QUESTIONS Marine Biology: Unit 6: Fish

Understand how hagfishes and lampreys differ from all other fishes

Hagfish and lampreys are classified as "jawless fish," meaning they lack jaws and paired appendages. Hagfish also lack vertebrae.

Describe how sharks, skates, and rays are related

They are all part of the cartilaginous fish group, meaning they possess jaws, paired fins, gill slits, and scales. Their skeletons are made of cartilage, making them more flexible.

Differentiate between cartilaginous fishes and bony fishes

Cartilaginous fish have a cartilage skeleton, while bony fish have a bone skeleton, which is denser and stronger. Cartilaginous fish have placoid scales, which are rough and tooth-like, whereas bony fish have cycloid or ctenoid scales, which are smooth or comb-like. Examples of cartilaginous fish include skates, rays, and sharks, while bony fish include salmon, trout, goldfish, and bass.

List and describe the morphological features that make sharks perfectly adapted for their environment

Lateral Line: detects changes in water pressure and vibrations. Ampullae of Lorenzini: detect electrical fields to help navigate and catch prey. Rows of Teeth: tear and grasp prey. Fins: provide stability and maneuverability. Tail: aids in movement, speed, and stability.

Understand how body shape correlates with lifestyle

Streamlined: minimizes water resistance, maximizing speed (e.g., sharks). Laterally Compressed: allows for easy maneuvering in tight spaces (e.g., angelfish, butterflyfish). Depressed: adapted for bottom-dwelling, gliding along the seabed (e.g., skates, rays). Elongated: allows wriggling through narrow spaces (e.g., eels).

Explain three roles coloration plays in bony fishes

Camouflage: blending into surroundings. Territorial: signaling dominance and authority in an area. Prey/Predator Relationship: helping fish either hide from predators or ambush prey.

Explain how fish maintain neutral buoyancy

Fish use a swim bladder, a gas-filled organ that adjusts its volume to maintain buoyancy at a constant depth without expending energy. Sharks lack a swim bladder and rely on a large oil-filled liver to stay afloat.

Explain and understand the various types of fish reproductive strategies

Oviparous: fish lay eggs that develop and hatch outside the mother's body (e.g., skates). Ovoviviparous: eggs develop inside the mother's body and hatch internally (e.g., sharks). Viviparous: fish give birth to live young (e.g., guppy). External Fertilization: eggs are laid, and sperm fertilizes them in the water (e.g., salmon). Internal Fertilization: the male introduces sperm directly into the female (e.g., sharks).

Differentiate between anadromous and catadromous species and give one example of each

Anadromous: born in freshwater, migrate to saltwater, then return to freshwater to spawn (e.g., salmon). Catadromous: born in saltwater, migrate to freshwater, then return to saltwater to spawn (e.g., American eel).

Explain the role of two sensory systems sharks possess

The lateral line detects vibrations and movement in the water, helping sharks locate prey and navigate in dark waters. The Ampullae of Lorenzini detect electrical fields, allowing sharks to sense prey hidden beneath the sand or in murky waters.

The skates and rays have many common body structures, but quite different body plans

Skates: small fins, no spines, fleshier tail, wave-like movement, oviparous, smaller in size. Rays: stinger or spine, ovoviviparous, wing-like flapping movement, venomous barb, larger size. Both: cartilaginous fish, live in similar environments, feed on benthic organisms.

Describe how sharks can eat their prey whole but still manage to digest it. What specific organs do they possess that allow them to do this?

Sharks have blade-like triangular teeth that allow them to swallow their food whole. They possess a spiral valve, a corkscrew-shaped intestinal structure that increases surface area for nutrient absorption, helping them efficiently digest large prey.

The jawfish and seahorse depend on the males to take care of the eggs. What is the advantage of this reproductive strategy?

Since males are the primary caregivers, females can produce more offspring without waiting for the hatching process, increasing reproductive efficiency.

What are some of the advantages of hermaphroditism as a reproductive strategy in fish?

Hermaphroditism increases mating opportunities, particularly in low-population environments. It ensures reproductive success and enhances the chances of reproduction.

What characteristics would you expect to observe in a fish that was adapted to a sedentary life hiding among rocks and coral on a coral reef?

Cryptic coloration for camouflage, small fins for precise movements, strong pectoral fins for stability, and a laterally compressed body for maneuvering in tight spaces.

Several species of marine fish display different colors as juveniles and as adults. What might be the benefit of such an arrangement?

Avoids competition by signaling different social roles, provides camouflage suited for different life stages, deters predation by mimicking toxic species or blending in, and facilitates social signaling in species with complex hierarchies.

Make a table differentiating between the three modes of reproduction: oviparity, ovoviviparity, and viviparity. Provide an example of a fish for each category

Oviparous: eggs develop and hatch outside the mother's body (e.g., skates). Ovoviviparous: eggs develop inside the mother's body but hatch internally (e.g., sharks). Viviparous: fish give birth to live young (e.g., guppy).

Explain the role of hermaphroditism in fishes. Make sure to differentiate between synchronous and sequential. Include an example for each

Hermaphroditism allows fish to possess both male and female reproductive organs, maximizing reproductive success. Synchronous hermaphroditism means fish have both reproductive organs simultaneously (e.g., hamlet fish). Sequential hermaphroditism means fish change sex over time. Protogyny (female to male) occurs in wrasses, while protandry (male to female) occurs in clownfish.