0:00:03 > 0:00:07Created by fire and titanic upheavals of the Earth,
0:00:07 > 0:00:11islands make up one-sixth of the landmass of our planet.
0:00:12 > 0:00:16They are lenses through which to study
0:00:16 > 0:00:18the complex workings of evolution.
0:00:18 > 0:00:22Tropical islands have been important in the understanding
0:00:22 > 0:00:26of evolution ever since Charles Darwin visited the Galapagos
0:00:26 > 0:00:28early in the 19th century.
0:00:28 > 0:00:31We're going to visit three very different tropical islands
0:00:31 > 0:00:35to see what they can tell us about evolution, even today.
0:00:36 > 0:00:41Islands are the natural world's testing grounds,
0:00:41 > 0:00:44full of novel experiments in natural selection,
0:00:44 > 0:00:47and evolutionary wonders.
0:00:49 > 0:00:54But there's much more to evolution than the survival of the fittest.
0:00:54 > 0:00:56The phrase wasn't even in Darwin's first edition
0:00:56 > 0:00:58of The Origin Of Species.
0:01:00 > 0:01:03I'm exploring other major influences.
0:01:03 > 0:01:05Geology,
0:01:05 > 0:01:07geography...
0:01:07 > 0:01:08Hello!
0:01:08 > 0:01:10..isolation and time.
0:01:10 > 0:01:11You found this?
0:01:11 > 0:01:14- Yes.- Giants' bones.
0:01:14 > 0:01:18I'll be charting the life cycle of islands,
0:01:18 > 0:01:20from birth and colonisation
0:01:20 > 0:01:23to the burst of evolutionary creativity
0:01:23 > 0:01:25that often accompanies maturity...
0:01:27 > 0:01:29They take the leaves so delicately.
0:01:30 > 0:01:35..and what eventually happens when an island grows old and nears its end.
0:01:35 > 0:01:40You can almost feel this unforgiving rock return, ultimately,
0:01:40 > 0:01:41to sea level.
0:01:42 > 0:01:45Places of extinction as well as creation.
0:01:46 > 0:01:50Our story will reveal evolution in action.
0:01:50 > 0:01:54We've just discovered new species of the mouse lemurs.
0:01:54 > 0:01:58- So mouse lemurs are still actively evolving?- Yeah.
0:01:58 > 0:02:02And how life generates abundance,
0:02:02 > 0:02:04even from a blank slate.
0:02:06 > 0:02:09Islands are the ideal place to understand the rules
0:02:09 > 0:02:12that govern evolution.
0:02:31 > 0:02:35In this first episode of the series, I want to investigate how
0:02:35 > 0:02:38animals and plants colonise and evolve on a newborn island.
0:02:40 > 0:02:43The remote Pacific island of Hawaii is home to
0:02:43 > 0:02:47creatures as unusual as carnivorous caterpillars...
0:02:48 > 0:02:52..as hardy as volcano-adapted plants
0:02:52 > 0:02:54and acid resistant shrimps.
0:02:56 > 0:03:00And as exquisitely adapted to their environment
0:03:00 > 0:03:02as nectar-feeding honeycreepers.
0:03:03 > 0:03:07Here, too, is the secret of how one lucky species
0:03:07 > 0:03:09can transform into many.
0:03:13 > 0:03:17A new island is a new opportunity for life.
0:03:17 > 0:03:21An oceanic island is a kind of natural laboratory
0:03:21 > 0:03:24where we can see evolution playing out.
0:03:24 > 0:03:28It's the place to understand the rules that might govern
0:03:28 > 0:03:30the origin of new species.
0:03:34 > 0:03:382,400 miles from the nearest continental landmass,
0:03:38 > 0:03:43Hawaii is the most isolated group of islands in the world.
0:03:43 > 0:03:46Its eight major islands are all volcanic
0:03:46 > 0:03:50and none of them are over five million years old, making them
0:03:50 > 0:03:53geological infants, many millions,
0:03:53 > 0:03:56even billions of years younger than the continents.
0:04:11 > 0:04:16On Hawaii, everything is volcanic, everything is lava.
0:04:16 > 0:04:19Even the sand is made of tiny little bits of broken-up lava.
0:04:24 > 0:04:28This is the kind of place that arises from the sea due to volcanic activity
0:04:28 > 0:04:32and creates a tabula rasa for evolution.
0:04:37 > 0:04:41Before life of any kind can exploit such opportunities,
0:04:41 > 0:04:45it must first face one of the greatest challenges in nature.
0:04:48 > 0:04:54How does an animal or plant reach a newly-erupted volcanic island?
0:04:54 > 0:04:58Very few organisms have learned the trick. But one that has...
0:04:59 > 0:05:00..the coconut.
0:05:02 > 0:05:06Its large fruits are covered with a buoyant coat and inside,
0:05:06 > 0:05:09there's a nut with lots of nourishment in it
0:05:09 > 0:05:13and indeed, some flotation, a bit of air.
0:05:14 > 0:05:18On ocean currents, they can be carried huge distances
0:05:18 > 0:05:23and when they land on a sandy beach almost anywhere...
0:05:26 > 0:05:28..they can germinate.
0:05:28 > 0:05:32Their plentiful supply of nutrition means that a strong shoot
0:05:32 > 0:05:34can put down roots.
0:05:34 > 0:05:37As a result, sometimes it's thought with man's help,
0:05:37 > 0:05:42they have colonised virtually all the tropical waters of the Pacific.
0:05:42 > 0:05:47The coconut palm has learned the trick of wide dispersal.
0:05:48 > 0:05:51But for almost all other organisms, it's much more sporadic,
0:05:51 > 0:05:54much more chancy, much more difficult.
0:06:01 > 0:06:04Water is an obvious route to virgin land
0:06:04 > 0:06:07for those animals and plants adapted to it.
0:06:28 > 0:06:31Bravely battling the currents to feed on the algae that cling to
0:06:31 > 0:06:36the underwater rocks, turtles haul themselves on land
0:06:36 > 0:06:37to bask, most mornings.
0:06:43 > 0:06:48One of the first animals to arrive on a new volcanic island like this
0:06:48 > 0:06:51would have been a seagoing turtle.
0:06:51 > 0:06:54They would have loved to come in, bask in the sun
0:06:54 > 0:06:56and lay their eggs on the sandy shores,
0:06:56 > 0:06:59especially if there were no natural predators.
0:07:11 > 0:07:14Even so, the Hawaiian form of the green turtle is often
0:07:14 > 0:07:18regarded as a special subspecies, endemic to the island.
0:07:21 > 0:07:24Green turtles are found all over the Pacific.
0:07:24 > 0:07:27But on Hawaii, they've become endemic,
0:07:27 > 0:07:30a word derived from the ancient Greek, meaning "native".
0:07:32 > 0:07:35Long isolated from others of their kind,
0:07:35 > 0:07:39through natural selection, each new generation has become
0:07:39 > 0:07:42increasingly better adapted to the local environment.
0:07:46 > 0:07:49Turtles evolve very slowly.
0:07:49 > 0:07:53But one day, Hawaiian green turtles may be so genetically different
0:07:53 > 0:07:57from others of their kind, they will no longer be able to breed with them.
0:07:58 > 0:08:01They will have become a new species.
0:08:03 > 0:08:06This process is not always so slow.
0:08:08 > 0:08:13In fact, on the isolation of an island, some plants
0:08:13 > 0:08:17and animals can rapidly evolve into not just one, but many new species.
0:08:19 > 0:08:22Scientists call this adaptive radiation.
0:08:25 > 0:08:29And one of the best examples of it anywhere in the world
0:08:29 > 0:08:31is found on the Hawaiian island of Maui.
