Ah, autumn in New York City! The air is crisp, the leaves rustle underfoot, and there’s a peculiar smell in the air. But don’t blame the people; it’s actually coming from a tree called the ginkgo biloba.
The ginkgo biloba is a fascinating tree. It’s been around since before flowering plants and even witnessed the age of dinosaurs! It’s a unique species, standing alone in its category of seed-producing plants. However, its seeds have a very strong and unpleasant odor.
When the seeds fall to the ground, they release a smell similar to rancid butter. This might seem strange if the goal is to grow new trees. Unlike seeds that travel through the air, ginkgo seeds need help to move away from the parent tree to avoid competing for resources. Usually, plants use fruits to attract animals to eat their seeds. Animals then help spread the seeds by excreting them elsewhere, complete with natural fertilizer.
Now, let’s talk about avocados. The avocados we eat today are similar to those that grew in Mexico and Central America hundreds of thousands of years ago. They have thick skin, tasty flesh, and a large seed in the center. But today, no animals can eat an avocado seed whole without discomfort. The avocado continues to produce fruit for an animal that no longer exists.
Imagine a giant ground sloth, big and hungry, reaching for avocados. These sloths could chew the seeds enough to eat the fruit without harm. As they moved on, their digestive systems would process the seeds, allowing new trees to grow from them.
This relationship between plants and extinct animals is called an evolutionary anachronism. Biologists Daniel Janzen and Paul Martin introduced this idea in 1982. We all have evolutionary anachronisms, like goosebumps, our appendix, and facial hair—traits that evolved but are no longer needed.
Prehistoric megafauna, the large animals that helped spread these seeds, went extinct around 10,000 years ago. Many plants have struggled without them. Normally, these evolutionary anachronisms might lead to extinction, but humans have been cultivating these plants for thousands of years, allowing them to survive.
The avocado, for example, might have gone extinct, but because we love its taste, it continues to thrive. Similarly, the ginkgo biloba is still around because it provides excellent shade. It’s encouraging to know that we can help preserve plants whose natural partners are long gone.
Thanks to the remnants of evolution, a ginkgo tree grows in Brooklyn, dropping its seeds and waiting for a creature that will never return. If you’re curious about unusual fruits, evolutionary anachronisms, and extinct megafauna, check out “Ghosts of Evolution” by Connie Barlow.
Special thanks to Brian Switek, a fantastic paleontology writer, for his help with this topic, and to Mike Rugnetta from Idea Channel for inspiring this discussion. Thank you for reading, and stay curious!
Collect fallen ginkgo leaves from your neighborhood or schoolyard. Use these leaves to create an art project that represents the ancient history of the ginkgo tree. You can make leaf rubbings, create a collage, or design a poster that highlights the unique features of the ginkgo. Share your artwork with the class and explain what you learned about the ginkgo’s history and its evolutionary significance.
In groups, choose a plant or animal that is an example of an evolutionary anachronism. Research its history and the extinct animals it once interacted with. Create a short skit or role play to present to the class, illustrating how these relationships worked in the past and how they have changed over time. Discuss the impact of these changes on the plant or animal’s survival.
Design an experiment to explore different methods of seed dispersal. Gather various seeds and test how they travel using wind, water, or animals. Predict which method would be most effective for a seed like the ginkgo’s. Record your observations and present your findings to the class, explaining how seed dispersal is crucial for plant survival and how it relates to evolutionary anachronisms.
Create a timeline that traces the history of the avocado from prehistoric times to the present day. Include key events such as the extinction of its ancient seed dispersers and its cultivation by humans. Use images, drawings, and facts to make your timeline engaging. Present your timeline to the class and discuss how human intervention has helped preserve the avocado despite its evolutionary challenges.
Read selected chapters from “Ghosts of Evolution” by Connie Barlow. Write a book review that summarizes the main ideas and discusses how the book enhanced your understanding of evolutionary anachronisms. Share your review with the class and recommend whether others should read it. Highlight any surprising facts or insights you gained from the book.
Sure! Here’s a sanitized version of the transcript:
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Ahh, autumn in New York City. The crisp air, the rustling leaves, and what is that smell? It seems like something unpleasant is in the air! Don’t blame the people; blame this tree: the ginkgo biloba.
