Hello.
This is 6 Minute English from BBC Learning English.
I’m Rob.
And I’m Sam.
When we think about famous figures in the history of
science, people like Albert Einstein and
Marie Curie, the name of Charles Darwin often comes up.
Darwin is most famous for his theory of evolution,
the idea that animals change and adapt in response
to their environment.
In the 1830s he visited the Galapagos,
a string of islands in the Pacific Ocean
famous because of the unique animals living there.
It was while in the Galapagos, observing small birds
called finches, that Darwin started forming his theory of
evolution.
But today, the animals of the Galapagos face
the same pressures as animals across the world
because of the effects of man-made climate change.
Warming sea waters and more frequent extreme
weather events are affecting animals
as much as humans, so, in this programme,
we’ll be asking ‘can animals evolve
to deal with climate change?’
But first I have a question for you, Sam, and it’s about
Charles Darwin’s trip to the Galapagos.
In 1831, Darwin set sail around the world,
collecting samples of flora and fauna,
the plants and animals, of the places he visited.
But what was the name of the ship he sailed in?
a) HMS Beagle b) HMS Victory
c) SS Great Britain
Hmm, maybe it was B. HMS Victory.
Are you sure?
No.
OK.
I’ll reveal the correct answer later in the programme.
Now, it may have been the Galapagos finches that started
Charles Darwin thinking about how animals adapt to
their environment but, as naturalist, Kiyoko Gotanda
explained to BBC World Service programme The Climate Question,
Darwin’s first impression of the small birds
wasn’t very good:
When Darwin got to the Galapagos Islands,
he actually wasn’t that interested in the finches
– they were kind of a drab colour and didn’t have a
very interesting song.
He sampled, though, the finches from different
islands, and so when he got back to England he was
looking at all the variation in beak shape and size,
and body size and shape, and he was recalling how
certain finches were found on certain islands
but not on other islands.
In contrast to more colourful birds like Galapagos parrots,
the finches Darwin observed were drab, dull and
boring-looking, with little colour.
Instead, what Darwin noticed were variations in the finches’
beak, the hard, pointed part of a bird’s mouth.
Finches born with a beak that could help them get
more food were more likely to survive and have babies.
Over time, as the birds passed on their successful genes,
they adapted to fit in with their environment
– what we know as evolution.
So, if animals can evolve to survive their environment,
can they also evolve to cope with the impact humans
are having on the climate?
Well, there’s already some evidence to show they can.
Studies on birds in the Brazilian Amazon and red deer
on the Isle of Rum, in Scotland, show warmer temperatures have
caused animals to evolve smaller bodies.
It’s easier to keep cool when you’re small!
American conservationist Thor Hanson records and measures anole lizards
in the Caribbean.
He wants to see how the effects of man-made
climate change, in this case hurricanes, is affecting the lizards.
Listen to what Thor found out as he speaks with presenters of
BBC World Service’s The Climate Question.
What you can see is that large toe pads and strong
front legs give some lizards a tighter grip.
When they do start to let go and their body starts flapping
in the air like a flag, smaller back legs reduce
the drag, and allow them to cling on and survive the hurricane.
So the survivors were those lizards with those
characteristics, and they passed those traits along
to their offspring.
Thor’s lizards developed stronger front legs and smaller back legs,
allowing them to cling on, hold on to something tightly,
when hurricanes pass through.
It’s this trait, a genetically-determined
characteristic, that allows the lizards to survive,
and is passed on to their babies.
Thor checked other areas of the Caribbean where
hurricanes were frequent and found the same traits
in lizards there, proof of evolution in action.
But whereas we often think of evolution happening
over hundreds, even thousands of years, the changes in the
Caribbean lizards happened in around forty years,
something that would have surprised Charles Darwin.
Which reminds me of your question, Rob.
Yes, I asked you for the name of the ship Darwin sailed
around the world in.
Darwin’s ship was called the HMS Beagle and,
appropriately enough, it was named after an animal!
A beagle is a type of dog.
OK, let’s recap the vocabulary from this programme about
evolution, the way living things adapt to their environment
and pass these adaptations on to their children.
Flora and fauna is another way of saying the plants and animals
of a place.
Drab means dull and colourless in appearance.
A bird’s beak is the hard, pointed part of its mouth.
To cling on means to hold on very tightly.
And finally, a trait is a genetically-determined
characteristic.
Once again, our six minutes are up!
Join us again soon for more interesting topics and useful
vocabulary here at 6 Minute English.
Goodbye for now!
Bye!