[Biology Class Notes] on Ecology Pdf

Organisms And Their Environment

Ecology can be defined as a study of the interaction of living beings with their environment in an area. This interaction makes us able to understand the overall adaptation of the living things in their environment, which is a part of the continuity of the species. However, the accessibility of living beings in an area depends on the type of environment that is there. It can be noticed that the availability of a particular species of organisms depends indirectly on several factors like average temperature conditions, annual rainfall, the position of the earth with respect to the sun, etc. These factors together comprise to form the existence of biomes like rainforests, deserts, grasslands, etc. The weather conditions in a biome will further define the richness of species in that area. 

Next, you will learn about the abiotic components in a biological community of interacting organisms.

Abiotic Components in an Ecology

• Water: It is an important factor that affects life on this planet. Water is essential for the existence of the majority of the life forms. As in the case of humans, it can be observed that other organisms as well require water for temperature regulation and other physiological activities. It has been found that the species richness is denser near the water bodies.

• Temperature: The temperature affects the earth follows a geographical trend, and it directly affects life in an area. Temperature is responsible for carrying out several enzymatic reactions in living beings. Therefore, the biodiversity observed in various places on this planet varies along with the temperature gradient.

• Light: Light that comes directly from the sun is an important source of energy for living things and their environment. Plants use this energy to carry out the process of photosynthesis, which is basically the manufacture of the food in the plants. This energy gets passed on to the other organisms after they consume the plants, and then the other organisms consume these animals, and the food chain continues. 

• Soil: The type and availability of soil in an area determine the type of vegetation in that area. This affects the type of organisms that will be found in that area. The soil contains the essential minerals that are important to support the life of the various living beings.

An organism can be considered as a contiguous living system which includes animals, plants, fungi, and archaeon. Organisms are capable of responding to homeostasis, reproduction, growth, and stimuli. The organisms that are made up of a single cell are called unicellular, and the organisms that are made up of multiple cells are called multicellular. A group of cells together forms a tissue. 

The four-basic type of tissues found in the animals is muscle tissue, nerve tissue connective tissue, and epithelium. The tissues then come together from different organs. The organs are known to perform specific functions. The cells are the basic unit of an organism, and they are responsible for carrying out metabolism, cell division, cell contents, and response to the internal and external stimuli.  

Adaptation of Organisms to Environment

The living organisms are capable of adapting to the environment through a process known as biological variation. The adaptation process is different for different organisms, but their aim is the same, that is to adapt to the variation in the environment. Adaptation is especially important for the enhancement of the ability to survive. The behavior of the animals is an integral part of their adaptation process. Behavior includes the way they are built, and the way they behave to sustain in an environment. For example, the animals who live in the desert are known to retain water through their food or through the burrows in the earth to keep them hydrated. 

Population of Organisms      

The population of a species of an organism depends on the density of that species in a particular area. A local population is the one that occupies a smaller area and is smaller in size. Meta-population is when the local population is closely related together. The population ecology is important as it links the ecology with evolution and population genetics.

Attributes of Population

The following are the attribute around the population:

• Birth Rate: It can be defined as the birth rate of new individuals per unit of population per unit time. 

• Death Rate: It is the death rate of individuals per unit time depending on the various environmental changes such as competition, predation, and other changes.

• Population size: It is defined as the number of individuals of a species per unit area. 

• Sex Ratio: It is the ratio of the males to the females of a species in a given area.

Population Growth

The population of a species depends on various factors like availability of food, weather, predation, and competition. The changes in the population density depend on the factors like natality, emigration, immigration, and the mortality rate.