Evolution
How did all the incredible animals and plants on our planet get here? Join Bill Nye the Science Guy as we uncover the amazing, slow-motion process of evolution and discover exactly how living things change over millions of years to survive in a changing world.
The Greatest Survival Story Ever Told
They changed to fit their environments! The Earth has freezing poles, scorching deserts, and deep oceans. Over millions of years, living things slowly adapted and changed their physical bodies to survive perfectly in their specific, unique habitats.
No, evolution does not work like that! An individual animal cannot magically grow thicker fur just because the weather gets cold. Evolution is an incredibly slow process that requires hundreds or thousands of generations to pass down new, helpful traits to their babies.
Put Your Instincts to the Test
Think about how extreme traits develop in nature. Pick an answer for each question, then see if your instincts were right.
The giraffes born with naturally longer necks survived better! This is called Natural Selection. The ancient giraffes that could successfully reach the high food survived to have babies, while the short-necked ones did not. Over millions of years, the whole population evolved to have long necks.
Humans intentionally chose specific dogs to breed together! This is called Artificial Selection. By picking the fastest, smallest, or friendliest dogs to have puppies, humans bypassed natural evolution and created every single dog breed we see today.
Understanding the Science
Tap each card to uncover the biological mechanisms and ancient evidence that prove how life on Earth adapts, survives, and changes.
Key Concepts
Evolution
Tap to learn moreThe slow, gradual process where a species of plants or animals physically changes over many generations to adapt to their changing environment.
Natural Selection
Tap to learn moreThe rule of survival in the wild. The individuals best suited to their environment survive to pass on their winning traits, while those who cannot adapt go extinct.
Artificial Selection
Tap to learn moreWhen humans step in and intentionally breed specific plants or animals together to create highly desired traits, like a sweeter apple or a faster racehorse.
Fossils
Tap to learn moreThe preserved remains or traces of ancient, extinct life forms permanently trapped inside layers of sedimentary rock.
Mutation
Tap to learn moreA random, accidental change in a living thing's DNA blueprint that can occasionally create a brand new, helpful biological trait.
Adaptation
Tap to learn moreA specific physical or behavioural feature that has successfully evolved to help an organism survive in its unique environment.
DNA
Tap to learn moreThe complex, microscopic molecule inside every living cell that carries the vital genetic blueprint for how a living thing looks and functions.
Extinction
Tap to learn moreWhen every single member of an entire species dies out, almost always because they could not adapt fast enough to a drastically changing environment.
Try It: The Natural Selection Survival Lab
Welcome to the peppered moth forest!
Instructions: Use the slider to increase the pollution, turning the tree bark from light birch to dark soot. Then, activate the Hungry Birds! Watch carefully to see which moths safely survive to reproduce and how the population completely shifts to match the environment.
ENVIRONMENT IS STABLE
Apply Your Knowledge
Let us see if you can correctly identify the unique vocabulary of evolution.
Match the Concepts
Click an evolutionary term to select it, then click the matching description to place it.
best suited to their specific environment survive.
together to quickly create highly desired traits.
in rock layers, proving that life changes over time.
that can occasionally create a brand new trait.
Real World Challenge
If a sudden, extreme ice age permanently covered the entire Earth in thick, white snow, what specific random physical traits would help a population of brown bears survive and naturally evolve over the next thousand years?
What Has Changed Since This Episode Aired
This episode originally aired in 1995. While the fundamental laws of evolution discovered by Charles Darwin remain exactly the same, modern technology has completely revolutionised how we study biology!
Updated: Today, scientists do not just look at the physical shape of the bones! We have developed spectacular technology to actually extract ancient DNA directly from fossils. We can digitally read the genetic code of extinct creatures like Woolly Mammoths to see exactly how closely related they are to modern elephants!
Updated: Yes, humans no longer have to wait for random mutations! Scientists have developed revolutionary genetic tools like CRISPR, which allow us to precisely edit the DNA of living things in a laboratory. We can literally rewrite genetic code to cure diseases or make crops totally drought-resistant in a single generation.
Updated: Yes, thanks to a groundbreaking new field called Epigenetics! Scientists have discovered that while your underlying DNA code does not change quickly, your environment (like your diet, stress, or the climate) can actually turn specific genes "on" or "off" during your own lifetime. Even more amazingly, these temporary genetic switches can sometimes be passed down to your children, allowing populations to adapt to rapid environmental changes much faster than traditional evolution!
Test Your Understanding
Answer these 10 questions and get instant feedback. How many can you get right?
Results
Your score:
Reflection
Look out your window and think about the amazing variety of life in your own neighbourhood. How might a common animal, like a pigeon or a squirrel, continue to naturally evolve over the next million years if your city keeps getting hotter and more crowded?
Episode Discussion
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