Category: Geography

The endogenic and exogenic forces cause physical stresses and other chemical actions on the earth’s materials and bring changes to the surface of the earth. This is known as the Geomorphic process.

Endogenic and Exogenic forces

• The forces which work over the surface of the earth are called Exogenic forces and the forces that work inside the surface of the earth or which act interior of the earth are called Endogenic forces.
• The endogenic forces work is visible only after it causes sudden damage or severe damage. Still, on the other hand, exogenic forces create visible changes as these changes took hundreds or thousands of years.

The Endogenic processes are diastrophism and volcanism and the exogenic process is Weathering, mass wasting, erosion, oxidation, reduction, hydration and deposition. The exogenic process also depends on the climate, type and structure of the rocks.

Geomorphic agents are water, ice, wind etc. These agents remove materials and transport them over the slope and deposit them at a lower level.

Gravity is the directional force that activates all the downslope movement and also causes stresses on the earth’s material. Indirect gravitational stresses activate wave and tide-induced currents and winds. Without the gradients and gravity, there will be no mobility and no erosion and deposition are possible.

All the movement inside or outside the surface of the earth happens due to gradients from the higher level to the lower level, and from high-pressure to low-pressure areas etc.

The five geomorphic processes of weathering are

• Physical Weathering
• Erosion,
• Slumping,
• deposition and
• Mass Movement.

The four types of physical weathering are due to water, ice, plant and animals. Similarly, chemical weathering is due to water dissolving minerals in the rock, producing a new compound.

For example: When water reacts with granite, the Feldspar crystal inside the granite reacts chemically forming clay minerals, which weakens the rock and makes it more vulnerable to Weathering.

Geomorphic Processes Weathering due to glacial transportation, glacial deposition and glacial erosion.

FAQ

1. What are exogenic and endogenic forces?

The forces that act in the interior of the earth are called Endogenic forces. The forces that work on the surface of the earth is called Exogenic forces.

Interior of the earth

The earth’s interior can only be understood by indirect methods, as no one has gone deep inside the earth, due to high temperature and pressure.

The surface of the earth is due to a number of processes that happen deep inside the earth. The surface of the earth is due to exogenic as well the endogenic forces that happen inside the earth.

The radius of the earth is 6370 km and nobody has ever reached the centre of the earth. The information which we have got today is all based on observation and analysis of materials.

Inside the earth

The Interior of the earth consists of Crust, Mantle, and Core. The continental crust is made of Sial which is expanded as Silica and Al-alumina.

And Oceanic crust is made up of Sima which is expanded as Silicon and Magnesium.

The interior of the earth is extremely hot and reaches as high as 5000 degrees Celsius. This is probably because of two reasons. One is the heating when the earth is formed and the other is the heat from the decay of the radioactive elements.

Crust

The crust is the outermost part, and it is brittle. Its thickness varies from oceanic and continental areas. The crust in the oceanic region is thinner than the continental crust.

Its average thickness is 5km in the case of oceanic crust and its average thickness is 30 km in the case of continental crust.

The continental crust is thickest in mountainous regions. For example, the Continental crust is 70 km thick in the Himalayan region.

Mantle

The mantle is present after the crust. It extends from Moho’s discontinuity to a depth of 2900 km. The Mantle consists of a number of layers.

The upper layer of the Mantle is called Asthenospher that is extending up to 400km. The word Astheno means Weak. The lava comes through the Asthenosphere.

The crust of the uppermost part of the mantle is called Lithosphere and its thickness is about 10-200 km. The lower mantle extends beyond the asthenosphere which is in a solid-state.

Core

The Final layer of the Interior of the earth is the core. The core is located at the depth of 2900 km. The outermost core is in a liquid state and the innermost core is in a solid state.

The core is made of Nickel and Iron and due to it is also referred to as Nife Layer.

Cause of the interior of the earth to separate into layers

The earth is divided into layers because of gravity and density. The stratification of Earth into layers was the reason for the formation of the Earth’s iron core.

This Iron core is possibly formed by radioactive decay and strong gravitation. This might have caused high temperatures and made iron melt.

