Download Vertebrates

Vertebrates
Jawless fishes to Mammals
Gills to Lungs
Fish – one way circulation
Amphibians – circulation loop
Reptiles – partial septum - little mixing of
blood
Mammals 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 scales
Protective operculum over the gills
Swim bladder for buoyancy
Ray finned fish – most bony fish like the
tuna, bass, perch
Lobed finned fish – ancestor to the
amphibians
Osteicthyes
Perch anatomy
Lobed finned fish
Fish circulation
Fish Circulation
Fish
 One way
 Gills – body – heart
 http://www.hhmi.org/bioint
eractive/circulatorium/fra
mes.html
Diagram
Amphibians
Living a double life – part water/part land
Gas exchange through diffusion
Complete metamorphosis
Partially divided heart
Ex. Salamander, frogs
Amphibians
Amphibian circulation
Amphibian Circulation
 Loop
 Septum separates
atria into right and left
halves
 Ventricle pumps blood
from the heart
 Deoxygenated blood
enters
The right atrium then to
lungs
http://www.hhmi.org/biointer
active/circulatorium/frame
s.html
 Diagram
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
Reptile Circulation
 Septum extends into
the ventricle
 Blood going to the
body is more
oxygenated than
amphibians
 Ectothermic – cannot
maintain body temp.
through metabolism.
Must get heat from
external source
Reptiles
Archaeopteryx
Birds
Class Aves
Evolved during the mesozoic era
Honeycombed bones for lighter weight
Wings for flight, feathers made of keratin
Endothermic – warmed by own
metabolism
No teeth, grind food with gizzard
Birds
Mammals
Became diverse after the downfall of the
dinosaurs
Hair and mammary glands
Endotermic
Monotremes – duck-billed platypus and
echidna, egg-laying mammals
Marsupials – pouched mammals
Eutherians – placental mammals
Mammal Heart
Bird and Mammal Circulation
 4 chambered heart
 No mixing of blood
 Birds have multiple
airs sacs for the most
oxygen available to
the lungs.
 Mammals have less
oxygen per unit blood
Capillary beds
of lungs where
gas exchange
occurs
Pulmonary Circuit
Pulmonary
arteries
Pulmonary
veins
Aorta and
branches
Venae
cavae
Left
atrium
Left
ventricle
Right
atrium
Heart
Right
ventricle
Systemic Circuit
KEY:
Oxygen-rich,
CO2-poor blood
Oxygen-poor,
CO2-rich blood
Capillary
beds of all
body tissues
where gas
exchange
occurs
Figure 11.4
Echidna
Marsupials and Eutherian
Phylogenic Tree
Cladograms