Biota and their environment
Ecology: ecology is the study of reciprocal relationship between living organisms and their environment.
Autecology: the study of ecological relationship regarding a single species is called Autecology.
Synecology: the study of ecological relationship of many species living together and making a community is called Synecology.
Ecological factors: any external substance or condition which surrounds and affects the life of organism in any manner is called ecological factors. These factors are living and non living. The living factors are called as biotic and nonlivings are called as abiotic factors.
biotic factors:
Autotrops: all green plants, photosynthetic bacteria and cyanobacteria which are capable of making their organic food are known as autotrops.
Heterotrops: those organisms that depend on other for feeding are known as heterotrops. They are of 3 types:
1. Primary consumer: they are herbivores and depend on plants for food. E.g. cow
2. Secondary consumers: they are primary carnivores that depend on herbivores for food. E.g. fox
3. Tertiary consumers: they are carnivores that depend on primary carnivores for food. E.g. tiger
Decomposers: the microorganisms which breakdown the complex organic substance into simple form are known as decomposers. E.g. bacteria, saprophytic fungi etc. they are the recycler of ecosystem.
#interacting system in biotic community:
in a community, members of various species show interaction. They are as follows:
Positive interaction: in this type of interaction, either both or one is benefited but neither of them is harmed. They are categorized as:
Mutualism: it is also called as symbiosis. it is a type of +ve inter specific interaction in which members of two species favors growth and survival of each other. They cannot separate from each other. E.g. lichen is symbiosis association between algae and fungi.
Commensalism: it is a kind of +ve interaction of two species ,in which one organism is benefited while other is neither benefited nor harmed. E.g. epyphytes grow on other plants for support but not for food.
Protocooperation: it is a type of +ve interaction in which both are benefited but can live separately. E.g. crow feed on lice of cow’s body and cow gets relaxed.
Colonization: some species of plants and animals live in colony for protection from predator or environmental condition, proper utilization of food, reproduction etc. E.g. volvox.
Social organization: it is a kind of +ve interaction in which species live in group and maintain division of labour among individual for better adjustment. E.g. honey bee colony consist 3 types of bee, queen is fertile female, drone is male and workers are sterile female.
Aggregation: it refers to gathering of organisms in large number to bring change in physiology and behavior of members.
Negative interaction: it is the interaction in which a member is harmed. It can be categorized as:
Predation: this is a direct interaction o two species in which one organism kills another for food. Killing animal is called predator and killed animal is called prey.e.g. Tiger feeds on deer.
Parasitism: a parasite is an organism that depends on other for nourishment and shelter. Parasitism is one sided relation in which parasite gets benefited and host gets harmed. E.g. fungi, bacteria etc.
Competition: it is a negative interaction in which member of different species competes for common resources. E.g. tiger and wolf for deer
Antibiosis: it is a relationship between two organisms of different species in which one organism inhabit the growth of another organism. E.g. penicillium doesn’t allow the growth of bacteria.
Abiotic factors:
Light: light play an important role in photosynthesis, chlorophyll formation, stomata movement and transpiration. It also affects the animals in metabolism, growth, pigmentation and locomotion.
Atmospheric gas: nitrogen and oxygen are the major atmospheric gases. O2 is mainly produced by plants during photosynthesis and is absorbed by animals during aerobic respiration. N2 is used in formation of nitrates by bacteria and nitrates act as fertilizer for plants.
Soil: soil provides nutrients, water and attachment to plants. Water from soil mainly fulfills the water requirement of plant .soil pores stores oxygen and these gas are taken by microorganism living inside soil. Bacteria of soil convert dead bodies of plant and animal into simple inorganic and organic compounds which increase the fertility of soil and support plant development.
Topography: it is the land factor which depends upon latitude and altitude. The distribution of land on earth varies from place to place such as size, shape of mountain,hills,slopes etc. the condition of land is directly proportional to the climatic variation and distribution of plants and animals.
Temperature: most of the organism can survive from the temperature range of 5-35 degree Celsius except certain bacteria. Organisms are killed at high temperature due to denaturation of enzymes while some are killed at low temperature due to freezing of body fluids.
Wind: wind cause fall of flower, buds, fruits, seeds. It also cause bending of crops called as lodging. Wind increase transpiration rate and help in pollination and dispersion of spores.
Moisture: moisture helps in bryophytic reproduction, increase rate of transpiration and help in germination too.
