All biological systems from cells and organisms to populations, communities and ecosystems are affected by complex biotic and abiotic interactions involving exchange of matter and free energy. http://www.youtube.com/watch?v=rNfmew9C508 Essential knowledge 2.D.1

Biotic – LIVING Abiotic – NOT LIVING Biotic & Abiotic Factors CELLS COMMUNITIES ECOSYSTEMS

Biofilms are an example of how changes in abiotic factors can affect cells Colonies of bacteria that grow due to abiotic factors. They need something to attach to and a liquid flow. Slime layers build around the bacteria colony. Biofilms grow virtually everywhere, in almost any environment where there is a combination of moisture, nutrients, and a surface. Biofilms grow in rain forests and in deserts, as "desert varnish."

Organism activities are affected by interactions with biotic and abiotic factors. • Symbiosis (mutualism, commensalism, parasitism) • Predator–prey relationships • Water and nutrient availability, temperature, salinity, pH

SYMBIOSIS Leafhoppers are protected by ants in a symbiotic relationship. The ants protect the leafhoppers from predators and in return the leafhoppers feeding on plants exude honeydew from their anus that provides energy and nutrients to tending ants.

Predator-Prey Relationships

The stability of populations, communities and ecosystems is affected by interactions with biotic and abiotic factors. KEYSTONE SPECIES

The stability of populations, communities and ecosystems is affected by interactions with biotic and abiotic factors. ALGAL BLOOMS