Ecology

An ecosystem is a community of living organisms in conjunction with the non-living components of their environment (things like air, water and mineral soil), interacting as a system.

Important features of ecology are:

*It is normally an open system with a continuous, but variable influx and loss of materials and energy.

*An ecosystem is an overall integration of the whole mosaic of the interacting organism and their environment.

*It is a basic functional unit with no limits of boundaries.

*It consists of biotic and abiotic components interacting with each other.

*Its functional unit is capable of energy transformation, circulation and accumulation.

Different types of the ecosystem are present in different areas.

The biosphere is an example of as open system. The input and output of substances take place in their system. There can be reinvestment of new substances in the biosphere.

The largest ecosystem of the earth is Biosphere. The biosphere is a part of the earth where life can exist. It is a highly integrated and interacting zone comprising of atmosphere (air) hydrosphere (water) and lithosphere (land). It is a narrow layer around the surface of the earth. The biosphere is absent at extremes of the North and South Poles, the highest mountains and the deepest oceans.

Biosphere

The location or place where an organism lives is called a habitat. The organisms depend for their food, water, air, shelter and other needs on their habitat. A biome is a plant and animal community that covers a large geographical area. Some of the major biomes of the world are: forest, grassland, desert and tundra biomes.

All the organisms and the abiotic components of the environment from the ecosystem of the place. thus ecology deals with the organism and its environment.

The correct order of biological organization ranging from organism to biosphere is - A population is a group of individuals within the same species, within the same area, and that are capable of reproducing with one another. A community is a defined as the populations of two or more species within the same geographical area and within the same time period. An ecosystem is a community along with its abiotic (non-liv- ing) components, such as the water and air. A biome is a large ecological area with similar climatic conditions. A biome can have multiple ecosystems within it. The biosphere includes all living organisms along with the spheres they interact with (lithosphere, hydrosphere, etc.). Several communities together form an ecosystem. One or more ecosystems are found in a fixed terrain.

Field, garden are artificial ecosystem while forests, ponds and lakes are natural ecosystems.

The term ecosystem was first used by A.G. Tansley. Hence statement (1) is correct. Biotic components are the living things that shape an ecosystem. Autotrophic components are self-feeding organisms of the ecosystem. These produce their food themselves. Hence statement (2) is also correct. Consumers are organisms of an ecological food chain which receive energy by consuming other organisms. These organisms are formally referred to as heterotrophs. Hence, statement (3) is wrong. Organic matter is recycled in an ecosystem by decomposers. Decomposers are organisms such as bacteria and fungi that break down the organic matter of the dead bodies of plants and animals into inorganic material. Hence statement (4) is also wrong.

In a given ecosystem, these are generally more producers than primary consumers, and more primary consumers than secondary consumers, and so on.

All organisms in an ecosystem depend upon each other. If the population of one organism rises or falls, then this can affect the rest of the ecosystem. If the foxes in the food chain above were killed, the population of rabbits would increase because they are no longer prey to the foxes. Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation.

An artificial ecosystem meets all the criteria of a natural eco-system but is made and controlled by humans. Orchards, farmlands, gardens and human-made reservoirs are some examples of artificial ecosystems. Ecosystems can broadly be categorized as Aquatic and Terrestrial ecosystems. Grasslands, forests and deserts are examples of terrestrial ecosystems while lakes, rivers and oceans fall under aquatic ecosystem. Notably, agriculture under human ecosystem has been instrumental to the existence of society and development. Hence (a) is the correct answer.

There are mainly two kinds of ecosystem-Aquatic and Terrestrial. Marine ecosystems are the biggest ecosystems, which cover around 71% of earth's surface and contain 97% of our planet's water. Thus option (d) is the correct answer.

Aquatic ecosystem refers to living and non-living parts of a water body and the interactions that take place among them. Aquatic ecosystems can be categorized in the marine ecosystem and freshwater ecosystem. Marine ecosystem covers approximately 71% of the earth's surface and contains approximately 97% of the planet's water.

