Identification: finding out what something is
How can a scientist determine the quantity and type of organisms living in an area, and why is it important? Identification and estimation are important keys in determining these answers. Having a clear idea of how many and what kind of organisms live in a specific area can tell scientists a lot. For example, they can record data on several occasions and learn about how populations and communities may change over time. With such information they can find answers to many other questions and also create new questions to explore.
Scientists use a variety of methods and tools to find answers to questions. Some tools and methods are very sophisticated while others are simple and uncomplicated. In the above example, it is obviously very difficult to count every organism in an entire area (or community); in this case quadrats and simple mathematical computations are often the tools and methods of choice. A quadrat is a square of a determined size (usually 1 meter or 1/2 meter square) which is placed on a portion of the area/community to be studied, in a tidepool zone, for instance. By counting how many organisms are in the quadrat and multiplying that by the number of quadrats that would fit into a certain area, estimates can be made about population sizes for each kind of organism that lives in an area. Another way to gather information about the organisms in the quadrat is to measure them and determine their actual size (length) and ranges of sizes. This will give an idea of the likely range of sizes for individuals within a given category. In the following activity students get an opportunity to use similar skills in their classroom.