木曜日は、マリーのはてな日記/Marie the Scientist
/Why did dinosaurs die out but some other animals live on? 」
/Why did dinosaurs die out but some other animals live on?
One day after school, my friend Haruto and I were looking for something interesting on the internet.
Just then, Haruto said,
“I can’t believe it.
A four-year-old girl in England was taking a walk with her Dad and guess what?
She found a footprint of a dinosaur in a rock.
Look at this picture.”
”This is amazing.
The footprint is so clear.”
”Scientists say this footprint is from 220 million years ago.
Oh, this is so cool.
I wish dinosaurs were still alive today.”
I really agreed with Haruto.
Then I wondered why dinosaurs disappeared from earth but we humans still live.
So Haruto and I decided to go to the science museum and asked a dinosaur expert.
“Sir, we have a question.
Why did dinosaurs die out but some other animals live on?”
“Do you both think all dinosaurs are dead?”
“To tell you the truth.
Dinosaurs didn’t all die out.
Some of them are still here.
Can you guess who they are?”
“I know lizards.”
But the answer is birds.”
“Birds are dinosaurs?”
“A long, long time ago, birds were born as one type of dinosaurs and they still live.”
“But birds aren’t big and strong like tyrannosaurs.
“That’s a good point.
What’s the difference?”
“Birds are small and birds have beaks for mouths.
“Those can be reasons why birds are still alive.”
“What do you mean?”
“When big dinosaurs died out, earth was very cold.
So there was not much food.
Maybe small animals were able to live on small amounts of food.
Thanks to their beaks, perhaps birds were able to eat small and hard things like plant seeds.”
“Birds and other small animals live through the difficult times.
Humans evolved from one of those animals.”
So the food was the key point.”
Animals that can eat different kinds of food are called generalists.
Animals that can eat only one kind of food are called specialists.
We know from history that generalists are stronger in difficult situations.
Eating all kinds of foods gives you the power to live.”
“I think I understand.
Pandas can only eat bamboo leaves so they won’t be able to live if there are no bamboo trees.”
“Humans are generalists, right?
That’s why we are still alive.
Thank you, sir!”
On our way home, Haruto said that he was now going to eat everything.
He respected tyrannosaurs before but now he also respects generalists.