Marine Biology Exam 2 Study Guide

Radial Symmetry

Body parts are arranged in a circular pattern around a central axis

Bilateral Symmetry

Body parts are arranged in such a way that only one plane through central axis will divide animal up into similar halves

5 Forms of Suspension Feeding

Sieving, direct interception, inertial impaction, gravitational deposition, and diffusional deposition

Porifera - Body features

Ostia, spongocoel, osculum, choanocytes, archeocytes, spongin, and spicules

Porifera - Body forms

Anconoid (simple), Syconoid, Leuconoid (complex)

Porifera Ecological roles

Compete for space, food chain, symbiotic relationships, and recycle Ca2+

Cnidaria

Radially symmetric, network of nerve cells, cnidocytes

Cnidaria - Hydrozoa

Colonial and have polyp and medusa stages

Cnidaria - Scyphozoa

Medusa stage prominent; reduced/absent benthic polyp stage

Cnidaria - Anthozoa

Polyp stage dominates, no medusa stage

o Sea anemones - Hydrostatic skeletons.

o Corals - Scleractinia corals (hard) vs. Octocorals (soft)

Ctenophora

Comb plates, continuous gut, lack cnidocytes, bioluminescent

Platyhelminthes

Flatworms, most live in sand/mud; Turbellaria (free-living), Trematodes and Cestodes (parasites)

Nemerteans

Ribbon worms, proboscis with stylet

Lophophorates - Phoronids

Secrete leathery tube (protein/chitin) around their bodies

Lophophorates - Bryozoans

From encrusting colonies; abundant and small (less than 1 mm); no circulatory system

Lophophorates - Brachiopods

Covered by shell, nonsymmetrical, have pedicle

Sipunculids

Proboscis with tentacles (peanut worms)

Priapulids

"Penis worms"

Nematodes

Most abundant multi-cellular animals

Annelids

Hydrostatic skeletal movement

Polychaetes - Errant vs. sedentary; non-selective vs. selective; epitokes

Pogonophorans - No mouth or digestive tract, Riftia

Ecological Roles of Marine Worms

Nutrient cycling, food chain and habitat

Aspects of Mollusks

Head-foot, visceral mass, radula, veliger

Polyplacophorans (chitons)

Adhesive force/piston

Scaphopods (tusk shells)

Captacula

Gastropods

Striated cone, slipper limpets, nudibranchs (cerata)

Bivalves

Lack radula, filter feeders, catch muscle, shipworms

Nautiloids

Large coiled shell with septa and siphuncle; jet (no fins)

Coleoids

Multiple arms and tentacles have jets and fins (Cuttlefish, squid, and octopus)

Buoyancy mechanisms of cuttlefish

Once ideal gas volume is reached, alter ion concentration of fluid in cuttlebone so osmotic pressure = hydrostatic pressure to maintain ideal conditions

Adaptive coloration of Cephalopods

Chromatophores, reflecting cells, skin papillae

Patterns of Cephalopods

Uniform, mottle, disruptive

Muscular hydrostatic of Cephalopods

3D arrays of muscles that act as both compressive and tensile elements, that have constant volume and capable of complex movements (elongation, shortening, bending, and torsion)

L/D Ratio for Cephalopods

Larger = Greater length-speed changes for a given change in diameter / Smaller = Greater force for a given change in diameter

Squid males have

Modified arms with spermatophores

Live fast and die young

Terminal spawners

Chelicerate Arthropods

Horseshoe crabs and sea spiders

Mandibulate Arthropods

Crustaceans (abundant)

Decapods

Crabs, lobsters, shrimp

Decapods - Males

Copulatory pleopods

Decapods - Crabs

Zoea larval stage

Decapods - Shrimp

Nauplius larval stage

Stomatopods (Mantis shrimp)

Fastest feeding strikes of any animal

Euphausiids (Krill)

Suspension feeders, swarms, important role in polar seas

Cirripedia (Barnacles)

Cirripeds, large penis, sessile

Chaetognatha

Grasping spines with toxins

Water vascular system

Madreporite, ampulla, tube feet

Asteroidea (Sea stars)

Extrude stomachs; Crown of thorns

Ophiuroidea (Brittle stars)

Mobile, slender arms

Echinoidea (Sea Urchins/Sand dollars)

Aristotle's lantern

Holothuroidea (Sea Cucumbers)

Respiratory trees, cuvierian tubules

Crinoidea (Feather stars, Sea lilies)

Suspension feeders, filter small organisms from water using tube feet and mucous nets

Characteristics of Echinodermata

Few predators (spiny skins), can be important predators (Crown of thorns) and herbivores (Sea urchins), notochord (Slender skeletal rod), dorsal, hollow nerve tube, pharyngeal gill slits, post-anal tail

Urochordata

· Ascidiacea (Sea squirts) - Two siphons

· Thaliacea (Salps) - Solitary or colonial

· Larvaceans - Mucous houses

Cephalochordates

Sea lancelets

Vertebrates

Fishes (Mostly marine fishes in shallow, warm water)

