What is an animal? Introduction to Animals Multicellular chemoorganoheterotrophs Eukaryotes that lack cell walls and chloroplasts Have mitochondria Are motile at some point in their lives Contain collagen Germ Layers Cells of developing embryos diverge into layers that then turn into specific tissues and organs Tripoblast: 3 germ layers (Endoderm, Mesoderm, and Ectoderm) Diploblast: 2 germ layers (Endoderm and Ectoderm) Tissues and Organs Animals can either have or lack tissue and organs Tissue: group of cells of similar type that function as a single unit Epithelial, muscle, nervous, and connective Organs: composed of multiple tissue types linked together into a physiological unit with a specific function Structural Support Types of Symmetry Support: Animals devised ways of supporting themselves Hydrostatic skeleton: action of muscles compressing the fluid in body cavities Exoskeleton: hardened structures outside of their bodies Endoskeleton: hardened structures enclosed by the cells of their bodies http://evolution.berkeley.edu/evolibrary/images/symmetrydiagram.gif 1
Life Cycles of Animals Development and growth to the exclusion of reproduction Larval: life stages shown by large changes in morphology (ex: insects) Juvenile: morphology that looks very similar to adults (ex: humans) Sponges! Asymmetrical Endoskeleton Phylum Porifera Phylum Porifera Sponges! Internal structural material Spicules & Spongin http://1.bp.blogspot.com/_uostuswavio/ts5fyq5zjoi/aaaaaaaaabw/qhd b9a8ueso/s1600/scuba%252520sponges.jpg Phylum Porifera Sponges! Choanocytes** Collar cells, help move water through sponge Radially symmetric Polyp and Medusa phase 2
Radially symmetric Polyp and Medusa phase Hydrostatic skeleton (uses water to hold shape) Diploblasts (2 tissue layers: ectoderm, endoderm) Ectoderm (outside) Mesoglea (middle; not a tissue) Endoderm (inside) http://textbook.s-anand.net/wpcontent/uploads/2010/12/kebo104_page2_image3.png Cnidocyte** with nematocysts** Stinging cells used to capture & paralyze prey http://www.youtube.com/watch?v=6zjibc_n1zk Class Anthozoa (Anemones, Corals, Sea Pansy) No medusa phase Benthic (and mostly sessile) Class Scyphozoa (Jellyfish) Medusa phase dominant Bell with tentacles on bottom Not good swimmers Class Scyphozoa (Jellyfish) Medusa phase dominant Bell with tentacles on bottom Not good swimmers Only have polyp to produce more medusa http://www.dnr.sc.gov/marine/pub/seascience/ima ges/jflifec.gif http://www.funny-potato.com/images/animals/jellyfish/jellyfish.jpg 3
Class Hydrozoa (Obelia, Portugese Man-owar) Hydranth Gonangium Class Hydrozoa (Obelia, Portugese Man-owar) http://incrediblebeings.files.wordpress.com/2010/09/obelia_cycle.gif http://www.esu.edu/~milewski/intro_biol_two/lab_9_porifera http://siera104.com/images/bio/cndaria/obelia.jpg _cnidaria/images/obelia_medusa_stage.jpg Phylum Platyhelminthes Flatworms: Includes marine flatworms, flukes and tapeworms Bilaterally symmetric Acoelomate NOT Segmented Absorb nutrients and oxygen through skin http://images.tutorvista.com/content/animal-kingdom/body-cavity-conditions.jpe Have a blind gut (only open on one end), some have full gut No lophophore, no trochophore Phylum Playthelminthes Class Turbellaria (non-parasitic flatworms) Penis Fencing! Hermaphrodites Marine and Freshwater Phylum Playthelminthes Class Cestoda (tapeworms) Endoparasites Look like they are segmented, but are not called proglottids break off and allow tapeworm to spread http://www.quia.com/files/quia/users/jristvedt/anima l-diversity/platyhelminthes 4
Phylum Playthelminthes Class Trematoda (flukes) Endoparasites Live mostly on vertebrates No proglottids Segmented worms Bilaterally symmetry Segmented! Class Oligocheata (earthworms and terrestrial or freshwater worms) Few chaetae Have Clitella Class Hirudinea (leeches) Posterior sucker to hold onto prey Ectoparasites http://www.liberalbaptistrev.com/wp-content/uploads/2009/02/earthworm.jpg?w=300 http://topnews.net.nz/content/218972-swedish-doctors-use-leeches-reconstructingwoman-s-face Class Polychaeta (marine worms) Parapodia with many chaetae Molt to grow Bilaterally symmetric Cephalization Group Ecdysozoa http://nathistoc.bio.uci.edu/annel ids/dscf0036b.jpg 5
Phylum Nematoda Roundworms Whip-like body motion Molt cuticle to grow (not an exoskeleton) Not segmented Phylum Tardigrada Water bears Cuticle, not an exoskeleton https://www.youtube.com/watch?v=6h0e77t dyny https://dco.gl.ciw.edu/sites/dco.gl.ciw.edu/files/images/11414 _nematoda.jpg http://www.thrivenotes.com/wpcontent/uploads/2012/08/tardigrade1.jpg 6