Page 118 - Introduction to Paleobiology and The Fossil Record

PALEOECOLOGY AND PALEOCLIMATES 105

Suspension Herbivore Carnivore Modern
evolutionary
Osteichthyes fauna
Malacostraca Osteichthyes Chondrichthyes
Pelagic Gastropoda Mammalia Mammalia
Reptilia
Mammalia
Cephalopoda
Suspension Deposit Herbivore Carnivore
Gastropoda Cephalopoda
Polyplacophora Malacostraca
Bivalvia Gastropoda
Mobile Monoplacophora Echinoidea
Crinoidea Monoplacophora
Ostracoda Stelleroidea
Echinoidea Cephalopoda
Bivalvia
Articulata
Anthozoa
Attached Cirripedia Suspension Deposit Carnivore
low
Gymnolaemata Bivalvia
Passive
Stenolaemata shallow Echinoidea Bivalvia Bivalvia
Epifauna Gymnolaemata Gastropoda Bivalvia Gastropoda
Polychaeta
Bivalvia
Echinoidea
Polychaeta
active
Attached Stenolaemata Shallow Echinoidea Holothuroidea Malacostraca
Anthozoa
Polychaeta
erect Hexactineluda
Demospongia Polychaeta
Calcarea Infauna Deep
Gastropoda passive Bivalvia
Reclining Bivalvia
Stelleroidea Bivalvia
Anthozoa Deep Polychaeta Bivalvia Polychaeta
active Polychaeta
Malacostraca
(c)
100
soft-part faunas
skeletal faunas
80
mean α
Number of modes of life 60 Phanerozoic trends
40
20

0
Early Late E.M. Late Recent
Ediacaran Cambrian Ordovician Neogene
Geological time
(d)
Figure 4.21 Continued

During the last 600 million years the Earth zones: humid tropical (no winters and average

has oscillated at least five times between ice- temperatures above 18°C), dry subtropical
house and greenhouse conditions, spending (evaporation exceeds precipitation), warm
most of the time in greenhouse climates (Fig. temperate (mild winters), cool temperate
4.23). For much of the Precambrian the Earth (severe winters) and polar (no summers and
probably endured relatively cool climates. temperatures below 10°C). But can these
The Earth is generally divided into fi ve climate zones be recognized through deep time and be