1) Bionomics 2) Ecology 3) Environmental science 4) Palaeoecology 1) Palaeoecology 
Paleoecology (also spelt palaeoecology) uses data from fossils and subfossils to reconstruct the ecosystems of the past. It involves the study of fossil organisms and their associated remains (e.g. shells, teeth, pollen, and seeds), which can be used to interpret their life cycle, living interactions, natural environment, communities, and manner o...
(from the article `Silurian Period`) ...that commonly conformed to ecological zonation. One way in which zonation expresses itself is through bathymetric gradients (changes in light, ...
[n] - the branch of ecology that studies ancient ecology
paleoecology Ecology that deals with fossil organisms.
palaeoecology noun the branch of ecology that studies ancient ecology
The study of the relationships between ancient plants and animals and their environments.