As the molten iron moved to the center of the Earth due to gravity and it displaced the materials that are less dense to the surface.

Study of Interior of Earth

Scientists study the interior of the earth by studying seismic waves. These are recorded by an instrument called Seismograph. As it is impossible to drill the center of the earth, scientists use indirect observation of the underlying matters below the surface.

Ocean floor configuration

It helps in the know about the distribution of continents and oceans. the ocean floor is divided into three divisions based on its depth and as well the forms of relief.

The division is known as Continental Margin, deep-sea basin and mid-ocean ridges. The Ocean floor configuration

Continental Margins

Continental Margins are the transition between the continental shores and deep-sea basins. These include a continental shelf, continental slope, continental rise and deep oceanic trenches.

The deep oceanic trenches are one which is interesting part with respect to the distribution of oceans and continents.

Abyssal Plains

Abyssal Plains are extensive plains that lie between the continental margin and mid-oceanic ridges.

These are the areas where the continental sediments are deposited.

Mid Oceanic Ridges

Mid oceanic Ridges are an interconnected chain of mountains system under the ocean. These are the longest mountain chain on the surface of the earth, which are submerged under the ocean.

It is characterized by a central rift system at the crest, a fractionated plateau and a flank zone all along its length.

The volcanic activity zone occurs in the crest of the rift system.

Fractionated plateau and Flank zone

Fractionated plateau

Flank zone

• The flanks are market by set of mountain and hills, which are elongated and parallel to the ridge trend.

Crop calendar Tamil Nadu

Planting Seasons in Tamil Nadu is classified into 8 types. They are:

1. Navarai
2. Sornavari
3. Kar
4. Kuruvai
5. Early Samba
6. Samba
7. Late Samba/Thaladi/Pishanam/Late Pishanam
8. Late Thaladi

The crop calendar in Tamil Nadu is classified into 8 based on the Month of Sowing, Duration or Day. This duration is classified into Short duration, Medium and Long duration.

Tamil Nadu basically cultivated Paddy as main crops. Based on which the seasons are named.

Navarai

The month of Sowing is December to January. The Duration of the crop is less than 120 days.

Short duration varieties are sown. Varieties sown in Navarai are ADT 36, ADT 37, ASD 16, IR 64, ASD 18, ADT 42, ADT 43 MDU 5, ASD 20, etc.

The districts of cultivation are Tiruvallur, Vellore, Tiruvannamalai, Cuddalore, Villupuram, Tiruchirapalli, Perambalur, Karur, Nagapattinam, Madurai, Theni, Salem, Namakkal, Dindigul, Dharmapuri, Coimbatore, Erode, and Pudukkottai districts.

Sornavari

The month of Sowing is April to May.

The Duration of the crop is less than 120 days.

Short duration varieties such as

The districts of cultivation are Tiruvallur, Vellore, Tiruvannamalai, Cuddalore, Villupuram, Namakkal, and Dharmapuri districts.

Varities sown during Somavari are IR 64, ADT 36, IR 50, ADT 37, ASD 16, ASD 17, ASD 18, ADT 42, MDU 5, ASD 20, ADT 43, CO 47, ADT (R) 45, ADT RH1, ADT (R) 47, etc.

Kar

The month of Sowing is May to June. The Duration of the crop is less than 120 days.

Short duration varieties such as:

The districts of cultivation are Tirunelveli, Kanyakumari, Tuticorin, Erode, Coimbatore, Madurai, Theni, Dindigul, Salem, Namakkal, and Dharmapuri districts.

Varieties of paddy sown during Kar are ADT 36, IR 50, IR 36, IR 64, ADT 37, ASD 16, ASD 18, ADT 42, MDU 5, ASD 20, ADT 43, CO 47, ADT (R) 45 (Dindigul only), TRY (R) 2*, ADTRH 1, ADT (R) 47, etc.

Kuruvai

Kuruvai is also known as ‘Short Term’ in Tamil Nadu. The crops are grown in Tamil Nadu in Cauvery Delta.