The ginkgo biloba is a unique tree. It was around before every flowering plant on Earth and witnessed the age of dinosaurs. Out of the five categories of plants that produce seeds, the ginkgo stands alone as a singular species. It’s quite an evolutionary oddity, and unfortunately, its seeds have a very strong odor.
Beneath your feet, the fallen seeds release a chemical that resembles the scent of rancid butter. This might seem like an odd strategy if the goal is to propagate new trees. Unlike airborne seeds, which can disperse easily, seeds from trees need to be carried away to avoid competing with their parent plants for resources. Fruits are a way for plants to entice animals to eat their seeds. While we might discard these seeds, animals consume them, and later, they are excreted, complete with natural fertilizer.
Now, consider the avocado. The avocados we enjoy today are not vastly different from those that grew in Mexico and Central America hundreds of thousands of years ago. They have a thick skin, nutrient-rich flesh, and a large seed in the center. However, there are no animals today that can eat an avocado seed whole without discomfort. The avocado continues to produce fruit for an animal that no longer exists.
Imagine a giant ground sloth, hungry and capable of reaching those avocados. Since avocado seeds contain toxins, the sloth would chew them enough to access the flesh, consuming the entire fruit. As it moves on, its digestive system would process the seeds, and thanks to the natural properties of avocados, it wouldn’t be long before new trees could sprout from the seeds.
This relationship between living plants and extinct animals is known as an evolutionary anachronism. Biologists Daniel Janzen and Paul Martin popularized this concept in 1982. In fact, we all carry evolutionary anachronisms: goosebumps, our appendix, and facial hair are examples of traits that we have evolved but are no longer actively selected for.
Prehistoric megafauna, the large animals that used to help disperse these seeds, went extinct around 10,000 years ago. Since then, many plants have struggled without them. Normally, these evolutionary anachronisms might lead to extinction, but humans have been cultivating these plants for thousands of years, which has allowed them to survive.
The avocado, for instance, should have faced extinction, but because we enjoy its taste, it continues to thrive. Similarly, the ginkgo biloba exists primarily because it provides excellent shade. It’s encouraging that we can do more than just drive species to extinction; we can also help preserve plants whose natural partners are long gone.
Thanks to the remnants of evolution, a ginkgo tree grows in Brooklyn, dropping its seeds and waiting for a creature that will never return. If you’re interested in learning more about unusual fruits, evolutionary anachronisms, and extinct megafauna, check out “Ghosts of Evolution” by Connie Barlow, linked in the description.
Special thanks to Brian Switek, a fantastic paleontology writer, for his assistance with this episode, and to Mike Rugnetta from Idea Channel for inspiring this topic. Thank you for watching, and stay curious!
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Let me know if you need any further modifications!
Ginkgo – A type of tree known for its fan-shaped leaves and is often called a “living fossil” because it has existed for millions of years. – The ginkgo tree is unique because it has survived major extinction events that wiped out many other species.
Tree – A large plant with a trunk, branches, and leaves, which provides oxygen and habitat for many organisms. – The oak tree in our backyard is home to several bird species and provides shade during the summer.
Seeds – The reproductive part of a plant that can grow into a new plant, often protected by a shell or fruit. – After the flowers bloom, the plant produces seeds that can be collected and planted to grow new flowers.
Evolution – The process by which different kinds of living organisms develop and diversify from earlier forms over generations. – The evolution of the giraffe’s long neck is believed to help it reach leaves high in trees.
Extinct – A term used to describe a species that no longer exists anywhere on Earth. – The dodo bird is an example of an extinct animal that was last seen in the 17th century.
Animals – Living organisms that can move and consume organic material for energy, including mammals, birds, reptiles, and more. – Animals like elephants and lions are often found in the savannas of Africa.
Avocado – A fruit with a large seed and creamy flesh, often used in salads and known for its healthy fats. – The avocado tree in our garden produces fruit that we use to make guacamole.
Plants – Living organisms that typically grow in soil, have leaves, stems, and roots, and use sunlight to make food through photosynthesis. – Plants like sunflowers and roses need sunlight and water to grow and thrive.
Megafauna – Large animals, often from the past, such as mammoths and saber-toothed cats, that lived during the Ice Age. – Scientists study fossils to learn more about the megafauna that roamed the Earth thousands of years ago.
Preservation – The act of maintaining or protecting something from harm or decay, often used in the context of natural environments or historical artifacts. – Preservation of rainforests is crucial for maintaining biodiversity and protecting endangered species.
