Environmental Microbiology

Ecological Pyramids – Definition, Types, Importance

What are Ecological Pyramids? An ecological pyramid (also called a trophic pyramid, Eltonian pyramid, energy pyramid, or sometimes a food pyramid) is...

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This article writter by Sourav Bio on October 05, 2022

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Ecological Pyramids - Definition, Types, Importance
Ecological Pyramids - Definition, Types, Importance

What are Ecological Pyramids?

An ecological pyramid (also called a trophic pyramid, Eltonian pyramid, energy pyramid, or sometimes a food pyramid) is a diagram that shows the biomass or bioproductivity at each trophic level in an ecosystem.

Ecological pyramid
Ecological pyramid
  • An ecological pyramid is a picture that shows how the different living things at different trophic levels are related to each other.
  • G.Evylen Hutchinson and Raymond Lindeman gave it.
  • You can see that these pyramids look like real pyramids, with the widest part at the base, where the lowest level of the food chain, the producers, live.
  • The next trophic level, which are the primary consumers, move up to the next level, and so on.
  • When making these types of ecological pyramids, all of the calculations must take into account all of the organisms in a certain trophic level. This is because a sample space of just a few numbers or species will lead to a lot of mistakes.
  • A pyramid of energy shows how much energy is kept in the form of new biomass at each trophic level. A pyramid of biomass shows how much biomass (the amount of living or organic matter in an organism) is in the organisms.
  • There is also a number pyramid that shows how many different organisms are at each trophic level.
  • Most pyramids of energy stand straight up, but some can be upside down or have other shapes.
  • Ecological pyramids start at the bottom with producers, like plants, and go up through the different trophic levels (such as herbivores that eat plants, then carnivores that eat flesh, then omnivores that eat both plants and flesh, and so on). The top of the food chain is the most important level.
  • A bomb calorimeter can be used to measure biomass.

Types of Ecological pyramid

There are present different types of Ecological pyramid such as;

  • Pyramid of Numbers
  • Pyramid of Energy
  • Pyramid of Biomass

1. Pyramid of Numbers

A number pyramid is one of the varieties of ecological pyramids. The pyramid of numbers represents graphically the population or abundance of a species at each level of a food chain. The pyramid of numbers illustrates the number of creatures in each trophic level without taking their sizes or biomass into account.

Pyramid of Numbers
Pyramid of Numbers | Source: Swiggity.Swag.YOLO.Bro, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
  • A number pyramid represents the total number of persons (population) existing at each trophic level.
  • In 1972, Elton John coined the phrase “pyramid of numbers.”
  • This pyramid is quite effective when it comes to counting the number of creatures.
  • Simple counting can be performed throughout time to determine how an environment has changed. However, counting certain species, particularly early forms, might be challenging.
  • According on the number of organisms, the number pyramid might be either upright or inverted.

Types of Pyramid of Numbers

a. Pyramid of Numbers – Upright

  • From the lowest trophic level to the highest, the number of individuals declines in this pyramid.
  • In the ecosystems of grassland and pond, this type of pyramid can be found. Due to their profusion, grasses occupy the lowest trophic level (base).
  • Primary consumers, like grasshoppers, represent the next trophic level up.
  • There are fewer grasshoppers per square metre than there are blades of grass.
  • The next energy level is a simple carnivore, such as a rat. Rats have a smaller number than grasshoppers due to the fact that rats consume grasshoppers.
  • The next higher trophic level includes secondary carnivores, such as snakes. They consume rat.
  • The next trophic level above the apex predator, such as the Hawk, is the next higher level. As trophic levels increase, fewer individuals are present.
Types of Pyramid of Numbers
Types of Pyramid of Numbers

b. Pyramid of Numbers – Inverted

  • The exact opposite of upright pyramids are inverted pyramids.
  • This is evident in the tree ecology, where trees are the producers and insects are the consumers.
  • Food wastage while eating, food wastage during digesting, and food use during respiration and physical activity all contribute to the population reduction of higher tropic species.

2. Pyramid of Energy

The energy pyramid is a straight pyramid that shows how energy moves from people who make it to people who use it. It also shows how different creatures play a part in energy transmission. As energy moves from one trophic level to the next, energy pyramids show how much energy is needed in the next level. The rule of thermodynamics says that energy can’t be created or destroyed; it can only change from one form to another. This can be used to describe how energy moves through this pyramid.