Aquatic ecosystem refers to living and non-living parts of a water body and the interactions that take place among them. Aquatic ecosystems can be categorized in the marine ecosystem and freshwater ecosystem. Marine ecosystem covers approximately 71% of the earth's surface and contains approximately 97% of the planet's water.

Marine ecosystem is a most stable ecosystem. Marine ecosystem remains unchanged over a long period, irrespective up various geological and anthropogenic process.

Scientists divide ecosystems into terrestrial (land ecosystem) and non-terrestrial (non-land ecosystem). Ecosystems may be further classified by their geographical region and dominant plant type. Aquatic, marine, and wetlands constitute the non-terrestrial ecosystems, while the five major terrestrial ecosystems are desert, forest, grassland, taiga and tundra.

Wildlife conservation and prevention of environmental pollution is helpful in maintaining ecological balance. Deforestation adds to the environmental imbalance.

Deforestation is one of the main causes of ecological imbalance in India. While, desertification, floods and famines and rainfall variations are other causes of ecological imbalance in India.

It is lumbering which which disturbs the ecological balance.

Water management, afforestation and wildlife protection is associated with Ecological balance while industrial management is not associated with ecological balance.

The maximum population size that can ecosystem can support is called carrying capacity. It is the number of organisms that an environment can sustainably support. Hence option (b) is correct.

Ecological niche characterizes the position of a species within an ecosystem, comprising species habitat requirement as well as its functional role.

Any substance consumed to provide nutritional support for an organism is called food. Plants are self-feeding and make for their own food whereas animals depend on plants for food. Food chain depicts the flow of energy through different organisms in an ecosystem. Notably, this flow is unidirectional. The correct order of different components in the above food chain is as follows:

Grass      →      Grasshopper        →          Frog              →           Snake

↓                              ↓                                    ↓                                    ↓

(Producer) (Primary Consumer) (Secondary Consumer) (Tertiary Consumer)

Grass, goat and humans form a food chain -

Grass               →             Goat                →                Humans

↓                                        ↓                                              ↓

(Autotroph)  (Herbivorous consumer)  (Omnivorous consumer)

Biotic components are the living things that shape an ecosystem. Biotic components usually include:

Producers: e.g. plants.

Consumers: e.g. animals, humans

Decomposers: e.g. fungi and bacteria

Now most obvious aspect of nature is that energy must pass from one living organism to another. When herbivorous animals feed on plants, energy is transferred from plants to animals. In an ecosystem, some of the animals feed on other living organisms while some feed on dead organic matter. The latter form the detritus food chain. Each chain usually has only four to five such links. Food chains are not found within the population of a species. Because this would mean a human being eating another human being (human being are single species)

Mainly herbivores, in a food chain, are considered as primary consumers. In the given options, Deer is herbivorous hence it is a primary consumer. Ants fall under decomposer and primary consumers both. It eats plants and receives energy from cellulose. Tiger is carnivorous and the fox is omnivorous. Significantly, primary consumers feed on primary producers (plants). Hence option (a) is the correct answer.

Butterflies play a vital role in the pollination of many flowering plants, so their declining number may have an adverse effect on the pollination of plants. Butterflies act as the lower member in the food chain. They are the meal of spider, bird, snake etc. Therefore, the drop in a number of butterflies can adversely affect the food chain.

In food chain there are trophic levels i.e., Autotroph, Primary consumer, Secondary consumer and Tertiary consumer. The primary consumer is the herbivores (that feed on the plant), the secondary consumer is small carnivores (feeding on primary consumer) and the tertiary consumer is larger carnivores. So, in food chain, man is the primary as well as a secondary consumer who feeds on both plant, products and meat.

Phytoplankton, also known as micro-algae, are similar to terrestrial plants in that they contain chlorophyll and require sunlight to live and grow. Most phytoplankton are buoyant and float in the upper part of the ocean, where sunlight penetrates the water. Phytoplankton also requires inorganic nutrients such as nitrates, phosphates, and sulfur which they convert into proteins, fats, and carbohydrates.

