vertebrates jawless fishes to mammals gills to lungs fish – one way circulation amphibians –...
DESCRIPTION
Agantha - LampreyTRANSCRIPT
Vertebrates
Jawless fishes to MammalsGills to LungsFish – one way circulationAmphibians – circulation loopReptiles – partial septum - little mixing of
bloodMammals and Birds – completely divided
Fish
Classes• Agnatha – Jawless fish, evolved about 540
MYA. Ex. Lamprey• Chondrichthyes – cartilaginous fishes. Ex.
Sharks and rays• Osteichthyes – bony fish• Gills for respiration
Agantha - Lamprey
Jaw evolution
Sharks
Fast, powerful predators, Lateral line system – sensory organs
running down the side of the body for detecting vibrations in the water
Chondricthyes
Bony Fish
Hard skeleton with scalesProtective operculum over the gillsSwim bladder for buoyancyRay finned fish – most bony fish like the
tuna, bass, perchLobed finned fish – ancestor to the
amphibians
Osteicthyes
Perch anatomy
Lobed finned fish
Fish circulation
Amphibians
Living a double life – part water/part landGas exchange through diffusionComplete metamorphosisPartially divided heartEx. Salamander, frogs
Amphibians
Amphibian circulation
Reptiles
Watertight skin and eggs Internal fertilization – no water needed Ectothermic Scales made of keratin Lungs Dinosaurs were numerous during the Mesozoic
era By about 65 MYA, the dinosaurs were gone,
with only the birds left. Turtles, crocodiles, lizards and snakes
Reptile Heart
Reptiles
Archaeopteryx
Birds
Class AvesEvolved during the mesozoic eraHoneycombed bones for lighter weightWings for flight, feathers made of keratinEndothermic – warmed by own
metabolismNo teeth, grind food with gizzard
Birds
Mammals
Became diverse after the downfall of the dinosaurs
Hair and mammary glandsEndotermicMonotremes – duck-billed platypus and
echidna, egg-laying mammalsMarsupials – pouched mammalsEutherians – placental mammals
Mammal Heart
Echidna
Marsupials and Eutherian
Evolution of Primates
Evolved in late Cretaceous periodArboreal – tree dwellingLimber shoulder joints allows to brachiate
– swing from limb to limbProsimians – lemurs, tarsiersAnthropoids – Monkeys, humans, apes