4 levels of organization 4) ecosystem 2) population 3) community 1) individual

What is a community? Definition: It is a set of populations of different species sharing the same habitat.

What is an ecosystem? Definition: it is a community of living organisms interacting with one another and with the non living components of the environment they inhabit.

TROPHIC - RELATIONSHIPS FOOD CHAIN (trophic network) Definition: the feeding connections among living organisms in an ecosystem.

3) 4) 1) 2) TROPHIC LEVEL : The position of each organism in a food chain. 3) 4) 1) 2)

PRODUCERS Definition: Autotrophic organisms with the ability to create organic matter from inorganic matter in an ecosystem (often photosynthesis).

Two categories of matter Category Description Examples Inorganic Not necessarily produced by living organisms Water, minerals, CO2 Organic Matter that make up living organisms and that is created by them. Proteins, sugars Producers, such as phytoplankton, make their own food. This is why they are called autotrophic organism.

CONSUMERS Definition: Heterotrophic organisms that feed on other living organisms. They are incapable of producing their own food / energy !

Primary (first-order) Consumers These organisms feed on producers (plants) and their seeds. This organisms are herbivores, granivores and frugivores.

Second, Third, Fourth Consumers These organisms feed on primary consumers. They are carnivores such as wolves.

And what about omnivores? These animals are consumers of several orders at once. They may feed on plants, but also on other animals. Bear... Humans...

DECOMPOSERS They are organisms that feed on the waste and remains of other living organism. They feed on detritus (dead organic matter) They break organic matter into inorganic matter!

ECOSYSTEM DYNAMICS The material and energy flow is the exchange of matter and energy between the living organisms in an ecosystem and between those organisms and the environment. Who the !!$#^&$%!! are you?

Antoine Laurent de Lavoisier Law of Conservation of mass! “Nothing is lost, nothing is created; matter is transformed”

In nature, it’s the same !

CHEMICALS ARE RECYCLED! Producers convert inorganic material into organic material all the time. In the same time, decomposers break down organic material (detritus) and produce inorganic material. SEE PAGE 324; figure 10.9 Matter (atoms) and energy continuously pass from one environment to the next!

ENERGY FLOW Sunlight is usually the first source of energy in an ecosystem. Autotrophic organisms transforms it into chemical energy! At each trophic level, some energy is lost!

At the top; often less energy!

For example: proteins, glucose and lipids. The BIOMASS Definition: The total mass of organic matter in an ecosytem at any given time (metric tons). For example: proteins, glucose and lipids.

Primary Productivity Definition: The amount of new biomass generated by it’s producers (via photosynthesis)!

It will depend on growing conditions!

Ecological Succession A series of changes that occur in an ecosystem after a disturbance and that continue until the balance of the ecosystem is restored.

Whether it’s a forest fire or a clear cut, it will take many year before we get a nice old forest!