ecological studies

2. first to record observations on natural history
as a balance and regulation in nature
Basking Nile crocodiles, he noted, would open their mouths to give sandpipers safe access to
pluck leeches out, giving nutrition to the sandpiper and oral hygiene for the crocodile.
Theophrastus made extensive
observations on plant and animal
migrations, biogeography, physiology,
and their behavior, giving an early
analogue to the modern concept of
an ecological niche.
philosophical development of ecology

7.  The term `eco' refers to a part of the world and `system' refers to the co-ordinating units.
 An ecosystem (or ecological system) consists of all the organisms (biotic) and the physical environment (abiotic) which
interact with each other.

21. Ecosystems are controlled by external and internal factors.
External
Factors

22. Internal
Factors