Characteristics of Species
Organisms have particular roles they play in their ecosystem, also known as their niche. This consists of their required environmental conditions, the interactions they have with other species, and where they fit in the food web. It's often compared to the job an organism has in its ecosystem.
Organisms can vary significantly in the breadth of their niches.
Generalist Species
Generalists have very broad niches, meaning they are able to use a wide variety of resources. In addition, they are able to survive in a wide range of conditions and therefore have a high range of tolerance. This makes them highly adaptable and able to withstand changing environments.
Specialist Species
Specialists have very narrow niches, meaning they are able to use only specific resources. They have an advantage over generalists when conditions are stable in an environment. However, they have a low range of tolerance. This makes them less able to adapt to changing conditions, resulting in extinction being more likely.Â
Ecological Range of Tolerance
Each species has a range of conditions that it can endure before being negatively impacted; this is known as the ecological range of tolerance. Imagine some plants that you are trying to grow as house plants: a succulent (which is a type of cactus) and a pothos (which is a tropical plant) will require different amounts of watering. It applies to various environmental conditions, such as temperature, salinity, amount of sunlight, pH, amount of a particular pollutant, etc.
Due to genetic diversity, it is possible for individuals within a species to have different ranges of tolerance from each other. This concept applies both at the species level and the individual level.
The range of tolerance can be split up based on how the organism is affected.
The optimal range is where organisms will best thrive. They will survive, grow, and reproduce without much issue here.
The zone of physiological stress is where organisms can still survive the conditions, but they are not thriving. Populations tend to shrink due to stress that the organisms are facing which can result in infertility (or decreased fertility), decreased growth, lowered metabolisms, or other such impacts.
The zone of intolerance is where the organism cannot survive the condition. It dies.