ECOLOGY and ECOSYSTEMS


Ecology is the branch of biology dealing with the relations and interactions between organisms and their environment, including other organisms.

An ecosystem is a system formed by the interaction of a community of oranisms with their environment.  Along with the defnition, there are also many aspects of ecology and ecosystems to discuss.
A limiting factor is anything that prevents the number of organisms in a population.  There are many different limiting factors, such as:

The introduction to foreign species that may destroy a species already there, the number of predators will always affect the population.  If there are too many, there will obviously not be many species, for the predators have killed all the prey.  Another limiting factor is the temperature.  If the climate is very hot, organisms that prefer cooler climates will migrate, and vise versa.  Water is an important limiting factor.  In many places there is a limited amount of water supply.  If that water supply is low, there will not be many organisms living there.  Competition also plays a big part in limting populations.  When there is not a plentiful amount of food in an area, organisms may compete for food and shelter in this area, and the less fortunate must go live somewhere else.  

Another large part of Ecology is the relationships between organisms.  This is called Symbiosis.
There are three types of symbiosis.

Mutualism: Relationship between two species when both benefit.
Example:  Sea Anemones and Clownfish.  The Clownfish is safe from predators inside the Sea Anemone, and in return the Clownfish cleans the it.

Parasitism: Relationship between two species when one benefits and the other is harmed.
Example:  Heartworm in a Dog.  The heartworm lives in the Dog's heart, clogging the main arteries so only a trickle of blood can get through, and eventually the dog will die.

Commensalism: Relationship between two species when one benefits and the other is not affected.
Example:  A barnacle adhering to the skin of a whale.  The barnacle benefits by finding a habitat where nutrients are available, and the whale is not affected.









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