0:08:35 > 0:08:41Here live numerous species of Hawaii's rare honeycreepers.
0:08:42 > 0:08:48And among those most exquisite adaptations is the shape of the bill.
0:08:48 > 0:08:51This is what Darwin observed at
0:08:51 > 0:08:55the very cradle of the idea of evolution in the Galapagos Islands.
0:08:55 > 0:08:59Another group of finches, another group of modifications
0:08:59 > 0:09:02to bill form, in adaptation to mode of life.
0:09:05 > 0:09:08The first finches arrived on Hawaii five million years ago
0:09:08 > 0:09:13and quickly radiated and adapted into five distinct lifestyles.
0:09:13 > 0:09:16Insect-picking gleaners,
0:09:16 > 0:09:18generalists,
0:09:18 > 0:09:20long-beaked nectar eaters,
0:09:20 > 0:09:22seed lovers
0:09:22 > 0:09:25and parrot-beaked bark pickers.
0:09:26 > 0:09:29But each of these different lifestyles
0:09:29 > 0:09:31has spawned multiple species.
0:09:31 > 0:09:35The total tally of these endemic birds once exceeded 50.
0:09:40 > 0:09:44Hoping to glimpse one of Hawaii's iconic honeycreepers for myself,
0:09:44 > 0:09:48I join Hanna Mounce of the Maui Forest Bird Recovery Project.
0:09:52 > 0:09:55More than a mile above sea level, Hanna takes me on a long hike
0:09:55 > 0:09:59to reach a high belt of surviving native forest.
0:10:08 > 0:10:11After a long trek, we reach our destination.
0:10:13 > 0:10:16And it's full of evergreen ohia lehua trees.
0:10:20 > 0:10:22DELICATE BIRDSONG
0:10:22 > 0:10:26(What I can hear now is a sort of subtle birdsong.)
0:10:26 > 0:10:29(Yeah, you can definitely hear them now.)
0:10:29 > 0:10:31(We're hearing three right now.)
0:10:31 > 0:10:34You can hear Apapane, the Iiwi and the Maui 'alauahio.
0:10:35 > 0:10:38(I suppose they're feeding on nectar if they can find it.)
0:10:38 > 0:10:43(Yeah, so they're following mainly the ohia lehua blooms
0:10:43 > 0:10:46(but because there's not really any flowers right now,
0:10:46 > 0:10:49(they're also feeding on a lot of insects.)
0:10:53 > 0:10:57To get a closer look, we first set up mist nets.
0:11:09 > 0:11:12By alternating pre-recorded honeycreeper calls
0:11:12 > 0:11:16from speakers positioned to either side of the nets, with luck,
0:11:16 > 0:11:20Hanna and her colleague Chris will lure down these very rare
0:11:20 > 0:11:23and notoriously shy birds to tag them.
0:11:35 > 0:11:39(So there's a Maui 'alauahio up there right now.)
0:11:39 > 0:11:40(You can see that one, yeah.)
0:11:43 > 0:11:46The first honeycreeper to get snagged is an insect eater.
0:11:51 > 0:11:53So what's this guy called?
0:11:53 > 0:11:54A Maui 'alauahio.
0:11:54 > 0:11:57Its English name is the Maui creeper which is much easier.
0:11:57 > 0:11:59The Maui creeper. Is it endemic to Maui?
0:11:59 > 0:12:01Endemic to Maui.
0:12:01 > 0:12:02Efficient.
0:12:05 > 0:12:06Cute!
0:12:11 > 0:12:13So we have virtually exactly 30g.
0:12:17 > 0:12:20So this is an absolutely charming small honeycreeper.
0:12:20 > 0:12:22An insectivore, I guess.
0:12:22 > 0:12:25Yes, and it's endemic to Maui Island.
0:12:27 > 0:12:29OK, so I'm going to slip him back into there
0:12:29 > 0:12:32and I'm just going to make sure his head is up at the top.
0:12:32 > 0:12:34Yeah. Is that all right?
0:12:34 > 0:12:35Yep. There you go.
0:12:35 > 0:12:37And this is an adult male.
0:12:37 > 0:12:39He's at least two years old.
0:12:39 > 0:12:43We can tell that by his real yellow plumage.
0:12:43 > 0:12:46The oldest honeycreepers that we've found in this forest are,
0:12:46 > 0:12:48you know, 15-17 years old.
0:12:48 > 0:12:50That's old for a small bird, isn't it?
0:12:50 > 0:12:54For a 13g bird, that's pretty old!
0:12:54 > 0:12:55THEY LAUGH
0:12:55 > 0:13:00So does it have other anatomical adaptations for forest life?
0:13:00 > 0:13:02It does.
0:13:02 > 0:13:05Creepers aren't very good flyers, so they have short,
0:13:05 > 0:13:07rounded wings and they can really hop between trees
0:13:07 > 0:13:10and kind of work their way through the forest.
0:13:10 > 0:13:13And they're really adapted for the understorey of the native forest.
0:13:13 > 0:13:16You see them upside down and sideways and everywhere,
0:13:16 > 0:13:19trying to creep along the branches
0:13:19 > 0:13:23in order to chase the inverts and bugs and moths and things.
0:13:23 > 0:13:26Just a slight deflection on the bill.
0:13:26 > 0:13:29So, how does this little bird fit into the great radiation
0:13:29 > 0:13:33of the honeycreepers on the Hawaiian Islands?
0:13:33 > 0:13:38It's one of the older honeycreepers. Diverged very early.
0:13:38 > 0:13:41The different bill specialisations in honeycreepers are quite
0:13:41 > 0:13:43amazing and, unfortunately,
0:13:43 > 0:13:46we've lost the most specialised of the birds that we had.
0:13:46 > 0:13:50A lot of the honeycreepers that have not gone extinct
0:13:50 > 0:13:52are the more generalist,
0:13:52 > 0:13:55because they were able to hold on in changing habitats.
0:13:59 > 0:14:00Further down the mountainside,
0:14:00 > 0:14:05another set of nets has snared Maui's rarest honeycreeper.
0:14:10 > 0:14:12The Kiwikiu, or Maui parrot bill,
0:14:12 > 0:14:17uses its specialised bill to dig out grubs from beneath tree bark.
0:14:20 > 0:14:21Um...
0:14:24 > 0:14:25So there she is.
0:14:27 > 0:14:29Maui parrot bill.
0:14:29 > 0:14:30Let's see your bill.
0:14:30 > 0:14:34- You can see how she uses that bill on my finger.- Yeah.
0:14:35 > 0:14:37- Does it hurt?- No, not too bad.
0:14:39 > 0:14:43Wow! This, it's specialised for ohia trees, presumably?
0:14:43 > 0:14:47Ohia and koa, but specialised for the native forest,
0:14:47 > 0:14:49so he uses the bill like a chisel
0:14:49 > 0:14:53and can really have a lot of control over that lower mandible
0:14:53 > 0:14:58and dig out wood and bark, kind of like a continental woodpecker would.
0:14:58 > 0:15:01And this is really, really rare.
0:15:01 > 0:15:04These are the most endangered birds on Maui
0:15:04 > 0:15:07and one of the most endangered in all of Hawaii.
0:15:07 > 0:15:10There are only about 500 in existence.
0:15:10 > 0:15:15These guys are very long-lived. They only have one chick per year.
0:15:15 > 0:15:18Chick stays with its parents for sometimes a year,
0:15:18 > 0:15:22so they're very rare, very slow reproducing.
0:15:22 > 0:15:25Well, perhaps we should let her have some peace.
0:15:34 > 0:15:37The third and final honeycreeper the nets snag is called
0:15:37 > 0:15:39an Hawaiian amakihi.
0:15:41 > 0:15:46Its long, thin bill has evolved to help it feed on nectar.
