Updated Jan 2000 UNIT 1 Biology 303 Outline Introduction - syllabus, exams, labs, etc Biological Classification - Five Kingdom System Classifying the Animal Kingdom Categories used - Phylum to species Species names - binomial nomenclature The logic of classifications Phylogenetic trees Examples - Text Figs: 25.7-9,11 Monophyletic, Paraphyletic, and Polyphyletic classifications Kingdom Protista "Protozoa" - Mobile unicellular eukaryotes; a polyphyletic grouping formerly a phylum in the animal kingdom. Groups: A. "Flagellates" - move using flagella; diverse; polyphyletic Phytoflagellates - photosynthetic; polyphyletic Euglena, Volvox, dinoflagellates Zooflagellates (Phylum Zoomastigophora) - heterotrophic Trypanosoma, Trichonympha, Choanoflagellates B. "Sarcodines" - have pseudopodia, polyphyletic Phyla: Rhizopoda, Actinopoda, Foraminifera C. Phylum Apicomplexa - all parasitic; eg - Plasmodium, agent of malaria D. Phylum Ciliophora - Ciliates; eg - Paramecium SURVEY OF THE ANIMAL KINGDOM (Chapters 32-34) Overview of major animal groups - Fig. 32.3 Some problems faced by all animals ANIMAL DEVELOPMENT - In brief Early stages of embryology: Zygote to Gastrula In eggs with little yolk (Figs. 32.1, 47.9) Tissue differentiation in the gastrula - ectoderm, endoderm, mesoderm (Table 47.1) Protostomes vs deuterostomes (fig 32.6) spiral vs radial cleavage determinate vs indeterminate cleavage fate of blastopore origin of mesoderm schizocoelous vs enterocoelous coelom formation In eggs with much yolk frog eggs (figs 47.8, 47.10) bird eggs (fig 47.12) Neural tube formation (fig 47.11) Patterns of development in vertebrates Differentiation and cell lineages Phylum Porifera - sponges general features sponge body plan as a water filtering system (fig 33.2) low specialization of cell types sponge reproduction Phylum Cnidaria (=Coelenterata) general features body form radial symmetry sac-like body diploblastic: epidermis, gastrodermis, mesoglea gastrovascular cavity - feeding, digestion, food distribution cells of the epidermis and gastrodermis life cycles - polyp and medusa stages (fig. 33.3) taxonomic groups Class Hydrozoa: eg - Hydra, Obelia (fig. 33.6), Physalia, hydrocorals Class Scyphozoa - true jellyfish (33.5b) Class Cubozoa - box jellyfish Class Anthozoa - sea anemones, corals (33.5c,d) Phylum Ctenophora (fig. 33.7) Phylum Platyhelminthes - Flatworms Major Features (Fig. 33.9) bilateral symmetry distinct organs and organ systems triploblastic and acoelomate incomplete digestive tract Major Taxonomic Groups Class Turbellaria - planarians and other free-living forms (Figs. 33.8, 9) habitat cilia, hydrostatic skeleton, and movement feeding, excretion, nervous and reproductive systems Class Trematoda - flukes (Fig. 33.10) features: internal parasites with two or more hosts, pair of suckers, cuticle, reduced gut, large reproductive systems life cycles examples: Opisthorchis; Schistosoma (=Bilharzia) (Fig. 33.10) Class Cestoda - tapeworms (Fig. 33.11) features: intestinal parasites, no digestive system, most segmented, many have intermediate hosts example: beef tapeworm Pseudocoelomate animals - several phyla, two examples: Phylum Nematoda - roundworms (Fig. 33.13) Major Features: body form, pseudocoelom, muscles, cuticle, complete digestive tract Examples: vinegar eel, C. elegans, Ascaris, hookworm, Trichinella (Fig. 33.13b), filarial worms, Guinea worm Phylum Rotifera - rotifers (Fig. 33.12) Coelomate animals - all remaining animal groups have true coelom Phylum Mollusca - mollusks General body plan (Fig. 33.16) Major taxonomic groups Class Gastropoda shell - conical spiral torsion (Fig. 33.18) examples Class Bivalvia (Fig. 33.21) Class Polyplacophora - Chitons (Fig. 33.17) Class Cephalopoda (Fig. 33.22) Phylum Annelida - segmented worms General body plan (Fig. 33.23) Taxonomic groups Class Polychaeta (Fig. 33.24a,b) anatomy, trochophore larva variety of feeding styles Class Oligochaeta - earthworms and aquatic relatives (Fig. 33.23) Class Hirudinea - leeches (Fig. 33.24c) anatomy feeding Phylogeny of annelids Phylum Arthropoda - eg: spiders, insects, millipedes, crustaceans Definition - chitinized exoskeleton + joined appendages Other major features: segmentation, body regions, exoskeleton and molting, instars, serial homology, internal organs Taxonomic groups Subphylum Trilobita - trilobites (extinct) (Fig. 33.27) Subphylum Chelicerata - chelicerates Features: appendages, no antennae, body regions Taxonomic groups (Figs. 33.28-30) Horseshoe crabs: large, aquatic, compound eyes, gills Arachnids: smaller, terrestrial, 4 pair legs, mostly carnivores, feeding; examples: scorpions, spiders, daddy long legs, mites, ticks Subphylum Crustacea - crustaceans (Fig. 33.35) features: 2 pair antennae, biramous appendages, chewing mouthparts, mostly aquatic, compound eyes examples: water fleas, brine shrimp, krill, isopods, barnacles, decapods (shrimp, crayfish, crabs) Subphylum Uniramia - Myriapods and insects features: unbranched appendages, one pair antennae, chewing mouthparts, mostly terrestrial taxonomic groups myriapods - features and groups (millipedes, centipedes) (Fig. 33.31) insects (Figs. 33.32-34; Table 33.6) features: 3 pair legs, 3 body regions, metamorphosis insects and humans