Plants are self-feeding organisms that produce complex organic compounds such as carbohydrates, fats and proteins generally using energy from light (photosynthesis). These are known as autotrophs and are fundamental to the food chain of all ecosystems. There are called primary producers.

Each step or level of the food chain forms a trophic level. Tropic level-I includes autotrophs or the producers (i.e. green plants) which fix up solar energy and make it available for heterotrophs or the consumers. The herbivores (primary consumer) come at second, small carnivores at third and tertiary consumer (large carnivores) form the fourth trophic level.

Those plants which manufacture food by photosynthesis are called producers. Decomposers are nature's recyclers as they break down the 'organic matter found in the dead bodies of living beings. They (Producer and Decomposers) act as intermediaries between biotic and abiotic components.

Autotrophs like Green plants are the primary producers. Heterotrophs like Herbivores are the secondary producers.

All the pairs mentioned in the question are related to ecosystems but correctly matched is only (c). An ecosystem is a community of living organisms in conjunction with the non-living components of their environment. Since plants are living organism hence they are related to the ecosystem.

Decomposers are nature's recyclers as they break down the organic matter found in the dead bodies of living beings. The term 'organic matter' refers to the matter that comes from living organisms. Decomposers are mainly the microorganisms such as bacteria and fungi in the form of yeasts and moulds that break down bodies of dead organisms and release compounds that can be used by producers.

The correct order of a common marine food chain is -

Diatom

↓

Crustaceans

↓

Herrings

Solar energy is the primary source of energy in the ecological body. It is the driving force of an ecosystem.

Solar energy is the primary source of energy in the ecological body. It is the driving force of an ecosystem.

The flow of energy in the ecosystem is unidirectional (or one-directional). The energy enters the plants (from the sun) through photosynthesis during the making of food. This energy is then passed on from one organism to another in a food chain. The energy given out by the organisms as heat is lost to the environment. It does not return to be used by the plants again. This makes the flow of energy in the ecosystem 'unidirectional'. According to the first law of thermodynamics, energy can neither be created nor be destroyed in an isolated system. According to the second law whenever energy transforms into a new form, there is evident decay in its intensity. Similarly, with increasing trophic levels availability of energy decreases in the natural ecosystem.

The Ten Percent Law of transfer of energy from one trophic level to the next was introduced by Raymond Lindeman in first half of 1940s. According to this law, during the transfer of energy from organic food from one trophic level to the next, only about ten percent of the energy from organic matter is stored as flesh. The remaining is lost during transfer, broken down in respiration or lost to incomplete digestion by higher trophic level. When organisms are consumed, 10% of the energy in the food is fixed into flesh and is available for next trophic level (carnivores or omnivores). When a carnivore or an omnivore consume that animal, only about 10% of energy is fixed in its flesh for the higher level. Thus, at every level of the food chain (first, second, third and top level), the consumer converts only 10% of the accumulated energy inti his body weight.

Pyramid of energy is always upright, can never be inverted, because when energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step. Each bar in the energy pyramid indicates the amount of energy present at each trophic level in a given time or annually per unit area. Hence option (a) is correct.

Trophic levels are formed by interconnected organisms in a food chain, representing the flow of energy and nutrients producers, like plants, convert sunlight (solar energy) into chemical energy, while primary consumers eat producers. Secondary consumers feed on primary consumers and this sequence continues with tertiary consumers and beyond. Each level in the food chain represents a trophic level, showing the transfer of energy and nutrients between organism. Thus, option (d) is the correct choice as it includes all organisms linked in a food chain.

Energy is the basic force responsible for all metabolic activities. The flow of energy from producer to top consumers is called energy flow, which is unidirectional. Energy flows through the trophic levels i.e. from producers to subsequent trophic levels. This energy always flows from lower (producer) to higher (herbivore, carnivore, etc.) trophic level. There is a loss of some energy in the form of unusable heat at each trophic level so the amount of energy during the transfer from one trophic level to another decreases in an ecosystem.

