Ecology and Biodiversity

Biogeochemical cycles are also called as nutrient cycles. It includes gaseous cycles such as carbon cycle, oxygen cycle and sedimentary cycle. Sedimentary cycle consists of weathering of an existing rock followed by the erosion of minerals, transport and deposition. It has earth's crust as the reservoir pool. Examples of sedimentary cycle include sulphur cycle, phosphorous cycle, iron cycle, calcium cycle.

For the sedimentary type of biogeochemical cycles, the reservoir is earth's crust as the nutrients do not take any gaseous form rather they are either mineralized of immobilized but ultimately return to earth's crust by decomposition, leaching etc.

The inorganic nutrients cycle though more than the organisms, however, they also enter into the atmosphere, the oceans and even rocks. Since these chemicals cycle through both the biological and the geological world, we call the overall cycles biogeochemical cycles. 

Biogeochemical cycles are nutrient cycles. These are the cycles which are responsible for the recycling the nutrients which are present in the geosphere and atmosphere. The nutrient recycling takes place in the ecosystem and biomes. The recycling of nutrients helps in maintaining the nutrients in the available form for the uptake by the organisms.

Biotic factors of an ecosystem include all plant and animal species present in there. The abiotic factors include a physical environment in which they can survive. It includes light, temperature, humidity and other climatic condition as well as physical factors like soil. Thus, the correct answer is D. 

Herbaceous plants are plants with very flexible stems. Woody plants include trees and shrubs. These are the plants present in the terrestrial ecosystem. They convert solar energy into chemical energy through photosynthesis in which carbon dioxide and water are used in presence of sunlight to synthesize nutrients such carbohydrates in the form of glucose and release oxygen into the atmosphere. Since plants form the base of the terrestrial ecosystem they are the producers.

• Abiotic components: These are non-living components of the environment and consist of two things, materials and energy (that may be light or chemical energy). Materials include land, air, water, minerals, salts, atmospheric gases, rainfall, temperature etc.
• Biotic components: These are living components of the environment and divided into autotrophic and heterotrophic components. An autotrophic component is the producers or green plants while heterotrophic component includes consumers (primary, secondary and tertiary consumers) and decomposers (microbes).

Crop field is considered as man-made(anthropogenic or artificial) ecosystem. Natural ecosystem is developed in nature without human involvement, e.g., forest, ocean, etc.

• Abiotic components: These are non living components of environment and consist of two things, materials and energy (that may be light or chemical energy). Materials include water, minerals, salts, atmospheric gases etc.
• Biotic components: These are living components of environment and divided into autotrophic and heterotrophic components. Autotrophic component is the producers or green plants while heterotrophic component includes consumers (primary, secondary and tertiary consumers) and decomposers.

The products of ecosystem processes which have environmental aesthetic and indirect economic value are named as ecosystem services. Soil formation and soil protection are the major ecosystem services accounting for nearly 50% of their total worth. Plant cover protects the soil from drastic changes in temperature. There is little wind or water erosion as soil particles are not exposed to them. The soil remains spongy and fertile. There are no landslides and no floods. The plant cover of natural ecosystem absorbs polluting gases, causes settling of suspended particulate matter, removes CO2 and releases O2. Purified air becomes available. There is no overall depletion of nutrients as the same as repeatedly circulated and recirculated. This keeps the fertility of soil intact.

Ecological succession is the process of change in the species structure of an ecological community over time. It is primarily initiated by climatic factors (like temperature and rainfall) and biotic factors (like the introduction of pioneer species or human activity).

In ecology, the environment is divided into biotic factors (living components) and abiotic factors (non-living components). Abiotic factors include things like sunlight, temperature, water, and soil.

Biosphere reserves are areas of terrestrial and coastal ecosystems promoting solutions to restore the conservation of biodiversity with its sustainable use. The plan is to promote management, research and education in ecosystem conservation. This includes the 'sustainable use of natural resources'.

The species (including animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future are known as threatened species. The International Union for Conservation of Nature (IUCN) is the authority on threatened species, and it treats threatened species as a group of three categories, depending on the degree relative to which they are threatened. Those categories are Vulnerable species; Endangered species and Critically endangered species. As per the Red list of 2000, there are 11,096 threatened species.