part 5 – living on land from fish to (terrestrial) tetrapod
TRANSCRIPT
Part 5 – Living on Land
From fish to (terrestrial) tetrapod
“fishes” tetrapods
The Transition
Challenges of terrestrial living
“Fishes” Tetrapods
The players …..
Aquatic tetrapods
† Shallow water, freshwater aquatic tetrapod (lobe-finned fish)
Aquatic tetrapods
Icthyostega
Internal choanae
Internal choanae
Aquatic / terrestrial tetrapods
† Primitive aquatic tetrapods
† Primitive terrestrial tetrapods (on the way to amphibians)
Terrestrial tetrapods
2 terrestrial tetrapod groups
Amniotes (reptile/bird, mammal)
(Lepospondyli)
1.
† Primitive amniotes (pre- reptile/bird, mammal)
(Lepospondyli –
husk vertebrae)
1.
Temnospondyli
2.
Amphibians + (many) extinct things
Temnospondyli2.† Proto-Amphibians
(split vertebrae)
2 terrestrial tetrapod groups
Tetrapods
† aquatic
tetrapods
† semi-terrestrial
tetrapods
† Lepospondyli
Amniotes
† Temnospondyli
Amphibians
Terrestrial tetrapods
lobe-fin fish
†early tetrapods
Lepospondyli
Amnoita
Temnospondyli
Class Amphibia
† various dead ends
† various dead ends
† various dead ends
aquatic
terrestrial
fish
tetrapod
Some time scale
6 billion years
Cenozoic
Mesozoic
Paleozoic
600 million years
Paleozoic
Fish Events
Paleozoic
Tetrapod events (early)
Paleozoic
Tetrapod events (late)
Paleozoic Earth
Paleozoic Earth
Ordovician terrestrial habitats
Devonian terrestrial habitats
Carboniferous terrestrial habitats
Carboniferous millipede tracks
Meganeura
Carboniferous dragonfly
75 cm wingspan
Permian – cooler and drier
Permian Volcanism
Devonian – First tetrapods
Panderichthys
Tiktaalik
Acanthostega
Ichthyostega
Carboniferous – tetrapods diversify and move onto land
Pederpes
Loxomma
Amphibamus
Tuditanus
Permian – it all almost ends
Living on land
Pre-adaptations
Lungs
Limbs
Internal choanae
Pre-adaptations
Support and Movement
Fish
primitive (terrestrial) tetrapod
Terrestrial tetrapods
Vertebral innovations
Vertebral Columnfishes, pre-terrestrial tetrapods
Terrestrial tetrapods
zygapophyses
Early Tetrapods
Terrestrial
Aquatic
Limb Girdles
Fishes
opercular bones present
pectoral girdle skull connected
*
Panderichthys
Lobe-finned Fish
Tiktaalik
Basal tetrapod = “fish-o-pod”
Opercular bones lost
Vantastega
Skull / girdle connection lost
Tetrapods have necks
“fish”
tetrapod
“fish”tetrapod
Pelvic girdle
“Fishes”No connection to vertebral column
Lobefin fish
Primitive tetrapod
no connection
connection
Pelvic girdle
Eryops
Pectoral
Pelvic
Eryops
living amphibian pelvic girdle
Appendicular Skeleton
lobe-fin fish
aquatic tetrapod
Appendicular Skeleton
early terrestrial tetrapod
later terrestrial tetrapod
“fish”
tetrapod
“fish”tetrapod
How many digits?
Physiology and soft anatomy
Switching from gill breathing (with lungs) to lung breathing
“Fish” – gills with lungs
Tetrapod – lungs with gills
Gill breathing – with lungs
Gill breathing – with lungs
Lung breathing
lobe-fin fish
†early tetrapods
Lepospondyli
Amnoita
Temnospondyli
Lissamphibia = Class Amphibia (s.s.)
† various dead ends
† various dead ends
† various dead ends
aquatic
terrestrial
fish
tetrapod