350 likes | 1.07k Views
Island evolution. Evolutionary forces on islands Evolutionary trends on islands. Morphology. Gigantism and nanism Loss of dispersal abilities. Pringleophaga marioni, Marion Island. Lepidoptera: Tineidae. Paractora dreuxi, Marion Island. Diptera: Helcomyzidae.
E N D
Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Gigantism and nanism Loss of dispersal abilities
Pringleophaga marioni, Marion Island Lepidoptera: Tineidae Paractora dreuxi, Marion Island Diptera: Helcomyzidae
Galapaganus, Galapagos Islands Sequiera et al. 2000
7.2 Mya winged/apterous mainland/island Naupactus xanthographus Naupactus verecundus Naupactus dissimulator Galapaganus howdenae Galapaganus galapagoensis Galapaganus caroli Galapaganus vandykei Galapaganus collaris Galapaganus conwayensis Galapaganus ashlocki Sequiera et al. 2000
Coleoptera 80 Orthoptera 60 Diptera ArcSine-transformed % flightless (mainland areas) 40 Hemiptera 20 0 Thysanoptera 0 20 40 60 80 ArcSine-transformed % flightless (oceanic islands) Psocoptera Roff 1990 Neuroptera
Sphenisciformes 18/18 1 Struthioniformes 15/15 1 Gruiformes 17/122 17 nr of species flightless/total nr of transitions
Porzana sandwichiensis (+?1884), Hawaii Islands Porzana monasa (+1828), Kosrae Island Porzana atra, Henderson Island Porzana palmeri (+1920, 1948), Laysan Island
125 000 y Amauornis akoof Amauornis favirostris Porzana monasa Porzana tabuensis Porzana atra Porzana sandwichensis Amauornis bicolor Amauornis olivieri Porzana palmeri Porzana pusilla Porzana parva Porzana fusca Porzana paykullii Porzana carolina Porzana fluminea Porzana porzana Anurolimnas fasciatus Poliolimnas flaviventer Slikas et al. 2002
Rodriguez solitaire, Pezophaps solitaria, Rodriguez Dodo, Raphus cucullatus, Mauritius
Anas chlorotis, New Zealand Anas nesiotis, Campbell Islands Anas aucklandia, Auckland Islands
Cormorant, Phalacrocorax carbo Flightless cormorant, Phalacrocorax harrisi, Galapagos
1cm mandibles Apteribis, Hawaii Islands (+)
Chelychelynechen quassus Thambetochen xanion Ptaiochen pau Anas wyviliana Thambetochen chauliodous Kauai Molokai Oahu Maui Lanai Hawaii moa-nalo (+), Hawaiian Islands Sorensen et al. 1999
number of evolutionary transitions number of flightless species total number of species Ostriches Struthionidae 1 1 1 Africa Rheas Rheidae 2 2 South America Cassowaries Casuariidae 4 4 Australia, New Guinea Kiwis Apterygidae 3 3 New Zealand Emus Dromaiidae 1 1 Australia Moas Dinornithidae 13 13 New Zealand Dromornithidae 8 8 Australia Elephant birds Aepyornithidae 9 9 Madagascar Dodos Raphidae 2 2 2 Mascarene Islands Rails Rallidae 17 17 122 Various islands Kagus Rhynochetidae 1 1 1 New Caledonia Parrots Psittacidae 1 1 358 New Zealand Ibises Plataleidae 3? ? ? Hawaii Penguins Spheniscidae 18 1 18 Southern hemisphere Cormorants Phalacrocoracidae 1 1 37 Galapagos Islands Grebes Podicipedidae 3 3 21 South America Murres Alcidae 1 1 23 Atlantic Ocean Ducks Anatidae 4 2 148 Various coastlines
"There is a very curious point in the astounding proportion of Coleoptera that are apterous; & I think I have grasped the reason, viz that powers of flight wd be injurious to insects inhabiting a confined locality & expose them to be blown to the sea" Darwin, 1855 natural selection for energy re-allocation random drift not countered by selection Loss of dispersal abilities ecological release (lack of predators)
Gavidae Phasantidae 2.0 Log winglength (cm) 1.0 Bird families No flightless species Contains flightless species 0 0 1 2 3 4 Log body mass (g) McCall et al. 1998
Broom stick, Bidens pilosa, Tropics Bog Beggarticks, Bidens conjuncta, Hawaii Islands
pappus achene Lactuca muralis, Vancouver Island Cody & Overton 1996
2.0 2000 1500 Volume pappus / Volume achenes 1000 500 0 mainland 1-4 5-7 8-9 10+ Age (years) Lactuca muralis, Vancouver Island Cody & Overton 1996
Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Gigantism and nanism Loss of dispersal abilities Development of woodiness
Narrowleaf plantain, Plantago lanceolata, Eurasia Plantago princeps, Hawaii
Competition hypothesis growing taller is advantageous Longevity hypothesis woodiness allows extended lifespans, increases chance of sexual reproduction Climate hypothesis islands have milder and moister climates Development of woodiness
Island evolution Evolutionary forces on islands Evolutionary trends on islands Morphology Gigantism and nanism Loss of dispersal abilities Development of woodiness Tendency towards melanism
lower predation pressure tendency towards melanism thermal advantage
70 60 50 40 Melanism frequency (%) 30 20 10 0 insular inland coastal Viper, Vipera berus, Swedish islands in the Baltic Sea Forsman 1995
0.9 Annual survival rate 0.7 zigzag males 0.5 melanistic males 1986-87 87-88 88-89 89-90 90-91 Year Viper, Vipera berus, Swedish islands in the Baltic Sea Forsman 1995
Japanese four-lined ratsnake, Elaphe quadrivirgata, Yakushima Island Tanaka 2007
16 12 melanistic striped deviation from preferred range (°C) 8 4 0 Jul Sep Oct Nov Month Japanese four-lined ratsnake, Elaphe quadrivirgata, Yakushima Island Tanaka 2007