an emergent
website design
by
peter jay stein, md, ma
atmosphere
asthenosphere
lithosphere
regolith
biosphere
hydrosphere
This 54 page synopsis of the evolution
of the Earth, the origin and progression of life, and the
emergence of humans as descendants of the hominin lineage, divides the last 4.57 billion years into progressively overlapping, imagistic, time segments, to outline our place in biological existence.
magnetosphere
ionosphere
TWENTY-ONE
Emergent Reptiles
their divergence and the appearance of
mammals
adapted from Biology, 2015, 10th Edition, pp. 688-697.
(class) jawed fishes
(class) cartilagenous fishes
(class) bony fishes
lobe-finned fishes
(superclass) tetrapods
(class) reptiles
tiktaalik - transitional - 375 mya
(class) amphibians
(clade) amniotes
(subclass)
DIAPSIDS
(subclass)
SYNAPSIDS
skull temporal bone openings
double pair
single pair
ANAPSIDS
(order) testudines:
turtles, tortoises
temporal bone openings
lost
(superorder) lepidosaurs
(order) squamates:
snakes, lizards
(superorder) ichthyosaurs:
mesozoic marine reptiles
(superorder) archosaurs
(order) crocodilia
pterosauria (extinct):
mesozoic flying reptiles
saurischia (extinct)
mesozoic dinosaurs:
tyrannosaurus rex
ornithischia (extinct)
mesozoic dinosaurs:
triceratops
BIRDS
THERAPSIDS:
e.g., lycaenops,
a small predator during the late Permian period
(extinct)
MAMMALS
hair, mammary glands, endothermy
monotremes
(prototheria)
egg-laying.
platypus
marsupials
(metatheria)
pouch.
kangaroo
eutheria
well-developed placenta
vivipary
(class) jawless fishes