20_AirWaterW11

20_AirWaterW11 - Intro To Animals • Air vs water •...

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Unformatted text preview: Intro To Animals • Air vs water • Buoyancy • Example: Ctenophores • Falling (Stoke’s equation) – Plankton – Complex life cycle • Example:Cnidarians – Filter feeding • Example: Sponges • Jet propulsion – Example: Scyphozoa (in Cnidarian Clade) What Major Characters Define Animal Clades? • Tissue Layers – Epithelial Tissue – Diploblasty – Triploblasty • • • • • • Body symmetry – Radial vs bilateral Presence of Coelom Segmentation Embryology Genetics Other Animals Multicellularity Choanoflagellates Porifera Cnidaria Ctenophora Acoelomorpha LOPHOTROCHOZOA Rotifera Loss of coelom Platyhelminthes Segmentation Annelida Molluska ECDYSOZOA Nematoda ANIMALIA PROTOSTOMES Bilateral symmetry BILATERIA DEUTEROSTOMES Coelom, cephalization, CNS Arthropoda Segmentation DEUTEROSTOMES Echinodermata Segmentation Chordata • Epithelium Characters: Tissues – Tightly joined cells that cover surface • Diploblastic: Endoderm & Ectoderm • Triploblastic: Endo-, Ecto-, and Mesoderm Asymmetry Symmetry Radial symmetry Sponge No plane of symmetry Jellyfish Multiple planes of symmetry Bilateral symmetry Lizard Single plane of symmetry Posterior Anterior Figure 32-5 Air vs. Water: Density Fresh Water Sea Water Fats and Oils Muscle Crustacean exoskeleton Bone Shell-Mullosk 1000 kg/m3 1025 915-945 1050-1080 1900 2060 2700 Insect exoskeleton 1200-1300 (don’t memorize values, but know relative density) Buoyancy • Easier to be buoyant in water • Use materials that are less dense than water – Fats and oils – Air (e.g. fish swim bladder) • Reduce heavy materials – Bone – Shell Physalia physalis, Portuguese Man O’ War Choanoflagellates Multicellularity Ctenophora LOPHOTROCHOZOA Ctenophores Bilateral symmetry ANIMALIA PROTOSTOMES BILATERIA ECDYSOZOA DEUTEROSTOMES Coelom, cephalization, CNS DEUTEROSTOMES Ctenophores • Open water • Diploblastictwo issue layers – 2 tissue layers endoderm and ectoderm no – mesoderm endoderm and ectoderm – No mesoderm • Complete gut • Move by using band of cilia • Catch small prey with sticky cells Ctenophores & Buoyancy • Neutrally buoyant – No bones or shell – Little muscle • Mesoglea – Between tissue layers – Exclude sulfate ions (heavy ions) – Less dense than H20 – Low metabolic activity Buoyancy in Air? • Lowest density possible biologically>density of air • Can’t be neutrally buoyant in air • BUT- some living things “float” in air without flying or gliding. How? Pollen Dandelion Seeds Fall, but very slowly • Stokes “Law” (do not memorize) How fast you sink increases as Size increases Your density (ρ1) increases > fluid 2gd 2(ρ1−ρ2) ν= 36µ The viscosity of the fluid decreases € What does this mean? Stokes Law: implications • Organisms can’t change the density or viscosity of air or water • Organism size and density can change • Density adaptations- we’ve seen => fall very slowly • size if very smalldrag, fall more slowly Size- be very small, fall very slowly projections inc. dandelion seeds foraminiferans • Projections- increases drag, fall more slowly – Dandelion seeds – Foraminiferans Stokes Equation: being small • Smaller objects fall more slowly • If slow enough, currents and eddies will keep afloat • Air-organisms must very small • Water- organisms can be much larger and float Marine Plankton: Stokes and Buoyancy Adaptations • Plankton=small organisms, larvae and gametes that drift with the currents • Consequences in water: – “large” single celled organisms in plankton (e.g. foraminferans) – External fertilization – Complex life cycle – Filter feeding Complex Life Cycle in Animals • Life cycle goes through 2 ecologically distinct phases • Marine & FW organisms can have a dispersing larval phase – Easier when they can use fluid medium • Can also have distinct life stages larvae can float, and disperse corals just stay there Fertilization larvae Metamorphosis 2N Adult 1N Gametes 2N Choanoflagellates Cnidaria Multicellularity LOPHOTROCHOZOA Cnidaria Bilateral symmetry ANIMALIA PROTOSTOMES BILATERIA ECDYSOZOA DEUTEROSTOMES Coelom, cephalization, CNS