Keys and Factors Affecting Distribution

Keys for Identifying Organisms

Keys are tools used by scientists to identify and categorise organisms based on their observable characteristics.
Keys usually present a series of choices, each of which details a specific characteristic.
Your response to each choice will guide you to the next appropriate choice, eventually leading to the identification of the organism.
There are two types of keys: dichotomous keys, which offer two choices at each step; and branched keys, which offer multiple choices.

Quadrats are a tool used in ecology to study the distribution of organisms in a habitat.
They are square frames, often made of metal, which are placed over a section of habitat for observation.
All organisms within the quadrat are counted. This process is repeated in multiple sections to get a sample that represents the larger habitat.
The use of quadrats allow for random or systematic sampling. Random sampling involves placing quadrats at random locations, while systematic sampling involves placing them at regular intervals.

Abiotic factors: Non-living factors such as temperature, pH, light intensity, and availability of water.
Biotic factors: Living factors such as predators, prey, parasites, and competition for resources such as food, mates, and territory.
Human impact: Human activities like deforestation, pollution, and urbanisation can also greatly influence the distribution of species.
Changes in these factors may alter the habitat of a species and thus influence its geographical distribution.

Changing distribution trends can suggest wider environmental changes, such as climate change, and they often have knock-on effects on other species in an ecosystem.
A species’ changing geographical distribution can also have economic implications if it’s a crop species or it’s involved in a food chain crucial to a fishing or hunting industry.
Understanding and monitoring distribution trends is crucial in conservation efforts to protect endangered species and biodiversity.