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BIO 202 UNCW exam 3
Bilateral symmetry - ✔️ ✔️ Major evolutionary advance Well suited for forward movement Often associated with cephalization Protostome - ✔️ ✔️ "1st mouth" Spiral cleavage Determinate (mosaic) cleavage Blastopore becomes mouth Two major subgroups: Ecdysozoa and Lophotrochozoa Deuterostome - ✔️ ✔️ Radial cleavage Indeterminate (regulative) cleavage Blastopore becomes anus Echinoderms and Chordates Acoelomates - ✔️ ✔️ No body cavity Space filled with mesodermal cells Primordial Soup Hypothesis - ✔️ ✔️ Life evolved from simple organic compounds present on Earth at time of its infancy
- Oparin and Haldane Life - ✔️ ✔️ Something that metabolizes, grows, and reproduces What makes an animal an animal? - ✔️ ✔️ Multicellularity Heterotrophy Muscle tissue Hox genes Most animals reproduce sexually Metazoa - ✔️ ✔️ multicellular organisms (true animals) Developmental Sequence - ✔️ ✔️ 1. Gamete Formation
- Fertilization
- Cleavage
- Gastrulation
- Organogenesis
- Growth
Radial Symmetry - ✔️ ✔️ Cnidarians, Ctenophores and some sponges Pseudocoelomates - ✔️ ✔️ body cavity but not a true coelom Have body cavity but not a true coelom since it's only partially surrounded by mesoderm Eucoelomates - ✔️ ✔️ True coelom Possess true coelom that is entirely surrounded by mesoderm Why is body cavity important? - ✔️ ✔️ Greater flexibility Space for organs Exposes more cells to surface exchange Hydrostatic skeleton: for movement and strength while burrowing Segmentation - ✔️ ✔️ Serial repetition of similar body segments Allows for specialization of body regions Allows for functional redundancy NO longer used for disentangling evolutionary relationships Ecdysozoa - ✔️ ✔️ Arthopods and nematodes Have exoskeleton made of cuticle Molt to grow (ecdysis) Lophotrochozoa - ✔️ ✔️ Initially grouped strictly based on molecular data Members also share morphological features Lophophore: feeding tentacles Trochophore: ciliated larvae Platyhelminths lack both characteristics but are grouped here based solely on molecular data Phylum Porifera - ✔️ ✔️ Sponges Loose aggregation of cells Pores and canals for filter feeding Spicule skeleton Sessile Mostly marine, all aquatic Large range of size and color
Gastrovascular Cavity (gut) Mostly marine, all aquatic Phylum Cnidaria - ✔️ ✔️ 10,00 species corals, jelly fish, sea anemones, and hydras ecologically important 2 main body types: Polyp and Medusa (dimorphism) Stinging cells on tentacles canned cnidocytes Mesoglea - ✔️ ✔️ Jellylike layer that is much thicker in medusa that makes medusa buoyant Cnidocytes - ✔️ ✔️ specialized stinging cells are used for defense and prey capture Contains stinging organelles (nemaocysts) After firing, cell is absorbed and another is produced Class Scyphozoa - ✔️ ✔️ True jellyfish, mostly floating Class Cubozoa - ✔️ ✔️ Box jellies with bells almost square fast swimmers (rarely was up on shore) Can produce fatal stings Class Anthozoa - ✔️ ✔️ All polyps, NO medusa stage Largest class (6000 species 3 subclasses (2 primary): Hexcorallia(hard corals and anemones) and Octocorallia(soft corals) Coral Reefs - ✔️ ✔️ Hard corals (Hexacorallia) are reef builders Skeleton is calcium carbonate (CaCO3) Have zooxanthellea living in their tissues Phylum Ctenophora - ✔️ ✔️ Comb Jellies, 150 species Rowns of comblike plates for locomotion NO nematocysts, but have adhesive colloblasts instead Flatworms - ✔️ ✔️ First appearance of bilateral symmetry Evolution of cephalization 3 well defined germ layers: ectoderm, mesoderm, and endoderm NO colem, just gut cavity Space between gut and ectoderm filled with mesodermal cells Advances in nervous coordination and appearance of excretory system Phylum Platyhelminthes - ✔️ ✔️ Large range in size (<1mm to 7m)