Pyramid of Energy
Pyramid of Energy | Image Credit: Swiggity.Swag.YOLO.Bro, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
  • The best way to figure out what each trophic level does in an ecosystem is to use an energy pyramid.
  • An energy pyramid shows how much energy is at each trophic level as well as how much energy is lost when a species moves up or down a trophic level.
  • So, the pyramid is always going up, and it has a big energy base at the bottom.

Characteristics of Pyramid of Energy

  • The rate at which food (in the form of energy) moves through the food chain determines how energy pyramids are built.
  • Even though some species have less mass, the total amount of energy they use and pass on is much higher than that of species with more mass.
  • Most energy pyramids are tilted because each trophic level gives out less energy than it takes in.
  • For example, in ecosystems with open water, producers have less bulk biomass than consumers.
  • But the amount of energy saved and passed on should be more than it was on the last level.

Levels of Pyramid of Energy

Producers

  • The producers and the energy they can give off make up the first level of the energy pyramid.
  • Most of these producers are autotrophs, which are organisms that make their own food by getting energy from non-living sources.
  • These are often plants that get their energy from the sun.
  • Some autotrophs get the energy they need from the soil instead of the sun. Autotrophs are things like earthworms and fungi that grow on their own.
  • On the other hand, producers like mushrooms and earthworms get less energy from the soil than green plants do from the sun.
  • At the bottom of the energy pyramid, you can only find heterotrophs, which are organisms that get their food from organic carbon, usually from other organisms.

Primary Consumers

  • The second level of the energy pyramid is comprised of primarily herbivorous primary consumers.
  • Herbivores are organisms that obtain all of their nutrition and sustenance from plants.
  • After absorbing the sun’s energy, plants transmit it to their principal consumers.
  • This facilitates the transfer of solar energy from one trophic level to the next.
  • Although humans are not entirely dependent on primary consumers, their presence in the ecosystem is crucial. Otherwise, the system will malfunction.

Secondary Consumers

  • Secondary users comprise the third level of the energy pyramid.
  • Carnivores is a popular term for these organisms. Secondary consumers are organisms whose survival and nourishment depend on primary consumers.
  • The carnivores would not exist if there were no primary consumers.
  • The energy that was formerly provided by producers to the primary consumers is now transmitted to this level.
  • This permits a more efficient transfer of energy.

Tertiary Consumers

  • Tertiary users are located at the bottom of the energy pyramid. It refers to the proportion of secondary carnivores that ingest both primary and secondary consumers.
  • At this stage, the energy level of the ecosystem is complete.
  • The unused plant energy is returned to the environment, including the soil, water, and atmosphere. Afterwards, it is often sent into space.
  • To preserve the stability of the planet, it is essential that all levels of the energy pyramid receive adequate energy.

Advantages of the pyramid of energy

  • It takes into account the output rate over a period of time.
  • The life spans of two animals with comparable biomass may vary greatly. Thus, comparing their total biomasses directly is inaccurate, but their productivity can be compared directly.
  • Using energy pyramids, the relative energy chain within an ecosystem may be compared, as can the energy chains of other ecosystems.
  • No inverted pyramids exist.
  • Addition of solar energy is possible.

Disadvantages of the pyramid of energy

  • The pace of an organism’s biomass production must be determined, which requires tracking its growth and reproduction over time.
  • The problem of attributing species to a certain trophic level persists. In addition to allocating decomposers and detritivores to a particular level, there is the issue of classifying organisms in food chains.

Examples of Pyramid of Energy

  • Suppose a deer consumes a plant containing 100 calories of dietary energy.
  • Only 10 calories are stored as dietary energy because a portion of it is used for the deer’s metabolism. A lion that consumes a deer receives far less energy.
  • As a result, as energy goes from the sun to the producer to the herbivore to the carnivore, its usefulness decreases.
  • As a result, the energy pyramid will always remain erect.

3. Pyramid of Biomass

A biomass pyramid is a graphical representation of the biomass contained in a unit area at several trophic levels. It illustrates the relationship between biomass and trophic level, as well as the biomass available at any given time in each trophic level of an energy community.

