Understanding Fossils: An Introduction to Invertebrate Palaeontology
Peter Doyle, Florence M. Lowry
Language: English
Pages: 423
ISBN: 2:00318053
Format: PDF / Kindle (mobi) / ePub
The first introductory palaeontology text which demonstrates the importance of selected fossil groups in geological and biological studies, particularly in understanding evolutionary patterns, palaeoenvironmental analysis, and stratigraphy. Part one explores several key concepts, such as the processes of fossil preservation, the determination of evolutionary patterns, and use of fossils and statigraphical tools. Part two introduces the main fossil groups of value in these applied fields. Part three concentrates on the examination of important case histories which demonstrate the use of fossils in diverse practical examples. Evolutionary studies, palaeoenvironmental analysis, and stratigraphical applications are documented using up-to-date examples supported by overviews of the principles.
from controlled experiments on populations. The route by which genetic information is passed from one generation to the next is sufficiently complex to allow a number of points where errors can develop. For example, the duplication process by which RNA is derived from DNA is complex and often imperfect. The recombination of chromosomes is also frequently inaccurate. The important point to remember is that mutations are without direction. In that sense they are random, even if certain patterns can
shelf areas. Conversely, a fall in sea level may increase the competition for ecospace among marine organisms, and therefore lead to species extinction. Another hypothesis is climatic change. The Earth's climate has fluctuated between 'ice-house' and 'greenhouse' states through geological time. Climate, especially temperature, is an important limiting factor on organisms today. It is possible to identify extinctions that are probably climate controlled, such as the extinction of large mammals in
are cap-like. Gastropod shells have a single chamber and no internal dividing walls, and are therefore readily distinguished from the other coiled molluscs, the cephalopods, which have chambers designed to aid in flotation (Chapter 9). All snails are capable of movement upon their muscular foot through muscular contractions. Together with their well-developed heads, the foot can be completely retracted within the shell, and the opening or aperture can be closed off by an organic or calcareous lid
record. The processes that follow death, however, govern the potential for the subsequent incorporation of the organism into the fossil record. 2.2.2 Effects on the Dead Organism before Burial The death of the organism leads to an immediate commencement of the breakdown and decay of the body parts. This break-down is arrested through the process of rapid burial, or through otherwise excluding the supply of oxygen. Rate of burial is the biggest single factor in determining the preservation of a
range, biozones have been erected for the Jurassic alone. This is complicated by the geographical restriction of some groups in the late Jurassic, but still remains one of the best and mostly highly developed biozonation schemes for any part of the stratigraphical column. This is discussed futher in Chapter 23. Belemnites also have potential, but are not widely used as they are less diverse and poorly known. 9.5 SUGGESTED READING Detailed taxonomic studies of the cephalopods can be found in the