Biomass Definition (Ecology)
Biomass in ecology refers to the total mass of living organisms—plants, animals, and microorganisms—in a given ecosystem at a specific time. It can be measured as species biomass or community biomass and serves as an indicator of energy flow through food chains. Biomass comes in different physical forms. However, it is typically composed primarily of cellulose and the rest is hemi cellulose and lignin.
This Story also Contains
- What is Biomass?
- Biomass Definition in Ecology
- Types of Biomass
- How is Biomass Measured?
- Biomass and Energy Flow in Ecosystem
- Pyramid of Biomass
- Biomass NEET MCQs
Biomass plays a key role in understanding ecosystem productivity and energy transfer. It can also be defined as the mass of one or more species (species biomass) or the group of all species living in a colony (community biomass). Biomass includes all microorganisms, plants and animals. It is an important part of the class 12th chapter Ecosystem in Biology.
What is Biomass?
Biomass is biological material derived from living, or recent living organisms. Biomass equally applies to both animal and plant derived material. Biomass is primarily found in the biological wastes, municipal solid waste from industrial and home use. These are called biomass feedstocks. Biomass is the oldest energy source.
Biomass Definition in Ecology
In terms of ecology, biomass is defined as the total population of all the living organisms existing in a given ecosystem at a given time. Generally, biomass is calculated as the total natural mass of an organism. However, other applications consider only the tissue mass of an organism and exclude bones, teeth, horns, and shells. Some other calculations calculate the mass of organically bound carbon atoms (C).
Biomass, in ecology, is the total mass of living organisms present in a given area or ecosystem at any given time. It is composed of all plants, animals, microorganisms, and so forth. Biomass is a good means through which the level of energy present in a particular ecosystem may be determined since living organisms store sun-derived energy in the form of organic matter created by such processes as photosynthesis.
Biomass is an important feature of the ecological process, as it represents the energy and nutrients to which higher trophic levels are able to gain access within a food web - herbivores, carnivores, etc. Biomass can be very different between biomes, for instance, biomass is much more significant in the densest vegetation of tropical rainforests and relatively lower in deserts. Measurements of biomass can help ecologists understand ecosystems' productivity, energy flow, and sustaining ability towards living forms.
Types of Biomass
There are 2 types of biomass:
Species Biomass: It is the total mass of a single species within a given area. It focuses on one particular type of species like a specific tree.
Community Biomass: It is the total mass of all the living organisms, including all species in a specific ecosystem at a given time. It considers the total mass of all different species interacting within the same area.
How is Biomass Measured?
Biomass is measured in terms of dry mass of tissue per unit area or the mass of carbon in an organism. Dry mass is the mass of an organism after its water has been removed. To remove water, the organism is dried in an oven for several days. Dry mass is generally measured in grams or kilograms per meter squared (g m-2, kg m-2). Calorimeters are used to measure the biomass. A calorimeter burns the biomass and calculates the chemical energy released per gram.
Biomass and Energy Flow in Ecosystem
Biological activities require consumption of energy which ultimately comes from the sun. Except for the deep sea ecosystem, the sun is the only source of energy for all ecosystems.
Sun: The energy used for all plant life processes is derived from solar radiations and all animals are further dependent on plants. Only 2 to 10% of the sunlight is used by the plants and the remaining is absorbed as heat by water or ground.
Producers: The green plants in the ecosystem are called producers. Major producers are herbaceous and woody plants. In an aquatic ecosystem, primary producers are various species like phytoplanktons, algae and higher plants.
Consumers: All animals depend on producers (directly or indirect) for their food needs. Hence, they are called consumers and heterotrophs.
Decomposers: The heterotrophic organisms, mainly fungi and bacteria, which meet their energy requirements by degrading dead and organic matter or detritus are called decomposers. They are also called saprotrophs.
Pyramid of Biomass
The pyramid of biomass is the graphical representation of biomass per unit area of different trophic levels, with the producers at the base and carnivores at the top. Biomass is calculated by the mass of each individual multiplied by the number of individuals at each trophic level. Upright pyramid of biomass in a terrestrial ecosystem and inverted pyramid in an aquatic ecosystem. The pyramid gives information about the trophic structures and framework for the study of ecosystem energetics. It also allows us to observe the changes in the ecosystem due to several factors.
