Marine Vertebrates Flashcards
What is a notochord?
A simple supporting rod with nerves running down it
What is a hag fish?
An Agnatha with a rudimentary skull, no vertebrae and no jaws (rasping disk around the mouth)
What are Lamprey?
They are simple cartilaginous vertebrae
They have lots of strength and flexibility
What is the evolution of jaws?
Gill arches - supported by boney rods
Bones adapted to jaws 430 Ma
Ross fold over to create the jaws
What are Gnathostoma?
Chondrichthyes
Cartilaginous fish - sharks, rays and Chimaeras
Flexible powerful swimmers
What are the features of sharks?
No swim bladder Oily liver provides limited buoyancy Propelled using powerful caudal tail Pectoral fins provide lift Actively pump water over their gills when resting Sensitive to chemicals and em fields Jelly filled pits at the front of the head that can detect minute changes in voltage Viviparous - live young
What are Gnathostoma?
Osteichthyes
Bony fish
2 types
Lobe finned
Ray finned
What are the features of bony fish?
Ossified bony endoskeleton
Gills protected by operculum
Swim bladder
What is a swim bladder?
Gas is secreted into the swim bladder to control buoyancy
What are the types of Ray finned fish?
Salmonidae
Sconbridae
Gadidae
Syngnathidae
What are Salmonidae?
Trout and salmon
What are Scombridae?
Mackerel and tuna
What are Gadidae?
Cod and Haddock
What are Synganthidae?
Seahorses and pipefish
What are the features of lobe finned fish?
Fins contain rod shaped bones and thick muscle
Fins used to walk along the seabed
Shallow swampy environments
What is a coelacanth?
A living fossil - thought to have been extinct 75 Ma but actually still alive
What is the evolution of limbs?
Tetrapods limbs evolved from lobe fins
Swim bladders evolved from lungs
How did tetrapods evolve from lung fish?
Retained gills
Use lungs to absorb extra oxygen from the air
‘Walked’ in shallow swamps
First ancestor of reptiles, amphibians and mammals
What are Chelonia?
Turtles Ectothermic Shell formed by vertebrae ribs and dermal ossification of the skin Migrate huge distances Eat jelly fish
What are Squamata?
95% of living reptiles Sea snakes - very venomous Marine iguanas Forgage in the sea Return to land to warm up - ectothermic
What are crocodilia?
Last dinosaur survivors
Confined to tropics and sub tropics
Features of birds
Warm blooded - maintain high metabolic activity Feathers adapted from scales Occupy every terrestrial habitat Modified lightweight bones No bladder
What are the features of marine birds?
They have specialised glands to to excrete salt
Sensitive sense of smell for fish oils
