Eliza Ewing – TEDx Talk TRANSCRIPT
This is a story about two things.
Firstly, it’s a story about cephalopods. Specifically, the cephalopods in a special subclass called Coleoidea – octopuses, cuttlefish and squids. It’s a story about where they came from and how they came to be some of the most captivating and intelligent animals on the planet.
But it’s also, to some degree, a story about me. And a story about how I learned that weird can be beautiful.
See, when I was a kid, I was weird. I was chubby and shy, excruciatingly sensitive about my looks, heartbroken that I was never invited to sleepovers or parties. I wanted to be cute and perky, but I wasn’t.
I was big and strong and serious in a distinctly uncute and unperky way. No matter what I did, I always stuck out. Weird became the word I used to sum up the avalanche of negative things that I felt or thought about myself.
It was the embodiment of this nagging feeling I had, that I never quite fit in.
Meet Sepia apama, the giant cuttlefish. He never fits in either. For instance, he has one of the largest brain-to-body ratios of any invertebrate. He perceives his world with a magnificent optical system that gives him 360-degree vision and the ability to see and use directionality of light, otherwise known as polarization, and otherwise unavailable to animals with complex eyes, including humans.
When he needs to disguise himself, he’ll activate a complex network of color-changing cells called chromatophores to change color in a fraction of a second, or hypnotize his prey by flashing moving displays of color across his body in a way that is literally impossible for any other animal.
Could you imagine that despite all that, this little guy is colorblind? Equally colorblind, but now glowing, is this bigfin reef squid. He also has chromatophores that let him change color at the drop of a hat, which he uses for camouflage and signaling. He also has a high concentration of cells called iridophores, which let him be iridescent in his nighttime waters.
Like his cousins, he has hundreds of suckers covering each of his arms. Each sucker is individually enervated by the brain so that he not only feels what he touches, but tastes and smells it, too.
Some larger species of squid, like the famous giant and colossal squids – which are hard to document but which, we think, could grow in excess of 50 feet long – also have claws on their suckers that can rotate 180 degrees, for the more efficient grabbing of large prey. Isn’t that horrifying?
There are no claws here, but there are plenty of strange things about the octopus. This octopus, Octopus vulgaris, to be specific, the common octopus, has exactly one single hard part – the hard beak, hidden in the middle of her arms. That means that any hole larger than that beak is fair game for squeezing through or hiding in.
Inside the beak is a long spine covered tongue, called a radula. When she captures prey, she’ll use these unorthodox mouth parts to drill a hole into its eyeball and inject it with a cocktail of immobilizing neurotoxins.
But she still has to be careful when she eats because her brain is shaped like a doughnut, and it circles her esophagus. Too big a bite of something with a sharp edge could puncture the esophagus and damage the brain. Wild! That was a lot, and I’m sure you have questions.
Possibly the first one is why on earth I want to talk to you about this? I’m studying to be an evolutionary biologist. Evolutionary biologists are scientists who study not only how organisms change over time, but why they change.
We’re interested in the relationships between organisms, and between organisms and their environment that cause them to change or to develop new characteristics and behaviors. Part of that is understanding what the organisms are like today; part of it, understanding what they may have looked like millions or even billions of years ago.
If we start with today, cephalopods are marine invertebrates. In the specific subclass I study, there are three kinds: octopuses, cuttlefish and squids. They share certain characteristics, like their beak, the number of arms they have – octopuses have eight, cuttles and squids have eight arms plus two special feeding tentacles for a total of ten – complex eyes, color-changing skin, and a siphon that they use to swim with, which is like if you had to catch your lunch by breathing really, really hard in the other direction.
There are others, but the main thing they share is a lineage, and that’s one of the weirdest things about them. Octopuses, cuttlefish and squids are members of the phylum Mollusca. They are molluscs, just like barnacles, clams, oysters and snails.
Think about that. This proves for all time that your family reunions are not the only ones full of people you can’t believe you’re related to. Their ancestry is weird, and the obvious question to a biologist is, “What relates a snail to a squid?” Well, like every other organism on the planet, octopuses, cuttlefish and squids are the product of a process called evolution.
Millions of years ago, cephalopods looked more like the modern nautilus. Their soft bodies were inside of hard shells, with their eyes and tentacles poking out of one end – usually, actually, pointed down.
These shells came in a variety of shapes. Some were round, like the modern nautilus, some looked like ice cream cones, and at times, paperclips, spirals or curlicues like this one were all fashionable, for reasons that are still debated.