Classifica=on of Organisms. Chapter 7. A Taxonomic Hierarchy 8/31/18. Systema=cs or taxonomy. Animal Taxonomy, Phylogeny, and Organiza=on.

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1 Classifica=on of Organisms Chapter 7 Systema=cs or taxonomy Study of the kinds and diversity of organisms and of the evolu=onary rela=onships among them Animal Taxonomy, Phylogeny, and Organiza=on A Taxonomic Hierarchy Table 7.1 Taxon Any grouping of animals that shares a par=cular set of characteris=cs Taxonomic categories Hierarchically arranged (broader to specific) Domain, kingdom, phylum, class, order, family, genus, species Copyright 2016 McGraw-Hill Educa;on. All rights reserved. No reproduc;on or distribu;on without the prior wriden consent 1

2 Nomenclature Binomial system of nomenclature Interna;onal Code of Zoological Nomenclature No two animals have the same binomial Every animal has only one correct name Humans are named Homo sapiens which is abbreviated H. sapiens Molecular Approaches to Animal Systema=cs Relatedness of animals reflected in proteins and DNA Nuclear and mitochondrial DNA Ribosomal RNA Domains and Kingdoms Figure 7.2 Three lineages of life. Three major lineages (Domains) Eubacteria Bacteria Archaea Extremophile microbes Eukarya Organisms with compartmentalized cells 2

3 Animal Systema=cs Goal Arrange animals into groups that reflect evolu=onary rela=onships Single ancestral species and all descendants (= monophyle=c group) Approaches to Animal Systema=cs Phylogene=c systema=cs or cladis=cs Ancestral character states or plesiomorphies Common to all members of a group Indicate shared ancestry Cannot be used to describe rela=onships within the group because present in all members Called symplesiomorphies Outgroup Related group not included in study group Used to help decide whether a character is ancestral or has more recently derived Approaches to Animal Systema=cs Figure 7.4 Interpre=ng Cladograms. Derived characters Arisen since common ancestry with the outgroup Called synapomorphies Clade Related subset within a lineage or cladogram Cladogram Depicts a sequence in the origin of derived character states 3

4 Approaches to Animal Systema=cs Figure 7.5 Cladogram showing vertebrate phylogeny. Hierarchical nes=ng Cladograms represent nested groups that share synapomorphic characters. The less inclusive the nest is, the more closely related the organisms. Copyright 2016 McGraw-Hill Educa;on. All rights reserved. No reproduc;on or distribu;on without the prior wriden consent Approaches to Animal Systema=cs Figure 7.6 Phylogene=c tree showing vertebrate phylogeny. Evolu=onary systema=cs Tradi=onal approach Homologies useful in classifica=on Phylogene=c trees depict rela=onships, =me, and abundance Copyright 2016 McGraw-Hill Educa;on. All rights reserved. No reproduc;on or distribu;on without the prior wriden consent 4

5 8/31/18 Op=onal to put in notes Compare figures 7.5 and What kind of informa=on is common to both representa=ons? 2. What kind of informa=on is present in figure 7.5 that is not in figure 7.6? 3. What kind of informa=on is present in figure 7.6 that is not in figure 7.5? 4. How are the rela=onships between rep=les, birds, and mammals represented differently in the two figures? 5. How do the differences in ques=on 4 above reflect differing approaches of evolu=onary systema=cs and phylogene=c systema=cs? Sec=on 7.2 Table 7.2 Figure 7.7 Asymmetry. Symmetry describes how parts of an animal are arranged around a point or axis. Copyright 2016 McGraw-Hill Educa;on. All rights reserved. No reproduc;on or distribu;on without the prior wriden consent 5

6 8/31/18 Figure 7.8 Radial symmetry. Figure 7.9 Bilateral symmetry. Table 7.3 Other Pacerns of Organiza=on Unicellular (cytoplasmic) level of organiza=on Figure 7.10 Diploblas=c body plan. Pro=sts (unicellular) Sponges (cell aggregate) Diploblas=c organiza=on Copyright 2016 McGraw-Hill Educa;on. All rights reserved. No reproduc;on or distribu;on without the prior wriden consent Ectoderm (outer cellular layer) Endoderm (inner cellular layer) Mesoglea (middle, noncellular) 6

7 Other Pacerns of Organiza=on Triploblas=c Organiza=on Mesoderm Third =ssue later found between ectoderm and endoderm Suppor=ve, contrac=le, and blood cells Body cavi=es oeen present Organ development Surface area for diffusion of gases, nutrients, wastes Storage Hydrosta=c skeletons Elimina=on of wastes and reproduc=ve products Facilitate increased body size Figure 7.11 Triploblas=c body plans. a) Triploblas=c acoelomate Mesoderm forms solid mass b) Triploblas=c pseudocoelomate Body cavity not en=rely lined by mesoderm Gut is not associated with muscle or connec=ve =ssue c) Triploblas=c coelomate Body cavity completely surrounded by mesoderm Mesenteries suspend visceral structures in body cavity Higher Animal Taxonomy Sec=on 7.3 Animalia is monophyle=c Molecular and embryological evidence Five basal phyla probably originated independently from other animal groups Bilaterally symmetrical phyla Protostome phyla Spiral, determinate cleavage Trochophore larval stage Ecdysozoa Molt a cu=cle Lophotrochozoa Deuterostome phyla Radial, indeterminate cleavage 7

8 Figure 7.12 Animal taxonomy. Figure 7.13 Developmental characteris=cs. Copyright 2016 McGraw-Hill Educa;on. All rights reserved. No reproduc;on or distribu;on without the prior wriden consent 8