The Wallace Line - Lecture Slides - Plant Geography | BOTANY 422, Study notes of Geography

Download The Wallace Line - Lecture Slides - Plant Geography | BOTANY 422 and more Study notes Geography in PDF only on Docsity! 1 The Wallace Line Alfred Wallace, one of the premier zoobiogeographers, wrote the definitive treatise “Distributions of Animals” in 1876 where he summarized the known distributions and causes of their biogeographical patterns Alfred Wallace’s main interest was in the vertebrate fauna of the Indo-Malay Archipelago from Asia to Australia where he clearly saw a sharp faunistic break Wallace’s trips Sclater’s & Wallace’s faunistic regions Probably his most important trip he ever made was a 6 km ferry ride from Bali to Lombok The Wallace Line “In the archipelago . . . there are two distinct faunas rigidly circumscribed, which differ as much as those of South America and Africa, and more than those of Europe and North America” [Letter to Henry Bates in London (1858)] Sclater’s & Wallace’s faunistic regions Wallace’s trips The Wallace Line “The boundary line often passes between islands closer than others in the same group. I believe the western part to be a separated portion of continental Asia, the eastern the fragmentary prolongation of a former Pacific continent” Looking east from Bali across 6 km Lombok Straits “In the archipelago . . . there are two distinct faunas rigidly circumscribed, which differ as much as those of South America and Africa, and more than those of Europe and North America” [Letter to Henry Bates in London (1858)] The Wallace Line 2 Cover plate from Distributions of Animals Wallace graphically depicts what has since been termed the “Wallace Line” in his book by showing birds and mammals that are found in the Oriental (Borneo, left) and Australian (New Guinea, right) sides tarsier tree kangaroo tree shrew tapir lory raquet-tailed kingfisher Oriental Fauna Australian Fauna The Wallace Line • Wallace Line — the imaginary line separating the Oriental and Australian biotas — extends between Bali and Lombok and between Borneo/Philippines and Sulawesi • Several other lines have been proposed in the region based on particular groups of animals or plants. • Main issue with most lines is what do with Sulawesi (Celebes) The Wallace Line Crested black macaque Bear cuscus (marsupial) Backbone of Sulawesi Sulawesi, with its mixture of Oriental and Australian fauna, was so perplexing to Wallace, that he vacillated back and forth on where to place the island The Wallace Line Now know that the two regions are different continental plates that have been moving independently — the Asian and Australian plates The IndoMalay - New Guinea Archipelago area includes island groups mostly confined to either of two continental shelves: Sunda shelf — Asian Sahul shelf — Australian The Wallace Line 5 Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) 1. Pattern originally thought to include “identical species” (Gray listed 134) but now believed to be largely congeneric not conspecific. By 1992 the list included only 8 conspecific examples, and by 1999 only 1. Phryma leptostachya var. asiatica Phryma leptostachya var. leptostachya Lopseed, Verbenaceae Eastern North America - Eastern Asia Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) 2. Up to 120 genera of plants have been cited as exhibiting this pattern. If remove genera (like blue beech) with western North American or western European distributions as well, then 65 genera in 42 different families involved Carpinus caroliniana American hornbeam, blue beech Betulaceae Carpinus betulus Europe Eastern North America - Eastern Asia Liriodendron tulipfera Tulip tree, Magnoliaceae Liriodendron chinense Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) 2. . . . and included in the 65 genera are trees 1 sp. E. Asia vs. 1 sp. E. North America Eastern North America - Eastern Asia Hamamelis virginiana Witch hazel, Hamamelidaceae Hamamelis mollis Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) 2. . . . and included in the 65 genera are trees 2 spp. E. Asia vs. 2 spp. E. North America Eastern North America - Eastern Asia 6 Parthenocissus quinquefolia Virgnia creeper, woodbine, Vitaceae Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) Parthenocissus heneryana 2. . . . and included in the 65 genera are vines 9 spp. E. Asia vs. 3 spp. E. North America Eastern North America - Eastern Asia Campsis radicans Trumpet creeper, Bignoniaceae Campsis sp. Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) 2. . . . and included in the 65 genera are vines 1 sp. E. Asia vs. 1 sp. E. North America Eastern North America - Eastern Asia Jeffersonia diphylla Twinleaf, Berberidaceae Jeffersonia dubia Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) 2. . . . and included in the 65 genera are herbs 1 sp. E. Asia vs. 1 sp. E. North America Eastern North America - Eastern Asia Podophyllum peltatum Mayapple, BerberidaceaePodophyllum hexandra Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) 2. . . . and included in the 65 genera are herbs 1 sp. E. Asia vs. 1 sp. E. North America Eastern North America - Eastern Asia 7 Nelumbo lutea Lotus lily, Nelumbonaceae Nelumbo nucifera Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) 2. . . . and included in the 65 genera are herbs 1 sp. E. Asia vs. 1 sp. E. North America Eastern North America - Eastern Asia Sanguinaria canadensis Bloodroot, Papaveraceae Eomecon chionantha Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) 3. In few cases, the disjunction involves different but closely related genera Eastern North America - Eastern Asia Diervilla splendens Bush honeysuckle, Caprifoliaceae Weigela florida 3. In few cases, the disjunction involves different but closely related genera Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) Eastern North America - Eastern Asia 4. The disjunction typically involves E. North America and E. Asia . . . Four quick points (reviewed in Jun Wen’s 1999 paper in Ann Rev Ecol Syst) Eastern North America - Eastern Asia 10 Phylogenetic analyses of 11 putative pairs of vicariad species - are they sister species? Hamamelis — NO New Twists - Molecular Systematics Hamamelis Witch hazel, Hamamelidaceae Eastern North America - Eastern Asia Phylogenetic analyses of 11 putative pairs of vicariad species - are they sister species? Gledistsia — NO New Twists - Molecular Systematics Gleditsia Honey locust, Fabaceae Eastern North America - Eastern Asia Phylogenetic analyses of 11 putative pairs of vicariad species - are they sister species? Panax — NO New Twists - Molecular Systematics Panax quinquefolius American ginseng, Araliaceae Eastern North America - Eastern Asia Nyssa sylvatica - sour gum, black gum,black tupelo Phylogenetic analyses of 11 putative pairs of vicariad species - are they sister species? Nyssa — +/- New Twists - Molecular Systematics Eastern North America - Eastern Asia 11 Phylogenetic analyses of 11 putative pairs of vicariad species - are they sister species? Symplocarpus — YES New Twists - Molecular Systematics Symplocarpus renifolius Symplocarpus foetidus, skunk cabbage Eastern North America - Eastern Asia Molecular clocks - when did the species diverge and at same time? New Twists - Molecular Systematics 1. Liriodendron - tulip trees 13 mya 2. Magnolia - magnolias 2 mya 3. Campsis - trumpet creepers 25 mya Eastern North America - Eastern Asia New Twists - Molecular Systematics from reading! Recent analysis of 100 examples of disjunctions (33 with absolute time divergences) among these four areas provides some new insights on the Holarctic Flora Eastern North America - Eastern Asia New Twists - Molecular Systematics animalsplants % of examples showing various disjunct patterns 1. Plants show considerably higher proportion of Eastern Asia - Eastern North America disjunct pattern than do animals Eastern North America - Eastern Asia 12 New Twists - Molecular Systematics animalsplants % of examples showing various disjunct patterns 2. Plants show considerably lower proportion of Western North America - Eastern North America disjunct pattern than do animals 1. Plants show considerably higher proportion of Eastern Asia - Eastern North America disjunct pattern than do animals Eastern North America - Eastern Asia New Twists - Molecular Systematics Arrows indicate inferred directions of dispersal 3. Eastern Asia is source of 20 of the disjuncts, and Eastern North America only 1. These dispersal events occurred over the last 30 my and with Beringia the likely route. Eastern North America - Eastern Asia Summary: Tertiary, as well as present day distributions, indicate that a widespread Arcto-Tertiary or Holarctic Flora existed, especially during 25-3 mya, throughout the entire North Temperate region, and facilitated by Bering and North Atlantic land bridges. Is vicariance a mechanism for the repeated pattern? • Vicariad species recognized on morphological similarity are not necessarily sister species using phylogenetics. • The large range in estimated time splits for vicariad species indicates that vicariance alone is not an adequate explanation. • Dispersal and speciation did not all occur at the same time in all groups. Eastern North America - Eastern Asia