Scope of Ecology
Ecology is the study of how organisms with their environments. It gives an idea of distribution and abundance of organisms. Biosphere is the entire portion of the earth which is inhabited by life. The environment of an organism can be divided into two: Abiotic and biotic environment. Abiotic factors include temperature, light, topography, pH, soil and water. Biotic factors include plants and animals. Ecological niche of a species refers to its ‘lifestyle’ – how it lives, what it does, how it interacts with other members of its ecosystem. The habitat is where the species is found.
Changing Environments of the Biosphere
Biosphere is thin, life supporting skin consisting of seas, lakes, stream, land and atmosphere. Biosphere is a mosaic of habitats differing in abiotic factors such as temperature, rainfall and light. These affect the distribution of biotic factors such as the type of vegetation. On the basis of extremes of temperature, light and other abiotic factors, organisms have diverse adaptations in the biosphere. Endotherms maintain internal temperature. Water is essential to life. All ecosystems are driven by solar energy and plants are directly dependent on it. Tropical forests are resulted due to low light levels. Physical structure, pH and mineral composition of soil limit the distribution of plants and hence of the animals that feed on those plants. Wind amplifies the effects of environmental temperature on organisms by increasing heat loss due to evaporation and convection. Catastrophic events such as fires, hurricanes, typhoons, and volcanic eruptions can devastate biological communities.
Responses of Organisms to Environmental Change
Environments change in time as well as space. Individual organisms can respond to changing environments by mechanisms that are behavioral, physiological or morphological. Response such as migration of animals and birds in response to change in temperature is an example for behavioral response. Physiological responses are slower than behavioral responses. Morphological responses are the slowest. Internal anatomy of the body maybe changed due to change in the environment.
Terrestrial Biomes
The world’s major communities like deserts, tropical rain forests, grasslands and the like are known as Biomes. Tropical forests are found near the equator. Savanna is tropical or semi tropical grassland with scattered individual trees. Desert is the harshest of all biomes. Chaparral consists of dense, spiny shrubs with tough ever green leaves. Temperate grasslands are found in regions of relatively cold temperature. Temperate forests grow in the regions where there is sufficient moisture to support the growth of large trees. Taiga is also known as coniferous forest. Tundra has plants which form shrubby or mat like vegetation.
Aquatic Communities
The aquatic communities can be divided as fresh water and marine. Rivers and streams are bodies of water continuously moving in one direction. These communities are dynamic, changing significantly from the source to the point at which they empty into an ocean or lake. Estuaries are the areas at which a fresh water river or stream meets the ocean. The end points of many rivers and streams are ponds and lakes. Phytoplanktons and zooplanktons thrive in them. Marine environment is made up of photic and aphotic zones. Marine communities are based on depth – Littoral zone, neritic zone and oceanic zone.
