510 likes | 831 Views
Fishes. Bio II Rupp. Types of Fishes. Jawless Cartilaginous Bony. Fish Characteristics. 4 hallmarks of chordates Sharks Lateral line Ampullae of Lorenzini Operculum. Gills Tail types Scale types Fish musculature Swimming and the swim bladder. Taxonomy. Kingdom Animalia
E N D
Fishes Bio II Rupp
Types of Fishes • Jawless • Cartilaginous • Bony
Fish Characteristics • 4 hallmarks of chordates • Sharks • Lateral line • Ampullae of Lorenzini • Operculum • Gills • Tail types • Scale types • Fish musculature • Swimming and the swim bladder
Taxonomy • Kingdom Animalia • Phylum Chordata • Subphylum Vertebrata
Hagfish Class Myxini
Lampreys Class Cephalospidomorphi
Sharks, skates, and rays Class Chondrichthyes
Ray-finned fishes Class Actinopterygii
Lobe-finned fishes Class Sarcopterygii
Chordate Hallmarks • Notochord • Hagfishes and lampreys keep this their entire lives • Made of thick-walled and fluid-filled cells pressed closely together
Chordate Hallmarks • Dorsal hollow nerve cord • Neural tube formation • Anterior becomes the brain
Chordate Hallmarks • Pharyngeal gill slits/pouches
Fish Definition • For our purposes: • A gill-breathing, poikilothermic (cold-blooded), aquatic vertebrate that possesses fins and a skin that is usually covered in scales • Approximately 25,000 species • Two basic body forms • Agnathans—jawless • Gnathostomes—jawed
Agnathans • Cephalospidomorphi—lampreys—ectoparasites • Myxini—hagfishes—scavengers
SuperclassGnathostomes • Cartilaginous fishes • Class Chondrichthyes—approx. 850 species • Subclass Elasmobranchii—sharks, skates, and rays • Dogfish anatomy
Gnathostome Reproductive Strategies • Internal fertilization • Oviparous—some species lay eggs immediately after fertilization • Ovoviviparous—retain the developing young in the uterus and they are nourished by yolk sacs • Viviparous—young are nourished by a placenta
SuperclassGnathostomes • Bony fishes, aka osteichthyes • Class Actinopterygii—ray-finned fishes • Class Sarcopterygii—lobe-finned fishes
Osteichthyes Adaptations • Operculum • Tail types • Skin and scales • Musculature • Swimming • Swim bladder • Gills
Operculum • A bony plate attached to a series of muscles running over the gills • Aid in more efficient respiration • Bernoulli’s Principle of Fluid Dynamics
Scale Types • Scales are embedded in the dermis and covered by the epidermis • Types • Ganoid • Cycloid • Ctenoid • Placoid
Typical in sharks Placoid scales
Fish Musculature • Myomeres-segments of the muscle • Myospeta—division point of the myomeres • Vertical septum and horizontal septum of body cavity
Fish Musculature • Red muscle or dark muscle is used in regular swimming • Red muscle is dark due to extra myoglobin and extreme vascularization • Red muscle is often referred to as the bloodline • White muscle for escape response
Swimming • Short muscular bodies and lunate tails for most efficient swimming
Swim bladders • Maintain neutral buoyancy and depth control • Balloon-like structure • Pulls gas out of the water to inflate • Two types • Attached to gut—ancient fishes • Detached from gut—more modern fishes • Fish without swim bladders: tuna, flounder, sharks, deep ocean fish • Sharks have a huge fatty liver to maintain neutral buoyancy
Gills • Made of filaments called lamellae • Rich with blood vessels • Covered by operculum or gill slits • Counter current blood flow of blood and water increases efficiency—demonstration • Gill arches are the point of attachment for lamellae • Gill rakers remove debris from gills • Larger gill surface is often correlated with higher fish activity levels