Body flattened dorsoventrally with cillia on bottom of body to facilitate movement. Both free living and parasitic Free living have some freshwater and terrestrial species, most are marine Parasitic species can be ecto-and endoparasites, often multiple hosts (some in humans) Flatworm form and function - ✔️ ✔️ Have mouth, pharynx and intestine (usually branched) Incomplete digestion system (one opening) Nervous system of connecting nerves in ladder pattern Ocelli(eye spots), ear like organs, chemical and mechanical receptors Well developed reproductive organs Muscle fibers for locomotion Flame cells - ✔️ ✔️ Protonephridia Cells used for excretion and osmoregulation Have tuft of flagella Fluid passes through ducts and excretory pores Flatworms reproduction - ✔️ ✔️ Both asexual and sexual Asexual by bud formation or fission Sexual reproduction: nearly all are hermaphrodites with complex reproductive organs Some require host for hatching (parasitic forms) Class Turbellaria - ✔️ ✔️ Mostly free living Muscles and cilia for movement Some gliding over mucous from adhesive glands Class Monogenea - ✔️ ✔️ Ectoparasites, mainly on fish Single host (direct life cycle) Attach to gills and fed of bodily fluids (blood) Only damaging in crowded conditions (can lead to suffocation) Class Trematoda - ✔️ ✔️ All parasitic flukes Endoparasitic in vertebrates Suckers and hooks for adhesion, sense organs minimal Subclass Digenea Intermediate host (mollusc) and Definitive host (vertebrate) One hatched egg can generate many progeny Important parasites of humans and domestic animals Liver flukes, blood flukes, lung flukes Class Cestoda - ✔️ ✔️ Tapeworms
No head (reduced cephalization) Most are marine Circulatory, excretory , respiratory sysytems present Bivalvia form and function - ✔️ ✔️ Dorsal ligament for opening and abductor muscles for closing Mantle posteriorly modified into openings for water (siphons) Foot moved anteriorly for locomotion Bivalvia feeding - ✔️ ✔️ Gills highly modified for feeding Cilia flows over 2 gills Mucous ensnares food which is passed along grooves to mouth
- ✔️ ✔️ Bivalvia locomotion - ✔️ ✔️ Valves are used for swimming in scallops Some Bivalves are sessile, secret cement or threads (oysters & mussels) Class Cephalopoda - ✔️ ✔️ All marine (high salinity) and carnivorous Giant squid is largest invertebrate known Shell is reduced in many, absent in Octopus Foot highly modified and moved toward head Locomotion by jet propulsion through ventral funnel (siphon): modified mantle Cephalopoda form and functiion - ✔️ ✔️ No cilia on gills, use muscular contraction of mantle for water flow Closed Circulatory system Largest brain of invertebrates, complex eyes Visual communication Most have ink glands for defense Nautilus - ✔️ ✔️ 60 - 90 tentacles External shell No ink gland No chromatophores Buoyant shell- chambers filled with gas Cuttlefish - ✔️ ✔️ Chromatophores: Pigment cells in the skin Expand and contract to induce color change For camouflage, alarm or courtship displays All cephalopods (except nautilus) have chromatophores
Phylum Annelids - ✔️ ✔️ Single Phylum of ~15,000 species Majority marine, but most familiar are freshwater(leeches) or terrestrial(earthworm) First appearance of segmentation Coelom segmented with septa Presence of of setae for locomotion or as an anchor Segmenttion - ✔️ ✔️ Serial copies of internal organs (besides main blood vessel, gut and nerve cord) very precise movement is possible very good for burrowing as each segment can move independently provides redundancy, failsafe. Injury does not mean death Allows for specialization (more seen in Arthropods) Class Polychaeta - ✔️ ✔️ Largest class (10,000 spp) Mostly marine Paired appendages called parapodia for locomotion and respiration(osmosis), also have gills Sedentary (tubicolous) or errant lifestyles Lifestyle tied to food habits Hydrothermal Vent worms - ✔️ ✔️ All 150 species are marine and found near hydrothermal vent Lack mouth and digestive tract: gut tissue forms and organ (trophosome) that becomes filled with chemosynthetic bacteria Bacteria in trophosome fix the chemicals leaving the vents: use hydrogen sulfide as an energy source to produce organic compunds from CO Class Oligochaeta - ✔️ ✔️ Many terrestrial and freshwater, includes earthworms Most have setae Feed on decayed organic matter Gas exchange across skin, no gills Hermaphroditic: Clitellum- glandular region of the body, used in reproduction Class Hirudinea - ✔️ ✔️ Mostly freshwater, many lack setae Many are carnivores with a proboscis Anterior and posterior suckers for attatchment True bloodsuckers with cutting jaws: anterior sucker is small and contains the mouth; creates a wound with saw-like jaws Leeches drink other animals' blood, usually vertebrates Function of Choanocyte - ✔️ ✔️ Flagellum beats to create water current Microvilli cptures food particles and begins phagocytosis Can filter lots of water as much as 20,000x the volume of sponge in 24 hours Sponge skeletal structure - ✔️ ✔️ Major structural protein in metazoa is collagen
