VisionIAS - Video Classroom Lecture

Environment Class 02

DESERT (9:14 AM)

Climatic condition: Average annual rainfall is 25 cm/annum.
High temperature in case of hot desert and low temperature in case of cold desert.
Very high diurnal range of temperature.
Region:
Hot deserts on the western margin of the continent in the tropics.
Deserts such as Atacama, Sonoran desert ( Arizona), Mojave, Namib, Kalahari, Great Victoria, Gibson, Simpson, etc -> Dry Continental airmass.
Cold deserts such as rain shadow zones and continentality. Examples are the Gobi Desert, Takla Makan, in China, the Karakum Desert in central Asia, and Ladakh. etc
They have xerophytic adaptation.
Flora-Desert grass, Shrub, Cactus, Date palm, acacia, Babool.
Fauna- Desert camels, Rattlesnake, Sand boa, Kangaroo rat.
Adaptation of xerophytic vegetation:
Short growing.
Dense and deep root system.
Drought resistant.
Thorns instead of leaves.
Green Stem.
Succulent leaves. Example Cactus.
Waxy layer.
Thick and hard coatings on seed to protect from heat.
Animals:
Burrowing Animals.
Nocturnal.
Known for Aestivation ( Summer sleep).
Survive in low amounts of water.
Low surface-to-body area. Example camel.
Long Ear for losing heat.
Excrete concentrated Urine Example kangaroo Rats etc.
Challenges:
Overgrazing
Habitat degradation
Spread of invasive species.
Pollution and soil erosion
Climate change worsening the situation by impacting rainfall, temperature etc

RAINFOREST BIOME (10:13 AM)

Temperate Rainforest: High rainfall throughout the year.
Vegetation is dense, Thick, and Tall but not as diverse as tropical rainforest.
The highest tree is the Giant Sequoia.
Known for lumbering industry due to less diversity.
Tropical rainforest:
Climate- Hot and Wet climate.
Temperature is high throughout the year
High and uniform rainfall throughout the year.
Average Annual rainfall 200 to 250 cm per annum
Known for Laterite soil.
Rainfall because of the convection. Process.
Regions:
Papua New Guinea.
Niger is part of Africa.
Northern part of South America.
Flora:
Carnivore plants such as Pitcher plants.
Fauna:
Big size snakes (Green Anaconda), Rat, Piranha fish ( Amazon)
Reptiles, amphibians.
Amazon river dolphins (Boto). ( * Gangetic river dolphin- Susu, Yangtze river dolphin-Baiji).
Bird of paradise in Papua New Guinea.
Toucans (Amazon).
The jaguar is the top predator of the Amazon.
Africa- Apes: Gorillas, and chimpanzees left Africa now in South East Asia, bonobos, and gibbons left Africa ( Southeast Asia)
Apes in India India: Hoolock Gibbon ( North East India)
Gorillas are found only in Africa.
Apes vs Monkey
Apes have larger brains, no tail, and Tool-making capacity. Much more intelligent than a monkey.
Capacity to recognize themselves in the mirror.
Apes follow cannibalism to threaten opponents, for example, silverback Gorillas.
Orangutans are known for using sticks as tools.
Adaptation in trees- tall rowing, Epiphyte, multilayer vegetation, carnivorous plants also adaptation, tips of leaves
Apes- Strong grip etc
Issues and challenges:
Deforestation.
Agriculture such as palm tree cultivation in South East Asia.
Cattle ranching. Example Amazon forest, America, etc
Biodiversity loss
Shifting cultivation.
Soil degradation
Forest fire.

AQUATIC ECOSYSTEM (11:29 AM)

Zones of the aquatic ecosystem:
Vertical zones:
Aphotic zone; oxygen is available
Photic zone abundant sunlight, photosynthesis possible. When photic zones near coastal regions they have access to nutrients.
Photic zones extend up to 200 meters below that aphotic zone.
Aphotic zones are also called Profundal zones.
Profundal zone- oxygen, sunlight, and photosynthesis limited. Continuous respiration consumes oxygen. Through vertical mixing oxygen and nutrients are supplied to the aphotic zone. Diurnal migration ( Daily migration ) between Photic and aphotic zone.
Horizontal zone:
littoral zone. Shallow part, closer to land, abundance of life.
Pelagic zone: open waters away from land, deeper depths, Limited life due to lesser nutrient availability.
Benthic zone: Bottom zone, Abundance of nutrients as dead organism settles on the ocean floor, chemotrophic species otherwise limited life.
Species in the aquatic ecosystem:
Planktons: Drifter or free floaters, microscopic. Present in marine as well as fresh water. Distribution is decided by winds, ocean currents, waves, tides, etc
They are present only in the photic zone.
Types:
Phytoplankton: Capable of photosynthesis
Zooplankton: feed on phytoplanktons.
Nekton: :
Capacity to swim.
Examples are Fish, Crustaceans such as Krill, prawns, Octopus, turtles (reptiles), and mammals such as sea lions, whales, and dolphins.
Neustons: Organisms living in the water interface. Floating plants, insects.
Benthos: benthic organism, bottom-dwelling organism, not drifters, swimmers, or free floating.
They are capable of walking on the floor
Example Crabs ( walk sidewise), and lobsters.
Most of the benthos are scavengers
Sea urchins, starfish.
Hydrophytes:
Plants have roots in the soil but grow above the water.
Example Water hyacinth, lotus.

ECOTONE AND EDGE EFFECT ( 11:57 AM)

The transition zone between two ecosystems with a specific type of ecosystem with specific characteristics is developed. i.e Ecotone.
Example Wetlands between terrestrial and aquatic ecosystems.
Ecocline:
The gradual changes between two different ecosystems in terms of physical characteristics, nutrient availability, and species composition are referred to as ecocline.
Ecocline does not contain a specific and defined transition zone. Example Ecocline along mountains with an increase in altitude.
Edge effect- Changes in population or community structure that occur at the boundary of two habitats usually near ecotone is called an Edge effect.
Species that evolved due to the edge effect found around Ecotones are called Edge Species.
Example Amphibians, Mangrove trees, Water birds,

THE TOPIC OF THE NEXT CLASS- Geological time scale etc