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- ISLAND ARCHIPELAGOS LIKE GALAPAGOS
ARE FAMOUS AS NURSERIES OF EVOLUTION,
AND EQUALLY FAMOUS AS A NURSERY OF EVOLUTION
IS THE HAWAIIAN ARCHIPELAGO.
IT'S A STRING OF ISLANDS,
AND THEY'RE VERY, VERY YOUNG.
THE OLDEST ISLAND IS ONLY ABOUT 5 1/2 MILLION YEARS OLD,
AND THE YOUNGEST ISLAND
IS ONLY ABOUT 1/2 MILLION YEARS OLD.
AND THEY'RE STRUNG OUT LIKE A NECKLACE.
THERE'S A TECTONIC PLATE MOVING THAT WAY,
MOVING OVER A HOT SPOT, A VOLCANIC HOT SPOT,
WHICH IS PUNCHING THROUGH AND MAKING ISLANDS,
AND SO IT MADE THAT ONE FIRST, THEN THAT ONE,
THEN THAT ONE, THEN THOSE ONES,
AND NOW MOST RECENTLY, THE BIG ISLAND OF HAWAII.
THAT MEANS THAT ALL THE EVOLUTION
THAT'S GONE ON IN THE HAWAIIAN ARCHIPELAGO
HAS HAPPENED WITHIN THE LAST FEW MILLION YEARS.
AND ONE OF THE MOST SPECTACULAR EXAMPLES IS FRUIT FLIES,
DROSOPHILA.
DROSOPHILA ARE WELL KNOWN AS EXPERIMENTAL ANIMALS
THROUGHOUT THE REST OF THE WORLD,
BUT ON HAWAII, THEY'RE ESPECIALLY FAMOUS
AS BEAUTIFULLY SEXUALLY SELECTED.
THEY'RE KIND OF INSECT VERSIONS OF PEACOCKS.
THERE ARE LOTS AND LOTS OF SPECIES ON HAWAII,
AND THEY'RE ALL DIFFERENT.
THEY'RE ALL GORGEOUSLY COLORED AND SHAPED,
AND IT'S ALL BECAUSE OF *** SELECTION,
SELECTION FOR THE MOST ATTRACTIVE MALES.
HERE'S A FAMILY TREE OF FIVE DIFFERENT SPECIES
OF HAWAIIAN DROSOPHILA,
AND IT'S NO ACCIDENT THAT THE OLDEST SPLIT
IS BETWEEN THE FLIES ON THE OLDEST ISLANDS.
AND THEN AS YOU GO TO SUCCESSIVELY YOUNGER ISLANDS,
YOU GET SUCCESSIVELY MORE RECENT SPLITS
BETWEEN THE SPECIES OF FLY.
DROSOPHILA FLIES SHOW THE MOST ELEGANT COURTSHIP BEHAVIOR.
YOU CAN SEE HERE A MALE COURTING A FEMALE.
THE LATE JOHN MAYNARD SMITH,
WHO WAS ONE OF THE GREAT EVOLUTIONARY BIOLOGISTS,
USED TO DO A WONDERFUL IMITATION OF FRUIT FLIES COURTING,
THE COURTSHIP DISPLAY OF FRUIT FLIES,
FLAPPING HIS COATTAILS IN A MOST WONDERFULLY COMIC WAY.
EVERY SPECIES DOES IT IN A DIFFERENT WAY.
THEY DISPLAY THE DIFFERENCES BETWEEN THE WING PATTERNS
AND THE OTHER CHARACTERISTIC DIFFERENCES BETWEEN THE SPECIES.
THEY ALSO HAVE SONG,
A SORT OF SEQUENCE OF BUZZING NOISES
WHICH ARE CHARACTERISTIC OF THE SPECIES--
QUITE COMPLICATED, LIKE CRICKET SONG,
BUT DIFFERENT, OF COURSE.
AND IT'S MADE BY VIBRATING THE WINGS.
AND EVERY SPECIES HAS A DIFFERENT KIND OF SONG,
A DIFFERENT PATTERN OF SONG,
AND THE FEMALES OF THE SPECIES RECOGNIZE IT.
[rhythmic buzzing]
[rattling croaking]