Note for BSC 373 with Professor Harris at UA-Lecture 2
Note for BSC 373 with Professor Harris at UA-Lecture 2
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This 15 page Class Notes was uploaded by an elite notetaker on Friday February 6, 2015. The Class Notes belongs to a course at University of Alabama - Tuscaloosa taught by a professor in Fall. Since its upload, it has received 13 views.
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Date Created: 02/06/15
What is Systematics Systematic Biology eld of biology that deals with the diversity of life Systematics is usually divided into two areas Phylogenetic systematics eld of biology that deals with the relationships between organisms It includes the discovery ofthese relationships and the study ofthe causes behind this pattern Taxonomy the science ofnaming and classifying organisms Systematic biology provides the foundation for all of comparative biology Week Why be interested in Systematics The hypotheses of relationships among organisms generated by systematics form the basis for all comparative biology regardless of your biological discipline V thout taxonomy to give shape to the bricks and systematics to tell us how to put them together the house of biological science is a meaningless jumblequot Robert M May 1990 Week Why is Systematics so Important Systematics provides the knowledge essential for our well being and longterm survival because organisms including our own species interact together in a complex web oflife For example nature is he ultimate source ofour food raw materials and many medicines need to recognize classify and understandthe natural history of organisms in order to protect ourselves 39om diseases pests and invasive species our knowledge ofliving species can be applied to monitor the quality of our environment our knowledge ofliving species can help us use the Earth39s natural resources in a sustainable manner Week 82812 Recugnmun amp Desmpnun ur ammversm Recugnmun amp Descnpnun ur ammversny 1375pemesm pmamummeEanheachdav wmch adds up m an asmunmng an nnn sums msaPPanmE evenV231 Vuu use appmwmatw 3mm m an nnn m evem sums wary veanu su am vuuv We an nevcem mum wunu s neume w nave 52mm msdea phavmacv Thewphavmacv smmew backvavd mmemmmmeunacwm mmnemsm mew hamam CunsEuuenW NW2 cummue m mse mudwevsw w gamma have a mew many man an humanny What are me was and Pruducts ur Systemancs m Madam wqu Sv emalmswsmesmdvmme ms1urv mm un Eanh Remnsmdwgthe Yree mm mememmmmmmmewmm myquot mm sme muzmmuu Me mm smaHs mmmavvansmlame Wmmmm scannu nd mm Mummkmss an m waaniVV N Am NSF mm m Mme s magma amanv he mmmmmmc mm mm mm m was mums much mm mquot seman human vename 4 75mmmn5vemesham beenmswvared magma swarm mm mm mm m be mscamred 82812 82812 What are the Roles and Products of Systematics in Modern Biology yr 39439 739 litV 2 W a K 1 39 r 2 1V quotyn r nffhrmm lavMr Assembllng the Fungal Tree of Llie Week 2 What are the Roles and Products of Systematics in Modern Biology Phylogenetic patterns that result from systematic studies and classifications derived from them have predictive value Using phylogenetic analysis to discover new life forms for biotechnology Simple identification via phylogenetic classification of organisms has to date yielded more patent filings than any other use of phylogeny in industry Bader et al 2001 Week 2 What are the Roles and Products of Systematics in Modern Biology Using phylogenetic analysis to discover new life forms for biotechnology The thermal springs of Yellowstone Na ional Park Thermus aquaticus An enzyme from this species powers 39 39 polymerase chain g reaction used in thousands of labs to make Effw large amounts of DNA for 3 sequencing WW Week 2 What are the Roles and Products of Systematics in Modern Biology Phylogenetic patterns that result from systematic studies and classifications derived from them have predictive value Using phylogenies to discover snakebite antivenins Week 2 Venomous Snakes of Australia qu 3 w in Western brown Week 2 What are the Roles and Products of Systematics in Modern Biology Phylogenetic patterns that result from systematic studies and classifications derived from them have predictive value Using phylogenies to discover new drugs Week 2 828 12 What are me ro es and products of systemaucs m modem bwo ogy Phy ugeneuc pa emsthat yesumyum sys1emaue smmes and c assmcatmns awed vum hem have pvedu weva