Ecosystems

- Abiotic factors ( physical and chemical factors )

- Biotic factors ( related to living organisms )

Abiotic factors

- Light intensity : →Higher light intensity typically results in faster plant growth

→Vital for activities of living organisms (e.g. vision)

- Temperature : →Most organisms can survive within only a narrow range of temperatures

→Chemical reactions occurring in their cells require specific temperatures to occur at a fast enough rate to support life

- Water Availability : →Plays major role in the normal functioning of cells
→Medium for chemical reactions to take place

→Raw material for photosynthesis
→Exerts turgor pressure in plant cells, providing structural support to plant tissues

- pH : →Organisms living in aquatic habitats are adapted to a narrow range of pH
→If water is too acidic or alkaline for organism, their cells or body structures could be damaged

- Salinity : →Concentration of salts (dissolved) in water, such as water in rivers
→The higher the salinity, the lower the water potential of water and vice versa

- Dissolved oxygen content : →Oxygen content must be sufficient for organisms to respire aerobically to release energy

Biotic factors
- Organisms have adaptations that enable them to survive in their habitat
- They can be structural adaptations or behavioral adaptations

Ecology
- Ecology is the study of interactions between organisms and their surrounding environment

- Habitat → refers to a place where the organism lives
- Population → refers to a group of organisms of the same species living in a particular habitat
- Community → refers to all the populations of the different organisms living and interacting with one another in a habitat
- Ecosystems → refers to the interactions formed between living organisms in a community and their physical environment

Symbiotic relationships
- involves two different species which are in a close and long term interaction
- Parasitism → involves one species deriving benefit, while harming the other species
- Commensalism → involves one species deriving benefit, while the other species is unaffected
- Mutualism → involves both species benefitting from one another

Oppositional relationships
- involves two different species where aspects of each species’ survival directly oppose that of the other species.
- Predator-prey relationships → involve the predator hunting the prey for food