There are four types of trophic levels in the food chain of the ecosystem. They are-

First trophic level- Producer

Second trophic level- Primary consumers (herbivorous)

Third trophic level- Secondary consumers (carnivorous)

Fourth trophic level- Tertiary consumers (omnivorous)

Decomposers feed on all the above trophic levels. Hence option (c) is the correct answer.

The Pyramid of Biomass is a graphical representation that depicts the extent of biomass per unit area within different trophic levels in an ecological system. In grasslands and forests, there is a gradual decrease in the biomass of organisms at successive levels from the producers to the top carnivores. Thus, pyramids are upright. However, in a pond, as the producers are small organisms, their biomass is least and this value gradually shows an increase towards the apex of the pyramid, thus making the pyramid inverted in shape.

An inverted pyramid of biomass can be found in marine ecosystem. The pyramid of biomass in sea is generally inverted because the biomass of fishes far exceeds that of phytoplankton. Hence option (1) is correct.

In ecology, bionomics (Greek: bio = life; nomos = law) is the comprehensive study of an organism and its relation to its environment. Another way of expressing this word is the term currently referred to as "ecology". It stresses the value of natural systems which influence human systems and is not related to the management of life.

DDT is a non-biodegradable, biomagnifying pollutant (used as insecticide) which increases in concentration from producers, primary consumers, secondary consumers to tertiary consumers. In the question, only the snake represents the tertiary consumers, so the concentration of DDT will be highest in the snake.

In Earth science, a biogeochemical cycle is a pathway by which a chemical substance moves through both biotic and abiotic components of Earth. Biogeochemical cycles of nitrogen, phosphorus and carbon, etc. are found in nature.

Phosphorus is a chemical element found on Earth in numerous compound forms, such as the phosphate ion (PO), located in water, soil and sediments. Much of the phosphorus on Earth is tied up in rock and sedimentary deposits, from which it is released by weathering, leaching, and mining. Some of it passes through freshwater and terrestrial ecosystems via plants, grazers, predators, and parasites, to be returned to those ecosystems by death and decay. Much of it, however, is deposited in the sea, in shallow sediments, where it circulates readily, or in ocean deeps, whence it wells up only occasionally. Phosphorus is brought back to the land through fish harvests and through collection of guano deposited by seabirds.

Ecological succession is the gradual process by which ecosystems change and develop over time. In grassland, trees have already been cleared away due to fires in the past, which also changes the ground composition. Without the trees to hold them, water washes away most of the soil and the underlying ground becomes the pioneer population, which is then replaced by grass. The grass, however, absorbs most of the water before it reaches the roots of the shrubs. Thus, the ecological succession does not occur beyond the grass.

Biotic succession is a natural process of displacement of one particular community by another in a particular area. A scientist named Odum described it as a sequenced process. The correct order of biotic succession is as follows:

Nudation

↓

Migration

↓

Ecesis

↓

Reaction

↓

Stabilization

1. Nudation: It is the development of a bare site uninhabited by any organisms. The process is usually caused by disturbances. These factors can be either topographic (soil erosion, wind action etc); climatic (hails, storm, glaciations, fire etc.); or biotic (human activities).

2. Invasion or migration: The process of invasion or migration helps the arrival of seeds, spores or other reproductive propagules for establishment of species. Invasive species are non native organisms which can spread widely in a community.

3. Ecesis: This is the initial establishment of plant community. This is dependent on the soil structure. The stage is also called as 'colonization'. In this stage, the early colonizing species proliferate abundantly through germination, growth, and reproduction. Ecesis is due to allogenic mechanisms alone. This is the stage at which the pioneer species survive the dispersal mechanisms.

4. Reaction: The environmental conditions get modified by the action of species occupying the habitat. These changes subsequently trigger the displacement and replacement of one species by another.

5. Stabilization is the process by which the climax community gets established. A climax community is mature, self sustaining, stable and is the final stage of succession. The physical and chemical conditions are altered and stabilized to such levels that it supports the entire community. The climax communities are best adapted to the regions of succession and the community structure is likely to continue until another disturbance steps in.

