Lecture 2 and 3 Notes
Lecture 2 and 3 Notes 81463 - BIOL 3030 - 001
Popular in Vertebrate Biology
81463 - BIOL 3030 - 001
verified elite notetaker
Popular in Biological Sciences
80887 - BIOL 3150 - 001
verified elite notetaker
This 7 page Class Notes was uploaded by Abigail Towe on Sunday September 20, 2015. The Class Notes belongs to 81463 - BIOL 3030 - 001 at Clemson University taught by Richard W. Blob in Fall 2015. Since its upload, it has received 25 views. For similar materials see Vertebrate Biology in Biological Sciences at Clemson University.
Reviews for Lecture 2 and 3 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/20/15
Understanding Vertebrate Diversity There is diversity in form function and number of species for vertebrate life forms 0 The diversity in form consists of shape and size of special structures 0 The diversity of function refers to locomotion feeding and environment 0 There is also diversity because of the various species that existexisted I There are more than 60000 living species o plus more than 10 more fossil species The biological definitionconcept of species is reproductiver isolated group of organisms o The exceptionscomplications to this definition is I hybnds I fossil taxa morphospecies morphologically distinct The classification of species is the basic unit of diversity smallest description in the naming system c The hierarchical system Linnean systemof groups with groups starts with Kingdom gt Phylum gt Class gt Order gt Family gt Genus gt Species 0 Note Species have binomial names genus species I example Homo sapiens amp Tyrannosaurus rex Evolutionary Organization of Diversity 0 The Linnean methods naming system predates evolutionary theory I Linnean groups don t always indicate evolutionary relationships 0 Today if organisms have a shared feature then they are grouped together based on their evolutionary relationship to each other 0 Phylogenetic Systematics Cladistics used to show evolutionary trend I Systematics organizing diversity with a system non random I Phylogenetic tribe birth in Greek I Cladistic clade in Greek branch When looking at a cladogram o a cladogram is a diagram that demonstrates the taxon relationships by using branches 0 clade ALL descendants of a single common ancestor o The Taxon is the biologically recognizedaccepted group of organisms with common ancestry O 0 Character feature of an organism vertebrae scales teeth jaw Character state variety of a character present or absent I shared character states indicate taxa evolved from common ancestor Using cladistics O O O synapomorphy a shared derived feature plesiomorphy a primitive ancestral feature traits can be synapomorphies at one level of cladogram but plesiomorphies at others Monophyletic group another name for clade Greek one tribe Paraphyletic group does NOT include all descendants of a common ancestor NOT CLADES Grade paraphyletic taxa grouped together for convenience often because they share similar features NOT CLADES Outgroup clade outside clade being considered helps determine primitive features sister taxa adjacent branches on cladogram that form clade together nodes branching points on cladogram I the branching can rotate around the node doesn t have to be from left to right The most PARSIMONIOUS cladogram accepted one with most support fewest evolutionary changes If a character is in 2 groups that don t form a clade it means that I the character was lost intervening taxa I convergent evolution feature evolved independently in both taxa I You can check if you check the detailed structure bird vs bat wings are very different 0 feathers vs skin 0 bats long digits birds short o therefore bird and bat wings are analogous structures same function evolution converged on same design 0 Contrasts with HOMOLOGOUS structures truly the same across taxa Homology 1 context topographical relationships a if structure surrounded by same elements in 2 taxa probably homologous i examples finger bones of birds and bats both connect to metacarpals 2 development essential similarity sometimes only clear in embryos 0 Diversity occurred over a long time o The first vertebrates lived 520 million years ago 0 absolute dates can be measured by using radiometric dating of fossils I But majority of fossils are only used for relative dating 0 This only tells if the fossil is younger or older than others o This can be done with geologic time scale 0 The Geological Time Scale 0 breaks time into sequential named segments I Cenozoic o First period is tertiary 5566 million years ago 0 age of mammals O O I Mesozoic mammals and birds greatly diversified climate earth began cooling and drying staring