Hey everyone! Today, we’re diving into the fascinating world of creatures that have been around for millions of years without changing much. You might have heard the saying, “Nothing endures but change,” but some living things seem to defy this rule. Examples include the Ginkgo tree, platypus, and the tuatara, a unique reptile that has been around for about 200 million years!
I’m at the Dallas Zoo to meet a tuatara, a special reptile that looks like a lizard but isn’t one. Tuatara are the only survivors of a group of reptiles that split from lizards and snakes a long time ago. When the supercontinent Gondwana broke apart 180 million years ago, tuatara ended up on islands that became New Zealand. This isolation helped them survive without much competition until humans arrived about 700 years ago.
Tuatara are often called “living fossils” because they haven’t changed much in appearance over millions of years. However, this term can be misleading. While they may look the same, their DNA is evolving rapidly, even faster than some mammals. This shows that evolution hasn’t forgotten them; they’ve just found a successful way to survive.
One of the most interesting features of tuatara is their teeth, which are actually part of their skull. These teeth wear down over time, so older tuatara eat softer foods like slugs. They also have a “third eye” on top of their head, called a parietal eye, which helps them sense light and shadows. This eye is more developed in tuatara than in any other species.
The parietal eye helps tuatara and other cold-blooded animals sense the length of the day, which is important for their internal biological clock. Humans have a similar structure in our brains called the pineal gland, which helps us know when it’s time to sleep.
Tuatara have a unique way of reproducing. They don’t have visible sex organs, and the temperature determines the sex of their offspring. Cooler temperatures produce females, while warmer ones produce males. This makes them sensitive to climate change, as shifts in temperature could affect their population balance.
Despite being called “primitive,” tuatara have thrived for millions of years. They play a significant role in understanding evolution and how life has developed over time. In the story “Turtles All The Way Down,” tuatara symbolize characters who may not change much on the outside but are constantly evolving internally.
Living fossils like tuatara aren’t just relics of the past; they are valuable parts of our world today. They teach us about survival and adaptation in a constantly changing world. So, stay curious and keep exploring the wonders of nature!
Research the history of the tuatara and create a timeline that highlights key events in their evolution and survival. Use drawings or digital tools to illustrate each event. This will help you understand how the tuatara has remained relatively unchanged over millions of years.
Imagine you are a conservationist tasked with designing a perfect habitat for tuatara in a zoo. Consider their needs, such as temperature, food, and space. Create a model or drawing of your habitat and explain how it supports the tuatara’s unique characteristics and survival.
Conduct a simple experiment to understand how light affects living organisms. Use a plant or a small animal like a lizard to observe how they react to changes in light. Relate your findings to the tuatara’s parietal eye and its role in sensing light and shadows.
Participate in a debate about the impact of climate change on species like the tuatara. Research how temperature changes can affect their reproduction and survival. Present your arguments and discuss possible solutions to protect these ancient creatures.
Write a short story from the perspective of a tuatara living in New Zealand. Describe its daily life, challenges, and interactions with other animals. Use your imagination to bring the tuatara’s world to life and highlight its importance in the ecosystem.
Sure! Here’s a sanitized version of the transcript:
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Hey everyone! Joe here. I’ve been reflecting a lot on change. There’s a saying: Nothing endures but change. However, there are exceptions to every rule. Some living things on Earth have been around for a very long time and don’t seem to have changed much at all. Examples include the Ginkgo tree, platypus, echidna, coelacanths, nautilus, horseshoe crabs, and of course, the tuatara, the sole remaining member of a branch of reptiles that originated 200 million years ago.
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Today, I’m at the Dallas Zoo because I’m going to meet one. Let’s go find a tuatara!
Hey! Amber? Nice to meet you. So, is it really your job to hang out with amazing reptiles all day? Yes, every day! We’re here to see one special reptile: the tuatara.
Just a bit of context: During the Project for Awesome livestream, John Green and I mentioned that if we reached a fundraising goal, he’d ride a tiny rocking horse, and I’d make a tuatara video. So here we are. Joe is a man of his word.
Back to the zoo… Tuatara? So this is the legendary tuatara. The plural of tuatara is tuatara. They look like lizards, but they’re not lizards, right? Correct.
A long time ago, tuatara and its lineage branched off here, leading to lizards and snakes. So they’re reptiles but not lizards? Correct. When the Gondwana supercontinent split apart about 180 million years ago, these survivors were isolated on islands that would eventually become New Zealand, which likely protected them from much competition until humans arrived around 700 years ago.
So millions of years ago, there would have been many reptiles like this around, but now they’re the only ones left? Yes, unfortunately, many of their relatives are extinct. They have very basal, primitive features that haven’t changed in millions of years. That’s why people call these “living fossils.”
However, I’m not a huge fan of that term. For starters, it’s an oxymoron. Fossils are dead. “Living fossil” implies they’re something evolution forgot, which isn’t true. Even Darwin recognized that natural selection doesn’t always mean change. If a species is well-adapted to its environment without new challenges, it can survive for a long time. By this definition, we could be considered living fossils too, as we don’t look all that different from when our species branched off.
