1. There are differences in organisms (evidence gathered on Beagle)2. There is a struggle for existence (Malthus)3. In the struggle, certain differences will give those organisms possessing them an advantage (Darwin's contribution)4. These organisms will survive and reproduce in greater numbers (differential reproduction)5. Over long periods of time (Lyell), the whole species will change (evolution)reproductive isolating mechanisms - keep organisms of different species from interbreeding1. prematinga) habitat isolationb) temporal isolationc) behavioral isolationd) mechanical isolation2. postmatinga) gametic isolationb) zygote mortalityc) hybrid sterilityd) fitness of offspringBiology 222 Vertebrate Zoology Evolution/Basics Lecture Outline Page 1 of 121EVOL01222.doc January 4, 2001Based on Pough et. al, 1989. Vertebrate Zoology - 3rd Ed. MacMillanHickman et al., 2001. Integrated Principles of Zoology - 11th Ed. William C. Brown PublishersIntro to Vertebrates/Evolution - The BasicsTheme: The turtle as a typical vertebrate.Demonstration - TurtleQuestion - what is a vertebrate?characteristics - size from 0.1 gram to 100,000 kglength to 60mall habitatsall types of feeding strategiespresence of a vertebral column (and associated brain, spinal cord,etc.)50,000 extant species, up to 500,000 extinct speciesSome examples of vertebrates:Myxini - hagfishCephalaspidomorphi - lampreys 50 species (with myxinoidea)Elasmobranchii - sharks, skates, rays - 800 speciesHolocephali - ratfishCladista - bichers, reed fishChondrostei - sturgeon, paddlefishNeopterygii - gar, bowfinTeleostei - other ray-finned fishes - 21,000 species of fishActinistia - coelocanth - 1 speciesDipnoi - lungfish - 6 speciesMicrosauria/Caudata - salamanders & caecilians - 350 speciesTemnospondyli/Anura - frogs and toads - 3,500 speciesTestudomorpha/Testudines - turtles - 225 speciesLepidosauria - tuatara, lizards, snakes - 5,800 speciesArchosauria - crocodiles - 21 species crocsAves - birds - 9,000 birdsSynapsida - mammals - 4,000 species (17 groups)Biology 222 Vertebrate Zoology Evolution/Basics Lecture Outline Page 2 of 121EVOL01222.doc January 4, 2001Biology 222 Vertebrate Zoology Evolution/Basics Lecture Outline Page 3 of 121EVOL01222.doc January 4, 2001Classification of the turtle:Kingdom Animalia (Plantae, Fungi, Protista, Monera)Phylum ChordataClass AnapsidaOrder TestudomorphaFamily EmydidaeGenus Terrapene - box turtlesspecies carolina - eastern box turtleTerrapene carolina (Linnaeus, 1758)Note forms of order names, family names, proper handling of specific epithet(including author).Graptemys geographica (Le Seur) - 1827Note common namesBiology 222 Vertebrate Zoology Evolution/Basics Lecture Outline Page 4 of 121EVOL01222.doc January 4, 2001Go to BoardTaxa - any hierarchical grouping - a levelBasic taxonomy - Holotype - part of species descriptionmust be deposited in museummust be mentioned in textis the basis for future assignment of the nameparatypeadditional specimens representing the known variation of thespeciespriority - first description is the valid oneeach species must have unique specific epithetCommission of Zoological NomenclatureEvolutiongene - basic unit of selection - DNA code for protein AKA locusallele - differing form of gene - same protein, slightly differentgenotype - all the genes of an individualHaploid - only one allele for each gene - sex celldiploid - two alleles for each gene - somatic cellHomozygous - both alleles for a given locus are identical (diploid cell)Heterozygous - two different alleles at a given locusphenotype - the resulting traits (structural, behavioral, etc.) of a givengenotypeVariation - mutations are changes in the genetic code - they give rise to new alleles -alleles are combined into new genotypes (and phenotypes) through sexual reproductionand recombination. Variation is the basis for evolution.Biology 222 Vertebrate Zoology Evolution/Basics Lecture Outline Page 5 of 121EVOL01222.doc January 4, 20011. There are differences in organisms (evidence gathered on Beagle)2. There is a struggle for existence (Malthus)3. In the struggle, certain differences will give those organisms possessing them an advantage (Darwin's contribution)4. These organisms will survive and reproduce in greater numbers(differential reproduction)5. Over long periods of time (Lyell), the whole species will change(evolution)heritability - any variation must exist in the genes - be heritable - if natural selection is toact on it.Natural Selection - differential reproduction of differing alleles (genotypes, phenotypes)different levelsselection of individuals (and associated genes)genic selection (alleles going into sex cells)group or interdemic selection - species selection (controversial)Types of natural selection: ----- use bell drawings -----directional selectionstabilizing selection - driving force of allopatric speciationdisruptive selection - driving force of sympatric speciationBiology 222 Vertebrate Zoology Evolution/Basics Lecture Outline Page 6 of 121EVOL01222.doc January 4, 2001Biology 222 Vertebrate Zoology Evolution/Basics Lecture Outline Page 7 of 121EVOL01222.doc January 4, 2001Fitness - measure of the reproductive success (of an allele or individual)Inclusive fitness - fitness gained by the copies of your genes carried by relative's kin.sometimes one can maximize his own fitness by foregoing reproduction to help kin rear offspring - altruistic behaviorBiology 222 Vertebrate Zoology Evolution/Basics Lecture Outline Page 8 of 121EVOL01222.doc January 4, 2001Types of variation :1 - individual - each individual has a unique assortment of genes(genotype), and thus a unique phenotype.2 - polymorphism - several discrete phenotypes exist in a population3 - sexual dimorphism - a type of polymorphism where the phenotypes varyaccording to sex. Often reinforced by sexual selection4 - geographic - variation in populations according to geographiclocation.polytypic - a species with geographic variants pronounced enoughto be subspecies.monotypic - a species which shows little variation over its range.Speciationspeciation - the separation of a population into distinct breeding groups via naturalselection and other genetic processes, including chance.biological species - groups of actually (or potentially) interbreeding natural populationswhich are reproductively (genetically) isolated from other