Marine biology Glossary

Organism terminology for midterm exam on organisms

adductor muscle

a powerful muscle in bivalve mollusks that connects the two shells, allowing the animal to close them tightly

Amoebocyte

amoeba-like, motile cells found in invertebrates like sponges, mollusks, and echinoderms

Benthic

the study of organisms that live close the seafloor 

planktonic 

study of drifting organisms

nektonic

study of organisms that can swim independently on their own

Bioluminescence

production of light emitted from living organisms through chemical reactions

Branchial plume

used by nudibranch’s for respiration (filtering oxygen from water to breathe)

Byssus threads

strong fibers that mussels use to anchor themselves on rocks

Cephalization

evolutionary trend of concentrating sensory organs and nerve tissue at one end of an organism, forming a head (jellyfish)

cerata

finger-like horns on the backs of sea slugs that are used for respiration, defense, and feeding

Choanocyte

cell found in sponges that is crucial for feeding and water circulation

Ciliary mucoid feeder

invertebrate that uses both cilia and mucus to capture tiny food particles from the water

Coelom

fluid filled body cavity lined by mesodermal tissue, protects organs from shock

compressed

where animals are forced into smaller more vulnerable vertical zone due to environmental factors such as low oxygen

Cyanobacteria

microorganisms that have a role in nitrogen fixation and oxygen production

deposit feeder

organisms that consume organic matter from the seafloor sediment (detritus)

depressed

physiological stress and behavioral depression observed in marine animals, either by those kept in captivity or lack of sical interaction

Derived vs ancestral

ancestral - trait that was present in a distant ancestor, has been passed down unchanged

derived - trait that has evolved more recently, and is a modification of the ancestral form, appearing in recent lineage

Diffusion

passive movement of molecules like oxygen, nutrients, and ions from high to low concentration through seawater or across cell membranes

Eversible pharynx

tube-like organ that can get turned inside out and thrust out of mouth for feeding

Eversible proboscis

retractable feeding tube found in nemerteans (ribbon worms)

Gastrovascular cavity

digestive chamber found in primitive animals like cnidarians (jellyfish, corals) and flatworms that has a single opening serving both a mouth and an anus

grazer

organisms that consume algae and other plant like material

Heterotroph vs autotroph

heterotroph - can’t make their own food and obtain energy through consuming other organisms

autotrophs - primary producers that create their food food; mainly through photosynthesis 

mantle

feature of mollusks, used as a fold to hide organisms organs

Mesoglea

jelly-like layer found in jellyfish, sea anemones and corals that serves as structural support and buoyancy

Nematocyst

stinging organelle found in cnidarians that is used for prey capture and defense

Operculum

trap door that is found on fish and snails; for fish it covers + protects fills while helping with respiration, for snails it is a structure that seals thee shell opening to protect the snails body

Osculum

opening on sponger used as an exit for water, waste, and reproductive cells

Ostium

pores on sponge that allow water to enter sponge

Parapodia

appendages on segmented worms (polychaetes)

Planula larva

free-swimming ciliated stage of marine invertebrates (jellyfish, corals, sea anemones)

Pneumatocyst

gas filled bladder in marine organisms (seaweeds) that provide buoyancy

Porocyte

specialized cells in sponges that form pores allowing water to enter the animal

Radula

found in most mollusks such as snails, slugs, octopuses

Rhinophore

sensory organs (antennae) found in nudibranchs and other sea slugs, helps them smell and taste chemicals

Saxitoxins

neurotoxins produced by marine microalgae

Setose feeder

appendages covered in bristles or setae to filter food from water

Siphon

tube-like structure that allows mollusks to feed, respirate, and locomotion

Spicule

tiny needle-like skeletal elements (found in sponges) provide support and shape

Spongin

horny structure found in skeleton of sponges

Suspension feeder

organisms that strain small food from water column (catch particles in the water to eat)

Valve

articulating part of the shell of a mollusk, or “plate” in chitons