Rainfall: rainfall is the source of ground water and relative humidity. It is raw material for photosynthesis and is essential to maintain turgidity of soil.
Concept of ecosystem:
Trophic level: producers and consumers in ecosystem can be arranged in different feeding groups, each feeding groups is known as Trophic level. Thus the green plants which derive the food from sun are in first Trophic level. All the herbivores belong to 2nd Trophic level. All the primary carnivores belong to 3rd trophic level and all carnivores belong to 4th Trophic level.
Productivity: A constant input of solar energy is the basic requirement for any ecosystem to function and sustain.
Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis. It is expressed in terms of weight (g –2) or energy (kcal m–2). The rate of biomass production is called productivity.
It is expressed in terms of g–2 yr–1 or (kcal m–2) yr–1 to compare the
Productivity of different ecosystems. It can be divided into gross primary
Productivity (GPP) and net primary productivity (NPP). Gross primary
Productivity of an ecosystem is the rate of production of organic matter
During photosynthesis. A considerable amount of GPP is utilized by plants
in respiration. Gross primary productivity minus respiration losses (R),
is the net primary productivity (NPP).
GPP – R = NPP
Net primary productivity is the available biomass for the consumption
to heterotrops (herbivores and decomposers).
Secondary productivity is defined as the rate of formation of new organic matter by consumers. Primary productivity depends on the plant species inhabiting a
particular area. It also depends on a variety of environmental factors,
Availability of nutrients and photosynthetic capacity of plants. Therefore,
it varies in different types of ecosystems. The annual net primary
Productivity of the whole biosphere is approximately 170 billion tons
(dry weight) of organic matter. Of this, despite occupying about 70 per
cent of the surface, the productivity of the oceans are only 55 billion tons.
Rest of course, is on land.
Ecological pyramid:
Ecological pyramid is the graphical representation of ecological parameter like number, biomass and energy in different trophic level of ecosystem. The types of ecological pyramid are:
Pyramid of number: pyramid of number shows the relationship among the trophic level in terms of number. Pyramid of number in grassland ecosystem and in pond ecosystem is upright because number of producers are larger in number than primary consumer, primary consumer are larger in number than secondary consumer and secondary consumer are larger in number than tertiary consumers.Pyramid of number is inverted in parasitic food chain.
Fig- pyramid of number in pond ecosystem and pyramid of number in parasitic food chain respectively.
Pyramid of biomass: dry weight of organism is called biomass. in grassland ecosystem and forest ecosystem, the biomass of producer is maximum and there is gradual decrease in biomass of primary consumer, secondary consumer, tertiary consumer. So, pyramid of biomass is upright in grassland and forest ecosystem.
In pond ecosystem, biomass of producer is least. The biomass gradually increases in each trophic level. so; pyramid of biomass is inverted in pond ecosystem.
fig- pyramid of biomass in grassland ecosystem and pyramid of biomass in pond ecosystem respectively
pyramid of energy
It shows the relationship of organisms in terms of energy. green plants trap solar energy for the preparation of food. Only a fraction of energy is transferred to next trophic level because some amount of energy is utilized in metabolic activities of organism of each trophic level. So the energy is decreased in successive trophic level and the pyramid becomes upright.
Food chain: the transfer of energy in the form of food from one trophic level to other trophic level by the repeated process of eating and being eaten is called food chain. the types of food chain are:
Grazing: this type of food chain starts from green plants and ends to carnivores by passing through hervivors.this chain directly depends on solar energy.
Grasses--------grasshopper---------frog------snake
Detritus: this type of food chain starts from dead and decaying organic wastes which first goes to microbes and then to organism feeding on detritus and their predators.
Detritus-------detritvores-------detritus consumer
(Fallen leaf) (Fungi) (Insects)
Parasite food chain: in this type of food chain, smaller organism consumes larger organisms without killing.
Tree-----bird-----parasite------hyperparasites
Foodweb: In an ecosystem, food chains are interlinked together and intersect each other to form a complex network called food web.
The food web provides alternative pathway of food availability. it is also controller of overpopulation species.
