28 03 2005 12 28 00 STUDY GUIDE Unit II Lecture 8 Taxonomic hierarchy how organisms are classified Kingdom o Related divisions o Archaebacteria o Eubacteria true bacteria o Protista o Plantae o Fungi o Animalia Division o Groups of classes o Bryophyta mosses liverworts o Pslyophyta o Lycophyta club mosses o Sphenophyta horsetails o Pterophyta ferns o Cycadophyta cycads o Ginkgophyta Ginkgo biloba o Coniferophyta conifers o Gnetophyta gnetophytes o Magnoliophyta flowering plants o Groups of orders o Groups of families Class Order Family Genus Species o Related genera that share combinations of traits o First scientific name in binomial name o Species that have many characteristics in common o Second scientific name in binomial name o Set 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 species o Same species Broccoli kale cabbage cauliflower Dogs then have many different breeds King David came over for great spaghetti Biological species concept Species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups Offspring are fertile Lamarckism Traits acquired or diminished during the lifetime of an organism can be passed to its offspring Based on 2 observations though to be true in his day o Use it or lose it individuals lose characteristics they do not require develop those which are useful o Inheritance of acquired traits individuals inherit the acquired traits of their ancestors Thought the stretching by giraffes to reach leaves leads to offspring with longer necks Theory was later disproved Darwin Natural Selection Natural selection the differential survival reproduction of individuals with inheritable characteristics nature is the selective mechanism o Works on the individual phenotype which in turn changes the population gene pool o Long periods of time must be available in order to change to a completely different species Natural selection has 4 premises o Variation members of a population have individual differences that are inheritable Natural selection will not work in a population of clones key to variation is sexual reproduction o Overproduction natural populations reproduce geometrically Produces much more offspring than will survive o Competition individuals compete for limited resources Darwin struggle for existence o Survival to reproduce only those individuals that are better suited to the environment survive reproduce Survival of the fittest fit individuals pass onto a portion of their offspring the advantageous characteristics Evolution as descent with modification Linnaeus Father of systematic botany Artificial Selection Selective breeding as practiced by humans on domesticated plants Teosinte vs modern corn etc Gradualism Traditional view Evolution occurs as a slow steady accumulation of changes in animals organism Darwinian evolution Not much evidence Punctuated equilibrium Evolution proceeds with periods of inactivity followed by periods of very rapid evolution Conditions remain constant for long periods of time o Long periods of stasis no change in species Fossil record supports this view Lecture 9 3 Types of Natural Selection Directional o One trait at the extreme end of the range is favored over individuals with the average or opposite extreme of the trait o Average trait is favored over the extreme traits o Extreme traits are favored over individuals with the average Stabilizing Disruptive trait Evidence for evolution Can be found in extant organisms living organisms Comparative anatomy o See morphology Mimicry protective coloration o Mimicry a harmless species may resemble a dangerous species are not Some moths resemble wasps Coral snakes look similar some are venomous some Monarch butterfly is toxic Viceroy is not but the Viceroy mimics the monarch o Protective coloration coloration that allows an organism to blend with the environment Moths in bark in polluted England Stone plants resemble stones to protect themselves against herbivores Developmental biology very much alike Biogeography o Embryology early embryos of different mammal species look o Study of the geographical distribution of organisms o Unequal distribution of organisms on earth o Each species originated only once in one place point of origin Species spread out until they encounter a barrier physical environmental ecological o Endemic species species that occur only in a particular area that are usually rare Artificial selection o Selective breeding as practiced by humans on domesticated plants animals o Humans are the selecting force for specific desirable traits DNA biochemistry molecular biology o Genes provide an evolutionary record o If we evolved from a common ancestor We should have the same genetic molecule DNA We should use the DNA in the same way dogma Portions of our DNA should be the same Closely related organisms share large portions of DNA sequence humans monkeys Morphology Homologous organs o Organs similar in form in different organisms due to a common evolutionary origin o May have different functions o Same bone structure found in a human arm bat wing dolphin o Lettuce leaves pea tendrils cactus spines different functions flipper bird wing but same origin leaf Analogous organs o Organs that have similar look and or functions in different organisms but do not share a common evolutionary origin o Wings of insects vs wings of birds o In some plants stems may look function like leaves but they have different origins o Similar functions of tendrils climbing but different origin leaf vs stem Vestigial organs degenerate o Organs or parts of organs that are non functional o An organ loses its function no selective advantage to have it but no selective pressure to get rid of it o Vestigial leg bones in snakes whales appendix wisdom teeth in humans Convergent evolution Process by which unrelated organisms in a similar environment evolve similar adaptive structures physiological traits Cacti in North American deserts milkweed in Asia Euphorbia in Africa Fossil record Most compelling evidence for evolution Records for last 4 billion years of evolution Rare event Not complete but is ever growing Coevolution and Symbiosis Coevolution long term evolutionary adjustment of one group of organisms to another o Mutual evolutionary influence between 2 species that are totally dependent on each other o Each of the species