ECOLOGICAL PYRAMIDS iIN TELUGU

#ECOLOGICAL PYRAMIDS Introduction to Ecological Pyramids Ecological pyramids are graphical representations of the trophic structure of an ecosystem. They illustrate the relationship between different trophic levels in terms of the number of organisms, biomass, or energy present at each level. Ecological pyramids help us understand the organization, productivity, and energy flow within an ecosystem. The concept of ecological pyramids was introduced by the British ecologist Charles Elton in 1927. Therefore, ecological pyramids are also known as Eltonian pyramids. They provide a simplified representation of feeding relationships between organisms in an ecosystem. An ecological pyramid generally consists of producers at the base and different levels of consumers arranged above them. The shape of the pyramid varies depending on the type of ecological pyramid and the characteristics of the ecosystem. Types of Ecological Pyramids There are three major types of ecological pyramids: 1. Pyramid of Numbers 2. Pyramid of Biomass 3. Pyramid of Energy 1. Pyramid of Numbers The pyramid of numbers represents the number of individual organisms present at each trophic level in an ecosystem. It shows the numerical relationship between producers, herbivores, and carnivores. A. Upright Pyramid of Numbers An upright pyramid of numbers occurs when the number of organisms decreases from the producer level to the higher consumer levels. Example: Grassland ecosystem. Grass → Grasshoppers → Frogs → Snakes → Hawks In a grassland ecosystem, numerous grasses support a smaller number of herbivores. These herbivores support fewer secondary consumers, and the number of top predators is generally smaller. B. Inverted Pyramid of Numbers An inverted pyramid of numbers occurs when the number of producers is smaller than the number of consumers at one or more higher trophic levels. Example: A tree ecosystem. One large tree may support hundreds of insects, and these insects may support several parasites. Therefore, the pyramid may appear inverted or irregular. 2. Pyramid of Biomass The pyramid of biomass represents the total dry mass of living organisms present at each trophic level per unit area at a particular time. Biomass is generally expressed in grams per square metre or kilograms per square metre. A. Upright Pyramid of Biomass An upright pyramid of biomass is commonly observed in terrestrial ecosystems, such as forests and grasslands. Example: Forest ecosystem. The biomass decreases at successive trophic levels because energy is lost during transfer and organisms use energy for their metabolic activities. B. Inverted Pyramid of Biomass An inverted pyramid of biomass is commonly observed in many aquatic ecosystems. 3. Pyramid of Energy The pyramid of energy represents the amount of energy available or transferred at each trophic level per unit area per unit time. It is usually expressed in kilojoules or kilocalories per square metre per year. The pyramid of energy is always upright because energy decreases at each successive trophic level. Example: Producers → Primary consumers → Secondary consumers → Tertiary consumers Ten Percent Law The ten percent law was proposed by Raymond Lindeman in 1942. According to this ecological principle, approximately 10% of the energy available at one trophic level is transferred to the next trophic level, while the remaining energy is largely used in metabolic activities or dissipated as heat. For example: Producers: 10,000 kJ Primary consumers: 1,000 kJ Secondary consumers: 100 kJ Tertiary consumers: 10 kJ These values are illustrative. Actual transfer efficiencies vary among ecosystems and trophic levels. The ten percent law helps explain why food chains are usually short and why top predators generally receive less energy than organisms at lower trophic levels. Difference Between the Three Ecological Pyramids Pyramid of numbers: Represents the number of individual organisms at each trophic level. It may be upright, inverted, or irregular. Pyramid of biomass: Represents the total biomass of organisms at each trophic level. It is usually upright in terrestrial ecosystems but may be inverted in aquatic ecosystems. Pyramid of energy: Represents energy flow through successive trophic levels. It is always upright because energy is lost during transfer. Important Points for Competitive Examinations Charles Elton introduced the concept of ecological pyramids in 1927. Ecological pyramids are also called Eltonian pyramids. The three major types are pyramids of numbers, biomass, and energy. The pyramid of energy is always upright. The pyramid of numbers may be upright, inverted, or irregular. The pyramid of biomass is generally upright in terrestrial ecosystems and may be inverted in aquatic ecosystems. Raymond Lindeman proposed the ten percent law in 1942. Energy flow through ecosystems is unidirectional. -