Ecological imbalance and its consequences
Green house effects, causes and consequences:
We receive radiation from sun which makes our earth warm. When radiations having short wave length falls on the surface of the earth, most of them (especially visible and UV light) penetrates the atmosphere which acts like the glass or plastic roof and walls of a green house. Some of the heat energy is absorbed by the earth and the remaining portion of heat energy is reflected back into the atmosphere as infrared radiation of much longer wave length. Much of this reflected radiation can’t escape into the space. Certain gases such as Carbon dioxide (CO2), Ozone (O3), Methane (CH4), CFCs, water vapours absorb the heat radiation and send the IR radiation back to the earth to warm the surface. As a whole, these gases surround and act as ‘blanket’ around the earth. During normal conditions i.e. when CO2 level is maintained within a limit, this process is beneficial but if the concentration of CO2 in the air increases the temperature of the earth also increases disastrously which is called greenhouse effect. Such phenomenon of increasing of temperature is called global warming. In fact global warming is the consequence of greenhouse effect.
causes:
Due to increase in level of co2, ch4, no2. They are also called green house gases.
Air pollution by vehicles, industries etc.
consequences:
it results in global warming
Sea level increases due to melting of polar ice.
increase in temperature cause hurricanes and cyclones in ocean
Micro climate change takes place.
Ozone layer depletion, causes and consequences:
Ozone layer is the protective layer of the earth which traps the harmful rays’ incoming to earth. Due to depletion of ozone, ozone layer becomes thinner and thinner. Ozone layer is depleted due to the reaction of ozone with harmful pollutants like cfcs. cfcs are the pollutants which are used as coolant in air cooler, refrigerator etc. cfcs inter the stratosphere and remain there for years, where they breakdown in chlorine atom due to action of u/v rays. 1 molecule of cfcs can break 1000 molecules of ozone.
CCl2F2 CL + CCLF
CL + O3 CLO + O2
CLO + O CL +O2
CL + O3 CL+ O2
Consequences:
Due to more u/v radiation, there is increase in temperature of earth which can cause climate change.
If the ozone layer is depleted, u/v radiation comes to earth and cause skin cancer.
U/v radiation decreases the rate of photosynthesis.
u/v radiation decrease the number of Phytoplanktons in water bodies
it cause imbalance in ecosystem.
Control: to control the ozone layer depletion , global awareness on decreasing the use of cfc should be done.
Acid rain, causes and consequences:
Generally, acid rain means the rain of water containing excessive amount of acids.
Oxides of Slulphur, Carbon, and Nitrogen are major gaseous pollutant of air. These oxides are produced mainly by the combustion of fossil fuels, power plants, automobile exhaust, domestic fire etc. These oxides make layers and remains in the atmosphere. During rain, they react with water to form acids like Sulphuric acid, Nitric acid, Nitrous acid which then comes to the earth surface as acid rain or remain in the atmosphere in clouds or fogs.
Acid rain problem is a man made phenomena which increases dramatically due to the industrialization. Acid rain increases soil acidity thus and decreases fertility which makes life difficult for plants and animals.
What is its result?
increase in acidity of the soil and decrease in fertility of soil
decrease in productivity of cash crops
Rare plants and animals come to stage of extinct.
acid rain makes water acidic which kills the fishes of water
Carbonate rocks and mountain decomposes due to acid rain.
Concept of mountain ecosystem:
Nepal is situated on the southern slopes of the central Himalayas. The landlocked country is sandwiched between two Asian giants – China to the north and India to the east, south and west. The Himalaya in general and Nepal Himalaya in particular contributes significantly to the global biodiversity, largely because of rapid ecological changes at spatial scales, high level , and the unique ecosystem properties. The altitudinal changes in the Himalayan Mountains are so rapid that a 30-40 km-long transect may include tropical forest as well as alpine scrub or meadows. Considering the area of the country, Nepal has rich and fascinating biological diversity. The Indo Malayan and the Palaearctic realms add to the high level of biodiversity. Nepal is endowed with at least 2.3% of the lichen species, 2.4% of the fungi, 2.6% of algae, 5.1% of bryophytes, 3.4% of pteridophytes, 5.1% of gymnosperms, 2.7% of angiosperms, 1.4% of platyhelminthes, 0.2% of spiders, 2.6% of butterflies and moths, 0.7% of other insects, 1.0% of fishes, 1.0% of amphibians, 1.6% of reptiles, 9.35 of birds and 4.5% of mammals of the world. Not many studies have been conducted on the lower plants, animals and microbes. The number of species may increase significantly with research studies. There are 118 ecosystems with distinct biological communities, and 95 ecosystems are found in the country's mid-hills and the mountains.
