Biology of Coral Reefs Coral reefs are the largest structures ever built by living organisms can see from space Inhabited by a greater diversity of organisms than any other ecosystem A lot of strange organisms Each organism is linked to many others in a complex web of interactions Vulnerable to destruction by humans Have economic value Reefs protect coastlines from destruction by storm waves and shelter fish and other sea foods Other coral reef resources include aquarium animals building decorative materials pharmaceuticals and diving tourism Where are the coral reefs Need warm water between 25 degree North and 25 degree South Need sunlight shallow bottom and clear water Need normal salinity away from rivers Need water movement enough for oxygen Found along tropical subtropical coastlines in over 100 countries Corals are part animal plant and rock Rock as corals grow they deposit skeletons of calcium bicarbonate o Live tissue is a thin layer on the surface Animal corals are the cnidarians related to sea anemones and jelly fish o All cnidarians have a mouth ringed by tentacles and a very simple gut sac o Cnidarians tentacles are armed with stinging cells nematocysts for defense and prey capture o Sac with a mouth down is medusa o Sac with a mouth up is polyps Plant most important for coral nutrition are tiny single celled zooxanthellae that live in coral tissue o Zoox make food for the coral and help it deposit its skeleton o Coral provides zoox with nutrients Food acquisition by reef building corals They rely most heavily on food manufactured by single celled algae living in their tissue but can also capture animals with their tentacles Most corals are colonies of many polyps Coral colonies grow as polyps divide Each polyp builds a cup into which it can retreat Colonies of each coral species have a distinctive shape Some produce asexually when pieces break off and reattach Corals reproduce sexually Some species release eggs and sperm into the water where fertilization occurs and others only release sperm Spawning simultaneous release of eggs and sperm Fertilized eggs develop into tiny planula larvae that swim until they find a place to settle Larvae that escape predators and settle in a good spot grow into small corals o After many years corals produce egg or sperm completing their life cycle Diversity of Life on Coral Reefs Over 35 000 60 000 species Coral linneaus 1707 1778 biological classification systems o Biologists agree on a system for organizing knowledge about organisms based on evolutionary relationships Bacteria archaea animal kingdom plantae kingdom fungi kingdom and protists o Every species has a scientific name consisting of the genus and species Ex humans are homo sapiens Hierarchy Classification o Domain kind of cell o Kingdom o Phylus o Class o Order o Family o Genus o Species If you know the scientific name of an organism you can o Communicate with anyone in the world about it o Access published information o Learn about it by looking up characteristics of related species The most fundamental division of life is prokaryotes vs eukaryotes o Prokaryotes are very small simple cells ex algae bacteria o Prokaryotes Cells are tiny 250 000 can fit on a printed period Blue green algae colonies appear as slime filaments on unhealthy coral reefs o Eukaryotes Much larger cells In 4 kingdoms Protista all single celled Fungi made of filamentous hyphae Plantae make their own food using energy from light Animalia must eat food Protista o Single celled o Complex and much larger than prokaryotes o zoox in coral tissue are protists o Red tides are caused by protists makes some sea food toxic o Human diseases caused by protists include malaria giardia and sleeping sickness Plantae and nutrients o Plants make their own food using energy from light to transform water CO2 o Algae seaweeds soak up nutrients and water through their surfaces 3 kinds of algae on coral reefs green red and brown Red algae deposit calcium carbonate when they grow keeps reef together o Flowering plants acquire nutrients and water through their roots 2 groups of flowering plants seagrass meadow mangrove swamps Construct ecosystems adjacent to coral reefs Animalia o Animals have to eat o Birds fish and mammals are all in the phylum chordata backbone o Members of 29 other animal phyla live on coral reefs 1 Porifera sponges canals Filter food particles from water as they pump it through their Sponges are extremely simple flexible in form can regenerate from tiny fragments defend themselves with chemicals 2 Cnidarians corals sea anemones jellyfish All cnidarians have a sac like gut a mouth ringed by tentacles nematocysts stinging cells radial symmetry Colonial cnidarians soft coral coral and gorgonians 3 Annelida segmented worms earthworms All Annelida worms are bilaterally symmetrical divided into segments and have toxin filled bristles to discourage predators Feather dust worms have feathery tentacles to filter food from water 4 Mollusca clams sea slugs snails squid octopuses scallops oysters All Mollusca s have a muscular foot 5 Arthropoda crabs shrimp lobsters All arthropods have jointed appendages exoskeletons that they must shed to grow bilateral symmetry 6 Echinodermata starfish sea urchins sea cucumbers brittle stars sea lilies crinoids All echinoderms have pentaradial symmetry tube feet calcareous bits in their skin 7 Chordata sea squirts birds fish reptiles mammals All chordates have at some life stage a notochord post anal tail a dorsal hollow nerve chord pharyngeal slits The key distinguishing characteristics between animals and plants o Plants manufacture their own food using energy from sunlight Two phyla characterized by radial symmetry o Echinoderms and cnidarians Food on Coral Reefs Food is acquired on a coral reef by predation herbivory filter feeding deposit feeding relying on symbiotic microbes Swimming and drifting predators mobile prey o Large mouths and eyes o Stream lined bodies o Ex squid barracuda Swimming predators sessile sitting prey o Ex hawksbill turtle butterfly fish Bottom dwelling predators o Ex crabs snails starfish Defenses against predators o Hard shells snails o Toxins sponges sea slugs o Toxin bristles worms o Ink clouds squid o Camouflage decorator crab scorpion fish o Schooling collaborating clown fish hermit crab sea anemone o Defensive behavior spiny lobsters o Claws teeth shark stone crab o Puffing up puffer fish o Flying flying fish Herbivores o Ex green turtle
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