Consumers OCN201 Fall 2007 Zackary Johnson Department of Oceanography http://www.soest.hawaii.edu/oceanography/zij/education.html Major Concepts Consumers keep growth / biomass in check Primary consumers use a variety of techniques, depending on size, to graze (consume) phytoplankton Secondary consumers vary in size, form and function, fromjelliesto penguins and sharks Secondary consumers have many adaptations to their particular size, life style and habitat and are represented by many different phyla, including both invertebrates and vertibrates Unchecked growth is not sustainable How long would it take to fill the ocean with phytoplankton, starting with one 1μm cell growing at 1 division per day? (A) Days? (B) Years? Cell Volum me (m^3) Unchecked growth is not sustainable ocean volume = ~1.3 * 10 18 m 3 4E+18 3E+18 2E+18 1E+18 Cell Volum me (m^3) 1E+17 0.1 (C) Decades? 0 0 50 100 150 Days cells(d) = cells 0 exp(d*μ) 1E-19 0 50 100 150 Days ~120 days!! What are the major functional classifications of marine consumers? Primary consumers = consumers (i.e. not producers) of primary production. Anything that eats primary producers. Secondary consumers = consumers of everything else What mechanisms are used to attain food? Pelagic grazers use a variety of mechanisms to capture prey Protists (single celled flagellates): diffusion feeding, direct interception (raptorial feeding), filter feeding Crustacea (copepods): filter and raptorial feeding Chaetognaths (worms): raptorial feeding (ambush predators) Gelatinous Zooplankton (ex. jellies): tentacles, sticky cells and filter feeders Larval Fish: mainly raptorial feeders (some filter feeders, too) 1
Zooplankton (Macrothrix) pushing food into mouth Krill (crustacean) feeding Amoeba phagocyting another protist Feeding Mechanisms: Searching for Food Increasingly complex sensory & capture mechanisms are required to offset the fact that organism mass increases at a faster rate than surface area Flagellates Ciliates Crustacea Fish Direct Contact Filter feeding Structures Chemo & Mechanical Receptors Visual 0.001 mm 0.01 0.1 1 10 100 100 Body Size 0 (length) very large http://www.funsci.com/fun3_en/protists/exhibition.htm Radiolarians Strategy: increase surface area at expense of mass & organizational complexity Salps Baleen whales behavior: exploit patches figure after a drawing by M. Landry,pictures from J. Drazen (fish), D. Keith (salp), K. Sime (whale), www.mbayaq.org (copepod), R. Patterson (flagellates) Phylogeny of invertebrate consumers Arthropods Vertebrates Echinoderms Lophophores Cnidarians Ctenophores Sponges Ancestral Protist Segmented Worms Mollusks Round Worms Rotifers Flatworms Proboscis Worms Invertebrate Phyla Porifera (sponges) Cnidarians (jellies, corals, hydroids) Ctenophores (comb jellies) Worms (flat, round, segmented) Molluscs (clams, snails, squid, octopi) Arthropods (copepods, crabs, shrimp) Echinoderms (sea stars, brittle stars) 2
Porifera (sponges) Skeleton may be calcareous or silica spicules, or entirely of the protein collagen Benthic -- intertidal to abyssal Suspension Feeders (strain plankton) Source of many bioactive compounds Cnidarians- (anemones, corals, jellyfish) Radial symmetry Simple Digestive system (blind sac) No circulatory, respiratory or excretory systems Primitive nerve networks Cnidocytes (stinger cells) - prey capture, turf wars, defense Polyp Medusa Ctenophores - (comb jellies) All are marine Pelagic from 0 to >3000 m (few benthic creepers) Have eight rows of cilia (comb rows) Carnivorous Use tentacles with sticky colloblasts Some directly ingest prey (Beroe) Flat worms (Platyhelminthes) Turbellarian flatworms are marine, benthic Infauna from intertidal to deep sea Carnivorous or herbivorous Move by cilia or undulations Mouth but no anus The Worms Round Worms (Nematoda) Flow through digestive system Found