The highest numbers of plants occur between 1500 and 2500 m above the mean sea level. Thirty four percent of the biodiversity (plants and animal species) is found in highland (above 3000 m altitude), 63 percent in the midland (1000-3000 m) and 37 percent in the lowlands (below 1000 m). About 420 phanerogamic species are distributed in the areas that lie above 5000 m. The highest altitude at which angiosperm Christolae himalayayensis has been found in the world is at an altitude of 6300 m in the Himalaya. The interesting rate of loss of vascular plant species with a change in elevation in the alpine zone of central Nepal (>4000 m elevation) is equal to one species per 20 m of elevation gain - with a predicted complete absence of vascular plants above an elevation of 5700 m.
Five percent of the total area of the country is covered with different types of wetlands. The high altitude glacial lakes are 2323 in number and covers an area of 78.3 km2 , and some of these are very important because they attract endangered species such as the snow leopard, blue sheep, musk deer etc.
The country has not only important cultivated and domesticated plant and animal species, but also numerous species that are relatives of the wild species and are useful to plant and animal breeders. Cultivation in Nepal is found up to an altitude of 4200 m due to cold tolerant genes inherent in these crops species. The International Rice Research Institute (IRRI) has confirmed that Jumli Marsh" (paddy cultivated in the hilly district of Jumla) is one of the most cold tolerant varieties of paddy found in the world. Likewise, the genetic diversity of agricultural and horticultural crops is very impressive. It is estimated that Nepal has over 500 landraces of paddy, out of which one fifth is aromatic and fine paddy landraces. Mustang district is one of the driest and cold regions in Nepal. Triticale (Triticum x Secale hybrid) not only grows well in Mustang but it is produced at the scale of much 1 t of grain and over 30 t of leafy straw. Mountainous areas of the country have some indigenous breeds of animals and some of these are threatened. Lulu and Achhame cattle are faced with extinction and pure siri has become scarce. The country's Yak population is also decreasing while pigmy hog Pudke bandel is believed to be on the verge of extinct.
The mountain diversity is not only impressive but also important from the point of high endemism. There are 342 endemic plants and 160 endemic animal species in Nepal. About 53 percent of the total number of endemic angiosperm species is from the high altitude region of the country. Similarly, eight out of twenty endemic breeds of livestock are from the alpine species.
Forest conservation:
Forest in Nepal
Nepal is rich in biodiversity. Nepal possesses various types of forest .The types of forest in Nepal are as follows:
tropical forest:
Sal forest
tropical deciduous riverine forest
Tropical evergreen forest.
sub-tropical forest:
castanopsis forest
pine forest
alder forest
temperate forest:
lower temperate mixed broad leafed forest
temperate mixed evergreen forest
upper temperate mixed broad leaved forest
sub-alpine forest:
silver fir forest
birch-rhododendron forest
alpine forest:
tuniper- rhododendron forest
caragana-lonicera forest
alpine meadow
Importance of afforestation:
• The number of species of vascular plants is negatively affected by afforestation. Shade tolerant plant groups replace the original Heath land communities.
• Fungi and soil invertebrates respond to afforestation with an Increase in species richness.
• The total number of surface invertebrate species is similar for different habitats but species composition is radically different.
• The total number of bird species is similar between habitat types, but major changes take place in species composition and breeding densities.
it checks soil erosion and land slides.
it helps to reduce pollution.
Result of deforestation:
it cause decrease in aviability of forest resources which are important for survival of man.
it causes soil erosion and landslides during rainy season.
it destroys the natural habitat of wild animals and cause extinction of them.
it causes desertification because deforestation decrease the rate o rainfall.
in increases the amount of co2 in atmosphere
it destroys the natural beauty and demote tourism industry.
Water and land management:
Sources of water in Nepal:
rainfall(monsoon)
surface water
river(koshi)
lakes and ponds(phewa)
hot springs(at muktinath)
glaciers(khumbu)
ground water(water on soil, especially in terai region)
Use and importance:
agriculture(irrigation)
domestic use(drinking)
industrical use(draining)
tourism(rafting)
Conservation and management:
Creating public awareness in water conservation.
Purifying available fresh water.
Prohibiting discharging of waste in water resource.
storage of rain water
Utilization of ground water.
Removing water plants from water bodies.
Land management:
fertile land should not be used for non agricultural purposes
Deforestation should be stopped to prevent from land slide and soil erosion.
Afforestation must be carried out.
harmful chemicals must nut be disposed directly into land
on biodegrageble products like plastic, nylon must be burned
Regular moniterizing of land must be done to check the effect of flood and other calamities.