0:15:48 > 0:15:51The ancestors of today's honeycreepers were finches that
0:15:51 > 0:15:55were probably blown off-course during their annual migration.
0:15:58 > 0:16:02Genetic studies suggest they made an incredible 6,000 mile
0:16:02 > 0:16:06journey across open ocean, all the way from central Asia.
0:16:08 > 0:16:11The early bird gets the worm.
0:16:11 > 0:16:14Or in this case, inherits the island.
0:16:16 > 0:16:21And this same extraordinary story of a single founder leading to
0:16:21 > 0:16:26an adaptive radiation has happened again and again on Hawaii.
0:16:28 > 0:16:31My next stop is the protected rainforest
0:16:31 > 0:16:33of the neighbouring island of Oahu.
0:16:35 > 0:16:38I'm off to see another species whose ancestors were also blown to
0:16:38 > 0:16:40Hawaii on the wind.
0:16:42 > 0:16:44But this one is a plant.
0:16:50 > 0:16:54A member of Hawaii's park service guides me to a location where an
0:16:54 > 0:17:00endangered member of this radiation is being reintroduced to the wild.
0:17:04 > 0:17:07- How are you doing?- Good. How are you?- Good to see you.
0:17:07 > 0:17:13Chipper Wichman, president of Hawaii's National Tropical Botanical Gardens,
0:17:13 > 0:17:15is on hand to tell me its biography.
0:17:15 > 0:17:18Here we are in your natural habitat.
0:17:18 > 0:17:23Their oldest ancestor arrived here, dispersed here by wind.
0:17:23 > 0:17:24It's just a phenomenal event.
0:17:24 > 0:17:28- So, what are the chances of that happening?- Well, think about this.
0:17:28 > 0:17:31We're the most geographically isolated group of islands
0:17:31 > 0:17:34anywhere in the world, thousands of miles from any continental area,
0:17:34 > 0:17:37and I once had a professor who talked about, you know,
0:17:37 > 0:17:41what is the chance of something actually dispersing here by wind?
0:17:41 > 0:17:44Blowing through the wind and landing on these islands, reproducing itself.
0:17:44 > 0:17:49He said the chance of that is very, very, very, very, VERY improbable.
0:17:49 > 0:17:51He said, really, what does that boil down to?
0:17:51 > 0:17:53Give it enough time, it's guaranteed to happen.
0:17:57 > 0:18:00The plant in question is a specialist lobelioid
0:18:00 > 0:18:03that has co-evolved with the honeycreepers.
0:18:07 > 0:18:09So, let me show you one of my friends here.
0:18:09 > 0:18:12This is a Cyanea. This is Cyanea crispa
0:18:12 > 0:18:15and it's flowering right now.
0:18:16 > 0:18:19It's a really wonderful-looking flower.
0:18:19 > 0:18:23Yes. Here you can see the curved corolla
0:18:23 > 0:18:25and how this curved shape co-evolved
0:18:25 > 0:18:28with the curved beak of the honeycreepers,
0:18:28 > 0:18:31provided a little nectar reward for the bird
0:18:31 > 0:18:34and in return, it would get the pollen from the male parts
0:18:34 > 0:18:38of this flower, from the anthers here.
0:18:38 > 0:18:40So, the bird would get the pollen on its head
0:18:40 > 0:18:44as it got its nectar reward, it would go on and would carry it
0:18:44 > 0:18:47to another flower and was a very effective pollinator.
0:18:48 > 0:18:50And then, afterwards, a fruit?
0:18:50 > 0:18:53And then, comes back when the seeds are matured to eat the fruit,
0:18:53 > 0:18:58so this species evolved a fleshy fruit that was then
0:18:58 > 0:19:01eaten by the birds and dispersed to other parts of the island.
0:19:01 > 0:19:05Adapting from being a wind-dispersed ancestor to being a fleshy fruit
0:19:05 > 0:19:08that could be dispersed by birds was one of those
0:19:08 > 0:19:10strategies for exploiting the many,
0:19:10 > 0:19:12many niches that are available in the Hawaiian Islands.
0:19:12 > 0:19:16- So, different species for different altitudes presumably?- Absolutely.
0:19:16 > 0:19:19And different habits, as well? Some shrubby, some treelike?
0:19:19 > 0:19:22Some arborescent ones, some shrubby ones,
0:19:22 > 0:19:24some vegetative ones.
0:19:24 > 0:19:26I mean, the story of evolution
0:19:26 > 0:19:30in this tribe of lobelioids is simply amazing.
0:19:32 > 0:19:37This lobelioid is just one of 126 species endemic to Hawaii.
0:19:40 > 0:19:44All of them descended from one ancestral species.
0:19:46 > 0:19:49Sometimes called the founder effect,
0:19:49 > 0:19:52it's another story that highlights the rich evolutionary rewards
0:19:52 > 0:19:56of being the first to arrive on a remote island.
0:19:58 > 0:20:03The founder effect helps explain how Hawaii, at just 0.2% of the size
0:20:03 > 0:20:06of the continental United States,
0:20:06 > 0:20:10nonetheless contains nearly 15% of all US species.
0:20:13 > 0:20:18Another all-important factor is Hawaii's sheer ecological variety.
0:20:18 > 0:20:24No other island group in the world goes from cold desolate mountaintops
0:20:24 > 0:20:25to dense wet forest...
0:20:28 > 0:20:31..and tropical beaches in the space of only a few miles.
0:20:34 > 0:20:39It's the sort of place where almost anything can find a niche to thrive.
0:20:39 > 0:20:40If it can get here.
0:20:46 > 0:20:49One species that was carried here on wing and wind
0:20:49 > 0:20:52is the fruit fly Drosophila.
0:20:52 > 0:20:59Once alighted, a founding species took adaptive radiation to extremes.
0:20:59 > 0:21:04Astonishingly, genetic analysis has revealed that all 600 modern
0:21:04 > 0:21:06species of Hawaiian Drosophila
0:21:06 > 0:21:09are descended from a single pregnant female
0:21:09 > 0:21:12that arrived here more than five million years ago.
0:21:13 > 0:21:17Someone who gets a buzz out of flies is entomologist Dr Steve Montgomery.
0:21:22 > 0:21:29So, Steve, we have before us a mere four files containing flies.
0:21:29 > 0:21:32I notice nicely patterned wings.
0:21:32 > 0:21:35They are spots that help the females
0:21:35 > 0:21:37recognise males of their own species.
0:21:37 > 0:21:40So, what about this guy?
0:21:40 > 0:21:44Well, Drosophila silvestris, it lives in the forests of
0:21:44 > 0:21:46the Big Island of Hawaii and only that island,
0:21:46 > 0:21:49and they like Lobelia plants.
0:21:51 > 0:21:54This guy, a narrow triangular shape, rather different.
0:21:54 > 0:21:57That would be Drosophila grimshawi
0:21:57 > 0:22:00and it seems to be the most polyphagous.
0:22:00 > 0:22:03It has a wide choice of food plants,
0:22:03 > 0:22:06so the female will select akia plant,
0:22:06 > 0:22:10which has a lot of toxic chemicals, most flies won't even touch it.
0:22:10 > 0:22:13And last but certainly not least.
0:22:13 > 0:22:17Heteroneura. It's the only species in the Hawaiian Islands
0:22:17 > 0:22:20which has a hammerhead.
0:22:22 > 0:22:29Only in the males and it's used in a competition, to dominate.
0:22:29 > 0:22:31So, it's one of those head-to-head fights, is it?
0:22:31 > 0:22:36Head-butting much like the rams and the sheep species will do.
0:22:36 > 0:22:40When a female's ready to find a mate, she will come by there
0:22:40 > 0:22:45and the last one standing is the one that gets to make her an offer.