ue e denthg ememmg mseases th agenetmveseavm sbewg usedm mwey new memes mhmh msesenemmms Wm messes am ahmma Ween magnase andtvem newmseases mmemmmreee Aim as 82812 Taxonomy Imnmw e hem and mouse uv asszg umamsms Greek ems avmngemem and names avv e m 17m Camus Lmneeuspumsnee a we anamrmmv based an resemb ances Yvw kev veemes mms wsem vernaer usemHadav mew hvsvec s H evavcmca dxsmcahan Week 2 Week 2 Week 2 Binomial Nomenclature The twopart scienti c name of a species is called a binomial The first part of the name is the genus The second part called the speci c epithet is unique for each species within the genus The first letter of the genus is capitalized and the entire species name is Latinized Both parts together name he species not the speci c epithet alone For example Homo sapiens Hierarchical Classification Linnaeus introduced a system for grouping species I in increasingly broad categories Linking Classification with Evolution Depicting evolutionary relationships in branching phylogenetic trees Luna Mm a pardus MEPrmIs Eumpean familiarls lupus Amparo ripad skunk one ldomvs c dog woln an Msbmt s um ca rjs g mm quotmm cm 8 28 12 82812 Reading Phylogenetic Trees Each branch point represents the divergence of two species Deeper branch points represent progressively greater amounts of divergence WEEK 2 Phylogenetic Systematics Cladistics Uses qualitative characters to reconstruct the evolutionaw relationships using an algorithm requiring the least number of steps Principle of Parsimony Occam s Razor William of Occam ca 14th C When you have two or more competing theories that make exactly the same predictions the simpler is better WEEK 2 i ITaxon A 000 A B C D E Taxon B 001 39 Taxon C 011 Taxon D 111 Taxon E 111 l l Maximum Parsimony minimizes the number of evolutionary changes WEEK 2 Phylogenetic Systematics Cladistics Willi Hennig German entomologist that formalized the principles of phylogenetic systematics Members of a group share a common evolutionary history and are quotclosely relatedquot more so to members of the same group than to other organisms These groups are recognized by sharing unique features which were not present in distant ancestors These shared derived characteristics are called synapomorphies Vertebral column is a synapomorphy of Vertebrata Hair is a synapomorphy of Mammalia Week 2 22 The Assumptions of Cladistics Three basic assump ions 1 Any group of organisms are related by descent from a common ancestor General assumption made for all evolutionary biology t essentially means that life arose on earth only once and therefore all organisms are related in some way or other 2 There is a bifurcating pattern of cladogenesis New kinds of organisms may arise when existing species or populations divide into exactly two groups Probably the most controversial New kinds of organisms may arise when existing species or populations divide into exactly two groups The possibility of interbreeding between distinct groups Week 2 23 The Assumptions of Cladistics Three basic assump ions 1 Any group of organisms are related by descent from a common ancestor 2 There is a bifurcating pattern of cladogenesis 3 Change in characteristics occurs in lineages over time Most important assumption in cladistics Week 2 2 82812 Phylogenetic Systematics Cladistics A cladogram depicts patterns of shared characteristics among taxa In cladistic analysis a clade is defined by its evolutionary novelties Clade a group of species that includes an ancestral species and all its descendants Clades can be nested in larger clades but not all groupings or organisms qualify as clades Avalid clade is monophyletic signifying that it consists of the ancestor species and all its descendants Week 2 25 Types of Phylogenetic Groupings Monophyletic a group of organisms which includes the most recent common ancestor of all of its members and all of the descendants of that most recent common ancestor This group can be defined on the basis of synapomorphies J K U U M Le Week 2 gt 26 Types of Phylogenetic Groupings Paraphyletic a group including the most recent common ancestor of all members of the group but from which one or more descendent groups have been excluded this group cannot be defined strictly by synapomorphies G H J K U LF LJ Laid Week2 in m 27 828 12 Class Reptilia mu 2 2 L S 1 mum1M s g t Sa ox uhcn 3 x Ween Crocodiiians Birds i Annicom rpc 3 25 