Ecology: Organisms and Habitats

• Ecology provides a holistic perspective to biology and explains how organisms interact with each other and their physical habitats.
• Ecology studies anthropogenic environmental degradation and its socio-political issues.
• Ramdeo Misra (1908-1998) is known as the Father of Ecology in India.
• Misra obtained a Ph.D. in Ecology in 1937 under Prof. W. H. Pearsall from Leeds University, UK.
• He established ecology teaching and research at the Department of Botany of the Banaras Hindu University, Varanasi.
• Misra's research aided in understanding tropical communities, their succession, plant populations' environmental responses, productivity, and nutrient cycling in tropical forest and grassland ecosystems.
• Misra created the first postgraduate course in ecology in India.
• The Government of India established the National Committee for Environmental Planning and Coordination (1972) due to his efforts which later led to the Ministry of Environment and Forests (1984).
• The living world can be understood by investigating biological organization levels: macromolecules, cells, tissues, organs, individual organisms, population, communities, ecosystems, and biomes.
• Two types of questions can be asked: "how-type" questions, which investigate the mechanism of a process, and "why-type" questions, which seek the significance of the process.
• Ecology studies interactions among organisms and their abiotic environment.
• It is concerned with four levels of biological organization: organisms, populations, communities, and biomes.
• A population comprises a group of individuals of a species in a defined area, sharing resources, interbreeding, and has attributes like birth and death rates, sex ratio, and age distribution.
• Natural selection operates at the population level to evolve desired traits.
• Population ecology links ecology to population genetics and evolution.

Population Attributes

• Birth rates and death rates are the per capita births and deaths in a population that indicate change in numbers compared to population members.
• Sex ratio represents the proportion of males and females in a population.
• Age distribution indicates the percentage of individuals of a given age or age group within the population and when plotted creates an age pyramid.

Population Status

• The size of a population indicates its status in a habitat.