FIRST MID ASSIGNMENT 2: SUBMIT ON SATUR DAY(5/9/09)

4 a). Zonation of oceans:

FIGURE IS IN NEXT POST. OCEAN ZONES

Oceans cover more than 2/3rd of the earth’s surface. The ocean environment is characterized by its high concentration of salts and minerals. It supplies huge variety of sea-products and drugs. It also provides us iron, magnesium, phosphorous, natural gas.
Zones of oceans:
Intertidal zone: The ocean connect to the land via what is called the inter-tidal zone. Because of rising and falling tides, coastal areas are constantly changing, with various animals and marine plants living at the bottom, and on the seashore. Rocky coastal areas are host to fewer species due to the fact that only the highest of tides will reach the top of the cliffs.
Neritic zone: This is the relatively shallow ocean that extends to the edge of the continental shelf. Primary productivity here depends on planktonic algae growing as deep as the light can reach.
Epipelagic Zone: The surface layer of the ocean is known as the epipelagic zone and extends from the surface to 200 meters. It is also known as the sunlight zone because this is where most of the visible light exists.It is host to many species of fish and marine mammals, plankton ,and some floating seaweed. With the light come heat, responsible for the wide range of temperatures that occur in this zone.
Mesopelagic Zone: Below the epipelagic zone is the mesopelagic zone, extending from 200 meters to 1000 meters. The mesopelagic zone is sometimes referred to as the twilight zone or the midwater zone. The light that penetrates to this depth is extremely faint. It is in this zone that we begin to see the twinkling lights of bioluminescent creatures. A great diversity of strange and bizarre fishes can be found here.
Bathypelagic Zone: The next layer is called the bathypelagic zone. It is sometimes referred to as the midnight zone or the dark zone. This zone extends from 1000 meters down to 4000 meters. Here the only visible light is that produced by the creatures themselves. The water pressure at this depth is immense and temperature is low, In spite of the pressure, a surprisingly large number of creatures can be found here. Sperm whales can dive down to this level in search of food. Most of the animals that live at these depths are black or red in color due to the lack of light.
Abyssopelagic Zone: The next layer is called the abyssopelagic zone, also known as the abyssal zone or simply as the abyss. It extends from 4000 meters to 6000 meters. The name comes from a Greek word meaning "no bottom". The water temperature is near freezing, and there is no light at all. Very few creatures can be found at these crushing depths. Most of these are invertebrates such as basket stars and tiny squids. Three-quarters of the ocean floor lies within this zone. The deepest fish ever discovered was found in the Puerto Rico Trench at a depth of 8,372 meters.
Hadalpelagic Zone: Beyond the abyssopelagic zone lies the forbidding hadalpelagic zone. This layer extends from 6000 meters to the bottom of the deepest parts of the ocean. These areas are mostly found in deep water trenches and canyons. The deepest point in the ocean is located in the Mariana Trench off the coast of Japan at 10,911m. The temperature of the water is just above freezing, and the pressure is an incredible eight tons per square inch. That is approximately the weight of 48 Boeing 747 jets. In spite of the pressure and temperature, life can still be found here. Invertebrates such as starfish and tube worms can thrive at these depths.

Role played by the oceans in terms of providing resources and regulating climate: Oceans represent the largest and most diverse of the ecosystems; The sea has always played an important role in the life of those people who live around its shores. Salt water evaporates and turns to rain which falls on the land regions, while most of the oxygen in our atmosphere is generated by algae. Algae is also responsible for the absorption of large amounts of carbon dioxide from our atmosphere.
The oceans, which cover more than 70% of the earth’s surface, play a fundamental and complex role in regulating climate. The oceans absorb huge amounts of solar energy; ocean currents transport this heat from the equator toward the Poles. In the past, long-term, natural oscillations in the oceans’ capacity to store and transport heat have led to global temperature changes.
As part of a vast planetary cycle of evaporation and rainfall, the oceans are also fundamental to the movement of water around the globe. Measuring changes in precipitation patterns, and understanding how they may lead to droughts in some regions and flooding in others, is a major part of predicting the potential effects of global climate change on human activities and natural ecosystems.

4 b). Define Ecosystem and explain pond ecosystem:
Ecosystem: An ecological community together with its environment, functioning as a unit or Community of living organisms (populations of species) interacting with one another and with the non-living environment.

