Sept 5, 2013
What is ecology?
From Greek “Oikos”- meaning household
Composed fo hierarchy of complex systems
o Subsystems embedded with systems
o Can be as small as a single organism, or as big as the entire biosphere.
Biosphere Ecosystem Community Population Organism
Energy flux and cycling of nutrients
Interactions of population
Unit of evolution
Unit of natural selection
What is Ecology?
Total relationship of organisms to environment and each other (Hackel,
The struggle for existence. (Darwin, 1859).
Study of factors affecting the distribution and abundance of organisms
Scientific study of natural environment and the relationship of organism to
one another and their surroundings (Ricklefs, 2001).
Different view points
There area different ways of looking at the relationships of organisms to
o Some ecologists classify habitats and examine the relationship
Populations of living organisms are constantly evolving and adapting to
o Long slow process of change tracking the global environment
o Complex arms race- predators are evolving ways of tactics, and prey
are evolving better defense.
o Constantly producing new “variants”
o Changing and diversifying organisms which changes “systems” that
they area part and long term change even the global environment
itself Environment influence organisms
Organisms also change their environment
Over millions of years the activities of organisms have profoundly changed
the global environment.
Function connections: Who eats who?
Throughout history of life, plants, animals and microorganisms have evolved
to carry out different and complimentary functions in natural systems
Absorb and process dissolved organic matter
Some eubacteria become autotrophs
Protozoa feed on tiny bacteria and other organic
Algae become “green: