Interactions within an Ecosystem

Unit 1, Topic 1

What is ecology?

Ecology – the study of the relationship between living organisms and their environment

Ecologist – some who studies ecology

The Needs of Living Things

• Food• Habitat• Water• Exchange gases

Adaptations

An adaptation is an inherited characteristic that helps and organism survive and reproduce in its environment.

If an organism is said to be adapted it means that it is well suited.

Ecosystems

An ecosystem is the interaction between living and non-living things in a particular environment.

Interactions in Ecosystems

Symbiosis – occurs when two species live closely together in a relationship that lasts over time.

There are three types of symbiosis:

Mutualism

• a relationship between two different organisms, in which each partner benefits from the relationship.

• Example: Ants and aphids – the ants protect the aphids from predators, and in return they drink the sweet liquid that aphids excrete.

Parasitism

• A symbiotic relationship in which one organism benefits and the other organism is harmed.

• Parasite: the organism that meets its needs at the expense of the other organism

• Host: the organism that is harmed by the parasite

Example: Tapeworms and humans• The tapeworms can grow to 10m

long and live in the intestines of humans. They benefit by absorbing the nutrients from the human’s food and the human is harmed because it does not get the nutrients from the food it eats.

Commensalism

• A symbiotic relationship in which one partner benefits and the other partner appears neither to lose nor to gain from the relationship.

• Example: shark and remora – remoras attach themselves to a shark and benefit from the food droppings of the shark. The shark is not harmed, nor does it benefit.

Impacts on Ecosystems

• Some animals have a greater impact on their environment. Beavers cut down trees to make dams that actually change the flow of rivers and therefore affect where fish and other organisms can live.