Man is surrounded by various life forms, forces and conditions- both physical and biological. Sunlight, land, air and water form physical conditions whereas all the plants, animals, and microorganisms form biological conditions.
As per an assessment, about 600 million people inhabited urban areas of the world in the year 1950. But now urban areas have been recorded to be inhabited by about half of the total population.
Sun is the only source of energy in the biosphere. Every living being can get its share of energy through food only and the energy is directly or indirectly obtained from green plants only.
The physical and mental conditions that collectively affect the reproductive capacity of a male or a female are called as reproductive health. The reproductive health is most essential for reproduction.
Living beings interact among themselves in the same species, with the members of the other species, and with the components of the abiotic environment in an ecosystem. Interaction between the members of the same species is called as Intraspecific whereas the interaction among individuals of different species is called as Interspecific.
The predominant features that create structural complexity in the environment, such as plants or animals are called as a habitat.
A process, in which natural habitat is rendered functionally unable to support the plants and animals occupying it, is named as Habitat destruction. In the process of habitat destruction, plants and animals that previously used the place are displaced or destroyed, reducing biodiversity.
Environment may be defined as ‘Complete range of various sets of external conditions comprising- physical, biological, and for human beings- cultural, economic and political conditions; in which human beings and other life forms exist in continuous interactions among themselves.
Most animals of the same kind have same body parts. But their body parts differ in size, shape, colour and functions.
It is reported that about 30 million tones of dry leaves are dumped into landfills every year in America. In India most of these leaves are either burnt on the floor where they fall or collected by poor people and stored for burning during winter season to generate heat.
Abrupt changes in environment often do not give time to an organism to get ready and to face the challenges. As such the organism can survive only when it has sufficient abilities to tolerate these changes.
