1. 1.2 Ecosystems
Ecosystem – a part of a biome where abiotic factors interact with biotic components
Can be many hectares of land, or the size of an old log.
Within an ecosystem, there are many habitats.
The habitat of the red fox often includes the edges of forests or marshlands

2. Abiotic Interactions in Ecosystems
It is the abiotic components that allow the biotic components to survive in an ecosystem.
Abiotic factors include :
Oxygen - produced by green plants & micro-organisms.
Water - necessary for all life.
Nutrients - for growth.
Light - required for photosynthesis.
Soil - contains water &
nutrients.

3. Species can have many types of relationships in a population:
Symbiosis refers to the interaction between the members of two different species.
Commensalism - one species benefits, one is not affected
For example, the barnacles on a whale
Mutualism - both species benefit
For example, a bee gathering nectar from a flower
Parasitism - one species benefits, the other is harmed
For example, hookworm living in dogs

4. Biotic Interactions in Ecosystems
Community: all organisms that interact within an ecosystem.
Population: all members of a certain species within an ecosystem.
Species: all organisms within an ecosystem that have the same structure & who can reproduce with each other (and produce fertile offspring).

5. Niches, Competition and Predation
Niche: the role an organism has within an ecosystem.
also refers to the environment in which a species prospers
Competition: occurs when a limited resource is desired by 2
or more individuals in a niche.
this limits the size & health of individual
organisms, & perhaps the population .
“No two species can occupy the same niche at the same time”
Predation: the relationship between the “eaters” & the “eaten”.
Predators have adaptations to help them catch prey.
Prey have adaptations to help avoid predators.
Eg. spines & shells, camouflage and mimicry.

6. Biodiversity in Ecosystems
Biodiversity: the variety & number of different individuals & species in an ecosystem.
Healthy ecosystems generally have high biodiversity.
Most biodiversity losses occur from the loss of habitat.
Humans often have a negative
impact on biodiversity.
Ecological management
programs try to balance
human progress with
maintaining biodiversity.
Take the Section 1.2 Quiz