Simple Pond Ecosystem:

FIGURE IS NEXT POST: SIMPLE POND ECOSYSTEM
Pond ecosystems range in size from just a few square meters to thousands of square kilometers. Scattered throughout the earth. Many ponds are seasonal, lasting just a couple of months (such as sessile pools) while lakes may exist for hundreds of years or more. Ponds and lakes may have limited species diversity since they are often isolated from one another and from other water sources like rivers and oceans. Lakes and ponds are divided into three different “zones” which are usually determined by depth and distance from the shoreline.
Littoral Zone: The topmost zone near the shore of a lake or pond is the littoral zone. This zone is the warmest since it is shallow and can absorb more of the Sun’s heat. It sustains a fairly diverse community, which can include several species of algae (like diatoms), rooted and floating aquatic plants, grazing snails, clams, insects, crustaceans, fishes, and amphibians. In the case of the insects, such as dragonflies and midges, only the egg and larvae stages are found in this zone. The vegetation and animals living in the littoral zone are food for other creatures such as turtles, snakes, and ducks.
Limnetic Zone: The near-surface open water surrounded by the littoral zone is the limnetic zone. The limnetic zone is well-lighted (like the littoral zone) and is dominated by plankton, both phytoplankton and zooplankton. Plankton are small organisms that play a crucial role in the food chain. Without aquatic plankton, there would be few living organisms in the world, and certainly no humans. A variety of freshwater fish also occupy this zone.
Profundal Zone: Plankton have short life spans—when they die, they fall into the deep-water part of the lake/pond, the profundal zone. This zone is much colder and denser than the other two. Little light penetrates all the way through the limnetic zone into the profundal zone. The fauna are heterotrophs, meaning that they eat dead organisms and use oxygen for cellular respiration.

Temperature varies in ponds and lakes seasonally. During the summer, the temperature can range from 4° C near the bottom to 22° C at the top. During the winter, the temperature at the bottom can be 4° C while the top is 0° C (ice). In between the two layers, there is a narrow zone called the thermocline where the temperature of the water changes rapidly. During the spring and fall seasons, there is a mixing of the top and bottom layers, usually due to winds, which results in a uniform water temperature of around 4° C. This mixing also circulates oxygen throughout the lake. Of course there are many lakes and ponds that do not freeze during the winter, thus the top layer would be a little warmer.


5 a). Elements of an ecosystem and their interdependency:
Ecosystem: Community of living organisms (populations of species or biota ) interacting with one another and with the non-living (abiotic) environment.
All living things that inhabit an environment are Biotic Factors. All nonliving things that inhabit an environment are Abiotic Factors.
Abiotic Components:
Water, air, temperature, soil, nutrients, minerals, light levels, moisture, precipitation, salinity.
Biotic Components:
Producers, consumers, decomposers
Plants, animals, bacteria/fungi
Biotic interactions with abiotic components include predation, competition, symbiosis, parasitism, commensalism etc.


FIFURE IS IN NEXT POST:Figure: Relationships within an ecosystem


Figure: Relationships within an ecosystem
Organisms that make up the biotic component of an ecosystem are usually classified as autotrophs and heterotrophs, based on how they get their food or organic nutrients they need to survive.
Autotrophs(producers): are organisms that can manufacture the organic compounds they need as nutrients from simple inorganic compounds obtained from their environment. In most terrestrial ecosystems, green plants are the producers. In aquatic ecosystems, most of the producers are phytoplankton, consisting of various species of of floating and drifting bacteria and protist.
Most producers make their organic nutrients they need through photosynthesis. The overall net chemical change can be summarized as follows:
6 CO2 + 6 H2O + solar energy -----> C6H12O6 + 6 O2
Some producers , mostly specialized bacteria, can extract inorganic compounds from their environment and convert them into organic nutrient compounds without the presence of sunlight. These producers are called chemosynthesis. An example of this is around the hydrothermal vents in some parts of the deep ocean. Bacteria carry out chemosynthesis by converting inorganic hydrogen sulfide to organic nutrients.
Heterotrophs(consumers)-are organisms which cannot synthesize the organic nutrients they need and get their organic nutrients by feeding on the tissues of producers or other consumers. There are several classes of of consumers, depending on there food source.
1.Primary consumers (herbivores) feed directly on plants or other producers.
2.Secondary consumers (carnivores) feed only on primary consumers.
3.Tertiary or higher level consumers feed only on animal-eating animals.
4.Omnivores can eat both plants and animals.Examples are pigs, rats, cockroaches, and humans.
5.Detrtivores (decomposers and detritus feeders) live off of detritus, parts of dead organisms and castoff fragments and waste of living organisms. Decomposers digest detritus by breaking down the complex organic molecules in these materials into simpler, inorganic compounds. Decomposers consist of various bacteria and fungi.
5 b). Bidiversity Types: Genetic Diversity and Species Diversity..
Biodiversity is a modern term which simply means " the variety of life on earth". This variety can be measured on several different levels.
Genetic - variation between individuals of the same species. This includes genetic variation between individuals in a single population , as well as variations between different populations of the same species. Genetic differences can now be measured using increasingly sophisticated techniques. These differences are the raw material of evolution.
Species - species diversity is the variety of species in a given region or area. This can either be determined by counting the number of different species present, or by determining taxonomic diversity. Taxonomic diversity is more precise and considers the relationship of species to each other. It can be measured by counting the number of different taxa (the main categories of classification) present. For example, a pond containing three species of snails and two fish, is more diverse than a pond containing five species of snails, even though they both contain the same number of species. High species biodiversity is not always necessarily a good thing. For example, a habitat may have high species biodiversity because many common and widespread species are invading it at the expense of species restricted to that habitat.