The concept of 'Ecological Transition' was first used by John W. Bennett. He proposed the concept in his book "The Ecological Transition: Cultural Anthropology and Human Adaptation". "Ecological transition" mean, the development of an anthropocentric orientation toward the natural world that emerged in the Western Renaissance but has since characterized every civilization and nation. Ecologically speaking, the transition is expressed in the growing incorporation of Nature into Culture and by the breakdown of local self sufficiency-the ability of the local group to satisfy its needs with existing resources in a particular geographical range.

The entire sequence of communities that successively change in a particular area are called 'Sere'.

The movement of nutrient elements through various components of an ecosystem is called the nutritional cycle. This nutritional cycle is also called the biogeochemical cycle.

"Ecology is permanent economy" is the slogan of Chipko Movement. 'Narmada Bachao Andolan' was against the construction of a multi-modal dam on the Narmada river. 'Appiko Movement' was started in Karnataka for  environmental protection.

The Chipko movement was a forest conservation movement in India started in 1973. Gaura Devi (1974) gathered other women around her village in the Garhwal Himalayas and prevented loggers from felling trees by sticking to the trees. This act by illiterate tribal and village women to reclaim their traditional forest rights was a dramatic moment known as Chipko Andolan' , a non-violent struggle that gave birth to the modern Indian environmental movement.

The ecological footprint is a measure of human demand on the Earth's ecosystems. It's a standardized measure of demand for natural resource that may be compared with the planet's ecological capacity to regenerate. It can be defined as the biologically productive area required to provide for everything people need to sustain their life. It includes fruits, vegetables, wood, fibres, fossil fuel use and also the release of carbon dioxide. Its unit is Global hectares.

The ecological footprint is a measure of human demand on the Earth's ecosystems. It's a standardized measure of demand for natural resource that may be compared with the planet's ecological capacity to regenerate. It can be defined as the biologically productive area required to provide for everything people need to sustain their life. It includes fruits, vegetables, wood, fibres, fossil fuel use and also the release of carbon dioxide. Its unit is Global hectares.

Social Cost of Carbon is a measure, in monetary value, of the long-term damage done by a tonne of carbon dioxide (CO₂) emission in a given year. EPA (Environmental Protection Agency) and other US agencies use estimates of the social cost of carbon to evaluate the climate impacts of rule making.

According to the World Development Report, 2010, the Millennium Ecosystem Assessment describes the following five major categories of ecosystems services: Provisioning Services

Regulating Services

Supporting Services

Cultural Services

Preserving Services Supporting services are those that are necessary for the production of all other ecosystem services. They differ from provisioning, regulating, and cultural services in that their impacts on people are either indirect or occur over a very long time. For example: Soil formation and retention, nutrient cycling, crop pollination, water cycling etc. 'Production of food and water' is considered under Provisioning Services, while 'Control of climate and disease' is a Regulating Service. 'Maintenance of diversity is a Preserving service.

Eucalyptus consumes more ground water than other trees. That is why it often called 'enemy of the environment'. The water level goes down across the area of Eucalyptus plantation.

Eucalyptus consumes more ground water than other trees. That is why it often called 'enemy of the environment'. The water level goes down across the area of Eucalyptus plantation.

Eucalyptus consumes more ground water than other trees. That is why it often called 'enemy of the environment'. The water level goes down across the area of Eucalyptus plantation.

Lentic Ecosystem refers to the static water habitats like ponds, lakes, swamps and marshes. Lotic Ecosystem refers to the dynamic water habitats like rivers.

The area that acts as a boundary or a transition zone between two ecosystem is known as Ecotone. The recognition of a transition zone between two ecological system by Clements could be called the beginning of ecotone research.

Ecotone is a region of transition between two biological communities.

Ecotones are areas of steep transition between ecological communities, ecosystems, and/or ecological regions along an environmental or other gradient.

