaces so that really the body that we think of as bad or ineffective for forward motion is very effective for creating the flow which enables that animal to feed [Music] in later work Costello revealed that each jellyfish shape creates its own distinct current allowing it to capture different prey but what may be most profound about Costello's discovery is that the first animal to launch itself from the seafloor and swim may have done so to ensnare its prey not to
give chase it's incredibly simple but very effective system becomes a little more sinister when you realize that it's the mechanism for these animals to swim through the water and essentially kill all their prey [Music] millions of years ago unlikely pioneers sparked a revolution cnidarians set animal life in motion assuring behavior on to life stage locked in the glorious and often savage ballet animals have followed in the megarians wake [Music] I know emotion is extremely complex it's really one of the characteristics that we usually attribute to animals the ability to [Music] we use nerves we use
muscles we use sensory cells all things which the cnidarians invented in the course of their evolution [Music] so much of what we take for granted today began with cnidarians [Music] they are the unsung heroes of the animal kingdom simple creatures that forever set into motion the Magnificent shape of life [Music] [Music] [Music]
