Marine Science Semester 2 Final Exam Study Guide 2025

Dorsal Side

Top of animal

Ventral Side

bottom of an organism, often referring to the belly or underside.

Anterior Side

The front side of an organism, typically where the head or face is located.

Posterior Side

Opposite of anterior; the back side of an organism.

Radial symmetry

A type of body symmetry in which body parts are arranged around a central axis, allowing for multiple planes of symmetry.

Bilateral symmetry

A type of body symmetry in which the body can be divided into two identical halves along a single plane, typically resulting in distinct left and right sides.

Kingdom

A major taxonomic rank that classifies living organisms into groups based on shared characteristics, encompassing multiple phyla.

Phylum

A rank in the biological classification system that groups together related classes based on similar characteristics and evolutionary history.

Class

A taxonomic rank below phylum and above order that groups together organisms sharing common attributes.

Order

A taxonomic rank below class and above family that categorizes organisms based on further shared characteristics and evolutionary traits.

Family

A taxonomic rank below order and above genus, used to group organisms that are closely related and share a set of characteristics.

Genus

A taxonomic rank below family and above species, which includes one or more species that are closely related.

Species

A taxonomic rank below genus, which identifies individual organisms that can interbreed and produce fertile offspring.

Porifera

• sponge

Cnidarian

a phylum that includes aquatic animals like jellyfish and sea anemones, characterized by their stinging cells called cnidocytes.

• jellyfish

• sea anemone

Echinodermata

a phylum of marine animals that include starfish, sea urchins, and sea cucumbers, known for their radial symmetry and a water vascular system.

• sea star

• sea urchin

• sea cucumber

Mollusca

a diverse phylum of invertebrate animals that includes snails, clams, and octopuses, characterized by their soft bodies, often protected by a hard shell

• octopus

• clam

• snails

• kiten

Arthropoda

a phylum that includes invertebrate animals like insects, arachnids, and crustaceans, characterized by their exoskeleton, segmented bodies, and jointed appendages

• crab

• shrimp

• crustacean

• insect

• spider

• centipede

Chordata

a phylum of animals that have a notochord at some stage of development, including vertebrates like mammals, birds, and fish, as well as some invertebrates

• dolphin

  • shark

Order of taxonomic terms

1. Domain

2. Kingdom

3. Phylum

4. Class

5. Order

6. Family

7. Genus

8. Species

Binomial Nomenclature

two word - name

Rules for writing proper scientific names

• underlined/italicized

• genus name starts with capital letter

• species name in all lowercase

Pelagic

Open water

Benthic

Sea floor

3 S’s of sand

1. sorted

2. shape

3. size

Sediment size from largest to smallest

coarse sand → medium sand → fine sand → silt → clay

Summer Beach

• low tide allows for berm to build up

• smaller & well sorted sand

Winter Beach

• high tide erodes berm

• deposit larger sediment

Spherical Sediment Grains

• high energy environments

• particles are transported over long distances

Angular Sediment Grains

• low energy environments

• minimal transport

• retaining sharp edges

Abiogenic sand

Formed from non-living sources; minerals, rocks

Biogenetic sand

From living organisms, coral fragments, shells, calcium carbonate

Open Circulatory System

• Blood isn’t always enclosed in vessels

• Blood flows through the body

Closed Circulatory System

• Blood is always contained in vessels

• Blood flows through arteries, veins

Marine chemical that makes up shells of mollusks

Calcium Carbonate (CaCO3)

Bivalve

• clams

• mussels

• scallops

Gastropod

• abalone

• nudibranch

• limpets

Cephalopod

• squids

• octopus

• cuttlefish

Polyplacophora

Chiton

Foot

used for movement, burrowing, or attachment to surfaces

Mantle

Secretes shell and lines the mantle cavity

Mantle Cavity

Houses gills/lungs; for excretion, respiration

Visceral Mass

Most of the internal organs

Endoskeleton

Internal support structure, protects internal organs, attachment for muscles

Exoskeleton

External protective covering, support and protects body

Exoskeletons of bivalves are made of

Calcium carbonate

Exoskeletons of crustaceans are made of

Chitin

Suspension feeders

Filter tiny particles (plankton, organic matter) from water using gills or siphons

Grazers

Scrape surface using radula, algae and biofilm on rocks

Defense mechanisms of cephalopods

• ink release

• jet propulsion

• camouflage

• tentacles and beak

Sessile

satin one place; immobile

• clams, mussels, scallops

Motile

Adapt to almost every marine environment in the world

• snails, slugs, octopus, squid

Ectotherm

Rely on external sources of heat to regulate body temperature (cold blooded)

Endotherm

Generate their own body heat internally; maintain relative constant body temperature

Holothuroidea

Eat: debris in benthic zone

Example: sea cucumber

Unique features: Thick leathery skin, toxins to prevent them from getting eaten

Asteriudea

Eats: Bivalves and barnacles

Example: Sea star

Unique features: Benthic community, keystone species

Echinoidea

Eats: herbivores, algae

Example: sea urchins and sand dollars

Unique Features: ocean acidification threats, found on sandy beaches

Keystone Species

Organisms that play a crucial role in the ecosystem, if sea stars are removed everything could fall apart

Male (jimmy) Crab

Female (sook) Crab

Cycloid scale

• smooth edges

• overlapping pattern

  • salmon

  • carp

Ctnoid Scale

• tiny spines along border

  • perch

Ganoid Scale

• Diamond shaped

  • sturgeon

  • garfish

Placoid Scales

• tiny tooth like structures

• same material as teeth

  • Sharks

  • Rays

  • Skates

    

Bony fish

Have a gill cover; operculum; protects and regulates water flow

Cartilaginous fish

Have exposed gill slits

Bony fish buoyancy

Through their swim bladder, can adjust position in water by regulating amount of gas inside

Cartilaginous fish buoyancy

Fish lack swim bladders; relying on oil-rich liver and skeleton to help with buoyancy

Calico Bass

Garibaldi

Yellowtail/Yellowfin

Dolphinfish/Dorado

Sculpin

California Sheephead

Salmon