Geology Reference
In-Depth Information
TABLE 22.4
Mesozoic Biologic Events
Geologic
Period
Invertebrates
Vertebrates
Plants
Climate
66
Extinction of ammonites,
rudists, and most
planktonic foraminifera
at end of Cretaceous
Extinctions of dinosaurs,
flying reptiles, marine
reptiles, and some marine
invertebrates
Angiosperms evolve
and diversify rapidly
Climate becomes more
seasonal and cooler at
end of Cretaceous
Seedless plants and
gymnosperms still
common but less
varied and abundant
North-south zonation of
climates more marked
but remains equable
Continued diversification
of ammonites and
belemnoids
Placental and marsupial
mammals diverge
Cretaceous
Rudists become major
reef builders
146
Ammonites and
belemnoid cephalopods
increase in diversity
Much like Triassic
First birds (may have
evolved in Late Triassic)
Seedless vascular plants
and gymnosperms only
Jurassic
Ferns with living relatives
restricted to tropics live
at high latitudes, indicat-
ing mild climates
Scleractinian coral
reefs common
Time of giant sauropod
dinosaurs
Appearance of rudist
bivalves
200
The seas are repopu-
lated by invertebrates
that survived the
Permian extinction
event
Mammals evolve from
cynodonts
Warm-temperate to
tropical
Cynodonts become extinct
Ancestral archosaur gives rise
to dinosaurs
Land flora of seedless
vascular plants and
gymnosperms as in
Late Paleozoic
Mild temperatures extend
to high latitudes; polar
regions may have been
temperate
Triassic
Bivalves and echinoids
expand into the infaunal
niche
Flying reptiles and marine
reptiles evolve
Local areas of aridity
251
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