0:22:47 > 0:22:52A vast abundance of fruit flies on Hawaii created the ideal
0:22:52 > 0:22:54opportunity for a fly-eating insect to thrive.
0:22:56 > 0:22:58But Hawaii had none
0:22:58 > 0:23:01until another ancestor was also blown here by the wind.
0:23:03 > 0:23:07A caterpillar normally eats shoots and leaves.
0:23:07 > 0:23:10This one has disguised itself as a twig.
0:23:11 > 0:23:14As this unsuspecting fly approaches...
0:23:25 > 0:23:29The ultimate endemic, the Hawaiian carnivorous caterpillar.
0:23:30 > 0:23:32After their arrival on these islands,
0:23:32 > 0:23:36an abundance of fruit flies offered them an unprecedented opportunity
0:23:36 > 0:23:41to swap vegetarianism for a more nutritious protein-based diet.
0:23:43 > 0:23:47Steve was the scientist who first discovered this bizarrely
0:23:47 > 0:23:49modified inchworm caterpillar.
0:23:49 > 0:23:52So, you actually made this discovery yourself?
0:23:52 > 0:23:55Yes, I was curious enough to bring it back
0:23:55 > 0:23:59and offer it some of the thousands of flies in our lab, and people
0:23:59 > 0:24:03couldn't believe it when I told them I had an ambushing inchworm.
0:24:03 > 0:24:08- Now, is that that unique to Hawaii? - This behaviour is indeed unique.
0:24:08 > 0:24:13It evolved in Hawaii and it worked in Hawaii,
0:24:13 > 0:24:16because there weren't any praying mantises, or mantispids,
0:24:16 > 0:24:17or other raptorial predators,
0:24:17 > 0:24:21so an unlikely candidate like an inchworm
0:24:21 > 0:24:23could occupy the carnivore niche.
0:24:27 > 0:24:30So, we have 18 species of ambushing inchworms.
0:24:30 > 0:24:33That's quite a mini radiation, isn't it? All of its own.
0:24:33 > 0:24:36Well, they cross that adaptive zone.
0:24:36 > 0:24:41They exploded into... Every island has at least four or five species.
0:24:41 > 0:24:43So, a story you've met before.
0:24:43 > 0:24:47The opportunities are available and they left the flowers, or in
0:24:47 > 0:24:52addition to the flowers, they added on live prey to their diet and
0:24:52 > 0:24:57through changes in behaviour, bit by bit, it became an obligate predator.
0:24:57 > 0:25:01They'd rather starve than switch back to a vegetarian diet.
0:25:03 > 0:25:07It can wait six weeks between meals and this is a large meal.
0:25:07 > 0:25:09I won't have to feed it for another month.
0:25:13 > 0:25:16Of the 18 species of carnivorous caterpillars,
0:25:16 > 0:25:20more than half have evolved to become obligate predators.
0:25:21 > 0:25:25In other words, they have specialised to such a degree
0:25:25 > 0:25:27there's no turning back.
0:25:28 > 0:25:30So when one of these gets hungry...
0:25:33 > 0:25:37..it would rather eat its own kind than a plant.
0:25:42 > 0:25:44But being a caterpillar of any kind,
0:25:44 > 0:25:46let alone a fruit fly,
0:25:46 > 0:25:50provides opportunities for other colonists to make a good living.
0:25:53 > 0:25:56Today, they can be found all over the Hawaiian Islands.
0:26:00 > 0:26:02Spiders.
0:26:03 > 0:26:07The one I hope to examine today is often found high up in the canopy...
0:26:09 > 0:26:12..where one of a team from the University of Hawaii at Hilo
0:26:12 > 0:26:15on the Big Island, Brendan Cote, is searching.
0:26:21 > 0:26:24Down below, his colleague, Ellie Armstrong,
0:26:24 > 0:26:27is checking the leaf litter and lower branches,
0:26:27 > 0:26:30cos in Hawaii's native forests,
0:26:30 > 0:26:33spiders have adapted to live almost everywhere.
0:26:37 > 0:26:39It might not look like a giant,
0:26:39 > 0:26:41but many of this spider's relatives
0:26:41 > 0:26:44are barely visible to the human eye,
0:26:44 > 0:26:47making this moth hunter a relative colossus.
0:26:49 > 0:26:54- So this is Orsonwelles.- That's its real Latin scientific name?
0:26:54 > 0:26:55Real Latin name, yes.
0:26:55 > 0:26:59So this guy is in the family Linyphiidae and generally,
0:26:59 > 0:27:04- linyphiids are actually quite small sheet web spiders, so they'll...- Ah!
0:27:04 > 0:27:06That doesn't look like a particular giant to me.
0:27:06 > 0:27:09Presumably, was this named because Orson Welles was known
0:27:09 > 0:27:11both for his - what shall we say? - stature,
0:27:11 > 0:27:14in intellectual and other directions?
0:27:14 > 0:27:17- Sure, stature and charisma, maybe. - Right, OK. Well, it's charismatic.
0:27:17 > 0:27:20- Right.- So this is a giant among its kind?- It is, yeah.
0:27:20 > 0:27:24This is probably the biggest spider in the family Linyphiidae.
0:27:24 > 0:27:27They're normally really, really tiny sheet web spiders.
0:27:27 > 0:27:31So although this is an interesting thing about island gigantism,
0:27:31 > 0:27:35we tend to think that means the thing is the size of a football or bigger,
0:27:35 > 0:27:37but, of course, if you start very, very small,
0:27:37 > 0:27:39- this is still a giant. - Yes, relatively.
0:27:39 > 0:27:41It's relatively large, I should say.
0:27:43 > 0:27:46This giant may be the big-name star,
0:27:46 > 0:27:50but another endemic Hawaiian spider has evolved to steal the show
0:27:50 > 0:27:54from right under Orsonwelles's mandibles.
0:27:54 > 0:27:58So this guy is Ariamnes and as you can see,
0:27:58 > 0:28:00it's really brilliantly gold.
0:28:01 > 0:28:05What's interesting about these guys is some of them are kleptoparasites.
0:28:05 > 0:28:09- Which means...?- Some of them will actually go in other spiders' webs
0:28:09 > 0:28:13- and steal their prey.- Oh, yes, the shoplifting ones.- Exactly.
0:28:13 > 0:28:16- Klepto, yes.- Yeah, so kleptoparasitic, yeah.
0:28:18 > 0:28:22Even though he seems a little clumsy, he's very sneaky.
0:28:24 > 0:28:26Ellie and her team still don't know
0:28:26 > 0:28:29how many spiders live on the Big Island.
0:28:30 > 0:28:32It could be many hundreds.
0:28:37 > 0:28:40So, Ellie, how do spiders manage to get to a remote place
0:28:40 > 0:28:43like the Hawaiian chain in the first place?
0:28:43 > 0:28:45So spiders can disperse amazing distances
0:28:45 > 0:28:47across thousands of miles of ocean
0:28:47 > 0:28:50and what they generally do is the spinnerets
0:28:50 > 0:28:52on the end of their abdomen,
0:28:52 > 0:28:55they release silk and then the silk will create a balloon
0:28:55 > 0:28:57that the wind can then catch and disperse the spider
0:28:57 > 0:29:01across to these really remote island chains like Hawaii.
0:29:05 > 0:29:10But some larger insects, like moths, possibly used a different trick
0:29:10 > 0:29:14to make the 2,000-odd-mile journey from either Asia or America.
0:29:19 > 0:29:22In fact, they may have used stepping stones.
0:29:26 > 0:29:29To get down to the tectonic truth
0:29:29 > 0:29:33of how an island's geology determines its evolutionary destiny,
0:29:33 > 0:29:37I'm bound for Pu'u 'O'o, an erupting volcanic vent.
