Disruptions v Connections


All living things need to obtain energy. In an ecosystem, some organisms, known as producers, produce their own food to obtain energy. There are also some organisms, known as consumers, that consume other organisms to obtain energy. A final group of organisms, known as decomposers, obtain energy by breaking down dead organisms and waste matter. The energy relationship between organisms in an ecosystem is known as a food web.

All organisms have a role in a food web. The producers make food by transforming energy from the Sun, water, and nutrients into carbohydrates and other molecules. Primary consumers eat producers to obtain energy. In turn, secondary consumers will obtain energy from primary consumers, and tertiary consumers will obtain energy from secondary consumers. Decomposers break down dead organisms into basic nutrients that producers can use to make their food. In this activity, you will determine the roles of different organisms in an aquatic food web and identify the ecological relationships between different organisms.


Natural or human-induced factors that directly or indirectly cause a change in an ecosystem are referred to as "drivers." A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely, by altering one or more direct drivers. Most of the direct drivers of change in ecosystems and biodiversity services currently remain constant or are growing in intensity in most ecosystems. The most important direct drivers of change in ecosystems are habitat change (land use change and physical modification of rivers or water withdrawal from rivers), overexploitation, invasive alien species, pollution, and change to climate patterns.

    Aquatic biomes:

* represent the largest biomes on earth
* 70% of the earth's surface is water
* includes marine (salt water) and freshwater biomes
* temperature variations are slight in aquatic biomes
* also, water is not a limiting factor!
* as a result, aquatic biomes are typically more stable

1) amounts of available oxygen and carbon dioxide

2) temperature

3) light--needed for photosynthesis

    * area with light is called the PHOTIC ZONE

    * area without light is called the APHOTIC ZONE

4) amounts of dissolved minerals

Although most ecosystems are capable of recovering from the impact of some minor disruptions, human activities have sometimes increased the level of such disruptions so as to bring about a more undesirable and longer lasting change in the environment upon which all life depends. Such disruptions will directly affect at least one part of an ecosystem and this in turn may affect other parts.

Environmental damage caused by humans has the potential to ultimately make our ecosystem less suitable for our species. Human activities have upset various natural systems and have had negative affects on the biotic and abiotic environment. Although most ecosystems can recover from minor disruptions, some human activities have caused changes that cannot be reversed.