Ecology: ecology is the study of reciprocal relationship between living organisms and their environment.
Autecology: the study of ecological relationship regarding a single species is called Autecology.
Synecology: the study of ecological relationship of many species living together and making a community is called Synecology.
Ecological factors: any external substance or condition which surrounds and affects the life of organism in any manner is called ecological factors. These factors are living and non living. The living factors are called as biotic and nonlivings are called as abiotic factors.
biotic factors:
Autotrops: all green plants, photosynthetic bacteria and cyanobacteria which are capable of making their organic food are known as autotrops.
Heterotrops: those organisms that depend on other for feeding are known as heterotrops. They are of 3 types:
1. Primary consumer: they are herbivores and depend on plants for food. E.g. cow
2. Secondary consumers: they are primary carnivores that depend on herbivores for food. E.g. fox
3. Tertiary consumers: they are carnivores that depend on primary carnivores for food. E.g. tiger
Decomposers: the microorganisms which breakdown the complex organic substance into simple form are known as decomposers. E.g. bacteria, saprophytic fungi etc. they are the recycler of ecosystem.
#interacting system in biotic community:
in a community, members of various species show interaction. They are as follows:
Positive interaction: in this type of interaction, either both or one is benefited but neither of them is harmed. They are categorized as:
Mutualism: it is also called as symbiosis. it is a type of +ve inter specific interaction in which members of two species favors growth and survival of each other. They cannot separate from each other. E.g. lichen is symbiosis association between algae and fungi.
Commensalism: it is a kind of +ve interaction of two species ,in which one organism is benefited while other is neither benefited nor harmed. E.g. epyphytes grow on other plants for support but not for food.
Protocooperation: it is a type of +ve interaction in which both are benefited but can live separately. E.g. crow feed on lice of cow’s body and cow gets relaxed.
Colonization: some species of plants and animals live in colony for protection from predator or environmental condition, proper utilization of food, reproduction etc. E.g. volvox.
Social organization: it is a kind of +ve interaction in which species live in group and maintain division of labour among individual for better adjustment. E.g. honey bee colony consist 3 types of bee, queen is fertile female, drone is male and workers are sterile female.
Aggregation: it refers to gathering of organisms in large number to bring change in physiology and behavior of members.
Negative interaction: it is the interaction in which a member is harmed. It can be categorized as:
Predation: this is a direct interaction o two species in which one organism kills another for food. Killing animal is called predator and killed animal is called prey.e.g. Tiger feeds on deer.
Parasitism: a parasite is an organism that depends on other for nourishment and shelter. Parasitism is one sided relation in which parasite gets benefited and host gets harmed. E.g. fungi, bacteria etc.
Competition: it is a negative interaction in which member of different species competes for common resources. E.g. tiger and wolf for deer
Antibiosis: it is a relationship between two organisms of different species in which one organism inhabit the growth of another organism. E.g. penicillium doesn’t allow the growth of bacteria.
Abiotic factors:
Light: light play an important role in photosynthesis, chlorophyll formation, stomata movement and transpiration. It also affects the animals in metabolism, growth, pigmentation and locomotion.
Atmospheric gas: nitrogen and oxygen are the major atmospheric gases. O2 is mainly produced by plants during photosynthesis and is absorbed by animals during aerobic respiration. N2 is used in formation of nitrates by bacteria and nitrates act as fertilizer for plants.
Soil: soil provides nutrients, water and attachment to plants. Water from soil mainly fulfills the water requirement of plant .soil pores stores oxygen and these gas are taken by microorganism living inside soil. Bacteria of soil convert dead bodies of plant and animal into simple inorganic and organic compounds which increase the fertility of soil and support plant development.
Topography: it is the land factor which depends upon latitude and altitude. The distribution of land on earth varies from place to place such as size, shape of mountain,hills,slopes etc. the condition of land is directly proportional to the climatic variation and distribution of plants and animals.
Temperature: most of the organism can survive from the temperature range of 5-35 degree Celsius except certain bacteria. Organisms are killed at high temperature due to denaturation of enzymes while some are killed at low temperature due to freezing of body fluids.
Wind: wind cause fall of flower, buds, fruits, seeds. It also cause bending of crops called as lodging. Wind increase transpiration rate and help in pollination and dispersion of spores.
Moisture: moisture helps in bryophytic reproduction, increase rate of transpiration and help in germination too.
