U of M ANTH 1001 - Lecture 8 9-28-17 Speciation (19 pages)

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Lecture 8 9-28-17 Speciation



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Lecture 8 9-28-17 Speciation

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Pages:
19
School:
University of Minnesota- Twin Cities
Course:
Anth 1001 - Human Evolution
Human Evolution Documents
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9 28 2017 1 Bake Sale Anthropology Club Bake Sale Today from 10am 2pm Willey Hall right outside this very classroom Any questions about Anthro Club can be answered at the bake sale table Proceeds fund the Undergraduate Anthropology Club Annual Conference 2 1 9 28 2017 Darwin s 5 theories regarding evolution 1 Species change evolution as such 2 All organisms share a common ancestry 3 Evolution is gradual 4 Evolution leads to speciation 5 Evolution occurs through Natural Selection 3 Convergent Evolution 2 9 28 2017 Speciation bridging micro and macro evolution Micro evolutionary processes four forces patterns of Macro evolution speciation common ancestry above the species level A common comment on the street Forming new species is impossible because the first reproductively isolated organism will be incapable of mating with any other organism 5 Speciation bridging micro and macro evolution This reasonable but unfounded misconception is based in the idea that speciation is an EVENT rather than a PROCESS getting there is half the fun Indeed perhaps the very best evidence supporting evolution is the process of speciation 3 9 28 2017 Scale of Macroevolution Age of life on Earth 3 500 000 000 years Washington Ave Bridge 1 500 feet Each foot 26 million years Each inch 200 000 years the age of our species H sapiens Thickness of your hair 0 004 inches or 777 years Plenty of time for speciation given documented microevolution 7 Liger cross from a male lion and female tiger Species Life can be clustered into distinct types Species are real biological concepts Species are difficult to define Liger couple by Hkandy Own work Licensed under CC BY SA 3 0 via Commons https commons wikimedia org wiki File Liger couple jpg media File Liger couple jpg Mule cross from a male donkey jack ass and female horse mare Hybrid vigor but still sterile 8 4 9 28 2017 Speciation as gene flow complete hybridization same species how do you get from complete hybridization to NO hybridization no hybridization different species 9 The Biological Species Concept Species are a group of interbreeding organisms Reproductive isolation OR Connected through gene flow Adjacent Islands Distant Islands 10 5 9 28 2017 The Ecological Species Concept Reproductive isolation not necessary Natural selection keeps species distinct from one another Relies upon the concept that hybrids have less Fitness 11 The Ecological Species Concept Almost half of all species not reproductively isolated Some species have little or no gene flow Pacific Checkerspot Butterfly individual s range 100m populations separated by 100s km 12 6 9 28 2017 Allopatric Speciation Geographic isolation physical barrier Combination of reproductive isolation and natural selection Etymology allopatric and alone from Greek allos other 13 Allopatric Speciation Character displacement Large beaked birds outcompete medium beaked birds in dry habitats Move to wetter areas selection favors small beaks Example Santa Cruz Island finches Reinforcement evolution of characters to increase reproductive isolation 14 7 9 28 2017 Reinforcement can lead to the Species Mate Recognition Concept Examples Guenons of Africa 15 Stages of incomplete hybridization Biased sex ratio Functional non gametic incompatibility Behavioral incompatibility Sex biased hybrid fertility Reduced overall hybrid fertility Second generation hybrid sterility Geographic incompatibility Temporal incompatibility Hybrid sterility Hybrid inviability Reduced hybridity 16 8 9 28 2017 Examples ring species Species boundary no mating Phylloscopus trochiloides trochiloides Greenish Warbler 17 Examples dogs Dogs are all the same species 18 9 9 28 2017 Examples dogs Dogs are all the same species 19 Speciation as the interaction between the Biological Ecological Species Concepts in historical time Etymology Parapatric parallel Sympatic same 20 10 9 28 2017 Olive Baboon bonded Hamadryas Baboon defense polygyny Parapatric Speciation in progress 21 22 11 9 28 2017 derived traits derived traits derived traits Lahr Foley 2006 23 ALA 5 ChimeIn Question Which mechanism is acting when a physical barrier results in speciation A Allopatric speciation B Parapatric speciation C Sympatric speciation D Biological species concept E Natural selection Text 20082 plus your answer to 14352154567 24 to answer via SMS 12 9 28 2017 Before we introduce the hominins how do we tell who descended from whom Homology ancestry or Convergence analogy 25 Homology or convergence 26 13 9 28 2017 Levels of analysis As a wing As a forearm 27 Creating Evolutionary or Phylogenetic Trees So how do we chose which traits to examine when making trees 28 14 9 28 2017 Creating Evolutionary or Phylogenetic Trees Shared Derived Convergence Derived Ancestral 29 Spider monkey Warm blooded Hair color Premolar Tail yes tan 3 yes Baboon yes grey 2 yes Gorilla yes black 2 no Carrot Top yes orange 2 no 30 15 9 28 2017 How are they related 31 yes yes yes yes Warm blooded 32 16 9 28 2017 yes yes Is warm bloodedness a useful trait for yes determining relationships among these primates yes 33 black tan grey Is hair color a useful trait for determining relationships among these primates orange 34 17 9 28 2017 2 3 2 Is premolar a useful trait for determining relationships among these primates 2 35 no yes yes Is the presence of a tail a useful trait for determining relationships among these primates no 36 18 9 28 2017 Loss of tail Loss of premolar Full orbital convergence Warm blooded Warm blooded Hair color Premolar Tail yes tan 3 yes yes yes yes grey black orange 2 2 2 yes no no 37 Cladistics Primitive or Ancestral characters even though homologous do not help in sorting relationships Unique characters do not help in sorting relationships Only SHARED DERIVED characters can sort relationships within a group 38 19


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