Chordates/fish Flashcards
Fish diversity: # of species # of families % freshwater Temp range
28-32,000 species
445 families
39% freshwater
Temp range -2- +44
4 classes of fish:
Agnatha (jawless)
Placoderms (extinct)
Chondrichthyes (sharks, Rays, chimeras)
Osteichthyes (bony fish)
Agnatha characteristics:
evolution, extinction, physical traits
Evolved 530 MYA during Cambrian Many extinct during the Devonian (370 MYA) Jawless No stomach Cartilaginous skeleton No paired fins 2 chambered heart
Hagfish Characteristics
30-35 species Live in deep water; scavengers Uses slime No scales Marine hagfish are isosmotic Has skull but no vertebral column
Characteristics of lampreys
~ 40 species
Osmoregulatory
Parasitic
Larval stage called ammocoete-undergo metamorphosis; filter feed
As adults, suck blood & fluids w/ keratinization teeth
Characteristics of Placoderms
Evolution, extinction, major innovations
Evolved 440 MYA during Silurian
Extinct 410-350 MYA
Innovations:
- hinged jaw
- paired fins
Characteristics of Chondrichthyes:
Evolution, diversity, physical traits
400 MYA
12 orders, 45 families, 800 species (most are sharks and rays)
Paired fins and hinged jaws
Cartilaginous skeletons; big size
Many use fat for buoyancy (usually in liver)
Osmoregulatory
Stiff fins, ventilation of gills
What does the ampullae of lorenzini do?
Allows sharks/Rays/skates to sense electromagnetic fields emoted by prey
Characteristics of Osteichthyes (bony fish)
415 MYA ~ 25,000 species Lobe finned:rise to tetrapods Teeth fused to jaw bone Fin rays, flexible Mucus for protection & to reduce drag High diversity
Fish body forms:
Give examples for:
A) laterally compressed
B) dorso-centrally compressed
C) Fusiform
D) Ovate/truncated
A) mola, flatfish
B) Rays
C) tuna, sharks
D) tilapia
Fish feeding strategies:
Generalist Specialist Filter feeders Pursuit hunters (biters) (sharks) Suction feeding Slurpers Pickers Grazers (parrot fish) Ambush (eels, flatfish)
Reasons for color patterns
Disruption-stripes, fake eye spots
Camouflage
Advertisement (poisonous)
Countershading (blending with open sea)
Breeding strategies of fish:
Nests (ex. Garibaldi)
Brooding (seahorse)
Broadcasting
Difference between
A) viviparous
B) ovoviviparous
C) oviparous
A) live bearing (like mammals)
B) live birth from eggs inside female
C) birth from eggs outside of female
Characteristics of phylum Chordata
Notochord Dorsal hollow nerve chord Pharyngeal slits Muscular tail Segmented 3 germ layers endoskeleton Well developed coelom Ventral heart