Agnatha

Jawless eel-like fishes

· Hagfish - Slime producers and scavengers

· Lampreys - Bidirectional respiratory flow

Chondrichthyes

Cartilaginous fishes

Sharks

Lack swim bladders, denticles, large livers with squalene (oil), carnivores

Skates

No tail spine, fleshier trail with prominent dorsal fins, sinusoidal wave, oviparous (mermaid's purse), and in temperate waters

Rays

Some have tail spine, flap pectorals (Stingrays often use an undulation), ovoviviparous, and in tropical waters

Chimaeras

Different from cartilaginous fish by: upper jaw attached to braincase, adults lack a spiracle, and one gill slit covered with an operculum

Osteichthyes

Primitive and modern ray-finned bony fishes

Evolutionary trends in scales

Ganoid -> Cycloid -> Ctenoid

Adaptive coloration and Countershading

Outline disruption, eye disguise, eye mimics (ocelli), cryptic coloration, warning (aposematic) coloration

Locomotion

Myomeres and sinusoidal swimming

Red vs. White Muscle

· Red muscle - Slow speed, long sustained strokes, many mitochondria and myoglobin, and aerobic respiration

· White muscle - Fast speed, short burst acceleration, few mitochondria and myoglobin, and anaerobic respiration

Respiratory system

Countercurrent system in which the outflowing water has a tension far lower than the blood leaving the gill

Gill pump

Water is pumped over the gills by a dual pumping system providing predominantly unidirectional flow of water over the gill surface

Ram ventilation

Generation of respiratory current by swimming with mouth (and opercular valves) open so that water can continuously flow over the gills; no visible breathing movement

Coelacanths, sharks, skates/rays Osmoregulation

Nearly isosmotic, urea + TMAO (trimethylamine oxide), rectal gland

Marine ray finned fish Osmoregulation

Hypoosmotic, lose water/gain salts at gills, drink, and export salts (chloride cells and kidney)

Buoyancy

Dynamic lift, large livers with oil, swim bladders

· Physotomes - Connected between swim bladder and esophagus

· Physolist - No connection between swim bladder and esophagus

Vision

Spherical lens that moves forward and backward

· Rod - Low light intensity

· Cone - High light intensity and color sensitivity

Mechanoreceptors

· Lateral Line - Superficial neuromasts (velocity) and canal neuromasts (acceleration)

· Ears - No swim bladder/swim bladder far away (particle displacement); partial/full connection to swim bladder (sound pressure + particle displacement)

Electroreception

Can detect minute electric potential (4 uA) produced during breathing in flounder (Ampullae of Lorenzini)

Regional Endothermy

Countercurrent heat exchangers

Reproduction in Fish - Oviparity

Eggs develop externally

Reproduction in Fish - Ovoviviparity

Eggs develop internally with no uterine connection

Reproduction in Fish - Viviparity

Live birth with uterine connection

Reproduction in Fish - Oceanodromous

Migrating within oceans typically in between spawning and feeding areas

Reproduction in Fish - Anadromous

Spend life at sea but must return to freshwater to spawn offspring

Reproduction in Fish - Catadromous

Spend life in freshwater but must return to salt water to spawn offspring

Marine Reptiles

Amniotic egg, circulation system, kidneys, scaly skin

Marine crocodiles (1)

Strong swimmers, large, tounge salt gland, TSD 31.6 C for females

Marine turtles (7)

Osmoregulation, salt glands above eyes, natal homing, in water mating every 1-5 years, male combat, TSD 29.9 C for females, low survivorship, esophageal keratinized projections

Leatherback Turtle

Inertial heterotherms, thick hide, food (jellyfish)

Green Turtle

Herbivorous (rest are carnivorous)

Marine iguana (1)

Galapagos, herbivorous, tear and nasal glands, strong swimmers, minimal parental investment

Sea snakes (65)

Most are ovoviviparous, some have venom, strong swimmer, extended submergence (large lung, trachea, skin gas exchange, lower MR), good eyesight, salt gland underneath tongue

Seabirds

Endotherms with countercurrent heat exchangers, salt glands to expel excess salts, use preening for insulation and buoyancy

Slope soaring and dynamic soaring

Save energy, many have complex mating behaviors

Shorebirds

Long beaks and legs, feed in intertidal and shallows; oyster catchers, plovers, sandpipers, stilts herons

Gulls and relatives

Gulls, terns, skuas, jaegers (hawks and vultures of the sea/aerial pursuit), skimmers, alcids (ecological equivalents of penguins)

Pelicans and relatives

Pelicans (surface plunging), boobies (blue footed, red footed, Nazca aka masked), cormorants (pursuit divers), frigatebirds (pirates/aerial pursuit), albatrosses (largest wingspans), storm petrels (pattering)

Penguins

Adapted to life in seas, pursuit diving with wings, extended dive times, streamlined feathers store air for drag reduction