6 a). BIO-DIVERSITY hot-spots:
A biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity that is threatened with destruction.
In 1988, British ecologist Norman Myers developed the concept of biodiversity hotspots to address the dilemma of identifying areas most important for preserving Species. Many areas of global significance face tremendous pressure from logging, agriculture, hunting, and Climate change. The hotspots strategy emphasizes risks of species extinction since species loss is irreversible. Since these species can only be found in specific areas, the loss of such areas would be considered “irreplaceable.” The strategy also emphasizes species endemism.
To qualify as a biodiversity hotspot the regions must support at least 1,500 plant species found nowhere else in the world and Such areas must have lost at least 70 percent of its original Habitat.
It has been estimated that 50,000 endemic plants which comprise 20% of global plant life, probably occur in only 18 ‘hot spots’ in the world. Countries which have a relatively large proportion of these hot spots of diversity arereferred to as ‘megadiversity nations’.
Biodiversity Hotspots in India :
Western Ghats (Sahyadri Hills):
The Western Ghats , also known as the Sahyadri Hills , is a mountain chain running from the north to the South and is isolated by the Arabian Sea to the West, the arid Deccan Plateau to the East, and the Vindhya-Satpura ranges to the North. They have different vegetation types: scrub jungles and grasslands at low altitudes, dry and moist deciduous forests, montane grasslands and shoals, and the precious tropical evergreen and semi evergreen forests. Complex topography, high rainfall and relative inaccessibility have helped the region retain its biodiversity. Of the estimated 17000 species of flowering plants reported from india, about 4780 species are found in the western ghats region, of which 1720 (more than 1/3rd ) are endemic. Of the 372 species of mammals found in india, 63 are in the western Ghats, of which 16 are endemic. in addition 91 species of reptiles and 84(50%) species of amphibians(62%) are also endemic to these region. Some of endemic species in these region are:
Lion-tailed macaque, Nilgiri Hangul, Malabar Civet, Nilgiri marten, Indian gaint sqirrell, small travancore flying squirrel and Nilgiri Tahr.
Indo-Burma ( Eastern Himalayas ) :
Geographhically these area comprises Nepal, Bhutan and neighboring states of Northern India. There are 35000 plant species found in the Himalayas, of which 30% are endemic. Out of the 372 species of mammals found in india, 300 are in the western Ghats, of which 12 are endemic. In addition 48 out of 176 species of reptiles, 42 out of 85 species of amphibians and 15 out of 977 birds are also endemic to these region. The eastern Himalayas are also rich in wild plants of economic value and huge wealth of fungi, insects, mammals and birds.





