STUDY GUIDE – Unit IILecture 8Taxonomic hierarchy, how organisms are classified:KingdomRelated divisionsArchaebacteriaEubacteria (true bacteria)ProtistaPlantaeFungiAnimaliaDivisionGroups of classesBryophyta- mosses, liverwortsPslyophytaLycophyta- club mossesSphenophyta- horsetailsPterophyta- fernsCycadophyta- cycadsGinkgophyta- Ginkgo bilobaConiferophyta- conifersGnetophyta- gnetophytesMagnoliophyta- flowering plantsClassGroups of ordersOrderGroups of familiesFamilyRelated genera that share combinations of traitsGenusFirst scientific name in binomial nameSpecies that have many characteristics in commonSpeciesSecond scientific name in binomial nameSet of individuals that are closely related by descent from a common ancestor & ordinarily can reproduce with each other, but not with members of any other speciesSame speciesBroccoli, kale, cabbage, cauliflowerDogs- then have many different breedsKing David came over for great spaghettiBiological species conceptSpecies are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groupsOffspring are fertileLamarckismTraits acquired or diminished during the lifetime of an organism can be passed to its offspringBased on 2 observations though to be true in his dayUse it or lose it- individuals lose characteristics they do not require & develop those which are usefulInheritance of acquired traits- individuals inherit the acquired traits of their ancestorsThought the stretching by giraffes to reach leaves leads to offspring with longer necksTheory was later disprovedDarwin, Natural SelectionNatural selection- the differential survival & reproduction of individuals with inheritable characteristics, nature is the selective mechanismWorks on the individual phenotype which in turn changes the population gene poolLong periods of time must be available in order to change to a completely different speciesNatural selection has 4 premisesVariation- members of a population have individual differences that are inheritableNatural selection will not work in a population of clones- key to variation is sexual reproductionOverproduction- natural populations reproduce geometricallyProduces much more offspring than will surviveCompetition- individuals compete for limited resourcesDarwin- struggle for existenceSurvival to reproduce- only those individuals that are better suited to the environment survive & reproduceSurvival of the fittest- fit individuals pass onto a portion of their offspring the advantageous characteristicsEvolution as descent with modificationLinnaeusFather of systematic botanyArtificial SelectionSelective breeding as practiced by humans on domesticated plants & animalsTeosinte vs. modern corn, etc.GradualismTraditional viewEvolution occurs as a slow & steady accumulation of changes in organismDarwinian evolutionNot much evidencePunctuated equilibriumEvolution proceeds with periods of inactivity, followed by periods of very rapid evolutionConditions remain constant for long periods of timeLong periods of stasis- no change in speciesFossil record supports this viewLecture 93 Types of Natural SelectionDirectionalOne trait at the extreme end of the range is favored over individuals with the average or opposite extreme of the traitStabilizingAverage trait is favored over the extreme traitsDisruptiveExtreme traits are favored over individuals with the average traitEvidence for evolutionCan be found in extant organisms- living organismsComparative anatomySee morphologyMimicry & protective colorationMimicry- a harmless species may resemble a dangerous speciesSome moths resemble waspsCoral snakes look similar- some are venomous & some are notMonarch butterfly is toxic, Viceroy is not, but the Viceroy mimics the monarchProtective coloration- coloration that allows an organism to blend with the environmentMoths in bark in polluted EnglandStone plants resemble stones to protect themselves against herbivoresDevelopmental biologyEmbryology- early embryos of different mammal species look very much alikeBiogeographyStudy of the geographical distribution of organismsUnequal distribution of organisms on earthEach species originated only once, in one place (point of origin)Species spread out until they encounter a barrier- physical, environmental, ecologicalEndemic species- species that occur only in a particular area & that are usually rareArtificial selectionSelective breeding as practiced by humans on domesticated plants & animalsHumans are the selecting force for specific desirable traitsDNA- biochemistry & molecular biologyGenes provide an evolutionary recordIf we evolved from a common ancestorWe should have the same genetic molecule (DNA)We should use the DNA in the same way (dogma)Portions of our DNA should be the sameClosely related organisms share large portions of DNA sequence- humans & monkeysMorphologyHomologous organsOrgans similar in form in different organisms due to a common evolutionary originMay have different functionsSame bone structure found in a human arm, bat wing, dolphin flipper, bird wingLettuce leaves, pea tendrils, cactus spines- different functions but same origin (leaf)Analogous organsOrgans that have similar look and/or functions in different organisms, but do not share a common evolutionary originWings of insects vs. wings of birdsIn some plants stems may look & function like leaves but they have different originsSimilar functions of tendrils (climbing) but different origin (leaf vs. stem)Vestigial organsOrgans or parts of organs that are non-functional & degenerateAn organ loses its function, no selective advantage to have it, but no selective pressure to get rid of itVestigial leg bones in snakes & whales, appendix & wisdom teeth in humansConvergent evolutionProcess by which unrelated organisms in a similar environment evolve similar adaptive structures & physiological traitsCacti in North American deserts & milkweed in Asia & Euphorbia in AfricaFossil recordMost compelling evidence for evolutionRecords for last 4 billion years of evolutionRare eventNot complete but is ever growingCoevolution and SymbiosisCoevolution- long term evolutionary adjustment of one group of organisms to anotherMutual evolutionary influence between 2 species that are totally dependent on each otherEach of the species involved exerts selective pressure on the other, so they evolve togetherSymbiosis- ways in which 2 organisms can interactMutualism- both benefitLichens- fungus & algaeCoral