Lecture 3: Intro to Fish Physiology Flashcards
What is the significance of Amphioxus in fish evolution?
Amphioxus is a primitive chordate that provides insights into the early evolution of vertebrates.
What are Thelodonts?
Thelodonts are extinct jawless fish from the Silurian and Devonian periods, characterized by their small scales and flat bodies.
What distinguishes hagfish (Mixinoformes) from other vertebrates?
Lack of true teeth and jaws.
Produce large amounts of mucus/slime.
Have a notochord but no vertebrae.
What are lampreys, and how do they differ from hagfish?
Lampreys have a backbone-like structure and two semicircular canals.
They have two life stages: a larval (filter-feeding) stage and an adult (parasitic or non-feeding) stage.
What is the significance of the origin of jaws in fish evolution?
Jaws allowed fish to exploit new food sources, leading to the evolution of more diverse feeding strategies and body forms.
What are the 6 shared traits (synapomorphies) of cartilaginous fishes (Chondrichthyans)?
Dentition with tooth replacement.
Placoid scales.
Prismatic calcification of cartilage.
Unique fin structure.
Ampullae of Lorenzini (electroreception).
Pelvic claspers in males (used for internal fertilization).
What are placoid scales in cartilaginous fish?
Placoid scales are tooth-like structures that provide protection and reduce drag, inspiring biomimetic technologies (e.g., shark-skin swimsuits).
What is the function of the Ampullae of Lorenzini in cartilaginous fish?
These are electroreceptors that detect electric fields, helping sharks locate prey buried in the substrate.
What reproductive strategies do cartilaginous fish exhibit?
Oviparity: Egg-laying (e.g., skates).
Viviparity: Live birth (e.g., rays and some sharks).
What are the key features of bony fish (Actinopterygii)?
Lepidotrichia: Bilaminar, branching fin rays.
Swim bladder for buoyancy.
Ganoid, cycloid, or ctenoid scales.
What distinguishes rays from skates?
Rays: Live-bearing (viviparous), whip-like tails with stinging spines.
Skates: Egg-laying (oviparous), fleshy tails without spines.
What is unique about sturgeon and paddlefish (Chondrostei)?
They have cartilaginous skeletons despite being bony fish.
Paddlefish use sensory barbels to detect prey.
Sturgeon are valued for their eggs (caviar).
What are the three major groups of cartilaginous fish (Chondrichthyans)?
Sharks (e.g., mackerel sharks, hammerheads).
Rays and skates (batoids).
Chimaeras (ratfish).
Key features of Chimaeras
Unique jaw structure: upper jaw fused to skull
Gill cover
Tooth plates: ever-growing teeth for grinding prey
Venomous dorsal spine
Scaleless skin
Key features of Teleost fishes
Mobile premaxilla bone: provides flexibility for diverse feeding strategies such as suction feeding
Specialized Tail skeleton: for efficient swimming
Swim bladder
Diverse body shapes and habitats
