Marine Biology Notes
Marine Biology Review
Fish
- Ectothermic: Cold-blooded, body temperature depends on the environment.
- Endothermic: Warm-blooded, regulates internal temperature.
- Cartilaginous: Made of cartilage (e.g., sharks, rays).
- Electroreception: Detecting electrical fields (e.g., sharks).
- Chemoreception: Detecting chemicals (e.g., smell/taste).
- Mechanoreception: Sensing mechanical changes (e.g., vibrations).
- Pressure Detection: Sensing depth and water pressure.
- Photoreception: Sensing light (vision).
- Dermal Denticles: Tooth-like skin of sharks/rays.
- Spiracles: Openings behind eyes for water intake.
- Gill Slits: Openings for respiration in cartilaginous fish.
- Fins: Structures for balance, direction, movement.
- Concurrent Flow: Water and blood flow in opposite directions for gas exchange.
- Lateral Line: Detects vibrations/movement in water.
- Swim Bladder: Buoyancy organ in bony fish.
- External Fertilization: Eggs/sperm released into water.
- Spawning: Releasing eggs/sperm for reproduction.
- Oviparous: Lays eggs outside the body.
- Ovoviviparous: Eggs hatch inside the body.
- Viviparous: Gives live birth.
- Oviphagous: Embryos eat other eggs in the womb.
- Ray-Finned: Thin, web-like fins (most fish).
- Lobe-Finned: Fleshy, jointed fins (e.g., coelacanth).
Key Evolutionary Separations and Fish Characteristics
- Fish are the earliest vertebrates.
- Possess gills and fins.
- Lack limbs with digits, which distinguishes them from amphibians, reptiles, mammals, and birds.
- Many fish are ectothermic.
- Breathe through gills.
- Typically have scales and fins.
- Reproduce via external fertilization.
Fish Classes
- Agnatha: Jawless fish (e.g., lampreys, hagfish).
- Chondrichthyes: Cartilaginous fish (e.g., sharks, rays).
- Osteichthyes: Bony fish (e.g., tuna, salmon).
Agnatha Characteristics
- No jaws, round mouths, and cartilage skeletons.
- Examples include lampreys (parasitic) and hagfish (produce slime).
Chondrichthyes Characteristics
- Skeleton made of cartilage.
- Lack a swim bladder.
- Possess dermal denticles.
- Exhibit internal fertilization.
Shark Characteristics
- Cartilaginous skeleton.
- Replaceable teeth.
- Powerful swimmers with keen senses.
- Internal reproduction.
Shark Senses
- Lateral line: Detects vibration.
- Ampullae of Lorenzini: Detect electrical fields.
- Nostrils: Detect chemicals.
- Eyes: Detect light and movement.
Sharks and Their Teeth