Survey
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A Survey of Marine Animal Kingdoms Gastropods They make up over 2/3 of all the Mollusk species. Gastropod means “stomach foot”. Snails and Nudibranchs are the most common Gastropods. Class Gastropoda • Many snails can withdraw into the shell and close it off with a horny operculum. Gastropod Feeding Habits • Most gastropods are herbivores and feed by scraping off algae using the radula. • Some are scavengers of dead organisms • Others are carnivores that drill into other mollusks COLORFUL MOON SNAIL NORTHERN ABALONE CONE SNAILS HORSE CONCH • Florida state shell • Voracious carnivore QUEEN CONCH Ocular notch Busycon Gastropod egg cases Naticidae SHELL-LESS GASTROPODS SEA SLUGS & NUDIBRANCHS NUDIBRANCH MEANS “NAKED GILL” SHELL-LESS ANIMALS MUST PROTECT THEMSELVES WITH POISON/TOXIN, KEPT IN CERATA OR MUCUS BRIGHTLY COLORED TO “ADVERTISE” POISON ELEGANT NUDIBRANCH Florida Sea Goddess SPOTTED SEA HARE Parapodia Bi-Valves Class Bivalvia • Bivalve mollusks have two shells (valves) that are hinged. • clams, oysters, scallops, cockles, mussels, shipworms Bi-Valves Sessile. Filter feeders NO radula They take in, and release, water through a Siphon Tube. They breathe underwater using Gill Membranes. Some Bi-Valves are swimmers, such as scallops. They have separate sexes with sperm and eggs being released into the water (external fertilization). Clam Anatomy Soft-bottom burrowers • Rely on blade-like foot for burrowing • Rely upon long siphons Cockle Surface dwellers attached via byssus: threadlike anchors Pen Shell Arcidae Pinnidae Oysters Winged oysters Tridacnidae Giant Clam Mussels Pteriidae Cemented surface dwellers: No bysuss Several unrelated groups of “oysters” independently evolved ability to cement on one side. True oysters (Ostreidae), jewel boxes (Chamidae), thorny oysters (Spondylidae). Oyster Oyster Oyster reef Jewel box Thorny oyster CEPHALOPODS HI KIDS, MY NAME IS SQUIDWARD. WANNA MEET SOME OF MY RELATIVES? CHARACTERISTICS • MOST ADVANCED OF THE MOLLUSKS • ACTIVE SWIMMERS – … • EYES ARE HIGHLY DEVELOPED • ARMS & TENTACLES HAVE SUCTION CUPS TO HOLD PREY • BEAK-LIKE MOUTH TO BITE PREY • VENOM IN SALIVA PARALYZES PREY • CAN CHANGE COLOR RAPIDLY Class Cephalopoda • Most cephalopods have complex eyes with cornea, lens, chambers, and retina. • Largest invertebrate brain • Closed circulation Class Cephalopoda - Locomotion • Cephalopods swim by expelling water from the mantle cavity through a ventral funnel. Protection • Color changes effected by chromatophores (pigment cells) • Allows them to blend into their background • Squirting out water by jet propulsion helps escape predators • Squids also release an inky substance into the water Class Cephalopoda - Reproduction • Sexes are separate in cephalopods. • Juveniles hatch directly from eggs – no free-swimming larvae. • One arm of male removes a spermatophore from mantle cavity and inserts it into female. SQUID VERY ACTIVE SWIMMERS COMMONLY FOUND IN SCHOOLS VERY AGGRESSIVE PREDATORS 8 ARMS 2 TENTACLES SIPHON BEAK OF SQUID SQUID SUCKERS GIANT SQUID GIANT SQUID SQUID EGGS RMJA OCTOPUS RARELY SWIMS, CRAWLS WITH 8 ARMS LIVES IN HOLES/CREVICES/BURROWS FEEDS AT NIGHT – NOCTURNAL PREDATOR SQUIRT INK AS A DEFENSE TO ESCAPE VISCERAL MASS 8 ARMS SIPHON CEPHALOPODA Octopus joubini Caribbean reef octopus Atlantic pygmy octopus Octopus briareus http://www.eumed.net/malakos/Imahispa/Argonauta%20nouryi.jpg Octopus vulgaris Octopus vulgaris Common octopus Caribbean reef Sepioteuthis sepioidea squid GIANT PACIFIC OCTOPUS CHAMBERED NAUTILUS Trapped gas bubbles keep the nautilus buoyant