Lotic ecosystems are characterized by flowing waters. Examples include rivers, streams, brooks and springs. Here, the oxygen level is higher due to the continually moving waters of the current and the water is clearer. The flow of the water is different depending on the area of a river or stream. Lentic ecosystems are those whose water is still, and are made up of ponds, marshes, ditches, lakes and swamps. These ecosystems range in size from very small ponds or pools that may be temporary to large lakes.

Oceans are the cradle of life on Earth which harbours the highest level of biodiversity. No terrestrial ecosystem can match the biological richness of a coral reef, not only in some species but also in variety and originality of survival strategies.

Oceans are the cradle of life on Earth which harbours the highest level of biodiversity. No terrestrial ecosystem can match the biological richness of a coral reef, not only in some species but also in variety and originality of survival strategies.

The correct sequence of ecosystems in the order of decreasing productivity is - Mangroves, grasslands, lakes, oceans.

Arne Naess was a Norwegian philosopher who coined the term "deep ecology" in 1972.

Monoclimax was propounded by F.E. Clement. According to the mono-climax theory of succession (Clements, 1936), every region has one climax community toward which all communities are developing. He believed that climate was the determining factor for vegetation and the climax of any area was solely a function of its climate.

Joseph Grinnell referred to the "ecological or environmental niche" as the ultimate distributional unit of "species and subspecies".

Ecological niche is a term for the position of a species within an ecosystem, describing both the range of conditions necessary for persistence of the species, and its ecological role in the ecosystem. Ecological niche subsumes all the interactions between species and the biotic and abiotic environment.

The correctly matched list is as follows:

Ecological Concerns                                       Act was passed in

Wildlife Protection                           -                          1972

Environment (Protection) Act       -                          1986

The Scheduled Tribes and               -                         2006

other Traditional Forest Dwellers

(Recognition of Forest Rights) Act

The Forest (Conservation) Act        -                         1980

Hence, none of the option is correctly matched.

Pycnocline indicates a density gradient of any water system. Halocline shows salinity gradient of the water system. Thermocline shows a change in temperature with respect to the depth of a water system.

Winds blowing across the ocean surface push water away. Water then rises up from beneath the surface to replace the water that was pushed away. This process is called "upwelling. Water that rises to the surface as a result of upwelling is typically colder & is rich in nutrients. These nutrients "fertilize" surface waters, meaning that these surface waters often have high biological productivity. Therefore, good fishing grounds are found where upwelling is common.

Eco - sensitive zones are mentioned under the Environment (Protection) Act, 1986. Hence statement 1 is incorrect.

Prohibited activities: Tourism activities like flying over protected areas in an aircraft or hot air balloon, and discharge of effluents and solid waste in natural water bodies or terrestrial areas.

Regulated activities: Felling of trees, establishment of hotels and resorts, commercial use of natural water, erection of electrical cables, drastic change of agriculture system, e.g. adoption of heavy technology, pesticides etc. widening of roads.

Permitted activities: Ongoing agriculture and horticulture practices by local communities, rainwater harvesting, organic farming, adoption of green technology and use of renewable energy sources. Hence, statement 2 is also incorrect. Hence, option (d) is the correct answer.

All organisms in an ecosystem depend upon each other. If the population of one organism rises or falls, then this can affect the rest of the ecosystem. If the foxes in the food chain above were killed, the population of rabbits would increase because they are no longer prey to the foxes. So Assertion A is incorrect. Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation. Changes like these have triggered climate change, soil erosion, poor air quality, and undrinkable water. So R is correct.

Crop land is an exampel of human made biome.

Corals are invertebrate animals. Reefs are created by hard corals which secrete a skeleton that can turn into giant structures like Australia's 'Great Barrier Reef. Most of the world's coral reefs are located in tropical oceans near the equator. More than one-third of the world's coral reef is located in the territories of Australia. Indonesia and Philippines. Coral reefs are one of the most diverse ecosystems on the planet. These tropical marine communities occupy less than 1% of the ocean floor but are inhabited by more than 25% of all known marine fish species. 32 of the 34 recognized animal phyla are formed on coral reefs compared to 9 phyla in tropical rainforests.