The month of Sowing is June to July. The Duration of the crop is less than 120 days.

The districts of cultivation are Tiruchirapalli, Perambalur, Karur, Thanjavur, Nagapattinam, Tiruvarur, Pudukottai and Erode districts.

Varieties of paddy sown during Kuruvai are ADT 36, IR 50, IR 64, ASD 16, ADT 37, ASD 18, ADT 42, MDU 5, ADT 43, CO 47, ADT (R) 45 (except Karur), TRY (R)2*, ADTRH 1, ADT (R) 47, etc.

Early Samba

The month of Sowing is July to August. The Duration of the crop is less than 130 to 135.

Medium and Long during varieties of Paddy are sown.

The districts of cultivation are Tiruvallur, Vellore, Tiruvannamalai, Salem, Namakkal, Cuddalore, Villupuram, Madurai, Theni, Ramanathapuram, Dharmapuri, Coimbatore, Erode, Pudukkottai, and Nilgiris districts.

The Varieties of paddy sown during Early Samba are IR 20, White Ponni, CO 43, Ponmani, PY 4, ADT 38, TRY 1, ASD 19, ADT (R) 44, CORH 2, etc.

Samba

The month of Sowing is August. The duration of the crop is 130 to 135 days and less than 150 days.

Medium and long-duration varieties are sown. All the districts cultivate it.

The Varieties of paddy sown during Samba are Ponmani, ADT 40, Bhavani, IR 20, White Ponni, CO 43, Paiyur 1, PY 4, CO 45, TRY 1, ASD 19, CORH 2, etc.

Late Samba/Thaladi/Pishanam/Late Pishanam

The month of Sowing is September to October. The duration of the crop is 130-135 days.

Medium and long-duration varieties are sown. The districts of cultivation are Tiruvallur, Madurai, Theni, Coimbatore, Erode, Dindigul, Kanyakumari, Tirunelveli, and Tuticorin districts.

The Varieties of paddy sown during late Samba are ADT 38, IR 20, CO 43, Ponmani, ADT 39, TRY 1, ASD 19, ADT (R)46, etc.

Late Thaladi

The month of Sowing is October to November.

The duration of the crop is 115-120 days.

Medium and long duration varieties are sown.

The districts of cultivation are Thanjavur, Nagapattinam, Tiruvarur, Tiruchirapalli, Perambalur and Karur districts.

The Varieties of paddy sown during late Thaladi are ADT 38, IR 20, CO 43, Ponmani, ADT 39, TRY 1, ASD 19, ADT (R)46, etc.

Conclusion

We have discussed Crop calendar tamil nadu, the season, its respective months, life time of crops and also the varieties of paddy cultivated during the various seasons across the districts of Tamil Nadu.

Savanna food web

The Primary consumer in the Savanna food web is Zebras and elephants. The Secondary consumers are cheetahs, hyenas, etc. The Scavengers here are vultures, hyenas, and termites. The reason hyena is present in both Secondary and Scavenger is because it gets their food by hunting in groups and also Scavenging on dead animals.

In this biome, Tall grasses are dominant and are the primary producer. The tall grasses convert energy from the Sun and minerals, and nutrients from the soil into the biomass that forms the basis of this Food Web. One of the important examples savanna food web is the one that exists in Africa.

African savanna food web

In the African savanna food web, the savanna is essential and it is a treeless plain present in a tropical or subtropical area, which is grassland found in eastern Africa, and the Northern part of Southern America.

It generally consists of scattered trees and drought-resistant flora. Some of the famous savannas are the Serengeti Plains of Tanzania, the Acacia Plains of East Africa, the savannas of Venezuela, the Sahel, south of Sahara in East Africa, and the Australian Savanna.

These tropical grasslands are found between tropical forests and deserts. This biome is found between 10° to 20 ° N and S latitudes.

These are generally hot and dry and experience moderate to low rainfall. As a result of this climate, the grasses grow tall and sharp. The chief occupation of people living here is herding and basically, these are Nomadic.

