Chapter 5 - Ecosystems

Producers - Primary Consumers - Secondary Consumers - Decomposers

Organisms (usually plants) that convert some of the suns energy into stored chemical energy.

Herbivores. They obtain energy by consuming producers.

Carnivores. The obtain energy by consuming primary consumers.

Organisms that obtain energy by breaking down dead organisms from the three other levels.

Top - Secondary Consumers Middle - Primary Consumers Bottom - Producers

Only a small amount of energy is passed on to the next level. E.g. in a leaf, not all the suns energy makes it into the leaf. Remaining energy will be lost in many ways (heat) energy that is left over becomes available to the next feeding level when the plant is eaten.

A feeding hierarchy in which organisms in an ecosystem are grouped into trophic (nutritional) levels and are shown in a succession to represent the flow of food energy and the feeding relationships between them.

• Plant - Producer • Insect - Herbivore/ Primary consumer • Mouse - Omnivore/ Secondary Consumer • Hawk - Carnivore/ Tertiary Consumer

The best way to model a feeding relationship. More elaborate that single unbranched chains.

The maximum number of organisms that a particular environment can support over time.

Population size grows very slowly, and organisms mature and adapt to the environment.

With plentiful food, the population will grow quickly.

When the population size outgrows the amount of available food, growth will begin to plateau.

Food Available Births Deaths Number Coming In Number Moving Elsewhere Competition

A relationship in which one organisms feeds on another.

Interaction between two different organisms living in close physical association.

Parasitism Mutualism Commensalism

Relationship in which one organism (parasite) benefits whilst the other (host) is harmed. Example - Tapeworm living in the intestines of a cat. Tick living on a dog.

Relationship in which both species benefit. Example - Ants living in and protecting an acacia tree. Clown fish living among sea anemones.

Relationship in which one species benefits and the other is neither harmed nor benefited. Example - Hermit crabs using gastropod shells for shelter. Spiders building webs on plants.

Flooding Habitat Destruction Desertification Invasive Species

An overflow of water covers land not normally covered in water. Ecosystems of water based habitats are also impacted by runoff containing sediments and pollutants.

Natural habitat is displaced or destroyed and is not able to support the species present. Human activity such as urban sprawl, mining, drilling, logging and deforestation for farmland are the principle causes.