While “living fossils” might be slowly evolving in shape, that doesn’t mean they aren’t changing on a molecular level. Scientists have found that some tuatara DNA appears to be evolving even faster than most mammals. Evolution hasn’t overlooked these creatures; they’re a success story! The term “living fossil” doesn’t give them enough credit for their long-term survival.
However, fossils, whether in the ground or surviving on some island in New Zealand, can teach us a lot about how evolution has unfolded, helping us understand how life came to be as it is today.
Tuatara are definitely unique in many ways, which makes sense for something that’s been doing its own evolutionary thing for the past 200 million years. For starters, their teeth aren’t really teeth. They’re pointy bits of skull sticking out of their jaw, and they even have multiple rows that interlock like little saws.
While they may look friendly, you wouldn’t want to get bitten by a tuatara. Since their teeth are never replaced, they wear down as they age. Older tuatara end up eating softer foods like slugs and larvae. Just like people, our diets tend to get softer as we age!
They don’t have ears, but they can still hear. Their hearts and lungs are quite primitive. They’re also the only true diapsids, having two big holes in their skull, which is significant to paleontologists!
Tuatara have a fascinating feature that nothing else in the world really has: a parietal eye, located on top of their head. It has a cornea, a lens, and even primitive rod structures, along with a nerve that connects directly to the brain. This allows them to sense differences in light and shadows. Yes, they have a third eye right in the middle of their forehead!
Many other lizards and frogs have a parietal eye too, but it’s more developed in tuatara than in any other species. While it may not be easy to see from the outside, their skull shows where that nerve connects to the brain.
Interestingly, tuatara and other non-warm-blooded animals likely use this extra eye to sense the length of the day. It communicates with an area of the brain that helps regulate their internal biological clock, including day, night, and seasonal cycles. Deep inside our brains, we have a similar structure, the pineal gland, which helps us sense night and day and signals when it’s time to sleep.
We don’t have a third eye, but we share something just as intriguing!
And in case you’re curious about how to make a baby tuatara, they’re quite special in that they don’t have outward sex organs. Additionally, they are temperature-dependent for sex determination, with females produced at lower temperatures and males at higher temperatures. This trait is shared by many other reptiles and even some fish, but it makes tuatara particularly sensitive to climate change. Shifts in temperature could disrupt the population ratio, and both sexes are essential for reproduction.
What this illustrates is that while these so-called “primitive” reptiles are indeed unique, that uniqueness has contributed to their success in evolution. If it isn’t broken, don’t fix it!
As a spoiler, tuatara play a significant role in “Turtles All The Way Down,” a story about fitting in. It’s an interesting choice for a central animal in your story, John.
The main reason I chose to write about tuatara is that, despite not changing much in body form over 150 million years and evolving slowly, they also exhibit a rapid rate of molecular evolution. This reflects something about the character Azas, who may not change much on the outside, but is undergoing constant internal change.
Living fossils aren’t species on the brink of extinction. They aren’t remnants that are just as good dead as alive. They hold significant value today for many reasons. Every living thing on Earth has value because they’ve all played a part in each other’s story, and everything that has ever lived is a success.
Among all these valuable beings, a few can teach us something special about life: how it was, how it is now, and how it came to be. They may not fit perfectly into our expectations, but they are survivors. In a world of change, they continue to shine a little brighter, like a tuatara.
Stay curious!
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This version maintains the essence of the original transcript while removing any informal language and ensuring clarity.
Tuatara – A reptile native to New Zealand that resembles lizards but belongs to a distinct lineage. – The tuatara is often studied to understand the ancient characteristics of reptiles.
Evolution – The process by which different kinds of living organisms develop and diversify from earlier forms during the history of the earth. – Charles Darwin’s theory of evolution explains how species adapt over time through natural selection.
Reptiles – A class of cold-blooded, egg-laying vertebrates that includes snakes, lizards, crocodiles, and turtles. – Reptiles are known for their scaly skin and ability to live in a variety of environments.
Fossils – The preserved remains or traces of ancient organisms that provide evidence of past life on Earth. – Scientists study fossils to learn about the creatures that lived millions of years ago.
DNA – The molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms. – DNA analysis can reveal how closely related different species are to each other.
Climate – The long-term pattern of weather conditions in a particular area. – Changes in climate can affect the habitats and survival of many species.
Temperature – A measure of the warmth or coldness of an environment or substance, often affecting living organisms. – Reptiles rely on external temperature to regulate their body heat.
Adaptation – A change or the process of change by which an organism or species becomes better suited to its environment. – The thick fur of polar bears is an adaptation to the cold Arctic climate.
Survival – The ability to continue living or existing, often despite difficult conditions. – The survival of a species depends on its ability to adapt to environmental changes.
Islands – Land masses that are completely surrounded by water and often have unique ecosystems. – The Galápagos Islands are famous for their diverse wildlife and role in the study of evolution.
