The fishes Flashcards
(32 cards)
What are the classes of the fishes
Myxini and petromyzondita - jawless fishes
Chondricthyes - cartilaginous fishes
Sarcopterygii - lobe-finned fishes
Actinopterygii - Ray finned fishes
Describe class Myxini (hagfishes)
No scales or jaws
Fibrous and cartilaginous skeleton
Notochord- no vertebrate
Slime glands is the defining feature- used for defense
What is the circulatory system of class myxini?
Low pressure, single circuit, 3 accessory hearts and a main one
What are some characteristics of class pteromyzondita
No scales, jaws or appendages
no stomach, spiral folds in intestine
Single circulatory system - 1 heart
What mouth do hagfish have?
Sucker mouth with rows of epidermal ‘teeth’ for attachment
Salivary glands that secrete anticoagulant
What were the 2 main important events in vertebrate evolution?
Evolution of jaws
-Better gill ventilation
-Greater variety of food sources
Evolution of paired appendages
-counteract roll in locomotion
-controls tilt and lateral motion
What is unique about class chondricythes?
Cartilaginous fishes
Cartilaginous endoskeleton - no bony skeleton
Biting mouthparts
Paired appendages
sense organs and swimming musculature
What are the 2 subclasses of chondrichthyes?
Elasmobranchii
Holocephali
What are the members of subclass Elasmobranchii?
Sharks, skates and rays
Define heterocercal tail
A tail that provides lift and thrust, upper lobe extends over the lower lobe
Define the lateral line system
Senses disturbances and vibrations in water
Made of neuromast cells in a lateral line canal
Define Ampullae of lorenzini
Sensory structures used to detect weak electrical fields, found in sharks
Explain shark digestion features
J shaped stomach
Straight intestine with a spiral valve that increases surface area
Define Oviparous
Eggs reliant on yolk, develop outside female
Define viviparous
Embryo reliant on mother via placenta, lives inside
Define Ovoviviparous
Embryo develop inside mother, but reliant on yolk sac for nutrition
How are rays and skates specialized?
For life on ocean floor
Blunt teeth
Camouflage
Weaponized tail
Summarize subclass holocephali
Chimaeras
Large head
plate like teeth, no scales
Operculum (gill cover)
Summarize class sarcopterygii
Lobe-finned fishes
Early ancestor of tetrapods
What are some unique features of lungfish?
Lungs
Burrows and secretes a mucous cocoon - aestivation
What are some unique features of coelcanths?
Large
Heavy scales
Summarize class actinopterygii
Ray finned fishes
teleost and non teleost
What 4 features are important to fish success?
Locomotion
Respiratory system
Sensory systems
Efficient reproduction
What are mechanisms some fish use to reduce friction in locomotion?
Streamlined shape
Mucoid secretions
