BIO 358 1st Edition Lecture 5 Outline of Last Lecture I Characteristics of Order Cetacea II Classification III Suborder Mysteceti A Balaenidae B Balaenopteridae C Eschrichtiidae D Neobalaenidae II Suborder Odontoceti A Physteridae B Kogiidae C Ziphiidae D Monodontidae E Delphinidae F Phoconenidae G Platanistidae H Iniidae I Lipotidae J Pontoporiidae Outline of Current Lecture II Definition of Phylogeny A Monophyletic clades B Paraphyletic clades C Polyphyletic clades III Clade Handout Notes IV Identifying Monophyletic Groups A Investigate characters B Group them together based on similar characters V Synapomorphies vs Convergent Characters VI Pinniped Evolution VII Cetacean Evolution Current Lecture Phylogeny These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute tribe genesis Evolutionary relationships Correctly identify monophyletic clades Monophyletic Clade One tribe group taxon A group that contains an ancestor and ALL of it s descendants EVOLUTIONARY VALID GROUP Paraphyletic Clade AN EVOLUTIONARY INVALID GROUP PARAPHYLETIC CLADE Around near group A group that includes an ancestor and only some of its descendants Family mom dad brother me monophyletic Family mom dad no brother paraphyletic invalid evolutionarily Polyphyly group Invalid evolutionary group Many tribes A group that contains the descendants some or all of multiple ancestors diphyl polyphyly with two separate ancestors Monophyletic is the only valid evolutionary grouping Clade Handout ABCD evolutionary groups taxa clades 1 2 3 position of shared common ancestor 1 hypothesized common ancestor of ALL 2 hypothesized common ancestor of BC and D 3 hypothesized common ancestor of C and D nice nested cones that fit well with each other monophyletic How do we identify monophyletic groups 1 investigate traits characters across organisms morphological molecular 2 group organisms together based upon similarities of traits similarities MUST be due to shared common inheritance HOMOLOGY homology similarity shared by common inheritance ie we have 4 limbs tetrapods makes me different from a fish but how does it make us different from a cat or a dog need more specific homologies need something more specific to tell species apart Synapomorphy shared derived trait shared derived trait that uniquely defines a monophyletic clade all synapomorphies are homologies Convergent Character similarity based on shared common FUNCTION not inheritance i e these characters will have independent evolutionary histories homoplasy same thing Pinnipeds evolution large body size blubber specialize fur SPECIALIZED APPENDAGES gives them their names enhanced diving enhanced thermoregulation enhanced sensory systems ARE THESE SYNAPOMORPHIES or CONVERGENT CHARACTERS Evidence of Dyphyly fossil record pre 1989 PACIFIC ATLANTIC 23 million years ago 23 million years ago found phocids fossils for odobenids and otariids oldest known phocids 4 million years ago oldest phocid 19 million years of independant evolutionary history between the otoriids and odobenids and the phocids On face value suggests 19 million years of independent evolutionary history between the odobenids and the otoriids vs the phocids don t see first phocid for 19 million years in the pacific MUST BE THAT SIMILARITIES ARE CONVERGENT researchers avoided the use of highly functional characters when building phylogenies do pinnipeds use their appendages in a similar method 1988 graduate student questioned the premise of earlier studies Andre Wyss looked broadly across pinnipeds and other terrestrial carnivores and identified similarities INCLUDED APPENDAGES which people were avoiding demonstrated that all of the animals share synapomorphies across all of their body parts including flippers Enarliarctos fossil from the pacific A Berta et al 1989 discovered this fossil greater than 23 million years old transitional form swam with both fore and hind limbs suggests shared common ancestry of all pinnipeds in pacific longer ago than 23 million years ago Cetaceans Are they more closely ralated to mesonychids or artiodactyls easy to identify similarities between mustelids and ursids what about sperm whale how does one identify relationships to terrestrial mammal when extant species are so highly derived what are the synapomorphies Linnaeus identified them as fish Plan A fossils not complete data set BUT the earliest cetaceans were less derived than extant forms morphological similarities between cetaceans must be closer to Plan B molecular data different type of characters so morphology is not required problem only identifies relationships between extant species similarities between cetaceans and related terrestrial mammals will be more clear When plan A and plan B tell you two completely different stories Fossil record shows they are most closely related to mesonychids Mesonychids odd toed ungulates most closely related to cetaceans small wolf like animal Molecular data shows something else