0:29:41 > 0:29:47Now we're coming towards the summit and you can see the smoke.
0:29:47 > 0:29:50This is what the creative process looks like.
0:29:51 > 0:29:54And I can see through the clouds...
0:29:56 > 0:30:00...the lava lake. It's a sort of orange from here,
0:30:00 > 0:30:03but, of course, it's unbelievably hot liquid magma,
0:30:03 > 0:30:07liquid rock itself, where the lava is coming up
0:30:07 > 0:30:10from deep, deep plumbing into the mantle,
0:30:10 > 0:30:12the very birth of new land.
0:30:14 > 0:30:17It spews more or less continuously.
0:30:18 > 0:30:21The light is catching fresh lava
0:30:21 > 0:30:25so that you can see the tongues feeling their way to the low ground.
0:30:28 > 0:30:32Pu'u 'O'o is the latest outlet for a massive outpouring of lava
0:30:32 > 0:30:35from deep beneath the Earth's crust
0:30:35 > 0:30:37that is still making the Big Island bigger.
0:30:48 > 0:30:51On the lip of the giant Kilauea caldera,
0:30:51 > 0:30:54I meet Don Swanson of the Hawaiian Volcano Observatory.
0:30:58 > 0:31:02At the present day, the Big Island, Hawaii itself,
0:31:02 > 0:31:06is the youngest and therefore the largest of these volcanic islands.
0:31:06 > 0:31:08It's still active.
0:31:08 > 0:31:10There's abundant evidence of that.
0:31:10 > 0:31:12- That's correct.- And still growing. - And still growing.
0:31:12 > 0:31:18The volcano has been growing every time that lava goes into the sea.
0:31:18 > 0:31:22What's also forgotten, though, is that the island is growing up.
0:31:22 > 0:31:25Every time that a lava flow erupts under the surface,
0:31:25 > 0:31:28even if it doesn't expand the island, it is building it higher.
0:31:31 > 0:31:35But a volcanic island doesn't grow indefinitely.
0:31:35 > 0:31:39One day, it will stop spewing lava and start sinking back into the sea.
0:31:42 > 0:31:45This life cycle is tied to its geological position
0:31:45 > 0:31:48on the Earth's shifting tectonic plates.
0:31:51 > 0:31:53So how does that work, Don?
0:31:53 > 0:31:56How does that work from a perspective of the way geology
0:31:56 > 0:31:59is in control of an island's fate?
0:31:59 > 0:32:01There is a zone in the mantle
0:32:01 > 0:32:04that is hot enough for rocks to actually melt.
0:32:04 > 0:32:09- That's many kilometres down? - Probably about 100km or so down.
0:32:09 > 0:32:14Then this has to be rising into a plate
0:32:14 > 0:32:18of the Earth's crust that is moving across that hotspot.
0:32:18 > 0:32:22When that magma reaches the top of the plate,
0:32:22 > 0:32:25it erupts to form a volcano.
0:32:25 > 0:32:30But now the plate is continuing to move, move, move, move,
0:32:30 > 0:32:35and so its connection with the plume carrying the magma
0:32:35 > 0:32:38is more and more tenuous and eventually it snaps.
0:32:39 > 0:32:41Then a new volcano forms
0:32:41 > 0:32:44and then you go through the same process again,
0:32:44 > 0:32:49so this movement of the plate toward the north-west, over the hotspot,
0:32:49 > 0:32:52creates volcanoes after volcanoes after volcanoes
0:32:52 > 0:32:57and that's been going on for 70 million years or so.
0:32:57 > 0:33:02And those islands must have had life on them and probably life moved
0:33:02 > 0:33:07then down the chain to the younger islands as the older ones sank.
0:33:09 > 0:33:11Starting on the coast of Siberia,
0:33:11 > 0:33:14we can track the now vanished volcanic islands
0:33:14 > 0:33:18created by the hotspot using undersea bathymetric data.
0:33:19 > 0:33:24As we move east, we trace millions of years of history
0:33:24 > 0:33:27past the sunken remains of ancient islands to atolls
0:33:27 > 0:33:30and reefs just beneath the surface,
0:33:30 > 0:33:34all the way to the hotspot's current position beneath the Big Island.
0:33:35 > 0:33:37SONAR PING
0:33:42 > 0:33:45By hopping from one island to the next,
0:33:45 > 0:33:48a handful of founders spawned more than 10,000 modern species
0:33:48 > 0:33:50of terrestrial invertebrates.
0:34:04 > 0:34:07Other arrivals produce some descendants
0:34:07 > 0:34:10capable of rising to the greatest environmental challenges.
0:34:14 > 0:34:19Hawaii's most extreme conditions are found above the cloud line.
0:34:25 > 0:34:27On the highest part of the island of Maui
0:34:27 > 0:34:31lies the spectacular Haleakala National Park.
0:34:34 > 0:34:37Its volcanic cinder slopes are parched
0:34:37 > 0:34:39and almost completely devoid of life.
0:34:46 > 0:34:52Yet one species has adapted to living conditions of 25% less oxygen,
0:34:52 > 0:34:5550% more harmful ultraviolet light
0:34:55 > 0:34:58and temperatures that regularly plummet to zero.
0:35:01 > 0:35:05It's a distant relative of the humble daisy.
0:35:05 > 0:35:09Its hundreds of delicate roots gather nutrients for years
0:35:09 > 0:35:12before a single burst of reproductive brilliance.
0:35:14 > 0:35:18Though I'm rather surprised to find it living in the summit car park.
0:35:25 > 0:35:2710,000 feet up,
0:35:27 > 0:35:30on top of a volcanic mountain in Hawaii,
0:35:30 > 0:35:32lives a very special plant.
0:35:33 > 0:35:34The silversword.
0:35:36 > 0:35:40This is its earlier stage, its rosette stage,
0:35:40 > 0:35:42a tight bunch of leaves
0:35:42 > 0:35:44and on each leaf,
0:35:44 > 0:35:45silver hairs.
0:35:46 > 0:35:50They serve both to reflect the sunlight
0:35:50 > 0:35:51and to prevent water loss.
0:35:53 > 0:35:56This plant lives in really extreme conditions.
0:35:57 > 0:35:58It's biding its time.
0:36:10 > 0:36:13The rosettes get larger and larger, saving up energy.
0:36:14 > 0:36:19Then they erupt into a flowering spike, having saved up enough energy
0:36:19 > 0:36:22to produce an enormous number of flowers.
0:36:25 > 0:36:28This plant has just finished flowering and it reveals
0:36:28 > 0:36:32the true biological affinities of this extraordinary plant.
0:36:32 > 0:36:35It's related to the daisy, or the sunflower family.
0:36:37 > 0:36:40A huge island giant, if you like.
0:36:40 > 0:36:43Produces tens of thousands of seeds from a single plant.
0:36:44 > 0:36:46When it's flowered,
0:36:46 > 0:36:48it dies.
0:36:55 > 0:36:59This sad remnant is all that remains behind of the silversword.
0:37:01 > 0:37:02It's dead.
0:37:16 > 0:37:19At the opposite end of the altitude scale,
0:37:19 > 0:37:22a remarkable species lives in the extreme conditions
0:37:22 > 0:37:24created by recent volcanism.
0:37:29 > 0:37:33Few creatures tolerate living in the acidic water of volcanic rock pools,
0:37:33 > 0:37:36but every challenge is a potential adaptation.
0:37:40 > 0:37:45One that rises to it is hidden in the tiny crevices of this porous rock.
0:37:47 > 0:37:49It's a diminutive shrimp.
