Ray Finned Fish & Chondrichthyes Quiz

Class Agnatha

• Includes jawless organisms: lampreys and hagfish.

Class Chondrichthyes

• Comprises jawed fish: sharks, skates, and rays.
• Characteristics: lack swim bladder, possess a cartilaginous skeleton.

Phylum Chordata

• Key features:
  • Notochord develops into the vertebral column.
  • Nerve chord forms the brain and spinal cord before birth.
  • Pharyngeal slits present.
  • Postanal tail exists.

Bony Fish Characteristics

• Possess a swim bladder for buoyancy.
• Have bony scales covering their bodies.
• Maintain neutral buoyancy naturally.
• Reproduction primarily external and sexual.

Body Shapes of Fish

• Fusiform: typical streamlined shape.
• Depressiform: flattened structure.
• Globular: round morphology.

Mouth Position Types

• Superior: used for top feeding (e.g., surface feeders).
• Terminal: suited for predatory behavior (e.g., hunting).
• Inferior: designed for bottom feeding (e.g., scavenging).

Types of Fish Scales

• Ganoid: thick and heavy scales.
• Ctenoid: lighter, provides flexibility.
• Cycloid: similar to ctenoid, light and flexible.

Reproductive Terms

• Dioecious: refers to separate sexes in a species.
• Synchronous fish: functional gonads of both sexes present simultaneously.
• Sequential fish: ability to change sex over time (e.g., snook).

Osmoregulation

• Mechanism fish use to maintain solute balance in their bodies.

Reproductive Forms

• Oviparity: common reproductive method involving external fertilization (eggs and sperm).
• Hermaphroditic examples:
  • Protogyny: female to male transition (e.g., wrasses).
  • Protandry: male to female transition (e.g., anemonefish).

Scales of Sharks and Rays

• Denticles: small, backward-pointing scales providing texture.

Water Control in Sharks

• Sharks store urea to help manage water loss in saline environments.

Prey Detection

• Sharks have lateral lines and sensory pores to sense prey in their surroundings.

Reproductive Strategy in Sharks

• Ovoviviparous: eggs hatch internally, leading to live births.

Dogfish Shark Reproduction

• Follows ovoviviparous method with yolk sac nourishment during gestation, leading to live births.

Energy Efficiency in Sharks/Rays

• Use of backward-pointing scales to trap water, minimizing friction.
• Maintaining saltwater balance as elasmobranchs.
• Storing urea and other chemicals for buoyancy.
• Efficient dental structure aids predation.

Key Differences: Sharks vs. Bony Fish

• Sharks lack swim bladders; bony fish possess oily swim bladders.
• Sharks have cartilaginous skeletons; bony fish have bony skeletons.
• Sharks control water levels using urea; bony fish use different mechanisms.

Shark Organ Functions

• Liver: contains oil, aiding buoyancy by reducing body density.
• Spiral valve: increases intestinal surface area for enhanced nutrient absorption.