all over (terrestrial, freshwater, marine) Highly abundant, freeliving in benthic infauna Many other types are parasitic Segmented worms (Annelida) Major Class: the Polychaetes Mostly benthic, a few planktonic predatory epifauna tube dwelling infauna (deposit/suspension feeders) Mollusca - (Clams, snails, octopus, squid, et al.) Bivalvia (Clams, oysters, mussels) Gastropoda (snails, nudibranchs) Cephalopoda (squid, octupus, nautilus) Mollusca - (Clams, snails, octopus, squid, et al.) Bivalvia: many burrowing (clams) others adapted to hard substrates (mussels), suspension feeders Gastropods: primarily rocky substrates; a few pelagic; herbivores, carnivores, deposit suspension feeders; have radula (a toothed scraper) Cephalopods: Pelagic (squids) or Benthic (octopus), welldeveloped brains/eyes, ink sacs, radula, beaks; many can rapidly change colors (camouflage, communication) 3
Arthropoda Arthro pod = joint foot Body plan a variation on the Annelid theme (bilateral symmetry, segments with pair of appendages per segment) Exoskeleton (protection, leverage) Striated Muscle (quick, powerful) External Skeleton requires molting Echinoderms Echino derm = spiny skin Radial symmetry is secondarily derived (larvae are bilateral) Have a water vascular system (tube feet) Most are suspension or deposit feeders Sea stars also predatory Chordate Phylogeny Urochordates (salps, tunicates, larvacea) Invertebrates Vertebrates Gelatinous Pelagic Often colonial Suspension feeders Salps / Tunicates Can be very abundant in phytoplankton blooms Larvacea Small larva-like Secrete mucus mesh house Uses tail to create feeding current Catches food on filter Small fish-like Suspension feeder Can swim, but usually stays partly buried Cephalochordates Amphioxus The Major Fish Groups Jawless fishes (Agnatha) Cartilaginous fishes (Chondricthyes) Bony fishes (Osteicthyes) 4
No jaws No appendages Cartilaginous Hagfish: scavengers Agnatha Chondricthyes - Cartilaginous Fish Skeleton of cartilage No gas bladders, must swim to stay afloat Rays are flattened with smooth skin Sharks have rough skin with tooth-like projections Carnivores or Planktivores Chondricthyes: Planktivores Chondricthyes: Carnivores Osteicthyes - (Bony Fish) ~22,000 species From ~1 cm to 8 m Surface to 8370 m Good eyes (except where secondarily lost) Good Olfaction Lateral Line sensing system (water movement) Gill Rakers Gill Arch Detect very weak electrical signals given off by all living things Find food in sediments Filter Feeders Particle Pickers (ex. zooplankton) Coral muncher ex. sardines, anchovies use gill rakers protrusible mouth create suction through gills Parrot Fish 5
Ambush Predator Flounder Angler Fish Short Burst Predator Baracuda Partially endothermic - warm muscles Hydrodynamic - body shape - fin retraction High Speed Cruiser Often camouflaged, may use lures Tuna Predator Avoidance Camouflage/Countershading Schooling Fly Away! Reptiles, Birds, and Mammals Crocodile one type Snakes - 50 species Turtles Loggerhead Leatherback Hawksbill Olive Ridley Green Sea Turtle (Honu) Marine Reptiles Marine Birds albatross, shearwaters gulls and terns pelicans, cormorants, frigate birds penguins 6
Mammals (Class Mammalia) Endotherms (warm blooded) Blubber layers, thick hair Breathe Air Have Hair Live Young Milk Production in Females Carnivora polar bears, sea otter, pinnipeds Sirenians dugongs and manatees Cetaceans whales and dolphins Major Concepts - redux Consumers keep growth / biomass in check Primary consumers use a variety of techniques, depending on size, to graze (consume) phytoplankton Secondary consumers vary in size, form and function, fromjelliesto penguins and sharks Secondary consumers have many adaptations to their particular size, life style and habitat and are represented by many different phyla, including both invertebrates and vertibrates 7