0:37:53 > 0:37:55At the Waikiki Aquarium in Honolulu,
0:37:55 > 0:37:59the director, Dr Andy Rossiter, has been studying specimens
0:37:59 > 0:38:02gathered from a variety of different rock pools.
0:38:05 > 0:38:07One adaptation is their very small size.
0:38:07 > 0:38:09That is actually the adult size.
0:38:09 > 0:38:13It's probably about half a centimetre, 5mm?
0:38:13 > 0:38:16- So they are a shrimpy shrimp? - They are a shrimpy shrimp, yeah.
0:38:19 > 0:38:23I notice that all the jars have different figures for acidity.
0:38:23 > 0:38:25- Most of those are all rather acid.- Yes.
0:38:25 > 0:38:26So is that another adaptation?
0:38:26 > 0:38:29That's another adaptation, they're called acidophilic,
0:38:29 > 0:38:32which means they like, or can tolerate, high acidity.
0:38:34 > 0:38:36Descended from ocean-going shrimps,
0:38:36 > 0:38:38the Hawaiian red shrimp has evolved
0:38:38 > 0:38:41to survive entirely in volcanic rock pools.
0:38:43 > 0:38:47- These appendages look not unlike those of a normal shrimp.- Correct.
0:38:47 > 0:38:49They're just the basic shrimp plan,
0:38:49 > 0:38:52- but the thing to notice are the large eggs.- That's on the back?- Yes.
0:38:52 > 0:38:58Maximum in this species is about 20, so very few, large eggs.
0:38:58 > 0:39:02- Which for a crustacean is a very small number.- Very, very low number.
0:39:02 > 0:39:05When the larvae hatch, they themselves are large
0:39:05 > 0:39:08and the larvae have a yolk sac,
0:39:08 > 0:39:10which means they don't have to disperse,
0:39:10 > 0:39:14they can essentially stay in or near the habitat where they hatched.
0:39:17 > 0:39:19Because red shrimps have evolved
0:39:19 > 0:39:21never needing to leave their home pools,
0:39:21 > 0:39:25there's no genetic exchange between different populations.
0:39:26 > 0:39:29And this is prompting them to evolve into new species.
0:39:31 > 0:39:35Some of the populations have bright, bright red shrimps.
0:39:35 > 0:39:39Others have clear with no red at all and others have red and white bands.
0:39:41 > 0:39:43Research has been done on their genetics
0:39:43 > 0:39:45to see how closely related they are
0:39:45 > 0:39:48and there are eight separate populations
0:39:48 > 0:39:50within the entire Hawaiian Islands.
0:39:50 > 0:39:53So would it be an exaggeration to say that these are eight species
0:39:53 > 0:39:55that are kind of in the making?
0:39:55 > 0:39:57- Absolutely. - Potentially in the making.
0:39:57 > 0:40:01They differ by about 5% in terms of mitochondrial DNA.
0:40:01 > 0:40:03Just to put it into perspective,
0:40:03 > 0:40:06humans and chimpanzees are 98% similar.
0:40:06 > 0:40:08These guys are 95% similar.
0:40:11 > 0:40:13This is how speciation begins.
0:40:17 > 0:40:20Isolated from others of their kind,
0:40:20 > 0:40:24the red shrimp is separating into as many as eight new species,
0:40:24 > 0:40:28each adapted to the very specific conditions of their own homes.
0:40:34 > 0:40:35But it's a two-way process.
0:40:37 > 0:40:39Geology may divide populations,
0:40:39 > 0:40:43but other species can transform the volcanic rocks themselves.
0:40:45 > 0:40:47This is a fern, a tree fern,
0:40:47 > 0:40:50and here it is growing in naked lava.
0:40:51 > 0:40:53But ferns have minute seeds,
0:40:53 > 0:40:57spores - they're so tiny, they can be brought in on the wind.
0:40:57 > 0:40:59If they can find a place in the tiniest crack,
0:40:59 > 0:41:02they'll grow, they'll germinate,
0:41:02 > 0:41:04and that's a terribly important thing,
0:41:04 > 0:41:06because they begin to make soil.
0:41:06 > 0:41:11Over time, much of this harsh lava will be broken up by ferns
0:41:11 > 0:41:14and bacteria and turned into earth.
0:41:14 > 0:41:16Ferns are found all over the world,
0:41:16 > 0:41:20but Hawaii has evolved its own specialist soil-making tree,
0:41:20 > 0:41:22the 'ohi'a lehua.
0:41:23 > 0:41:26This is a small 'ohi'a tree
0:41:26 > 0:41:30that's taken root in, well, still quite bare lava.
0:41:31 > 0:41:35It's already flowering with these beautiful red flowers.
0:41:36 > 0:41:39Given time, not a huge amount of time,
0:41:39 > 0:41:41it will turn into lush forest.
0:41:54 > 0:41:57A lush tropical island populated by numerous plants
0:41:57 > 0:42:00and many small invertebrates is a habitat
0:42:00 > 0:42:03that can potentially support larger animals.
0:42:06 > 0:42:08One of the largest arrived by accident
0:42:08 > 0:42:11more than half a million years ago.
0:42:11 > 0:42:13BIRD CALLS
0:42:13 > 0:42:16Today, it seems determined to lead me around the houses.
0:42:29 > 0:42:30This is the nene.
0:42:31 > 0:42:33It's a very handsome goose
0:42:33 > 0:42:36and another Hawaiian endemic.
0:42:39 > 0:42:42It's actually very closely related to the Canada goose.
0:42:42 > 0:42:44It's a little bit smaller,
0:42:44 > 0:42:47but their skeletons are apparently almost identical.
0:42:48 > 0:42:52You can imagine a Canada goose getting severely blown off course.
0:42:56 > 0:43:00The survival of the nene owes quite a lot to Great Britain.
0:43:00 > 0:43:03When the population had shrunk to just a few pairs,
0:43:03 > 0:43:07some of them were transferred by Sir Peter Scott
0:43:07 > 0:43:10to the wildfowl centre at Slimbridge.
0:43:10 > 0:43:14There they were bred on until the population had increased to the
0:43:14 > 0:43:16point where they could be reintroduced into the wild.
0:43:16 > 0:43:18Since then, they've done very well.
0:43:20 > 0:43:22And here they're thriving.
0:43:22 > 0:43:23It's a success story.
0:43:29 > 0:43:32The nene's ancestors were strong fliers.
0:43:33 > 0:43:36But now, like many island birds,
0:43:36 > 0:43:37its wings have grown weak,
0:43:37 > 0:43:40it can barely carry it between Hawaiian islands.
0:43:44 > 0:43:47Flightless birds were once common on Hawaii
0:43:47 > 0:43:50and in Honolulu's Bishop Museum,
0:43:50 > 0:43:52they have one of the largest that ever lived here.
0:43:54 > 0:43:57We're going to look at one of the extinct giants
0:43:57 > 0:43:59of the Hawaiian Islands
0:43:59 > 0:44:03and Molly Hagemann, here in the Bishop Museum,
0:44:03 > 0:44:04is going to show me.
0:44:05 > 0:44:08So this is moa-nalo,
0:44:08 > 0:44:11which is an extinct goose-like duck.
0:44:11 > 0:44:15So one of the main features is the sternum,
0:44:15 > 0:44:17is completely smooth.
0:44:17 > 0:44:20- That's the sternum?- Correct.
0:44:20 > 0:44:23On a bird that can fly - this is from a nene.
0:44:23 > 0:44:25This is contemporary.
0:44:25 > 0:44:27You can see the difference inside in size
0:44:27 > 0:44:30and, obviously, the one feature that's missing from that
0:44:30 > 0:44:32is the large keel.
0:44:32 > 0:44:35- It's what we call on the chicken a breast bone.- Exactly, yes.
0:44:35 > 0:44:38This is where all the flight muscles would attach.