Pyramid of Biomass
Pyramid of Biomass | Image Credit: Swiggity.Swag.YOLO.Bro, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
  • At a particular trophic level, biomass is the amount of living material present in an individual or group of individuals per unit of surface area.
  • This type of ecological pyramid accounts for the amount of biomass present at each trophic level at each level.
  • The pyramidal representation of biomass is based on the second rule of thermodynamics.
  • This law states that energy cannot be generated or destroyed, but can be transported from one state to another.
  • In particular, energy is transported from producers to consumers, etc., and subsequently turned into biomass.
  • A biomass pyramid can be used to determine the quantity of biomass produced by organisms at different trophic levels.

What is Biomass?

  • In ecological terms, biomass refers to the total mass of all living or organic materials in an ecosystem at any one time.
  • Biomass can be separated into two classes: Community Biomass and Species Biomass
  • Biomass of all species in an ecosystem is known as species biomass.
  • Community biomass, on the other hand, refers to the total mass of all species that regard the designated community to be their habitat.
  • In terms of measuring biomass, species can range from people to microbes.

Features of Pyramid of Biomass

  • In this procedure, individuals at each trophic level are weighed rather than counted.
  • This yields a biomass pyramid, which depicts the total dry weight of all organisms at each trophic level at a given time.
  • To determine the biomass pyramid, the dry weight of all species in each trophic level is routinely collected and measured.
  • Since all trophic levels of creatures are weighed, the problem of size disparity is resolved. The unit for measuring biomass is grammes per square metre.

Types of Biomass Pyramid

a. Upward Pyramid

  • In the majority of terrestrial ecosystems, the biomass pyramid has a large base of primary producers and a lower trophic level on top.
  • Autotrophic producer biomass is at an all-time high.
  • The next trophic level, primary consumers, have a smaller biomass than producers.
  • The next higher trophic level, secondary consumers, have a lesser biomass than primary consumers.
  • There is a low amount of biomass at the highest trophic level.
Types of Biomass Pyramid
Types of Biomass Pyramid

b. Inverted Pyramid

A biomass inverted pyramid is a graphical representation of the biomass contained in a unit area at several trophic levels, with fewer producers at the base of the pyramid relative to consumers at higher trophic levels. In numerous aquatic ecosystems, the biomass pyramid may have an inverted form.

  • Inverted pyramids are pyramids with a small base and a wide apex.
  • It indicates that compared to herbivores and carnivores, the number of biomass at the first trophic level, also known as the producer level, is low.
  • Inverted pyramids are its proper name.
  • In certain aquatic habitats, the shape of the biomass pyramid may be inverted.
  • The base of the biomass pyramid is modest, with consumer biomass exceeding production biomass at any one time, and the pyramid is inverted.

Example of Inverted Pyramid

Biomass Pyramid of a Marine Ecosystem

  • The pyramid of biomass in the aquatic ecosystem is inverted.
  • The biomass of primary producers is significantly less than that of zooplanktons, which is less than that of small and large fish, which have the greatest biomass.
  • You may ask how this is feasible and how the ecosystem is able to thrive with so few phytoplanktons.
  • Because phytoplanktons have a quicker rate of reproduction and a shorter life span, despite the fact that their amount is lower at any given time, they refill frequently to fulfil the increased demand of zooplankton and larger fish.
  • A consumer can easily subsist on a modest amount of food if its production exceeds its consumption.

What is the Pyramid of Biomass?

  • At a particular trophic level, biomass is the amount of living material present in an individual or group of individuals per unit of surface area.
  • This type of ecological pyramid accounts for the amount of biomass present at each trophic level at each level.
  • The pyramidal representation of biomass is based on the second rule of thermodynamics.
  • This law states that energy cannot be generated or destroyed, but can be transported from one state to another.
  • In particular, energy is transported from producers to consumers, etc., and subsequently turned into biomass.
  • A biomass pyramid can be used to determine the quantity of biomass produced by organisms at different trophic levels.

Limitations of Pyramid of Biomass

  • Each trophic level looks to contain more energy than it actually does, which is one of the most severe downsides of a biomass pyramid.
  • Humans’ ingestion of other animals is a prime illustration of this.
  • The animal’s bone mass is determined. In contrast, the mass of the bones is not utilised at the next level of the biomass pyramid.
  • In a biomass pyramid, the mass that is not actually transmitted to the next trophic level is tallied.
  • Nevertheless, the biomass pyramid remains one of the most reliable methods for determining whether an ecosystem is out of balance.

