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Kingdom Animalia Professor Andrea Garrison Biology 3A Illustrations ©2014 Cengage Learning unless otherwise noted Kingdom Animalia • Domain Eukarya – Multicellular – Heterotrophic (consumers, decomposers) • Aerobic metabolism – No cell wall – Monophyletic group Animalia 2 Kingdom Animalia • Locomotion – Motile at some time in life • Some only as gametes • Reproduction – Sexual or asexual • Some switch back and forth in life cycle Animalia 3 Kingdom Animalia • Sexual reproduction – Short-lived haploid gametes – Fertilization – Diploid zygote – Mitosis leads to adult • Many mature through intermediate larval stages Animalia 4 Kingdom Animalia • Asexual reproduction – Bud off genetically identical structures – When present, alternates with sexual reproduction Animalia 5 Kingdom Animalia • Most evolutionists feel common ancestor a colonial flagellated protist related to choanoflagellates (we won’t study this group) – Based on anatomy and RNA sequences • Structure similar to cells in most primitive animal group Porifera (sponges) Animalia 6 Kingdom Animalia • Shows increasing levels of complexity • Very diverse body plans Animalia 7 Tissues • Subkingdom Parazoa – Least complex branch of animal kingdom – No tissues • Tissues are a group of similar cells functioning together – Several tissues can form an organ • Parazoa function at the cellular level – Each cell independent, can survive on its own » Do show division of labor – Put through sieve, cells will aggregate and form new organism – No symmetry – One phylum: Porifera (sponges) Animalia 8 Tissues • Subkingdom Eumetazoa – More complex branch of animal kingdom – All phyla other than Porifera – Have tissues – Embryonic tissues form in 2 or 3 concentric germ cell layers • All tissues and organs will develop from these layers Animalia 9 Eumetazoa Tissue/Organ Development • Diploblastic embryos have 2 germ layers (Cnidaria) – 2 layers allow for development of true tissues – Ectoderm gives rise to epidermis and nervous tissues – Endoderm gives rise to gut and associated glands Modified by A. Garrison Animalia 10 Eumetazoa Tissue/Organ Development • Triploblastic embryos have 3 germ layers (all other Eumetazoa) – 3 layers allow for development of organs with multiple tissues and organ systems with multiple organs – Ectoderm gives rise to epidermis, nervous system – Mesoderm gives rise to muscles, bones, circulatory system – Endoderm gives rise to gut and associated glands, respiratory system Animalia 11 Eumetazoa Symmetry • Radial symmetry – Radiata; • Cnidaria • Ctenophora – Bisecting along multiple planes gives mirror images – Slow moving – Receive sensory input from all directions Animalia 12 Eumetazoa Symmetry • Bilateral symmetry – Bilateria • All other phyla beyond Cnidaria and Ctenophora – Bisecting along only one plane gives mirror images • Anatomical terms at right – Has directionality to movement – Responds to sensory input in a directional fashion • Cephalization Animalia 13 Bilateria Body Cavities • Body cavities in bilateral animals show pattern of development – True coelom is a fluid-filled body cavity with cavity and organs lined with mesodermal tissue • Acoelomates – no body cavity • Pseudocoelomates – false body cavity • Coelomates – true body cavity Animalia 14 Acoelomates • No body cavity – Ectoderm produces epidermis – Mesoderm produces solid mass of tissue with embedded organs – Endoderm produces gut cavity Animalia 15 Pseudocoelomates – Fluid-filled body cavity; cavity and organs only partly lined with mesodermal tissue • Ectoderm produces epidermis • Mesoderm produces body wall and organs • Endoderm produces gut cavity – Not covered by mesoderm Animalia 16 Coelomates – Fluid-filled body cavity; cavity and organs completely lined with mesodermal tissue (peritoneum) • Ectoderm produces epidermis • Mesoderm produces body wall and organs • Endoderm produces gut cavity and associated organs Animalia 17 Embryological Development in Bilateria • Two groups of bilateral animals – Protostomes • Most invertebrates – Deuterostomes • Vertebrates and nearest invertebrate relatives – Differ in embryological development • Gut and coelom formation Animalia 18 Embryological Development in Bilateria • Stages of embryological development (brief) – – – – Fertilization Cleavage Blastulation Gastrulation Animalia 19 Embryological Development in Bilateria • Stages of embryological development – Fertilization • Forms zygote • Sperm burrows through membrane; sperm nucleus enters and fuses with egg nucleus Animalia; photo: http://www.pdimages.com/web9.htm 20 Embryological Development in Bilateria • Stages of embryological development – Fertilization – Cleavage • Forms morula; 16 – 64 cell stage • Mitotic division of zygote results in solid ball of cells • Embryo stays same size, cells get smaller Animalia 21 Embryological Development in Bilateria • Stages of embryological development – Fertilization – Cleavage – Blastulation • Forms blastula; 128+ cells • Morula hollows out Animalia 22 Embryological Development in Bilateria • Stages of embryological development – – – – Fertilization Cleavage Blastulation Gastrulation • Forms gastrula • Cells invaginate to form blastopore and archenteron (early gut cavity) • Germ layers form Animalia 23 Embryological Development in Bilateria A. Cleavage Protostomes Four-cell embryo Top view Eight-cell embryo Axis Top view Side view Spiral cleavage Determinate cleavage Deuterostomes Four-cell embryo Top view Eight-cell embryo Axis Top view Side view Radial cleavage Indeterminate cleavage Figure 31-5a, p. 674 Embryological Development in Bilateria Protostomes B. Mesoderm and coelom formation Deuterostomes Enterocoelom Archenteron Schizocoelom Blastopore After cells of the future endoderm have migrated to the inside of the embryo, mesoderm (red) differentiates near blastopore. Coelom originates as a split in mesoderm. After cells of the future endoderm have migrated to the inside of the embryo, mesoderm (red) forms from outpocketings of archenteron. Coelom forms from space captured by the outpocketings. Figure 31-5b, p. 674 Embryological Development in Bilateria C. Origin of mouth and anus Protostomes Anus Deuterostomes Mouth Coelom Gut Mouth Anus Blastopore develops into Blastopore develops into mouth; anus forms later. anus; mouth forms later. Figure 31-5c, p. 674 Segmentation • Found in both protostomes and deuterostomes – Not an ancestral character • Repeated units of identical body parts • Arises from mesoderm – May also show in ectodermal and endodermal structures • Advantages – Complete set of vital organs in each segment • Can withstand damage to one segment • Control/flexibility of movement (complete set of independent muscles in each segment) Animalia 27 Animalia 28