//
VisionIAS - Video Classroom Lecture
Vision-IAS Logo


Environment Class 03

DISCUSSION ON THE AIR POLLUTION AND WEATHER CONDITION IN DELHI (5:12 P.M.)

DISCUSSION ON THE PREVIOUS CLASS (5:27 P.M.)

RAINFOREST BIOME (5:28 P.M.)

  • Thick, dense, and luxurious forests that grow in the area of heavy rainfall.
  • Temperate Rainforest
  • These are the regions within the temperate latitudes where precipitation is available throughout the year.
  • Temperate rainforests are found in cool temperate western margin type of climate.
  • These areas receive good rainfall due to on-shore westerlies.
  • Vegetation is thick, dense, and tall growing.
  • They are majorly found along parts of Western Europe, Western Canada, and Southern Alaska.
  • The biodiversity is less in comparison to the tropical rainforest.
  • Tropical Rainforest
  • There is high temperature throughout the year with very few seasonal changes.
  • There is high precipitation in the region (above 200 cm). This is mainly the convectional rainfall.
  • Soil Characteristic
  • There is less humus in the soil due to the high decomposition rate.
  • The heavy rainfall leads to the percolation of the minerals downwards. 
  • The soil is laterite in nature due to this heavy leaching.
  • The soil is acidic due to the removal of salts. 
  • The topsoil is rich in aluminium and iron, making it a hard crust.
  • The soil is highly prone to soil erosion.
  • Fauna
  • The vegetation is evergreen, and will not sed the leaves in any particular season.
  • The vegetation is dense and luxuriant.
  • The vegetation is multilayered, which is an adaptation to capture the maximum sunlight.
  • There is low undergrowth, as there is little sunlight that reaches the floor of the forest.
  • Some vegetation like creepers and epiphytes are found here. They have adapted to climb the other trees.
  • There is high biodiversity due to the abundance of the temperature and precipitation.
  • The leaves have the drip tips.
  • The trees are hardwood. They are difficult to cut and transport.
  • The sunlight is the limiting factor. Only 2% reaches the surface.
  • For Example, Rosewood, Ebony, Mahogany, Rubber, Tapioca, carnivorous plants (Venus fly trap), etc.
  • Fauna (6:10 P.M.)
  • The rich diversity of animals including, insects, apes, reptiles, monkeys, mammals, etc is found.
  • Apes include Gorillas (Africa), Chimpanzees, Orangutans (South-East Asia), and Gibbons.
  • Hoolock gibbon is found in India.
  • Gliders are found here. For example, flying foxes, pygmy gliders, flying lizards, etc.
  • The snakes like green mambas are found here.
  • Animals can camouflage.
  • They are colourful and have special behaviour to survive the competition. For example, birds of paradise.
  • They have large tails and strong grip. For example, Monkeys.
  • They have large beaks. For example, toucans, hornbills, hummingbirds, etc.
  • The areas are the Congo Basin, parts of Venezuela, Indonesia, Malaysia, Papua New Guinea, the Amazon Basin, etc.
  • The biggest threat to tropical rainforests is from palm oil cultivation and commercial plantations.
  • The soil of Indonesia is rich in nutrients in comparison to the soil of the Congo and Amazon basins.
  • Even though it covers 50% of plant and animal diversity, it is present in only over 6% of the Earth's surface.

AQUATIC ECOSYSTEMS (6:57 P.M.)

  • It can be classified into Saline (Salinity greater than 35 parts per thousand), Brackish (Salinity between 5 and 35 parts per thousand), and Freshwater ecosystems (Salinity less than 5 parts per thousand).
  • Freshwater ecosystems can be either the lotic type or the lentic type.
  • A lentic ecosystem can survive a more drastic situation in comparison to a lotic ecosystem.
  • As per the availability of sunlight the aquatic ecosystem can be classified into the photic and aphotic zones.
  • In the photic zone, the food is produced through photosynthesis.
  • In the aphotic zone life is dependent on this photic zone. There is less light and oxygen here.
  • In the thermocline region, the aquatic organisms are almost transparent to evade the predators.
  • In the hypolimnion zone, the predators have adapted themselves by producing their light. This helps them to attract the prey.
  • The various zones in the aquatic ecosystem are:
  • Littoral Zone
  • The zone of the aquatic ecosystem is nearer to the land where the water is shallow, and the sunlight, oxygen, and nutrients are abundant. It is the zone of the aquatic ecosystem that is the richest in life. 
  • Pelagic Zone
  • The zone of the aquatic ecosystem is away from land. The water is deeper.
  • Benthic zone
  • The zone of the aquatic ecosystem along the bottom layer, where the sunlight and oxygen are limited.
  • Organisms in the Aquatic Ecosystem
  • Plankton
  • These are free-floating microorganisms.
  • These are present in the photic zone slightly below the surface.
  • They can be phytoplankton and zooplankton.
  • Phytoplankton are capable of producing food through photosynthesis.
  • Zooplankton are non-photosynthetic.
  • Nektons
  • These are not free-floating.
  • For example, Fish.
  • Benthos
  • These are the bottom-dwelling organisms. For example, crabs.
  • Neuston
  • These are the organisms that live just above the surface. 
  • Periphytons
  • They are also bottom living. They live on other structures like stems, leaves, etc. near the photic zone.
  • Hydrophytes
  • They live in freshwater with roots inside the soil and grow above the water level.
  • For example, Lotus, Mangroves, etc.

ECOTONES (7:30 P.M.)

  • The gradual change between the two ecosystems in terms of physical characteristics, nutrient availability, etc. is called ecocline.
  • Ecotone refers to the transition zone between the two ecosystems where a specific type of ecosystem develops.
  • For example, Wetlands, Grasslands, etc.
  • Edge effect
  • The changes in the population or community structure that occur at the boundary between two habitats are known as the edge effect.
  • In the ecotone, we find the abundance of the species, life, resources, etc. in comparison to adjoining ecosystems.
  • The edge species are especially found in the ecotones. They have certain special characteristics. 
  • For example, In the wetlands, we find the amphibians and the water birds.

WETLANDS (7:45 P.M.)

  • Wetland is a transitional zone between the terrestrial and the aquatic ecosystem.
  • Here the water depth doesn't exceed 6 m.
  • It is an example of ecotone.
  • Characteristics of Wetland
  • (a) The primary productivity is high due to the abundance of sunlight, water, and nutrients.
  • (b) The plant variety found is hydrophytes which are adapted for water-logged conditions 
  • (c) The soil type is hydric soil. It is saturated with water and has less oxygen.

THE TOPIC FOR THE NEXT CLASS: WETLANDS (CONTINUED)