0:44:38 > 0:44:41- This lost flight... Well, no predators, presumably?- Exactly.
0:44:41 > 0:44:45It didn't need to invest that energy into a keel
0:44:45 > 0:44:47and flight muscles
0:44:47 > 0:44:50and instead it redirected those resources
0:44:50 > 0:44:53to produce more robust limb bones.
0:44:53 > 0:44:56- So that's a limb bone?- Mm-hm.
0:44:56 > 0:45:00This is from a nene, a contemporary bird.
0:45:00 > 0:45:03I don't have to be a particularly perceptive scientist to see
0:45:03 > 0:45:06that one is three times as robust as that one.
0:45:06 > 0:45:07Exactly.
0:45:07 > 0:45:10So here we have the idea that if you don't use something,
0:45:10 > 0:45:12in this case flight muscles,
0:45:12 > 0:45:14then you tend to lose it?
0:45:14 > 0:45:17Exactly. Three million years ago
0:45:17 > 0:45:21something similar to a mallard would have colonised the Hawaiian Islands
0:45:21 > 0:45:24and then rapidly changed into what we see here.
0:45:24 > 0:45:28A ground dwelling, large duck?
0:45:28 > 0:45:30Who ate them up?
0:45:30 > 0:45:34Probably the Polynesians that colonised Hawaii
0:45:34 > 0:45:37because they were probably slow-moving.
0:45:37 > 0:45:41Erm, they were large, they probably tasted pretty good.
0:45:41 > 0:45:44It's a bit like a Hawaiian dodo,
0:45:44 > 0:45:48- except the dodo we know was derived from the pigeon family.- Mm.
0:45:48 > 0:45:51- Here's the duck family producing something else.- Yeah.
0:45:56 > 0:46:00The moa-nalo fell victim to an invasive species.
0:46:02 > 0:46:03Man.
0:46:07 > 0:46:11Polynesians made Honolulu their capital in the 11th century,
0:46:11 > 0:46:15bringing with them livestock and introducing new crops.
0:46:18 > 0:46:21Hawaii was changed for ever.
0:46:29 > 0:46:33The micro-propagation laboratory of the Lyon Arboretum
0:46:33 > 0:46:35is a modern-day Noah's Ark.
0:46:39 > 0:46:43These test tubes contain more than 100 species
0:46:43 > 0:46:46of critically endangered Hawaiian plants.
0:46:48 > 0:46:51The samples here share common vulnerabilities
0:46:51 > 0:46:52associated with island life.
0:46:55 > 0:46:58Descended from only one, or just a few ancestors,
0:46:58 > 0:47:00long isolated,
0:47:00 > 0:47:03they have also become highly specialised.
0:47:03 > 0:47:06They are often outcompeted by new arrivals.
0:47:09 > 0:47:12Out in the greenhouse is a familiar plant,
0:47:12 > 0:47:15that is being kept here for its own protection.
0:47:18 > 0:47:19Ah...
0:47:19 > 0:47:21This is the one I'm after.
0:47:23 > 0:47:26Even plants can lose
0:47:26 > 0:47:29protective characteristics in the safety of an island.
0:47:29 > 0:47:33And this looks like a mint.
0:47:33 > 0:47:35It is a mint but it's a mintless mint.
0:47:35 > 0:47:39It's lost what it didn't need
0:47:39 > 0:47:42which was the protective chemicals that protect most mints
0:47:42 > 0:47:44from being eaten by herbivores.
0:47:44 > 0:47:47It's the thing we like because of its delicious smell.
0:47:47 > 0:47:50This one doesn't have any of those,
0:47:50 > 0:47:52it's not gone to the trouble of making those chemicals
0:47:52 > 0:47:54any more because it didn't need them.
0:47:54 > 0:47:56Well, it didn't need them in the past.
0:47:56 > 0:48:00It needs them now because, of course, pigs, sheep and other
0:48:00 > 0:48:03herbivorous animals have come in and decimated the wild population
0:48:03 > 0:48:07which is why it's here among all the rare and protected plants.
0:48:07 > 0:48:12And it would be quite useless for flavouring your garden peas.
0:48:17 > 0:48:20By some estimates, before humans arrived,
0:48:20 > 0:48:26only one new species colonised Hawaii every 35,000 years.
0:48:30 > 0:48:33Once Europeans made contact,
0:48:33 > 0:48:36that number leapt to an average of one per month.
0:48:41 > 0:48:45For centuries, the Hawaiian Islands were unknown to Europeans.
0:48:45 > 0:48:50But all that changed when Captain Cook discovered the group
0:48:50 > 0:48:53and by the time Cook made his third visit,
0:48:53 > 0:48:57and prepared this map in 1779,
0:48:57 > 0:49:00it was with the latest technology of the time,
0:49:00 > 0:49:04Hawaii's place in the world was fixed for ever.
0:49:07 > 0:49:10It was doomed to change.
0:49:10 > 0:49:13Within ten years, missionaries were declaring it
0:49:13 > 0:49:15the new Eden
0:49:15 > 0:49:18but it was already a fragile Eden.
0:49:23 > 0:49:26To get an idea of the sheer scale of new species that have
0:49:26 > 0:49:29arrived on Hawaii, after Europeans made contact,
0:49:29 > 0:49:31I visit Manoa Falls,
0:49:31 > 0:49:34one of the most famous beauty spots in Hawaii.
0:49:38 > 0:49:41To help me see the proverbial wood from the invasive trees,
0:49:41 > 0:49:44I rejoin Chipper Wichman.
0:49:47 > 0:49:51So it's an extraordinary thought that this whole forest
0:49:51 > 0:49:55- has grown up in, what, 100 years, or so?- Yeah.
0:49:55 > 0:50:00This was probably... Everything you see here is 100 years or less.
0:50:02 > 0:50:05I mean, to me, that pink flower looks somewhat like a banana.
0:50:05 > 0:50:07It is, it's a flowering banana.
0:50:07 > 0:50:11It was introduced actually as an ornamental banana.
0:50:11 > 0:50:14Most of these plants were all brought here intentionally.
0:50:14 > 0:50:17- With unintentional consequences? - Absolutely.
0:50:19 > 0:50:21That's a hell of a tree.
0:50:21 > 0:50:25Albizia was actually brought intentionally to
0:50:25 > 0:50:29Hawaii in 1917 as a potential tree for reforestation in Hawaii.
0:50:29 > 0:50:33This particular tree right here is probably less than 50 years old.
0:50:33 > 0:50:34Good God!
0:50:34 > 0:50:38What else... I can see a conifer there.
0:50:38 > 0:50:41Don't tell me that's another invader, is it?
0:50:41 > 0:50:44Well, we call it, instead of an invasive species,
0:50:44 > 0:50:46a naturalised species.
0:50:46 > 0:50:49It's been able to establish itself independently.
0:50:49 > 0:50:53- It's a relative of the monkey puzzle. It's araucaria.- Araucaria.
0:50:53 > 0:50:56Originally brought here by the sailing ship captains who
0:50:56 > 0:50:59wanted replacement masts for their ships.
0:51:01 > 0:51:06- In a curious way, we've got a world sample of plants here.- We do.
0:51:06 > 0:51:10Which is, in one way, wonderful but another way, tragic.
0:51:10 > 0:51:12I'm not sure how to describe it.
0:51:16 > 0:51:19It might seem like the beautiful plants of Manoa Falls are harmless,
0:51:19 > 0:51:24and indeed many non-native species cause little harm...
0:51:27 > 0:51:28But on a small island,
0:51:28 > 0:51:31even a single invasive pest can wreak havoc.
0:51:35 > 0:51:40Biologist Chris Warren shows me an innocent-looking Jackson's chameleon.
