Explain what is Organismal Ecology?
Ecology at the Level of Individuals: We define ecology as the study of the relationships between organisms and the relationships between organisms and their environment. The term ecology is derived from the Greek term oikos, which means home, and logos, which means to study. Studying these relationships can be done at several levels of organization. For instance, scientists can study individual organisms of a particular species to determine which critical environmental (physical) factors affect characteristics such as their growth, physiology, reproduction, and behavior. Sometimes this type of ecology is called either organismal ecology or physiological ecology.
Environmental factors can be thought of as those physical (abiotic) and biological (biotic) factors that determine all of the immediate living conditions of an individual. These would include things like light, water, substrate, nutrients and minerals, chemistry, gases, food, temperature, humidity, wind, currents or wave motion, salinity, pH, predators, and disease. Countless studies have been conducted on individuals, which have determined optimal levels and ranges of a given factor for a particular species.
Limiting Factors and Limiting Resources : As such, any factor could represent the limiting factor, or the critical factor, if it acted in such a way as to adversely affect the survival or distribution of an organism. For example, low temperature by itself might prevent the reproductive process perhaps because sperm cells are not able to withstand temperatures below a certain point a lower limit of tolerance. If all other environmental factors were within so-called normal ranges of tolerance, temperature would be referred to as the limiting factor for the range of distribution of that species. In this way, any factor can theoretically act as a limiting factor in terms of where the organism can grow and survive. There usually are optimal levels of performance for a given factor. x
In much the same way, a resource can also represent a limiting factor. Sunlight, oxygen, phosphate, and nitrate can all limit the survival and distribution of an individual plant. This relationship is called the Law of Limiting Resources. In simple terms, the resource that is in shortest supply will represent the resource that limits the survival and growth of an organism. Were the resource to increase, it would no longer act to limit the growth, and growth would proceed until that resource, or another resource became limiting in some other way.
A potted plant can experience the effect of growth limiting resources. For instance, if, over time, the plant absorbed all of the fertilizer nutrients in the pots soil, growth of the plant would not continue unless more fertilizer was added to the soil in the pot.
On a larger scale, agricultural crop yields clearly reflect how limiting resources influence growth. Fields, in which crops are planted year after year, must receive fertilization in order to sustain yields. Simply stated, crops absorb the nutrients from the soil to build plant mass, which are then are harvested. Harvesting removes the nutrients from the field, effectively depleting the chemical building blocks, or nutrients from the soil. In this way, nutrients become limiting factors.