Page 92 - Introduction to Paleobiology and The Fossil Record

Chapter 4

Paleoecology and paleoclimates

Key points

• Fossil organisms provide fundamental evidence of evolution; they also allow the recon-
struction of ancient animal and plant communities.
• Paleoecologists study the functions of single fossil organisms (paleoautecology) or the
composition and structure of fossil communities (paleosynecology).
• The paleoecology of fossil organisms can be described in terms of their life strategies
and trophic modes together with their habitats; virtually all fossil organisms interacted
with other fossil organisms and their surrounding environment.
• Populations and paleocommunities may be analyzed with a range of statistical
techniques.
• Evolutionary paleoecology charts the changing structure and composition of paleocom-
munities through time.
• There have been marked changes in the number and membership of Bambachian mega-
guilds (groups of organisms with similar adaptive strategies), the depth and height of
tiering, the intensity of predation, and the composition of shell concentrations through
time.
• Ecological events can be classifi ed and ranked in importance; they can be decoupled in
signifi cance from biodiversifi cation events.
• Paleoclimates can be described on the basis of climatically-sensitive biotas and sediments
together with stable isotopes.
• Climate has been an important factor in driving evolutionary change at a number of
different levels.
• Feedback loops between organisms and their environments indicate that the Gaia
hypothesis is a useful model for some of geological time.

I do not know what I may appear to the world, but to myself I seem to have been only
a boy playing on the sea-shore, and diverting myself in now and then fi nding a smoother
pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered
before me.
Sir Isaac Newton (shortly before his death in 1727)