marine science chapter 8

Agnatha are what type of fish?

Jawless fish

Examples of Agnatha

Hagfish and lampreys

Key traits of Agnatha

No jaws; no paired fins; no scales; long cylindrical body; feed by suction

Where do hagfish live?

Exclusively marine (saltwater)

What do hagfish eat?

Dead and dying fish and marine mammals

How do hagfish protect themselves?

Produce large amounts of mucus

Where do lampreys live?

Freshwater and saltwater

How do lampreys feed?

Rasp into sides of fish with sucker mouth; consume blood and tissue

What are Chondrichthyes?

Cartilaginous fish (sharks, skates, rays, ratfish)

What is the skeleton of Chondrichthyes made of?

Cartilage

How many gill slits do sharks have?

5 to7 on each side

Name the 5 types of shark fins

Dorsal; pectoral; pelvic; caudal; anal

What is the first fin on the ventral surface of a shark?

Pelvic fin

How do sharks replace teeth?

Teeth move forward from rows behind like a conveyor belt

What kind of feeders are whale sharks?

Filter feeders (eat plankton)

What do sharks lack that bony fish have?

Swim bladder

What type of scales do sharks have?

Placoid scales (rough, triangular)

What type of tail do sharks have?

Heterocercal (unequal lobes)

What are claspers?

Male reproductive structures (extensions of pelvic fins)

Define vivipary

Live birth; embryo connected by placenta and umbilical cord

Define ovipary

Lays eggs (mermaid’s purse)

Define ovovivipary

Eggs hatch inside body then live birth

Why can’t sharks swim backward?

Their fins lack flexibility

What are Osteichthyes?

Bony fish

Examples of Osteichthyes

Rayfinned and lobefinned fishes

Mouth position in bony fish

Terminal (front of face)

What covers the gills of bony fish?

Operculum

Scale type in bony fish

Cycloid or ctenoid (smooth/transparent)

Tail type in bony fish

Homocercal (equal lobes)

What do many bony fish have for buoyancy?

Swim bladder

Purpose of streamlined body shape

Fast swimming (tuna)

Purpose of laterally compressed body shape

Quick bursts of speed (dory)

Purpose of dorsoventrally flattened body shape

Living on the bottom (rays)

Purpose of elongated body shape

Moving through narrow spaces (eels)

Purpose of irregular body shape

Camouflage (porcupinefish)

What do fish obtain from water?

Oxygen

What do fish release through gills?

Carbon dioxide

What is the lateral line?

System of pores/canals with neuromasts that detect vibrations

Why do fish school?

Protection and hydrodynamic efficiency

What is warning coloration?

Colors that show a fish is poisonous or dangerous

What is cryptic coloration?

Camouflage

What is disruptive coloration?

Patterns that break up the outline of a fish

Fish that eat seaweeds and plants are called what?

Grazers

What is an anadromous fish?

Lives in saltwater; spawns in freshwater

What is a catadromous fish?

Lives in freshwater; spawns in saltwater

What is sequential hermaphroditism?

Sex reversal over time (e.g., uhu)

What type of fertilization is copulation?

Internal fertilization

What type of fertilization is broadcast spawning?

External fertilization

Where do broadcast‑spawned eggs drift?

In currents as part of plankton

How do broadcast spawners increase survival?

Release many eggs

Describe seahorse reproduction

Female deposits eggs in male’s pouch; male becomes pregnant and gives birth