Rainfall: rainfall is the source of ground water and relative humidity. It is raw material for photosynthesis and is essential to maintain turgidity of soil.
Concept of ecosystem:
Trophic level: producers and consumers in ecosystem can be arranged in different feeding groups, each feeding groups is known as Trophic level. Thus the green plants which derive the food from sun are in first Trophic level. All the herbivores belong to 2nd Trophic level. All the primary carnivores belong to 3rd trophic level and all carnivores belong to 4th Trophic level.
Productivity: A constant input of solar energy is the basic requirement for any ecosystem to function and sustain.
Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis. It is expressed in terms of weight (g –2) or energy (kcal m–2). The rate of biomass production is called productivity.
It is expressed in terms of g–2 yr–1 or (kcal m–2) yr–1 to compare the
Productivity of different ecosystems. It can be divided into gross primary
Productivity (GPP) and net primary productivity (NPP). Gross primary
Productivity of an ecosystem is the rate of production of organic matter
During photosynthesis. A considerable amount of GPP is utilized by plants
in respiration. Gross primary productivity minus respiration losses (R),
is the net primary productivity (NPP).
GPP – R = NPP
Net primary productivity is the available biomass for the consumption
to heterotrops (herbivores and decomposers).
Secondary productivity is defined as the rate of formation of new organic matter by consumers. Primary productivity depends on the plant species inhabiting a
particular area. It also depends on a variety of environmental factors,
Availability of nutrients and photosynthetic capacity of plants. Therefore,
it varies in different types of ecosystems. The annual net primary
Productivity of the whole biosphere is approximately 170 billion tons
(dry weight) of organic matter. Of this, despite occupying about 70 per
cent of the surface, the productivity of the oceans are only 55 billion tons.
Rest of course, is on land.
Ecological pyramid:
Ecological pyramid is the graphical representation of ecological parameter like number, biomass and energy in different trophic level of ecosystem. The types of ecological pyramid are:
Pyramid of number: pyramid of number shows the relationship among the trophic level in terms of number. Pyramid of number in grassland ecosystem and in pond ecosystem is upright because number of producers are larger in number than primary consumer, primary consumer are larger in number than secondary consumer and secondary consumer are larger in number than tertiary consumers.Pyramid of number is inverted in parasitic food chain.
Fig- pyramid of number in pond ecosystem and pyramid of number in parasitic food chain respectively.
Pyramid of biomass: dry weight of organism is called biomass. in grassland ecosystem and forest ecosystem, the biomass of producer is maximum and there is gradual decrease in biomass of primary consumer, secondary consumer, tertiary consumer. So, pyramid of biomass is upright in grassland and forest ecosystem.
In pond ecosystem, biomass of producer is least. The biomass gradually increases in each trophic level. so; pyramid of biomass is inverted in pond ecosystem.
fig- pyramid of biomass in grassland ecosystem and pyramid of biomass in pond ecosystem respectively
pyramid of energy
It shows the relationship of organisms in terms of energy. green plants trap solar energy for the preparation of food. Only a fraction of energy is transferred to next trophic level because some amount of energy is utilized in metabolic activities of organism of each trophic level. So the energy is decreased in successive trophic level and the pyramid becomes upright.
Food chain: the transfer of energy in the form of food from one trophic level to other trophic level by the repeated process of eating and being eaten is called food chain. the types of food chain are:
Grazing: this type of food chain starts from green plants and ends to carnivores by passing through hervivors.this chain directly depends on solar energy.
Grasses--------grasshopper---------frog------snake
Detritus: this type of food chain starts from dead and decaying organic wastes which first goes to microbes and then to organism feeding on detritus and their predators.
Detritus-------detritvores-------detritus consumer
(Fallen leaf) (Fungi) (Insects)
Parasite food chain: in this type of food chain, smaller organism consumes larger organisms without killing.
Tree-----bird-----parasite------hyperparasites
Foodweb: In an ecosystem, food chains are interlinked together and intersect each other to form a complex network called food web.
The food web provides alternative pathway of food availability. it is also controller of overpopulation species.
