MISCONCEPTIONS INVERTEBRATE ZOOLOGY NATURAL SELECTION SELECTION CHAPTER 1,2: NATURAL SELECTION, EVOLUTION, CLADISTICS

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1 TH BASIS OF VOLUTION NATURAL SLCTION CHAPTR,: NATURAL SLCTION, VOLUTION, CLADISTICS INVRTBRAT ZOOLOGY Darwin's majr theries (Mayr 985) perpetual change cmmn descent multiplicatin f species gradualism natural selectin TH BASIS OF VOLUTION SLCTION law f natural selectin survival f the fittest? scial darwinism What is fitness? Darwinian fitness inclusive fitness relative fitness requirements fr natural selectin (imprtant) reprductin variatin heritability differential mrtality / fecundity COMMON MISCONCPTIONS ABOUT VOLUTION AND SLCTION TH IDA THAT TH NVIRONMNT ITSLF CAUSS CHANGS TO OCCUR OVR TIM GNTIC VARIATION IS NOT IMPORTANT? VOLUTION VIWD AS GRADUAL CHANGS IN TRAITS VOLUTION IS OVR. DIRCTIONALITY OF VOLUTION... TH IDA THAT VOLUTION HAS A GOAL, OR IS GOING SOMWHR... MAN VOLVD FROM MONKYS OR GORILLAS OR CHIMPS. these are nt true! MISCONCPTIONS

2 WHY STUDY INVRTBRATS? INVRTBRATS Invertebrates by far represent mst f the species f animals great diversity in many ways, the mst successful grups f rganisms are invertebrates inverts tell us much abut the wrld arund us A LITTL BACKGROUND PATTRNS OF DIVRSITY Althugh vlutin is nt directinal - evlutinary trends themes in bdy plan repeated patterns SURFAC ARA TO VOLUM RATIO CONSTRAINTS ON FORM Surface area increases while ttal vlume remains cnstant xchange xternal envirnment Muth Fd Animal bdy Bld CO O Respiratry Ttal surface area [Sum f the surface areas (height width) f all bxes sides number f bxes] Muth Gastrvascular cavity xchange xchange Nutrients Digestive Heart Circulatry Cells Interstitial fluid Ttal vlume [height width length number f bxes] 5 5 xcretry Surface-t-vlume (S-t-V) rati [surface area vlume] 6. 6 Anus Unabsrbed matter (feces) Metablic waste prducts (nitrgenus waste)

3 VOLUTIONARY TRNDS BODY PLANS Celmate Celm Bdy cvering (frm ectderm) develpmental patterns diplblasty triplblasty bdy cavity -- celms acelmate pseudcelmate eucelmate Pseudcelmate Digestive tract (frm endderm) Pseudcelm Digestive tract (frm endderm) Bdy cvering (frm ectderm) Tissue layer lining celm and suspending internal rgans (frm mesderm) Muscle layer (frm mesderm) Acelmate Bdy cvering (frm ectderm) Tissuefilled regin (frm mesderm) Wall f digestive cavity (frm endderm) DVLOPMNTAL PATTRNS BODY PLANS prtstmes spiral cleavage schizcely prtstmus determinate cleavage deuterstmes radial cleavage entercely deuterstmus indeterminate cleavage SPIRAL RADIAL rtifera acanthcephala mllusca gnathstmulida platyhelminthes nemertea gastrtricha ectprcta gnathifera annelida entprcta lphtrchza hemichrdata echindermata chrdata deuterstmia prtstmia bilateria cnidaria ctenphra prifera eumetaza r nemata nematmrpha ecdysza acela tardigrada arthrpda panarthrpda nychphra t

4 VOLUTIONARY TRNDS SGMNTATION metamerism prbably evlved 3 times panarthrpda chrdata annelida advantages: efficient lcmtin tagmatizatin redundancy VOLUTIONARY TRNDS SYMMTRY radial symmetry biradial pentaradial bilateral symmetry RADIAL SYMMTRY BILATRAL SYMMTRY hmlgy f the radius in vertebrates ADAPTATIONS? ANALOGY (HOMOPLASY) HOMOLOGY CONVRGNC human cat whale bat

5 MAKING SNS OF TRS SYSTMATICS embry develpment turtle chicken hrse human example tree: lphtrchza Bilateria ecdysza recapitulatin -- ntgeny recapitulates phylgeny atics -- phenetics cladistics (primitive vs. derived) synapmrphies - autapmrphies - synplesimrphies - CLADOGRAM OR PHNOGRAM OR TR (DNDROGRAM) CLADISTICS cnidaria mllusca annelida nemata arthrpda metamerism spiral cleavage bilateral symmetry ecdysis jinted appendages metamerism O A CB BC D O A D B C C B D A NODS CAN PIVOT. SAM TR TRS NODS CAN PIVOT. SAM TR TRS

6 chelicerata myriapda xencarida PHYLOGNTIC TRS AR USD TO CRAT TAXONOMIC UNITS... (TAXA, TAXON, GNUS, PL. GNRA) MONOPHYLTIC-- PARAPHYLTIC! entgnatha insecta cpepda malacstraca thecstraca HXAPODA CRUSTACA PANCRUSTACA POLYPHYLTIC -- branchipda PARAPHYLTIC -- TAXA / GROUPS PHYLOGNY OF SLCTD ARTHROPODS (RGIR, T AL., 00) tardigrada ichthystraca +pentstmida stracda SOM BASICS CLADISTIC ANALYSIS ways t cnstruct a tree Hennig argumentatin, Wagner ptimality parsimny - the simplest answer is prbably right - STPS 3 5 steps utgrup A 0 B C 5 B 5 A 3 ABCC B A B A C B MOR PARSIMONIOUS A D C B B C D A steps PARSIMONY? B steps C D A steps utgru A B C D WHAT 9 IF YOU ND UP WITH TRS? A D C B 3 3 AB 000

7 HOW DO W KNOW IF A TR IS A GOOD ON? SUPPORTING TRS parsimny jackknifing btstrapping TALKING ABOUT PHYLOGNIS TRMINOLOGY TO AVOID avid using terms that impse value n taxa mre evlved, highly evlved less evlved advanced higher THS TRMS HAV NO RAL MANING!