6 b). In Situ Conservation :- within the natural habitat:
In situ conservation maintains not only the genetic diversity of species, but also the evolutionary adaptations that enable them to adapt continually to shifting environmental conditions, such as changes in pest populations or climate. In situ conservation also ensures that along with target species, a host of other interlinked species are also preserved as a by-product. It is generally cheaper than ex situ methods (although not cheap). It may often be the only conservation option, for example for species with recalcitrant seeds.
In situ conservation measures involve designating specific areas as protected Areas. Protection may be offered at various levels, from complete protection and restriction of access, through various levels of permitted human use. It includes a system of protected areas of different categories, e.g. National Parks, Sanctuaries, Nature Reserves, Natural Monuments, Cultural Landscapes, Biosphere Reserves, etc. protected areas of India cover 156,700 km², roughly 4.95% of the total surface area.
The biosphere reserve concept has been developed through the Man and Biosphere (MAB) Programme of the United Nations Educational, Scientific and Cultural Organization (UNESCO). Biosphere reserves are an attempt to reconcile the problems of conserving biodiversity and biological resources, with sustainable use of natural resources for people.
Seven of the fifteen biosphere reserves in India are a part of the World Network of Biosphere Reserves, based on the UNESCO Man and the Biosphere (MAB) Program list are:
• Nilgiri Biosphere Reserve
• Nanda Devi Biosphere Reserve
• Sundarbans Biosphere Reserve
• Gulf of Mannar Biosphere Reserve
• Pachmarhi Biosphere Reserve
• Nokrek Biosphere Reserve
• Simlipal Biosphere Reserve
There are more than 600 Protected Areas in India of which 96 are National Parks (38,029.18 km², 1.16% of India's total surface area), 15 are biosphere reserves and over 500 are Wildlife Sanctuaries. They include a variety of ecosystems and habitats. Some have been created in order to protect highly endangered species of wild plants and animals found nowhere else in the world.
The Great Himalayan National Park is the largest sanctuary in this ecosystem and is one of the last homes of the beautiful snow leopard.
Dachigam Sanctuary is the only place where the rare Hangul or Kashmir stag is found. There are several Sanctuaries in the Terai region,
Kaziranga National Park is the most famous which has elephant, wild buffalo, gaur, wild boar, swamp deer, and hog deer, in large numbers, as well as tiger and leopard. Its bird life is extremely rich and includes ducks, geese, pelicans and storks.
The Manas Sanctuary, in addition to the above Terai species, also includes the rare golden langur and the very rare pygmy hog, the smallest wild boar in the world. The florican is found only in a few undisturbed grasslands in the Terai sanctuaries.
In the sal forests of Madhya Pradesh, there are several Protected Areas. Kanha offers a wonderful opportunity to observe wild tigers from elephant back. It is the only Protected Area in which a sub species of the Barasingha is found.
Bharatpur is one of the most famous water bird sanctuaries in the world. Thousands of ducks, geese, herons, and other wading birds can be seen here. This is the only home of the very rare Siberian crane which migrates to India every winter. During the last 20 years, the 30 or 40 Siberian cranes have dwindled to only 2 or 3. During 2002-03 no cranes were seen and it is possible that this beautiful bird will never again come to India.
In the Thar desert, the wild life is protected in the Desert National Park. Here large numbers of black buck, neelgai and chinkara can be seen. The Great Indian Bustard lives in these arid lands.
Ranthambor was the most well known sanctuary for observing tigers in the wild till about 3 or 4 years ago. Since then many tigers have been killed by poachers.
The Great and the Little Rann of Kutch have been made into sanctuaries to protect the very rare wild ass, the flamingo, the star tortoise and the desert fox.
In Gujarat, the Gir Sanctuary protects the last population of the majestic Asiatic lion. This thorn and deciduous forest is also the home of large herds of chital, sambhar, and nilgai.
The Sanctuaries of the Western Ghats and associated hill ranges protect some of the most diverse forest types in the country. The few examples of highly threatened species include the Malabar giant squirrel, the flying squirrel and a variety of hill birds, several species of amphibians, reptiles and insects. These regions are also rich in highly endemic plant life. Sanctuaries such as Bhimashankar, Koyana, Chandoli and Radhanagari preserve this rich flora in Maharashtra, Bandipur, Bhadra, Dandeli, Nagarhole, etc. in Karnataka, and Eraviculum, Perambiculum, Periyar, Silent Valley, in Kerala.In the Nilgiri Hills the rich forest Sanctuaries protect some of the last pockets of the Indian elephant in South India. Examples include Bandipur, Madhumalai, Wynad and Bhadra. During the last 10 years, a large number of the great tusker elephants of this region have been ruthlessly killed for their ivory. Now very few of these magnificent animals are left in these jungles.
Two important sanctuaries meant for preservation of coastal ecosystems are the Chilka Lake and Point Calimere. The Sunderbans protect the largest mangrove delta in India. The Marine National Park in Gujarat protects shallow areas in the sea, islands, coral reefs and extensive mudflats.Over a hundred Protected Areas have been created in the Andaman and Nicobar Islands to preserve their very special island ecosystems.
Ex Situ Conservation : - Outside the natural habitat
Conservation of a species is best done by protecting its habitat along with all the other species that live in it in nature. This is known as in-situ conservation, which is conserving a species in its own environment by creating National Parks and Wildlife Sanctuaries. However, there are situations in which an endangered species is so close to extinction that unless alternate methods are instituted, the species may be rapidly driven to extinction. This strategy is known as ex-situ conservation, i.e. outside its natural habitat in a carefully controlled situation such as a botanical garden for plants or a zoological park for animals, where there is expertise to multiply the species under artificially managed conditions. These breeding programs for rare plants and animals are however more expensive than managing a Protected Area.
There is also another form of preserving a plant by preserving its germ plasm in a gene bank so that it can be used if needed in future. This is even more expensive. When an animal is on the brink of extinction, it must be carefully bred so that inbreeding does not lead to the genetic makeup becoming weak. Breeding from the same stock can lead to poorly adapted progeny or even inability to get enough offspring. Modern breeding programs are done in zoos that provide for all the animal’s needs, including enclosures that simulate their wild habitats. In India, successful ex situ conservation programs have been done for all our three species of crocodiles. This has been highly successful. Another recent success has been the breeding of the very rare pygmy hog in Gauhati zoo. Delhi zoo has successfully bred the rare Manipur brow antlered deer. However the most important step of a successful breeding program is the reintroduction of a species into its original wild habitat. This requires rehabilitation of the degraded habitat and removal of the other causes such as poaching, disturbance, or other manmade influences that have been the primary cause of reducing the population of the species.