glaciers continents almost moved to how they are currently o First period is Triassic 225 million years ago 0 3 dates 0 O O O dinosaurs and mammals appeared pangea climate warm no polar ice sea levels higher flowering plants I Paleozoic oldest o First period is Cambrian 540 million years ago 0 3 events 0 0 first multicellular organism cambrian explosion most phyla appeared fish arthropods reptiles life on land began plans trees huge extinction o Plate tectonics o the continents change position through time o supercontinent Pangaea gt separated o Therefore the present vertebrate diversity was shaped by the past catastrophes 0 There were two major vertebrate extinctions at the end of Permian and Cretaceous Assembling a Vertebrate 0 Review 0 Cladistics is a method of using a diagram to organize our knowledge of vertebrate diversity evolutionarily using phylogenetic systematics I the branching pattern of relationships based on synapomorphies I Cladograms are useful to determine closest relatives and what they were like 0 First Vertebrate relativesorigins before vertebrates leading up to vertebrates we are observing is chordates o The Chordate synapomorphies they may be present at any stage of development 1 Notochord a the fibrous rod along the body axis 2 Dorsal hollow nerve cord DHNC a dorsal toward the back think back of a dog dorsal Postanal tail Iodine binding structure a endostyle thyroid 5 Pharyngeal pouchesslits a pouches from gut that can open to outside as slits in throat o Clades of chordates I Urochordates tunicates or sea squirts o there are about 2000 species I Cephalochordate lancelets or amphioxus o there are about 22 species 0 They like to burrow and have pharyngeal slits for filter feeding not gills c has myomeres segmental muscle in blocks 0 myomeres are derived from somites embryonic tissue blocks 0 found in vertebrates only but just not in urochordates I The oldest fossil confirmed that is a chordate is one named Pikaia o Dated from Middle Cambrian period about 500 million years ago Paedomorphosis retention they keep theirjuvenile traits throughout adulthood while they are sexually mature adult Another early specie BEFORE vertebrates is the Craniate o The craniates have synapomorphies have many that related to the head that include I cranium braincases cartilage or bony skull surrounding brain I complex sense organs I large threepart brain forebrain midbrain hindbrain I Neural crest cells I heart gills hemoglobin o Divided into two clades Hagfish and vertebrates I Hagfish c has the basic craniate features with neural crest o lack of definite vertebrae meaning NOT vertebrates has notochord throughout lifetime 0 about 45 species marine predator and scavenger 0 unique features 0 exudedischarge massive quantities of slime mouth tentacles reduce eyes 0 switch from male to female with age 0 lacking jaw and paired fins These so far have not been vertebrates but it s progress What exactly was our big steps to get us to assembling a vertebrate 0 Well the 2 basic mechanismsdevelopments are I separation of embryo cells divided into 3 layers germ layers that each produce different structures 0 endoderm cells 1st inner cells o mesoderm 2nd middle cells 0 The mesoderm differentiates into 3 parts I somites in segments next to nerve tube myomeres in vertebrates I intermediate mesoderm nephrotomes gt kidneys I lateral plate not segmented has blood vessels hean c this eventually splits to form a space called coelom o The gut and associated organs are suspended in body by membranes mesenteries formed from the lateral plate from mesoderm germ layer I Coelom allows organ movementexpansion but the mesenteries prevents reckless sloshing o ectoderm cells present at surface I folding and migration of those layers 0 Then eventually we got the tube within a tube design of the digestive tract I example chicken o Process 0 germ layer formation in chick representative chordate 0 there is a primitive streak 0 then a primitive knot forms 0 within the mesoderm the notochord is formed produced by primitive knot as it migrates toward the tail 0 The Dorsal Hollow Nerve Cord DHNC forms from a processes that involves rolling up of the ectoderm germ layer that overlies the notochord I basically the notochord is located underneath the ectoderm within the mesoderm So when the DHNC forms the ectoderm just rolls right up into a tube above the notochord As it rolls up the neural crest is dismantled and the cells migrate elsewhere in the body 0 the neural crest migrates through the body to make pigment cells tooth dentine parts of skull nerves and brain IN CRANIATES
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'