Ecological imbalance and its consequences
Green house effects, causes and consequences:
We receive radiation from sun which makes our earth warm. When radiations having short wave length falls on the surface of the earth, most of them (especially visible and UV light) penetrates the atmosphere which acts like the glass or plastic roof and walls of a green house. Some of the heat energy is absorbed by the earth and the remaining portion of heat energy is reflected back into the atmosphere as infrared radiation of much longer wave length. Much of this reflected radiation can’t escape into the space. Certain gases such as Carbon dioxide (CO2), Ozone (O3), Methane (CH4), CFCs, water vapours absorb the heat radiation and send the IR radiation back to the earth to warm the surface. As a whole, these gases surround and act as ‘blanket’ around the earth. During normal conditions i.e. when CO2 level is maintained within a limit, this process is beneficial but if the concentration of CO2 in the air increases the temperature of the earth also increases disastrously which is called greenhouse effect. Such phenomenon of increasing of temperature is called global warming. In fact global warming is the consequence of greenhouse effect.
causes:
Due to increase in level of co2, ch4, no2. They are also called green house gases.
Air pollution by vehicles, industries etc.
consequences:
it results in global warming
Sea level increases due to melting of polar ice.
increase in temperature cause hurricanes and cyclones in ocean
Micro climate change takes place.
Ozone layer depletion, causes and consequences:
Ozone layer is the protective layer of the earth which traps the harmful rays’ incoming to earth. Due to depletion of ozone, ozone layer becomes thinner and thinner. Ozone layer is depleted due to the reaction of ozone with harmful pollutants like cfcs. cfcs are the pollutants which are used as coolant in air cooler, refrigerator etc. cfcs inter the stratosphere and remain there for years, where they breakdown in chlorine atom due to action of u/v rays. 1 molecule of cfcs can break 1000 molecules of ozone.
CCl2F2 CL + CCLF
CL + O3 CLO + O2
CLO + O CL +O2
CL + O3 CL+ O2
Consequences:
Due to more u/v radiation, there is increase in temperature of earth which can cause climate change.
If the ozone layer is depleted, u/v radiation comes to earth and cause skin cancer.
U/v radiation decreases the rate of photosynthesis.
u/v radiation decrease the number of Phytoplanktons in water bodies
it cause imbalance in ecosystem.
Control: to control the ozone layer depletion , global awareness on decreasing the use of cfc should be done.
Acid rain, causes and consequences:
Generally, acid rain means the rain of water containing excessive amount of acids.
Oxides of Slulphur, Carbon, and Nitrogen are major gaseous pollutant of air. These oxides are produced mainly by the combustion of fossil fuels, power plants, automobile exhaust, domestic fire etc. These oxides make layers and remains in the atmosphere. During rain, they react with water to form acids like Sulphuric acid, Nitric acid, Nitrous acid which then comes to the earth surface as acid rain or remain in the atmosphere in clouds or fogs.
Acid rain problem is a man made phenomena which increases dramatically due to the industrialization. Acid rain increases soil acidity thus and decreases fertility which makes life difficult for plants and animals.
What is its result?
increase in acidity of the soil and decrease in fertility of soil
decrease in productivity of cash crops
Rare plants and animals come to stage of extinct.
acid rain makes water acidic which kills the fishes of water
Carbonate rocks and mountain decomposes due to acid rain.
Concept of mountain ecosystem:
Nepal is situated on the southern slopes of the central Himalayas. The landlocked country is sandwiched between two Asian giants – China to the north and India to the east, south and west. The Himalaya in general and Nepal Himalaya in particular contributes significantly to the global biodiversity, largely because of rapid ecological changes at spatial scales, high level , and the unique ecosystem properties. The altitudinal changes in the Himalayan Mountains are so rapid that a 30-40 km-long transect may include tropical forest as well as alpine scrub or meadows. Considering the area of the country, Nepal has rich and fascinating biological diversity. The Indo Malayan and the Palaearctic realms add to the high level of biodiversity. Nepal is endowed with at least 2.3% of the lichen species, 2.4% of the fungi, 2.6% of algae, 5.1% of bryophytes, 3.4% of pteridophytes, 5.1% of gymnosperms, 2.7% of angiosperms, 1.4% of platyhelminthes, 0.2% of spiders, 2.6% of butterflies and moths, 0.7% of other insects, 1.0% of fishes, 1.0% of amphibians, 1.6% of reptiles, 9.35 of birds and 4.5% of mammals of the world. Not many studies have been conducted on the lower plants, animals and microbes. The number of species may increase significantly with research studies. There are 118 ecosystems with distinct biological communities, and 95 ecosystems are found in the country's mid-hills and the mountains.
