adaptive radiations hawaiian archipelago - for adaptive ...22° 20° 18° 160° 158° 156° 154°...
TRANSCRIPT
We will examine adaptive radiationsin the context of the Hawaiian Islands
Adaptive radiations
Adaptive Radiations Hawaiian archipelago - the examplefor adaptive radiations
“Getting there is half the problem . . .but then they can’t go homeagain”
Sherwin Carlquist, 1965
Hawaiian archipelago - the examplefor adaptive radiations
“If one were to stand at the top of Mauna Loa, he could see all the climes of theworld at a single glance of the eye”
Mark Twain, 1866
Hawaiian archipelago - the examplefor adaptive radiations
“Assume nothing in Hawaiian natural history”
Frank Howarth, 1992
Hawaiian archipelago - the examplefor adaptive radiations
Most remote island system in the world• settled in 1st millenium byPolynesians
• made known to science byCaptain Cook in 1778
Hawaiian BiotaHawaiian biota: most are found nowhere else in the world and exhibit traitsuncharacteristic of their taxa
• around 1,000 species of flowering plants
• 225 species of ferns and allies
Hawaiian biota: most are found nowhere else in the world and exhibit traitsuncharacteristic of their taxa
• nearly 5,800 species of insects
• 130 species of spiders
Kamehameha butterflyHappyface spider
Hawaiian BiotaHawaiian biota: most are found nowhere else in the world and exhibit traitsuncharacteristic of their taxa
• 230 species of birds
• 800 species of terrestrial molluscs
Land snailsKauai O’o
Hawaiian Biota
Hawaiian biota: most are found nowhere else in the world and exhibit traitsuncharacteristic of their taxa
• no amphibians
• no terrestrial mammals
Hawaiian monk sealHawaiian bat
Hawaiian BiotaHawaiian biota: extinction on-going process both in past and present
Hawaiian honeycreepersExtinct snail, flightless duck, lobeliad
Hawaiian Biota
Hawaiian Archipelago
• 132 islands, reefs, & shoals
• 2,580 km on SE-NW line
• 99% of land lies on 8 mainislands near the hot spotbelow Lo’ihi
Hawaiian Archipelago
• hot spot stationary relative toPacific Plate motion
• forms hot spot trace
• potassium-argon datingindicates oldest islands furthestfrom hot spot
• hot spot stationary relative toPacific Plate motion
Hawaiian Archipelago
• plate motion changed 43 mya
• oldest seamounts subductedinto Aleutian Trench
• plate motion changed 43 mya
43mya
Hawaiian Archipelago
• Islands (and shoals) are simplyemergent tops of great underwatervolcanoes
• up to 10km above ocean floor
Mauna LoaUSGS ‘GLORIA’ side sonar
Hawaiian Archipelago
• actually double hot spot 30km apart
• Lo’ihi to Mauna Loa
• Kilauea to Mauna Kea
HawaiiOahu
Hawaiian Archipelago
• progressively older ages of islands well known
Hawaiian Archipelago
• real estate signs on recent lavaflow (80 years) on Big Island
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Kauai Present
NihauKaula
Oahu
Maui
Loihi Seamount
Molokai
LanaiKahoolawe Hawaii
Hawaiian Archipelago
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Kauai
0.5 Million Years Ago
Nihoa
NihauKaula
Oahu
Maui
Mahukona
Hawaiian Archipelago
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Kauai
1 Million Years Ago
Nihoa
NihauKaula
OahuMaui
Hawaiian Archipelago
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Kauai
2.5 Million Years Ago
Nihoa
NihauKaula
Oahu
Hawaiian Archipelago
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Necker
Kauai
5 Million Years Ago
Nihoa
NihauKaula
Hawaiian Archipelago
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Gardner Pinnacles
La Perouse PinnaclesNecker
Nihoa
7.5 Million Years Ago
Hawaiian Archipelago
Hilo (windward and wet) vs. Kona Coast in Hawaii (leeward and dry)
Hawaiian Climate• primary weather pattern is northeasterly trade winds• severe kona winds come from leeward side
Hawaiian Climaterainfall patterns
• tall mountains have dry summit (eastMaui)
• shorter mountains have extremely wetsummits (Kauai)
• steep, windward mountains (Oahu) havewet summit but drier Pali cliffs
Hawaiian Climaterainfall patterns
• double mountain system (as in Oahu)sets up complex rainfall gradient and adiversity of ecosystems
Hawaiian Climaterainfall patterns
• Wai’ale’ale on oldest (most eroded)island of Kauai is wettest spot in Hawaiiand possibly in the world
• 11.5 m of rain and presence of theAlakai Swamp
Hawaiian Climaterainfall patterns
• Pu’ukukui (5788 ft) on west Maui is 2ndwettest spot; xeric summit of Haleakala oneast Maui is 10,023 ft
Greensword bog - west Maui
Hawaiian Climaterainfall and porous soils
• fewer waterfalls (permanent)
Greensword bog
• fewer bogs than expected
• more pronounced deserts