Hi there! Welcome to MinuteEarth. I’m Jasper, and today we’re going to explore a surprising idea: you are a fish. Well, kind of. You don’t live in water, and you don’t have gills or fins, but there’s something fascinating about your connection to fish. It’s all about evolutionary history and how scientists classify living things.
In the past, animals were grouped together based on how they looked. This was before we understood evolution. Evolution teaches us that all animals are related through ancestry. The closer two species are on the evolutionary tree, the more recently they share a common ancestor. Sometimes, animals that look alike are not closely related at all.
Today, scientists use “clades” to name groups of species. A clade includes a single common ancestor and all its descendants. Imagine the tree of life: if you cut one branch, all the species that fall off form a clade. These species are more closely related to each other than to any species outside the clade.
For example, in the Great Ape section of the tree, if you cut a branch that includes humans and chimpanzees, you form a clade. This shows humans are more closely related to chimpanzees than to gorillas. If you cut higher up, including gorillas, you get a larger clade showing humans, chimpanzees, and gorillas are more closely related to each other than to orangutans.
To see how we’re related to fish, let’s look at a goldfish and a shark. Using our clade method, we cut the tree at the Gnathostomata branch to include both. Now, let’s add humans to the tree. Surprise! Humans are in the same clade as goldfish and sharks because you can’t separate humans from all fish without making more than one cut. So, if we grouped all “fish” together, humans and all mammals would be part of that group.
Is it wrong to say goldfish and sharks are fish but humans aren’t? Not really. It just means that category isn’t a clade. The traditional idea of “fish” as gilled, finned, water-dwelling animals can make us overlook this interesting truth: goldfish are more closely related to us than to sharks.
So, maybe you should start telling people you’re a fish! When they look puzzled, explain that you swim with the clade of thought.
If you’re curious about evolutionary trees, check out the app we created. Visit MinuteLabs.io and try the Tree of Life Explorer to build your own trees. Stay updated with our latest projects by subscribing to MinuteLabs on YouTube or supporting us on Patreon.
Using a large sheet of paper, draw an evolutionary tree that includes humans, goldfish, sharks, chimpanzees, and gorillas. Label each branch and explain how each species is related. This will help you visualize the concept of clades and understand how different species are connected through common ancestors.
Work in small groups to create a card game where each card represents a different species. Your goal is to group the cards into clades based on shared ancestors. Discuss with your group why certain species belong together and how they are related. This activity will reinforce your understanding of clades and evolutionary relationships.
Participate in a class debate on whether humans should be classified as fish based on evolutionary history. Prepare arguments for both sides, considering the traditional definition of fish and the scientific perspective of clades. This will help you practice critical thinking and understand different viewpoints on classification.
Visit MinuteLabs.io and use the Tree of Life Explorer to create your own evolutionary trees. Experiment with different branches and see how species are related. Share your findings with the class and discuss any surprising connections you discover. This online tool will enhance your understanding of evolutionary trees and clades.
Create an art project that represents the concept of humans being related to fish. Use any medium you like, such as drawing, painting, or digital art. Include elements that symbolize the evolutionary connections between species. Present your artwork to the class and explain the ideas behind your creation. This activity will allow you to express your understanding of the topic creatively.
Sure! Here’s a sanitized version of the transcript:
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Hi, welcome to MinuteEarth. I’m Jasper, and you are a fish. Well… sort of. Of course, you don’t live in water, nor do you have gills or fins. But there is certainly something interesting about you, and it has less to do with physical appearance and more to do with evolutionary history and how we classify species.
So, what makes a fish a fish? Traditionally, animals were grouped together based on shared physical characteristics, but this approach came long before we understood evolution. Evolution revealed that all animals are related by ancestry, and the more recently they share a common ancestor, the more closely related they are. Sometimes, animals that look very similar are actually quite distantly related.
Today, scientists name groups of species using “clades,” which take evolutionary relatedness into account. A clade is a group that includes a single most recent common ancestor and all of that ancestor’s descendants. An easy way to identify a clade is to cut one – and only one – branch off the tree of life. All the species that fall off will form a clade, and all species within that clade are more closely related to each other than to any species outside the clade.
For example, let’s look at the Great Ape section of the Tree of Life. We could cut here and have a clade for humans and chimpanzees. This shows us that we’re more closely related to chimpanzees than gorillas because gorillas are left out. But we could also go up a bit and make a cut that includes gorillas too. This is a larger clade and shows us that we’re more closely related to both chimpanzees and gorillas than to orangutans. So the whole evolutionary tree is actually a clade of clades of clades… all the way down to the tips.
To figure out how we relate to fish, let’s pick two animals we currently call fish – say, a goldfish and a shark – and first look at how they’re related to each other. Now let’s use our clade strategy and see if we can cut out a “fish” clade. To include both of these species, we’d need to cut the tree at the Gnathostomata branch.
Now let’s add humans to the tree and see where we are. That’s right! We’re actually in the same clade as goldfish and sharks because there’s no way to separate humans from all fish without making more than one cut. So if we wanted to group all the animals we currently call “fish” together under a clade naming scheme, humans – and in fact all mammals – would also need to be part of that group.
So is there something wrong with saying that goldfish and sharks are both fish, but humans aren’t? No, it just means that category isn’t a clade, and in some circumstances, that may be more useful. But if you think about it, that traditional association of the word “fish” with “gilled, finned, water-dwelling animal” does blind us to this interesting truth: although goldfish are related to sharks, they’re actually more closely related to us.
So maybe you should go around telling everyone that you’re a fish. And when people give you confused looks, just tell them you swim with the clade of thought.
You might have noticed some of the evolutionary trees in this video were created by an app. Well, we actually built that app, so you should definitely check it out! You can use it to explore the Tree of Life and build your own trees! Just visit MinuteLabs.io and look for the Tree of Life Explorer. You can also keep up to date with our latest creations by subscribing to MinuteLabs on YouTube or supporting us on Patreon.
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This version removes any informal language and maintains a professional tone while preserving the original content’s meaning.
Fish – A group of cold-blooded animals that live in water, have gills, and usually have fins and scales. – Many fish, like salmon, migrate long distances to spawn in freshwater rivers.
Evolution – The process by which different kinds of living organisms develop and diversify from earlier forms during the history of the earth. – The evolution of birds from dinosaur ancestors is a fascinating topic in biology.
Clade – A group of organisms believed to have evolved from a common ancestor, according to the principles of cladistics. – Scientists study the clade of reptiles to understand how they adapted to different environments.
Species – A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. – The giant panda is a species that is native to China and is known for its distinctive black and white fur.
Ancestor – An early type of animal or plant from which others have evolved. – The woolly mammoth is an ancestor of the modern elephant.
Tree – A diagram that shows the evolutionary relationships among various biological species based on similarities and differences in their physical or genetic characteristics. – The evolutionary tree of life illustrates how all species are related through common ancestry.
Humans – A species of highly intelligent primates known as Homo sapiens, characterized by their ability to use complex tools and language. – Humans have developed advanced technologies that allow them to explore outer space.
Goldfish – A small domesticated fish that is often kept in aquariums and is known for its bright orange color. – Goldfish are a popular choice for beginner aquarists because they are easy to care for.
Sharks – A group of cartilaginous fish known for their sharp teeth and predatory nature. – Sharks have been around for millions of years and are considered top predators in the ocean.
Mammals – A class of warm-blooded animals that have hair or fur and whose females produce milk to feed their young. – Mammals like dolphins and whales have adapted to live in the ocean, even though they breathe air.
