Systems - Otterville R
Systems - Otterville R
A system is a collection of related
parts that interact in some
Materials, energy and information
that enter the system from outside
Materials, energy, and information
that leave are outputs
A system can be:
• made up of many sub-systems
• be part of a larger system.
• E.g. An automobile is a system made up
many smaller systems like the engine
system, brake system and a fuel system.
• Each of these systems are connected to
one or more other systems.
• A change in one system will affect the
This is the area occupied by living organisms.
• In resent years this has expanded with the
finding of life deep underground.
• The biosphere has played a major role in the
shaping of our planet and still has a major
impact on climate, erosion and weather
What is ecology? (oikos = house or place to life; logos = study of
Ecology is the study of the way living things interact with each other
and their physical surroundings. It looks at the ways an organism is
molded by its surroundings, how they make use of these
surroundings, and how the area is altered by the presence and
activities of organisms.
These interactions involve energy and matter, which must flow
through the organism if it is to stay alive.
An organism is any form of life.
Organisms can be classified into species
- groups of organisms that resemble one another in appearance,
behavior, chemistry, and genetic code. They are the same
species if they can reproduce sexually to produce live, fertile
A population consists of all the members of the same species
living in a specific area at the same time.
The place where a population lives is known as its habitat .
Populations of all the different species occupying and
interacting in a particular place make up a community.
An ecosystem is a community of different species interacting with
one another and their no-living environment of matter and energy.
All the Earth’s ecosystems make up what is called the ecosphere or
Climate is the main factor that determines whether a given species
will thrive in an area. Biologists have divided the terrestrial (land)
portion of the biosphere into biomes .
These are large regions with a distinct climate and specific life
forms. E.g. Desert, grassland. Each biome may have many
ecosystems with communities adapted to the changes in soil,
climate and other factors throughout the biome.
The marine and freshwater portions of the biosphere are divided
into aquatic life zones.
Biodiversity is the genetic diversity, species diversity and
ecological diversity that are so important to life on this planet. It is
the result of adaptations that have evolved over billions of years
due to environmental changes in the Earth’s past.
Energy and the Food Chain
• If 10% of the energy
can be transfered
from one trophic
level to the one above
it, each trophic level
must have 10x the
energy as the one
• The number of
depends upon the
Secondary consumer primary carnivore
Usually no more than 5 links in a food chain. Why?
Detritivores, scavengers, and decomposers
Detritivores: consume litter, debris, and dung
clean-up dead carcasses
Decomposers: microorganisms that complete final breakdown of
There is limit to the number of trophic levels
in an ecosystem - maximum 3 or 4 because
of this energy loss - a consequence of the
2nd law of thermodynamics.
For example it takes a large population of
zebras and wildebeests to support a small
population of lions (1000 to 1!!!)
Humans eat steak and hamburger at a great
cost in energy.
•Again, nutrients (the
basic chemical building
blocks of all life) are
recycled in a living
•The key nutrients are
Oxygen, Nitrogen and
constitute 95% of all
Hydrogen and Oxygen (Water) Cycle
Cycles in Nature
• Click the image to play the video segment.