4.2 Key Groups of Marine Organisms

Question 1

Plankton

Answer 1

Microscopic free floating marine organisms

Question 2

Zooplankton

Answer 2

Planktonic consumers that are either floating or weakly swimming animals

Question 3

Echinoderms

Answer 3

A marine invertebrate group with pentaradial symmetry and tube feet

Question 4

Crustaceans

Answer 4

A marine invertebrate group with a hard exoskeleton, ten jointed legs and a nauplius larval stage

Question 5

Bony Fish

Answer 5

Fish that have a bony skeleton and belong to the class Osteichthyes

Question 6

Cartilaginous Fish

Answer 6

Fish that have jaws and skeletons made only of cartilage and belong to class Chondrichthyes

Question 7

Macroalgae

Answer 7

Marine producers such as kelp and seaweeds

Question 8

Marine Grasses

Answer 8

Aquatic flowering plants that are often found in estuarine and coastal environments

Question 9

Keystone Species

Answer 9

An organism that plays a unique and crucial role in the way an ecosystem functions; without keystone species, the ecosystem would be dramatically different or cease to exist altogether

Question 10

Larvae

Answer 10

A planktonic stage of development which occur between the egg and juveniles; found in nearly all species of fish and invertebrates

Question 11

Pentaradial Symmetry

Answer 11

Five arms (or fans) radiating from a central body cavity

Question 12

Tube Feet

Answer 12

Tubular projections that assist in locomotion, feeding, and respiration

Question 13

Nauplius

Answer 13

Distinctive larval stage of crustaceans

Question 14

Carapace

Answer 14

The part of the exoskeleton that protects the dorsal side of the cephalothorax

Question 15

Gills

Answer 15

The gaseous exchange surfaces of fish

Question 16

Operculum

Answer 16

A thin body flap of skin covering and protecting the gills

Question 17

Lateral line

Answer 17

A canal on the head and the side of the fish that contains sense organs; it is externally visible in bony fish but in cartilaginous fish it is under the skin

Question 18

Scales

Answer 18

Overlapping segments of bone covered by skin and mucus found on the outside of the fish

Question 19

Fins

Answer 19

Protrude from the body surface and assist in movement, stabilizing position, reproduction and protection

Question 20

Swim Bladder

Answer 20

A buoyancy organ found in bony fish

Question 21

Denticles

Answer 21

A type of overlapping scales that provides protection and improved hydrodynamic efficiency in sharks

Question 22

Gill Slits

Answer 22

External openings from the gills through which water taken in at the mouth can pass back to the ocean

Question 23

Holdfast

Answer 23

Strong, root-like structure that anchors the macroalgae to the seabed

Question 24

Stipe

Answer 24

Long, tough, vertical stalk similar to the stem of plants

Question 25

Blades

Answer 25

Leaf-like structures that ‘hang’ in the water and absorb light and minerals

Question 26

Gas Bladder

Answer 26

A gas-containing structure that provides buoyancy for some species of seaweed

Question 27

Root

Answer 27

Structure at the base of plant that anchors it to the substrate and absorbs nutrients from the sediment

Question 28

Rhizomes

Answer 28

A horizontal underground structure that enables seagrasses to reproduce asexually

Question 29

Leaf

Answer 29

Photosynthetic organ of plants

Question 30

Flower

Answer 30

Sexual reproductive organ of plants