Download 1.2 Ecosystems - Sardis Secondary

1.2 Ecosystems
• Ecosystem – a part of a biome in which abiotic (non-living)
factors interact with biotic (living) 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
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 & microorganisms.
• Water - necessary for all life.
• Nutrients - for growth.
• Light - required for
photosynthesis.
• Soil - contains water &
nutrients.
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).
• 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
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 .
• 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.
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