0:51:40 > 0:51:42So we've got a male here.
0:51:42 > 0:51:45- The one that looks like triceratops? - Like a triceratops, exactly.
0:51:45 > 0:51:48And a female. She has no horns.
0:51:50 > 0:51:53So presumably there is sexual selection working on...
0:51:53 > 0:51:56- Males, as usual, are the horny ones! - That's right!
0:51:56 > 0:51:58CHRIS LAUGHS
0:51:58 > 0:52:03When did he and she arrive here in the wild?
0:52:03 > 0:52:07They were released as pets inadvertently, or invertently.
0:52:07 > 0:52:10Maybe sometime in the 1970s.
0:52:10 > 0:52:13They escape for whatever reasons
0:52:13 > 0:52:16and then within a pretty short period of time,
0:52:16 > 0:52:21they're so abundant that it's almost not feasible to remove them.
0:52:22 > 0:52:24Well, they're pretty, little animals,
0:52:24 > 0:52:27but why should we be worried about what they do?
0:52:27 > 0:52:29They eat every invertebrate that they find,
0:52:29 > 0:52:34including lots of rare, threatened and endangered insects.
0:52:36 > 0:52:39Hawaii doesn't have native reptiles.
0:52:39 > 0:52:42Just the marine ones, sea turtles and things.
0:52:42 > 0:52:46So no terrestrial ones, so presumably these guys...
0:52:46 > 0:52:49What, they weren't expected and there's nothing to prey on them?
0:52:49 > 0:52:51Exactly.
0:52:51 > 0:52:55Unfortunately, they have spread maybe as much as they're going to.
0:52:55 > 0:52:59- That's just since the 1970s.- Yes.
0:52:59 > 0:53:03- That's a lot of damage in a short period of time.- Mm-hm.
0:53:03 > 0:53:07- Geological time, it's nothing at all. - It's nothing, yes.
0:53:13 > 0:53:17But there are other invisible killers brought here by man.
0:53:19 > 0:53:23Mosquitoes arrived with European and American ships in the 1800s.
0:53:23 > 0:53:26They spread avian malaria
0:53:26 > 0:53:28to Hawaii's native honeycreepers,
0:53:28 > 0:53:30causing devastation.
0:53:38 > 0:53:43Today, most honeycreepers only survive where mosquitoes cannot.
0:53:43 > 0:53:46Up at altitudes of several thousand feet.
0:53:52 > 0:53:56But, remarkably, after two centuries of exposure to malaria,
0:53:56 > 0:53:59some species of honeycreepers have started to move down
0:53:59 > 0:54:02to lower elevations again.
0:54:04 > 0:54:07It seems they've evolved a resistance.
0:54:11 > 0:54:13This is one of the fundamental rules of all evolution,
0:54:13 > 0:54:15it never stops.
0:54:23 > 0:54:25The beautiful Iao Valley on Maui
0:54:25 > 0:54:28is a sacred place to native Hawaiians.
0:54:32 > 0:54:35It's a good spot to ask how Hawaii's rich evolutionary
0:54:35 > 0:54:38diversity can be saved from extinction,
0:54:38 > 0:54:42with conservation scientist, Sam Gon III.
0:54:42 > 0:54:45You know, just as there are endemic plants and animals here,
0:54:45 > 0:54:48there are also endemic cultures.
0:54:48 > 0:54:53Hawaii and Hawaiians were in this place from 1,000 years ago
0:54:53 > 0:54:58and they existed here in 100% self-sufficiency
0:54:58 > 0:55:01with a remarkably small ecological footprint.
0:55:03 > 0:55:06Today, our self-sufficiency is down to 15%.
0:55:06 > 0:55:09Which means almost everything has to be bought in from outside?
0:55:09 > 0:55:12- That's right.- Which means, it's certainly not sustainable.
0:55:12 > 0:55:16No, if that influx of goods were to stop,
0:55:16 > 0:55:19in three weeks' time we'd probably be eyeing each other hungrily.
0:55:19 > 0:55:20You know...
0:55:20 > 0:55:22things would be bad.
0:55:22 > 0:55:25You're not a man given to despair, are you?
0:55:25 > 0:55:28No, you have to be an optimist to be in conservation, I think.
0:55:28 > 0:55:29I think so too.
0:55:29 > 0:55:33Everywhere that I go, I see places that have degraded
0:55:33 > 0:55:35from when I first saw them.
0:55:35 > 0:55:38I also see places where, with just a little bit of effort,
0:55:38 > 0:55:41keeping the non-native animals out
0:55:41 > 0:55:44and removing the most aggressive weeds,
0:55:44 > 0:55:46that the natives, given half a chance, will actually
0:55:46 > 0:55:47come back and thrive.
0:55:49 > 0:55:53Combining the wisdom of the past, with the science of the present,
0:55:53 > 0:55:56to reduce our ecological footprint,
0:55:56 > 0:55:59it seems like a good starting point for any conservationist.
0:56:02 > 0:56:04The question is,
0:56:04 > 0:56:07to what extent can a native Hawaiian diet sustain me?
0:56:09 > 0:56:12For 1,000 years, Hawaiians were able to
0:56:12 > 0:56:16live off the land of Hawaii in a self-sufficient way.
0:56:16 > 0:56:19This would've been a kind of rather typical repast.
0:56:21 > 0:56:23First of all, we have poi
0:56:23 > 0:56:26which is made from the taro root.
0:56:29 > 0:56:31It's a bit bland
0:56:31 > 0:56:33but it's not unpleasant.
0:56:33 > 0:56:35I'm told it's terribly nutritious.
0:56:35 > 0:56:38So much so that babies can be fed on it.
0:56:38 > 0:56:40The poi goes particular well with the lau lau.
0:56:40 > 0:56:42This is lau lau.
0:56:43 > 0:56:46It's typically pork wrapped in taro leaves,
0:56:46 > 0:56:48cooked in hot stones,
0:56:48 > 0:56:52often buried for 12 hours while the stones do their work.
0:56:52 > 0:56:54So the pork is...
0:56:57 > 0:56:58..deliciously tender.
0:56:58 > 0:57:00Mmm...
0:57:00 > 0:57:03The taro leaves suffuses the meat as well.
0:57:03 > 0:57:04It's really delicious.
0:57:04 > 0:57:07The taro leaves themselves taste a bit like a
0:57:07 > 0:57:11slightly coarse spinach or chard.
0:57:11 > 0:57:15For dessert, something prepared from the insides of a coconut.
0:57:15 > 0:57:18It's called haupia.
0:57:18 > 0:57:20It's like a rather thick yoghurt.
0:57:21 > 0:57:24Mmm. It's actually delicious.
0:57:24 > 0:57:26I'm sure it's very good for you too.
0:57:26 > 0:57:28As for eating all this lot,
0:57:28 > 0:57:30if I can manage to finish it off,
0:57:30 > 0:57:34I'd probably suffer from something called kanak attack.
0:57:34 > 0:57:38Which means a bad attack of wanting to have a long sleep
0:57:38 > 0:57:41before I could face any more food again.
0:57:47 > 0:57:51Volcanic islands like Hawaii and the species they generate
0:57:51 > 0:57:53live fast and die young.
0:57:55 > 0:57:58Most will be reclaimed by the sea
0:57:58 > 0:58:00after a few million years.
0:58:04 > 0:58:06But a few islands are almost immortal.
0:58:08 > 0:58:10In the next episode, we visit Madagascar.
0:58:12 > 0:58:16Not a volcano but a fragment of an ancient continent
0:58:16 > 0:58:20more than 90 million years old.
0:58:20 > 0:58:24And here, the vastness of time has created an extraordinary
0:58:24 > 0:58:27evolutionary wonderland.