The biggest threat to the Tropical savanna food web is human activities such as converting these biomes to Pastoral lands, Agricultural activities, over-grazing, livestock, logging, and the introduction of non-native plants, etc.

The types of savannas are Tropical and Subtropical Savannas, Temperate Savannas, Mediterranean Savannas, Flooded Savannas, and Montane Savannas.

It is referred to by different names around the world such as:

• Pampas in South America
• Pasture,
• Prairie in Northern America,
• Rangeland in the USA
• Steppe in Eastern Europe and Central Asia
• Veld in Africa.
• Downs in Australia

Food chains in the savanna

The Zebras and elephants graze on grasses. The Lion and cheetah eat Zebras. Mara eats pampas grass and Maned Wold hunts Mara. The Hyena hunts as well as scavenges.

There are Vultures, and termites, in Savanna that are also Scavengers. The decomposers or Detritivores are mushrooms, insects, and microorganisms.

To Summarise the Food chains in the savanna: Producers, Primary consumers, Secondary Consumers, and Scavengers.

Producers in the Savanna

The primary producers in a savanna represent a complex functional group consisting of species of different habitats, sizes, and physiological requirements. The subdivision of the primary producers into morphological types such as herbs and trees.

The herbs can be further separated into grasses and forbs, C3 and C4 photosynthetic types, nitrogen-fixing and non-fixing, deep and shallow-rooted, early and late growers and so on.

The functional group of plants is defined according to the habit and size. In Savanna ecosystems, it is vital to differentiate between Herbaceous and Ligneous plants. This is because there are plants related to different rates of organic matter production and accumulation.

The producers in the Savanna include Grass, Acacia Trees, baobab Trees etc. Here also people cultivate pearl millet, legumes, vegetable crops, fonio, African rice etc.

Primary consumers in the Savanna

Primary Consumers of the savanna or the Herbivores in Savannas comprise vertebrates and invertebrates. The vertebrates that are well known are the large native mammals – animals of browsers and grazers, which is a salient feature of many African Savannas.

Also, there are many smaller herbivorous animals in Savannas including Armadillos and porcupines. Although invertebrates such as grass-eating harvester termites are important features of savannas.

The termites, ants, and grasshoppers are neglected as components of the savanna yet these insect herbivores play an important role in the savanna process including consuming grass material and seed predation.

Primary consumers in the savanna are Ostrich, Zebra, Thomsons Gazelle, Grasshopper, Giraffes, Elephants, etc.

Secondary Consumers

Savanna’s secondary consumers are Lions, Cheetahs, Secretary Birds, Harrier Eagles, etc. Human is also part Savanna food chain and they compete with other organisms for food.

Scavengers

Scavengers in the savanna are Hyenas, vultures, detritivores or decomposers like Fungi, bacteria, other Microorganisms, termites, etc. Also, Black-backed Jackals are seen on the hunting grounds of a lion.

Sometimes the top predators like lions also scavenge food.

Decomposers

Like any other ecosystem, decomposers in the savanna play a very important role in the flow of energy. The decomposers such as Bacteria, Fungi, Earthworms, and Insects do the role of transferring the energy between producers and consumers.

Bacteria in Savanna

Bacteriareis great number colonize the savanna’s soil. The bacteria in the savannas sustain well where the temperature is above 25 degrees Celsius.

Also, bacteria such as Acidobacteria are immune to changes in the moisture of the soil. This Acidobacteria slows down when the soil has few nutrients left adaptation makes them survive in the Savannas.

The most prominent bacteria in the African Savannas are Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Gemmatimonadetes, Planctomycetes, and Verrucomicrobia.

Fungi

The soils in Savanna are poor in nutrients, have frequent droughts and are very acidic. Due to these harsh conditions, fungi are less distributed than bacteria.

The common fungi found in African savannas are Sarcoscypha dudleyi, Laetiporus sulphureus, and Trametes versicolor.

Conclusion

We have discussed the savanna food web such as its basis of the food chain, What eats what in this biome what this biome is its reasons for its dangerous future, and the names it is called around the world.

References

1. What Are the Trophic Levels in the Savanna? (sciencing.com)