Theme 2: Animals PDF

Theme 2- Animals ================ - Animals, fungi, choanoflagellates What are choanoflagellates? - Unicellular opisthokonta eukaryote - Sessile - Reproduces asexually - Closest to animalia among the opisthokonta - They have a collar around the flagellum that has contractile mi...

Theme 2- Animals ================ - Animals, fungi, choanoflagellates What are choanoflagellates? - Unicellular opisthokonta eukaryote - Sessile - Reproduces asexually - Closest to animalia among the opisthokonta - They have a collar around the flagellum that has contractile microfibrils - Has choanocytes in porifera (spongues) - Consumers of bacteria - Unicellular filter feeders - Multicellular eukaryotes - Chemoheterotrophic - Extracellular digestion - Has no cell wall - Motile (has some type of self-direct movement) - Oxidative phosphorylation for ATP - Sense and responds to the environment - Diploid stage is dominant - Developed from a blastula and underwent gastrulation - Cell membrane contains cholesterol - Has certain extracellular matrix such as collagen - Has cell- cell junction (tight, anchoring, and gap junction) - Multicellular eukaryotes - Photoautotrophic → fixes inorganic carbon using light energy - Has cell wall - Sessile - Haploid (gametophytes) alternates with diploid (sporophyte) - Has cell walls for cell shape maintains and protects cell - Has large vacuoles, which produces turgor against cell wall - Has chloroplast - Don\'t need to move but can be moved through growing up/down laterally, disperse by pollen/seed, phototrophic - Can be moved (mobility) or can move themselves (motility ) - Chemoheterotrophs - Most be mobile in order to get foods - Motility characteristics - Muscle - Sense and cephalization - Nervous, digestive, excretory, and skeletal systems - Locomotory - High metabolic rate - Some can be sessile - Diploid as dominate stage What is a clade? - A monophyletic group composed only of taxa with common ancestors sharing synapomorphies (shared derived, homologies) - Phylogeny that requires the least amount if proposed evolutionary change - First diverse fauna of large complex multicellular animals - First fauna with eyes and jaws - Homeotic genes → genes which regulate the development of anatomical structures - Represents evolutionary radiation of Animalia Animal Classification ===================== 1. Asymmetric →no major axis of symmetry 2. Radial symmetry → body can be cut into identical pie segments, no left/right or front/back 3. Bilateral symmetry→ body has mirror-image left-right symmetry Animals Characteristics: ======================== - Body cavities→ coelom - Acoelomate : no cavity enclosing the gut - Pseudocoelomate : cavity enclosing the gut lined with mesoderm on outer side, no inner side - Coelomate : gut suspended in cavity lined with mesoderm on both sides - Diploblastic animals → two embryonic tissue layers, endoderm and ectoderm - Triploblastic → three embryonic tissue layers, endoderm, mesoderm, and ectoderm - Bilateraians divided into - Protostomes : first opening in embryo becomes mouth - Deuteromoes : opening becomes anus first - Metameric segmentation (repeating) - Chordates, arthropods, annelids Phylum Ctenophora : comb jellies ================================ - Bridal symmetry Phylum Porifera ( sponges) ========================== - Asymmetrical - Sessile as adults - No nerves, filter feeders - Choanocytes flagellar actions - Suspension feeders Phylum Cnidaria ( jellyfish, coral) =================================== - Radial symmetry - Diploblastic - Shared derived of Cnidaria - Used to capture prey Colonial Cnidarians ------------------- - Siphonophores??? Protostomes ----------- - Lophotrochozoans - Have trochophore larva - Some also have lophophore feeding structure - Ecdysozoans - External cuticle that is shed to grow → ecdysis Lophotrochozoans- Phylums Platyhelminthes ----------------------------------------- - Acoelomates - no cavity between body walls and gut - No circulatory systems - Lophotrochozoans- Phylum Mollusca --------------------------------- - Body organised into food, mantle, and viscera - Unsegmented Lophotrochozoans- Phylum Annelida --------------------------------- - Metamerism - Well-defined segments Ecdysozoans ----------- - Growth in through ecdysis of the cuticle - Acellular - secreted by epidermal cells Ecdysozoans- Phylum Nematoda ---------------------------- - Pseudocoelomate - body wall lined with mesoderm, gut has no mesoderm envelope - Unsegmented Ecdysozoans- Phylum Arthropoda ------------------------------ - Jointed chitinous exoskeleton - Segmented body (has body parts) - Jointed limbs - Tagmatization → fusion of body segments Deuterostomes- Phylum Echinodermata ----------------------------------- - Bilaterally symmetrical larvae - Pentaradiate symmetry as adults - Water vascular system and tube feets Deuterostomes- Phylum Hemichordata ---------------------------------- - Pharyngeal gill slits - Dorsal nerve cords stomochord →notochord (rod-like) Deuterostomes- Phylum Chordata ------------------------------ - Notochord - Dorsal hollow - Nerves cord - Perforated - Pharynx (gill slits) - Segmented muscles with post-anal tail