Biotic and Abiotic Factors

Biotic Factors: Refers to all living components in an ecosystem that can affect populations or organisms.
Abiotic Factors: Non-living elements that influence living organisms in an ecosystem.

Biotic Example:
- The reintroduction of wolves into Yellowstone National Park (1995). This added a living organism to the ecosystem, impacting populations.
Abiotic Example:
- Atmospheric carbon dioxide levels over the last 50 years, contributing to global warming by demonstrating an increase in temperature, which is a non-living factor.

Both biotic and abiotic factors play critical roles in shaping ecosystems, affecting organisms, populations, and interaction dynamics.

Effects at Cellular Level

Definition: Biofilms are communities of bacteria that attach to surfaces and form a protective layer.
Formation Conditions: Required conditions include a surface for attachment and a flow of liquid (abiotic factors).
Characteristics:
- Bacteria that attach create a slime layer mainly composed of polysaccharides.
- This makes treatment with antibiotics ineffective as they do not penetrate the biofilm effectively.
Health Implications: Biofilms can contribute to chronic wounds, sinusitis, and other infections, indicating their impact on health.

Example: The relationship between the snowshoe hare and the Canada lynx.
- Lynx depend solely on the snowshoe hare for food, creating a cyclical population relationship.
- Data from the Hudson Bay Company Pelts study shows how hare populations influence lynx populations and vice versa.
Population Dynamics:
- As the hare population rises, lynx populations increase due to higher food availability. Conversely, when hare numbers decline, lynx populations subsequently decrease.

Case Study: The elimination of wolves from Yellowstone Park.
- Wolves are a keystone species that control elks' population, their removal allowed elk numbers to increase dramatically.
- As elk numbers increased, they overfed on young aspen and willow, leading to a decrease in these plant species and affecting beaver populations.
- Consequential rises in coyote populations were also observed as wolves are natural predators of coyotes.

The reintroduction of wolves has helped restore ecological balance in Yellowstone, demonstrating the complexity of interdependent relationships among species and the environment.

These examples illustrate the intricate connections of biotic and abiotic factors within ecosystems, emphasizing that changes in one area can lead to significant repercussions throughout the ecosystem.