L3 Notes Bild3 - Lecture 5: Species BILD 3 July 2, 2010 HOW...

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Lecture 5: Species BILD 3 July 2, 2010 HOW DO ORGANISMS DIVERSIFY? ADAPTIVE VARIATION SPECIATION ADAPTIVE RADIATION Adaptive Variation -Skin color – Just so stories -Artificial selection -rapid and dramatic results -why eugenics can’t work -Sexual selection - manipulation of males by females - Agents of evolution -variation enhances fitness - Sexual vs. asexual reproduction Speciation SPECIES: Groups of populations consisting of individuals capable of freely interbreeding with each other but not with members of other species. MAYR’s BIOLOGICAL SPECIES CONCEPT: Groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups. Typological species concept Linnaeus - species as created kinds Type specimens as a basis for taxonomy Concept of the “wild type” Morphological species concept : species look different Linnean binomial system of nomenclature Generic name followed by species name Homo sapiens or H. sapiens Genus, (plural: genera) Species Subspecies in the older trinomial system which recognized subspecies with formal names Homo sapiens sapiens and H. s. neanderthalensis Each taxonomic category is called a taxon (taxa) Hierarchy: genus, family, order, class, phylum (phyla) Kingdom, phylum, subphylum, class, order, family, genus, species AUSTRALIAN TOADLETS Pseudophryne corroboree – ALPINE MEADOWS P. australis – SYDNEY BASIN SANDSTONE
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NINE ALLOPATRIC SPECIES OF BAHAMIAN LAND SNAIL, Cerion sp. PETERSON FIELD GUIDE -Suggests visual clues that bird watchers can use to identify different species of very similar Fall warblers -Species may look alike to us but be clearly different from their own perspective. Biological species concept based on attributes important in reproductive isolation Other concepts mentioned in Campbell: Morphological species concept Phylogenetic species concept based on shared unique characters and history Evolutionary species concept based on all of the above plus a deeper understanding of history. Defined in terms of clusters of genetically related individuals. “Good” species Sister and daughter species Sibling species: closely related and cannot be distinguished on morphological grounds Cryptic species: just hard to identify Limitations of the Biological Species Concept • The biological species concept cannot be applied to: -Asexual organisms -Fossils -Organisms about which little is known regarding their reproduction Characteristics of Species Morphology Distribution or geographic range Geographic variation Clinal variation vs. chaotic patterns ECOGEOGRAPHIC RULES Size COLD HOT HABITAT GRADIENT Local races, varieties, subspecies Categories of convenience often based on very few morphological characters. Fail to capture natural variability.
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Peromyscus maniculatus Deer mouse 50 subspecies recognized Many on isolated islands Outmoded typological thinking Naming taxa without regard for population variability Species:
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L3 Notes Bild3 - Lecture 5: Species BILD 3 July 2, 2010 HOW...

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