9.3 Environments Through Time
Contextual Outline
There is little direct evidence about the inception of life but from the
available evidence, much of which has been gained from Australian rocks,
geologists have been able to piece together an increasingly detailed description
of the emergence of life. With the descriptions of fossil plants and animals,
people can visualise the world as it was.
Palaeoecologists are able to describe past climates by the chemical and
physical evidence from that time. When the information from the geological
record about plants, animals, landforms and climates is combined, it is possible
to describe past environments.
The geological record provides evidence of periods of mass extinction often
followed by periods when life forms have proliferated explosively. Some modern
theories that attempt to explain the mass extinctions evident in the fossil
record follow a neo-catastrophist model and evidence to support this model will
be examined. This module allows the relationship between habitat alteration and
the impact on life forms to be assessed and considers how much change leads to
mass extinctions. Rapid adaptations and radiations of new species are a
consequence of mass extinction events and the reasons for these will be
considered.
When scientists are able to relate past changes in life forms to changing
environmental conditions, they are then able to better predict the potential
impact of human assisted environmental change and habitat destruction on modern
life forms. When this is achieved, they may be better able to prevent more
species from becoming endangered or extinct.
This module increases the students’ understanding of the historical
background, the nature and practice, and the implications for society and the
environment of Earth and Environmental Science.