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Classification - Linnaean classification - A taxonomic survey - Dichotomous key - Phylogeny - Current technology - Clades Refer to chapter 19 in text. Also 20-22, 28, 29. Why the fancy names? These all are “fish” in their own way…. What is a “fish”? …none are actually fish. Linnaean classification - Swedish botanist ~ mid 1700s - Devised the binomial naming system (Genus species) - Scala Natura: Platonic idea of nature arrayed by graded perfection. - Described a hierarchical classification system, based on the sexual structures in plants…. - His students went out on expeditions, returning the first plants from much of the world. - His system was mostly morphological, (he divided man by social habits, too) and a bit arbitrary, but provided the skeleton for modern classification. Modern taxonomy domain kingdom phylum class order family genus species dear King Philip came over for great spaghetti Eukarya Animalia Chordata Mammalia Primate Hominidae Homo sapiens Eukarya Plantae Magnoliophyta Magnoliopsida Fagales Fagaceae Quercus virginiana ←Plantae - photosynthetic - cellulose cell walls - complex multicellularity A survey – 6 Kingdoms Protista ↓(newer: Protoctista) - single-celled eukaryotes - (crosses other categories) Animalia → - heterotrophic - complex multicellularity - internal digestion Fungi → - non-photosynthetic - external digestion - cell walls (chitin) - multicellular (mostly) Eubacteria ↓(bacteria) - no membrane-bound organelles, etc. - used to be “monera” with archaeans ← Archebacteria (archaeans) - prokaryotic (like Eubacteria) - includes extremophiles Plantae - photosynthetic - cell walls - complex multicellularity - Phyla (although in plants gymnosperm: these are “divisions”, not “phyla”) pines bryophyta: mosses You learned details about these in the botany unit. filicinophyta ferns angiospermophyta flowering plants Porifera - specialized cells, though not true tissues - sessile, porous - suspension feeders - choanocytes create a water flow. Animalia - Phyla Cnidaria - true tissues (Eumetazoa) - sessile or floating - gastrovascular cavity (one opening) surrounded by tentacles - cnidocytes↓: stinging cells. Animalia - Phyla Platyhelminthes - bilateral symmetry - motile, marine - flat, to enable diffusion - include some nasty parasites - flame cells act as primitive kidneys Animalia - Phyla http://classconnection.s3.amazonaws.com/337/flashcards/85337/jpg/rotifera1330306972770.jpg http://en.wikipedia.org/wiki/Rotifer#mediaviewer/File:Bdelloid_Rotifer.jpg Rotifera - microscopic, aquatic (mostly) - ciliated corona around head -reproduce often via parthenogenesis (without sexual reproduction) -alimentary (digestive) canal http://www.zin.ru/Annrep/2000/img/13-01.gif Their numerical dominance, often exceeding a million individuals per square meter and accounting for about 80% of all individual animals on earth, ... Wikipedia w source http://www.gardeningknowhow.com/wp-content/uploads/2013/05/beneficial-nematodes.jpg http://en.wikipedia.org/wiki/Nematode#mediaviewer/File:C_elegans_male.svg Nematoda - ‘roundworms’ - tubular digestive tract with mouth and anus - cuticle to provide structure - about half are parasites Mollusca - soft body, but hard shells, unless devolved. - muscular foot, visceral mass, and mantle - marine to terrestrial - radula: scraping mouth. (chiton, cephalopod, gastropod, bivalve) Animalia - Phyla Annelida - true body cavity - segmented Animalia - Phyla Arthopoda - segmented appendages - exoskeleton, for protection, muscle attachment, water retention Animalia - Phyla 2 of 3 species of animals are arthropods Tabulation of key features: Por Cnid true tissues No Yes symmetry No radial body cavity No No GI tract No GVC segmentation No No exoskeleton No No Plat Yes bilat. No GVC No No Mol Yes bilat. Yes Yes No No Ann Yes bilat. Yes Yes Yes No Arth Yes bilat. Yes Yes Yes Yes This leaves us on the brink of Chordata and the vertebrates. IB holds you to no more details here. The AP only teachers have pushed more of these chapters. (We hit the last two text sections under human evolution.) Phylogeny …looking at how structural relatedness suggests ancestral relatedness. The Tree of Life image that appeared in Darwin’s On the Origin of Species by Natural Selection, 1859. ..the only illustration. Now there is much more evidence, beyond morphology (homologous, analogous, vestigial, fossil) to suggest ancestral relatedness, especially molecular evidence. Cladistics is the updated concept of relatedness mapping, based heavily on DNA and RNA Ideally it is monophyletic (one ancestor), but may be paraphyletic (incomplete) or polyphyletic (not enough info. to be sure). Part of the trick is knowing which traits are derived, and which ancestral. http://waynesword.palomar.edu/lmexer3b.htm A clade consists of an ancestral species and all identified descendents; This cladogram is the coolest one around: It is based on organisms that have had their entire genomes sequenced. Green = Archaea Purple = Bacteria Pink = Eukarya You are the second to top in the pink, between the chimp and the Norwegian rat. Zoom in. www.newworldencyclopedia.org/entry/Cladistics Please read and follow the cladogram section in 19.2 (p342 ff). Parsimony is trying to find the least complicated path to explain the observed relatedness. This is the hypothetical case on p 502-503 in the text. Walk through it. The plans require 8, 9, and 10 mutation events, respectively. The first plan seems most likely. Currently there is so much information coming online, especially with DNA/RNA evidence, that biologists are partnering with computer scientists to develop new presentation paradigms: “For 25 species, there are more possible trees than there are stars in the known universe,” Dr. Westneat said. “For 80 species, there are more trees than there are atoms in the known universe.”2 Conventional methods provide a starting point, and supercomputers take it from there. Zimmer, Carl “Crunching the Data for the Tree of Life” Science Times/ The New York Times, 2/10/2009 http://www.nytimes.com/2009/02/10/science/10tree.html 2 QUESTIONS NOT DONE… CAN YOU FIGURE OUT YOUR OWN STUDY QUESTIONS? binomial Fungi Mollusca hierarchical classification Plantae radula taxonomy Monera Annelida domain Rotifera Arthopoda kingdom Nematoda exoskeleton phylum phylogeny class morphology order Porifera cladistics family sessile clade genus choanocyte Archaea species Cnidaria Eubacteria Protista cnidocyte Eukarya Animalia Platyhelminthes parsimony . flame cell . Plantae - photosynthetic - cell walls - complex multicellularity - Phyla (although in plants gynmosperms these are “divisions”, not “phyla”) ↓ bryophyta ↓ Vascular No Roots No Leaves No Seeds No Flowers No Yes Yes Yes No No ↑ filicinophyta This one is all review… with formal names. Yes Yes Yes Yes No Yes Yes Yes Yes Yes ↑ angiospermophyta