The highest numbers of plants occur between 1500 and 2500 m above the mean sea level. Thirty four percent of the biodiversity (plants and animal species) is found in highland (above 3000 m altitude), 63 percent in the midland (1000-3000 m) and 37 percent in the lowlands (below 1000 m). About 420 phanerogamic species are distributed in the areas that lie above 5000 m. The highest altitude at which angiosperm Christolae himalayayensis has been found in the world is at an altitude of 6300 m in the Himalaya. The interesting rate of loss of vascular plant species with a change in elevation in the alpine zone of central Nepal (>4000 m elevation) is equal to one species per 20 m of elevation gain - with a predicted complete absence of vascular plants above an elevation of 5700 m.
Five percent of the total area of the country is covered with different types of wetlands. The high altitude glacial lakes are 2323 in number and covers an area of 78.3 km2 , and some of these are very important because they attract endangered species such as the snow leopard, blue sheep, musk deer etc.
The country has not only important cultivated and domesticated plant and animal species, but also numerous species that are relatives of the wild species and are useful to plant and animal breeders. Cultivation in Nepal is found up to an altitude of 4200 m due to cold tolerant genes inherent in these crops species. The International Rice Research Institute (IRRI) has confirmed that Jumli Marsh" (paddy cultivated in the hilly district of Jumla) is one of the most cold tolerant varieties of paddy found in the world. Likewise, the genetic diversity of agricultural and horticultural crops is very impressive. It is estimated that Nepal has over 500 landraces of paddy, out of which one fifth is aromatic and fine paddy landraces. Mustang district is one of the driest and cold regions in Nepal. Triticale (Triticum x Secale hybrid) not only grows well in Mustang but it is produced at the scale of much 1 t of grain and over 30 t of leafy straw. Mountainous areas of the country have some indigenous breeds of animals and some of these are threatened. Lulu and Achhame cattle are faced with extinction and pure siri has become scarce. The country's Yak population is also decreasing while pigmy hog Pudke bandel is believed to be on the verge of extinct.
The mountain diversity is not only impressive but also important from the point of high endemism. There are 342 endemic plants and 160 endemic animal species in Nepal. About 53 percent of the total number of endemic angiosperm species is from the high altitude region of the country. Similarly, eight out of twenty endemic breeds of livestock are from the alpine species.
Forest conservation:
Forest in Nepal
Nepal is rich in biodiversity. Nepal possesses various types of forest .The types of forest in Nepal are as follows:
tropical forest:
Sal forest
tropical deciduous riverine forest
Tropical evergreen forest.
sub-tropical forest:
castanopsis forest
pine forest
alder forest
temperate forest:
lower temperate mixed broad leafed forest
temperate mixed evergreen forest
upper temperate mixed broad leaved forest
sub-alpine forest:
silver fir forest
birch-rhododendron forest
alpine forest:
tuniper- rhododendron forest
caragana-lonicera forest
alpine meadow
Importance of afforestation:
• The number of species of vascular plants is negatively affected by afforestation. Shade tolerant plant groups replace the original Heath land communities.
• Fungi and soil invertebrates respond to afforestation with an Increase in species richness.
• The total number of surface invertebrate species is similar for different habitats but species composition is radically different.
• The total number of bird species is similar between habitat types, but major changes take place in species composition and breeding densities.
it checks soil erosion and land slides.
it helps to reduce pollution.
Result of deforestation:
it cause decrease in aviability of forest resources which are important for survival of man.
it causes soil erosion and landslides during rainy season.
it destroys the natural habitat of wild animals and cause extinction of them.
it causes desertification because deforestation decrease the rate o rainfall.
in increases the amount of co2 in atmosphere
it destroys the natural beauty and demote tourism industry.
Water and land management:
Sources of water in Nepal:
rainfall(monsoon)
surface water
river(koshi)
lakes and ponds(phewa)
hot springs(at muktinath)
glaciers(khumbu)
ground water(water on soil, especially in terai region)
Use and importance:
agriculture(irrigation)
domestic use(drinking)
industrical use(draining)
tourism(rafting)
Conservation and management:
Creating public awareness in water conservation.
Purifying available fresh water.
Prohibiting discharging of waste in water resource.
storage of rain water
Utilization of ground water.
Removing water plants from water bodies.
Land management:
fertile land should not be used for non agricultural purposes
Deforestation should be stopped to prevent from land slide and soil erosion.
Afforestation must be carried out.
harmful chemicals must nut be disposed directly into land
on biodegrageble products like plastic, nylon must be burned
Regular moniterizing of land must be done to check the effect of flood and other calamities.
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