DEUTEROSTOMES Example: Cnidaria • Cnidarians – Have stinging cells “cnidocytes” to catch prey – Diploblastic – Incomplete gut – Radial symmetry – Alternate between polyp and medusa forms Cnidarians Anthozoans Scyphozoans Hydrozoans tentacles around the mouth move around using belt, jet proportions • “polyp” or sessile phase dominates •Includes corals, anemones, sea fans • “Medusa” or jellyfish phase dominates • Typically small • Includes the only freshwater Cnidarians •Simple polyp and medusa phases Example: Anthozoans- Coral • Form coral reefs • Contain zooxanthellae • Coral body plan polyps –manypolyp is stretchedwith blind gut over Many polyps over hard skeleton stretched each a mouth stinging celss can catch prey hard skeleton – Each polyp is a “mouth” with blind gut the organism is just a layer on the coral reefs – Stinging cells can catch prey How do they reporduce, disperse? Example: Anthozoans-Coral • Coral release “planula” larvae or release sperm and eggs that become planula larvae • Planula drift with current • Settle on reef and develop into coral colony (note: this is cgi) Example: Hydrozoans asexual phase MITOSIS changing form medusa (2n) IS IOS ME 0.5 mm some corals don have mudusa phase Zygote (2n) FE Sperm N (n) IO T A IZ L TI R Egg (n) M Figure 32-22 EI OS IS Mature Polyp (2n) feeding mouths shared gut Marine Plankton: Stokes Lay and Buoyancy Adaptations • Plankton=small organisms, larvae and gametes that drift with the currents • Consequences in water: – “large” single celled organisms in plankton (e.g. foraminferans) – External fertilization – Complex life cycle – Filter/suspension feeding Choanoflagellates Cnidaria Multicellularity LOPHOTROCHOZOA Cnidaria Bilateral symmetry ANIMALIA PROTOSTOMES BILATERIA ECDYSOZOA DEUTEROSTOMES Coelom, cephalization, CNS DEUTEROSTOMES Cnidarians Anthozoans Scyphozoans Hydrozoans • “polyp” or sessile phase dominates •Includes corals, anemones, sea fans • “Medusa” or jellyfish phase dominates • Typically small • Includes the only freshwater Cnidarians •Simple polyp and medusa phases Filter (suspension) feeding • Plankton in water= lots of food • Filter or suspension feeding – Internal-Suck in water to catch food – External-Use external filters, nets or mucus to catch food by tentacles • Animal can be sessile Choanoflagellates Sponges Multicellularity LOPHOTROCHOZOA Sponges Bilateral symmetry ANIMALIA PROTOSTOMES BILATERIA ECDYSOZOA DEUTEROSTOMES Coelom, cephalization, CNS DEUTEROSTOMES Example: Sponges • 3 major clades • No body plan symmetry • No distinct cell layers • No distinct tissue or organs Other Animals has cell type, no tissue Sponges Glass Sponges Hexactinellids Demosponges Calcareous sponges Calcarea • 6 pointed silica spicules • Silica spicules • Most diverse group •Calcium Carbonate spicules •More closely related to eumetazoa Example: Sponges Osculum 2. Water filtered of plankton exits osculum 1. Water and plankton enter in pores, goes through small canals Example: Sponges 1. Flagellated choanocytes (specialized feeding cells) create currents Spicules provide support 2. Water and plankton enters pores into small canals. 3. Choanocytes capture food with “collar” Why have many small pores and canals instead of one big one? Water and Air • Buoyancy & Stokes Law – Can be buoyant in water but not air – Marine & freshwater plankton – Filter feeding – Complex life cycle • Jet Propulsion Jet Propulsion Jet propulsion • Eject mass of fluid away from body to create thrust • Fluid density increases, thrust increase • Water can create 830 times thrust of air • Any animal strong enough to create thrust in air would be too heavy for it to work • Jet propelled animals only in water Example: Scyphozoans • In Cnidarian Clade – Cnidocytes – Diploblastic – Incomplete gut Medusa Planula Larvae Polyp • Jellyfish or medusa stage dominates complex life cycle – Medusa produces sperm & eggs Mature polyp budding off medusa Example: Scyphozoans • Use jet propulsion to move in water • Still not great at moving against currents • Predators – Use cnidocytes to capture prey ...
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