Systematics and Taxonomy Protozoans Parazoa

1. Systematics andTaxonomyProtozoansParazoa BIOL240.002 Zoology 29 September 2014

2. Determining Phylogeny • Set of related species: • a genus • part of a genus • a family • representative species of the various orders of a class • etc. • Character data • Morphological features • Present vs. absent • Number present • Relative size • Etc. • Genetic evidence • Gene sequences • Proteins • Computer analysis to minimize needed evolutionary changes in characters • Best tree requires fewest changes in characters of data set

3. Determining Phylogeny Fig. 4.3 p. 82

4. Molecular Genetic Data for Phylogeny Reconstruction • Techniques developed in late 1960s, 1970s, and 1980s • DNA Sequencing: determine and compare ACGT sequences • Often used to date divergence from MRCA Fig. 4.4 p. 83

5. Evolutionary Taxonomy vs. Cladistics • Evolutionary taxonomy thrived in the early and middle 20th century • Willi Hennig: Father of cladistics • New philosophy for phylogeny reconstruction • Biggest sticking point: • ETs often OK with paraphyletic taxa • Cladistsdead set against Fig. 4.8 p. 85

6. Monophyly vs. Paraphyly in Named Taxa • Monophyletic taxon: Includes all descendants of a most recent common ancestor (MRCA)—a clade • Paraphyletic taxon: Includes some but not all descendants of a MRCA (excludes some descendants) Fig. 4.5 p. 84

7. Fixing Paraphyly: Splitting vs. Lumping Fig. 4.7 p. 85

8. Paraphyly in the Amniote Vertebrates:The traditional classes Reptilia, Aves, and Mammalia Also paraphyletic: lizards Fig. 18.2 p. 369

9. Protozoans

10. Protozoan Paraphyly Fig. 4.7 p. 85

11. Protozoans, Fungi, and Animalia Fig. 5.25 p. 113

12. Protozoan Characteristics • Eukaryotic cells with organelles • Contractile vacuole • Feeding/Movement • Pseudopodia • Blunt lobopodia • Long, thin filipodiaor axopodia • Cilia and flagella (collectively, undulipodia) • Reproduction via fission and occasional conjugation Fig. 5.3 p. 97 Fig. 5.4 p. 98 Fig. 5.8 p. 101 Fig. 5.11 p. 103

13. Phylum Euglenozoa“true socket animal”—euglenozoans • Two related groups of flagellated protozoans: • 1) Typified by chloroplasts and stigma that is sensitive to light • 2) Internal parasites of plants and animals Fig. 5.12 p. 104

14. Phylum Ciliophora“eyelash bearing”—ciliates • Many cilia, often in rows • Oral groove leading to cytostome • Ciliary feeding • Locomotion in most, too, but some are sessile, including colonial spp. • Micro- and macronuclei • Micro: reproduction • Macro: cellular metabolism Fig. 5.15 p. 106 Fig. 5.16 p. 107

15. Ciliate Diversity Fig. 5.14 p. 106

16. Ciliate Reproduction Fig. 5.18 p. 108 Fig. 5.18 p. 108

17. Phylum Apicomplexa“tip twisted around”—apicomplexans • Internal parasites of various animal taxa • Apical complex: cluster of organelles and structures present in some life-cycle stages • Host cell penetration • Many have asexual stage in intermediate host, sexual stage in primary host • Ex: Plasmodium vivax Fig. 5.20 p. 109

18. Malarial apicomplexan (Plasmodium vivax) Fig. 5.21 p. 110

19. Phylum Foraminifera“hole bearer”—forams • Perforated external CaCO4test • SiO2 test in one genus • Long, thin, protruding filopodia form nets (aka reticulopodia) that capture food they contact Fig. 5.22 p. 110

20. Phylum Radiolaria“small sunbeam”—radiolarians • Perforated internal SiO2 (or SrSO4) test • Long, thin, protruding axopodiacapture food they contact Fig. 5.23 p. 111

21. Phylum Amoebozoa“to change animal”—naked and shelled amoebas • Pseudopodia • Lobo-, fili-, or axopodia • Some species with various types of organic or particulate tests with one or more openings • Some species are parasitic • Ex: Amoebic dysentery • Includes both groups of slime molds • Plasmodial slime molds • Cellular slime molds Fig. 5.6 p. 99

22. parazoa

23. Phylum Porifera“pore bearing”—5000+ (8499) spp. sponges • Cell differentiation with little tissue development • Pores and feeding current • Osculum: Current’s exit point, at top p. 118 Fig. 6.1 p. 119

24. Sponge Body Plans • Asconoid • Porocytes and no side chambers • Choanocytes line spongocoel • Syconoid • Ostia and side chambers • Choanocytes line radial canals • Leuconoid • Ostia and complex set of chambers with choanocytes Fig. 6.4 p. 121

25. Sponge Cell Types • Porocytes • Ascons only • Choanocytes • Flagellated feeding cells • Archaeocytes • Ameoboid cells • Pinacocytes • Epidermis-like • Collenocytes • Secrete collagen fibers in mesohyl • Sclerocytes • Secrete spicules • Spongocytes • Secrete spongin fibers Fig. 6.4 p. 121 Fig. 6.7 p. 122

26. Spicules and Spongin Fig. 6.9 p. 124

27. Sponge Reproduction • Asexual • Fragmentation • Budding • Gemmules with archaeocytes for overwintering or outlasting droughts • Sexual • Most are simultaneous hermaphrodites • Meiosis: • 2N choanocytes ( sperm or ova) • In some, 2N archaeocytes ( ova) • External or internal fertilization • Brood eggs, if latter • Ciliated larval stage for dispersal (parenchymula) Fig. 6.11 p. 125 Fig. 6.10 p. 125

28. Sponge Taxonomy and Systematics:Four Classes L ASL L SL >4 of 5 sponge spp.* 97 spp. 1 order 679 spp. 5 orders 7115 spp. 12 orders 607 spp. 5 orders Fig. 6.2 p. 119 *including all 162 freshwater sponge spp.

29. Phylum Placozoa“plate animal”—1 (1) sp. placozoan • Trichoplaxadhaerens • Originally discovered in marine aquaria • Asymmetrical, 2-3 mm wide, very flat • Four cell types in three layers • Secrete digestive enzymes, then absorb food • Asexual via budding or fragmentation • Sexual also (but poorly understood) HANDOUT