Example of Biomass Pyramid

  • Mice will consume grass seeds. The owl consumes the mice, while the mice consume the owl.
  • In this food web, grass has the most biomass.
  • Consequently, its biomass is located at the base of the pyramid.
  • In contrast, the owl has the lowest biomass in the food chain and hence occupies the top of the pyramid.
  • Pond ecosystem is the best illustration of an inverted pyramid. The ecosystem’s primary producer, phytoplankton, has a lesser mass than the ecosystem’s consumers, which are primarily fish and other insects.

Energy Flow in an Ecological Pyramid

  • Energy is transported between trophic levels when one organism consumes another and gets energy-rich compounds from its prey’s body.
  • However, because these transfers are inefficient, the length of food chains is restricted.
  • A portion of the energy that enters a trophic level is stored as biomass, a component of the bodies of animals.
  • This is the energy available to the next trophic level, as only energy stored as biomass may be consumed.
  • Only about 10% of the energy accumulated as biomass in one trophic level (per unit time) is eventually stored as biomass in the next trophic level (per unit time).
  • This pattern of fractional transfer limits the length of food chains; after a given number of trophic levels, often between three and six, there is insufficient energy flow to support a population at a higher level.

Features of the Ecological pyramid

  • On the same level of the pyramid are organisms that depend on a similar type of food-consumer relationships.
  • Located inside the ecosystem, the ecological pyramid has two to four strata.
  • The producers occupy the lowest tier of an environmental pyramid. The number and quantity of producers at this level are notably elevated.
  • The apex predators inhabit the highest rung of the ecological pyramid.
  • The number and quantity of consumers at the apex of the ecological pyramid are small.
  • At the apex of the pyramid, the supply of food energy steadily diminishes. Therefore, the shape of the pyramid’s apex is constrained and pointed.
  • The number of living organisms at the top of the environmental pyramid decreases gradually, but their size and volume increase.

Importance of Ecological Pyramid 

The reasons for the significance of the ecological pyramid in a biological system are given below.

  • The ecology pyramid considers the eating patterns of diverse organisms.
  • In an ecosystem, the ecological pyramids represent the number of living organisms.
  • It provides some clarity regarding the amount of energy transferred from one trophic level to the next in a biological system.
  • It provides information about the region’s biodiversity.
  • The ecological pyramid is built on the interaction between food producers and consumers.
  • If the order of the food chain is demolished, the biological pyramid will be destroyed and the entire ecosystem will be severely damaged.
  • It aids in maintaining balance and assessing the overall state of a biological environment.

Limitations of Ecological Pyramid 

The ecological pyramid has its own set of limitations because it overlooks a number of crucial perspectives. These are discussed in the following section:

  • The ecological pyramid is only applicable in the case of simple food chains.
  • This pyramid makes no mention of the rate at which energy is transferred from one trophic level to the next.
  • Even though their relevance to the environment is unsurpassed, significant energy sources such as trash and humus are completely disregarded in the ecological pyramid.
  • Similar species residing at different levels of a pyramid are not considered.
  • As with the food chain, several species may inhabit multiple trophic levels. Therefore, this method does not account for food webs.
  • Saprophytes are not accounted for in any of the pyramids, despite being an integral aspect of many ecosystems.
  • These pyramids only apply to basic food chains, which do not typically exist in nature.
  • These pyramids provide little information regarding seasonal and climatic differences.
  • They do not consider the notion of different levels of the same species existing.

References

  • https://en.wikipedia.org/wiki/Ecological_pyramid
  • https://www.geeksforgeeks.org/ecological-pyramid/
  • https://www.vedantu.com/biology/ecological-pyramid-and-its-types
  • https://prepp.in/news/e-492-ecological-pyramids-environment-notes
  • https://www.aakash.ac.in/important-concepts/biology/different-types-of-ecological-pyramid
  • https://eartheclipse.com/environment/ecosystem/ecological-pyramid-definition-types-examples.html
  • https://biologydictionary.net/ecological-pyramid/
  • https://www.biologyexams4u.com/2019/02/what-are-3-types-of-ecological-pyramids.html
  • https://www.yaclass.in/p/science-cbse/class-10/our-environment-12312/re-82656333-e3c4-4b96-8b39-0433913b7655
  • https://www.slideshare.net/AnkitAbhilashSwain/ecological-pyramids-ppt-133092700
  • https://ib.bioninja.com.au/options/option-c-ecology-and-conser/c2-communities-and-ecosyste/ecological-pyramids.html
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