Delrmiwchu Cam 93mm mm quotx nlrapiora Dliilmip cm 1 ritual111 Saurischia Dlnosauria Archosau ria Week 2 29 Types of Phylogenetic Groupings Polyphyletic term applied to a group of organisms which does not include the most recent common ancestor of those organisms the ancestor does not possess the character shared by members of the group 7i G H39 J Li Lu Lag Week 2 82812 10 Notropis Weekz Phylogenetic Systematics Cladistics In cladistic analysis a clade is defined by its evolutionary novelties Synapomorphy a shared derived character that is an evolutionary novelty unique to a particular clade Apomorphy is a derived character unique to an individual clade or lineage Hair is a synapormorphy for Mammalia relative to other vertebrates hairlessness is an apomorphy apomorphic character for whales relative to other mammals Weekz 31 Phylogenetic Systematics Cladistics Clades are not defined by primitive characters Symplesiomorphy a shared primitive character for the taxa under consideration Plesiomorphy a primitive character for the taxa under consideration For example when examining relationships within Vertebrata a vertebral column would be a symplesiomorphy or a plesiomorphic character Weekz 33 82812 11 Phylogenetic Systematics Cladistics Systematists compare ingroup species with outgroup species to differentiate between synapomorphic and symplesiomorphic characteristics Ingroup the set oftaxa which are hypothesized to be more closely related to each other than any are to the outgroup Outgroup any taxa or taxon used to help resolve the polarity of characters and which is hypothesized to be less closely related to each of the taxa under consideration than any are to each other Taxon taxa any named group of organisms not necessarily a clade Week 2 Phylogenetic Systematics Cladistics Outgroup comparison assumes that homologous characters shared by the outgroup and ingroup must be primitive characters that predate the divergence of both groups from a common ancestor Homology two structures are considered homologous when they are inherited from a common ancestor which possessed the structure This may be difficult to determine when the structure has been modified through descent Character heritable trait possessed by an organism characters are usually described in terms of their character states e 9 quothair presentquot v quothair absentquot where quothairquot is the character and quotpresentquot and quotabsentquot are its states Was 2 Phylogenetic Systematics Cladistics M Lancelet Outgroup Lamprey Tuna Salamander Turtle Leopard CHARACTERS Week 2 82812 12 Phylogenetic Systematics Cladistics 6 39C E 3 g g 1 Q a 8 E 8 g g 3 3 i3 U l 3 Hair000 0 0 1 Amniotic shelled egg Fourwalkinglegs V Hingedjaws 77 Turtle I Vertebralcolumn o i Ha lg 39 baygckybmelw Salamander Amniotic egg Va f 7 I Lamprey La ncelet o utgroup 9 b Week2 37 A Few More Definitions 0 Cladogenesis the development of a new clade the split ing of a single lineage into two distinct lineages speciation Convergence convergent 1 evolution similarities that have arisen independently in two or more organisms that are not N closely related m vvvv A Week2 A Few More Definitions 0 Crown group all taxa descended from a major Cladogenesis event recognized by possessing the clade39s synapomorphic characters 0 Stem group all the taxa in a clade preceding a major Cladogenesis event They are often difficult to recognize because they may not possess synapomorpies found in the crown group Week2 39 82812 13 82812 Crown v Stem Groups Stem ma 2mm 5 I 3 mm WM n TREE TERM NOLOGY cummun a omWch a su swstergruup c ades tem na taxa tree Remember c ades cah rotate 0h branches O O 0 I a O Though the trees ook dwfferent the re abohsh ps between taxa remam the Same 14 Homology v Analogy Analogy In Systematics we refer to analogous characters as homoplasy or homoplasious characters Convergent evolution Parallel evolution Week 2 Why do names change Two important goals of classification are in conflict Need for stability for communication Need to reflect correctly our best knowledge about evolutionary relationships Crucial that a phylogenetic group be monophyletic Any subsequent evolutionary study based on false information about the group s real membership is likely to be false correspondingly Week 2 The saga of the rainbow trout For most of 20th century known as Samo gairdneri Richardson 1836 Week 2 82812 16