Biomass NEET MCQs
Q1. Which of the following statements is true about the Pyramid of Biomass?
It always shows a pyramid shape in all ecosystems.
It represents the total mass of organisms in a given area.
It is a graphical representation of the energy available at each trophic level.
It can never be inverted in an ecosystem.
Correct answer: 2) It represents the total mass of organisms in a given area
Explanation:
Pyramid of Biomass
A pyramid of biomass essentially quantifies the total living or organic matter present in a specific area at each trophic level within an ecological community. This includes the biomass of producers, such as plants, at the base, followed by herbivores that consume these plants, and subsequently, the carnivores that feed on the herbivores, known as first-level carnivores. The biomass is measured in units of mass per unit area.
It's crucial to note that in terrestrial ecosystems, the biomass typically decreases as we ascend the pyramid. For example, the biomass of a solitary tree is significantly greater than the collective biomass of various birds that depend on it for food. Similarly, the biomass of these birds is substantially more than their parasites. This inverse relationship between biomass and trophic levels is a common observation.
In aquatic ecosystems, particularly the sea, we often encounter an inverted pyramid of biomass. This phenomenon arises because the biomass of fishes, which occupy higher trophic levels, frequently surpasses that of phytoplankton, the lowest producer. Phytoplankton, despite their small size, are the foundation of the aquatic food chain due to their high reproduction rates and vast numbers. Consequently, the inverted pyramid in the sea is quite typical, reflecting the disproportionate biomass distribution among various trophic levels in marine environments.
The structure of these pyramids provides insights into the efficiency of energy transfer and the complex interactions that define an ecosystem's structure and function. The clarity and simplicity of the concept are essential for a comprehensive understanding of ecological dynamics.
Hence the correct answer is option 2) It represents the total mass of organisms in a given area.
Q2. In an ecosystem, which of the following is the most common shape of the Pyramid of Biomass?
Inverted pyramid
Diamond shape
Hourglass shape
Pyramid shape
Correct answer: 4) Pyramid shape
Explanation:
"In most ecosystems, the shape of the Pyramid of Biomass is a pyramid, where the biomass of the lower trophic levels is higher than the biomass of the higher trophic levels."
This is because, in most ecosystems, the biomass of the lower trophic levels is greater than the biomass of the higher trophic levels due to the transfer of energy between trophic levels being less than 100% efficient. This results in a decrease in biomass and energy available at each higher trophic level.
Hence, the correct answer is option 4) Pyramid shape.
Q3. If 20 J of energy is trapped at producer level, then how much energy will be available to peacock as food in the following chain?
Plant ⇾ Mice ⇾ Snake ⇾ Peacock
0.02J
0.002 J
0.2 J
0.0002J
Correct answer: 0.02 J
Explanation:
Pyramid of energy - The energy flows in an ecosystem from the producer level to the consumer level.
- wherein
At each trophic level, 80 to 90% of energy is lost. Hence the amount of energy decreases from the producer level to the consumer level. This can be represented in a pyramid of energy level to the consumer level. This can be represented in a pyramid of energy.
Hence, the correct answer is option 1) 0.02 J.
Frequently Asked Questions (FAQs)
Terrestrial biomass includes ecosystems on land. The base of the ecological pyramid consists of plants that contribute the most to total biomass. Some examples of these producers are lawns, shrubs, and trees. These plants have higher biomass than consumers who eat cattle, zebras, giraffes, buffaloes, deer, and small insects. Secondary consumers such as tigers, lions, bears, and snakes have less biomass than primary consumers. In pasture ecosystems, grasses are the primary producers. The biomass pyramid is most comprehensive at the bottom and narrows at the top.
The pyramid of biomass refers to the graphical representation of different kinds of biomass present in a unit area at multiple trophic levels. The two main types of biomass pyramids are inverted pyramids and vertical pyramids. The biomass pyramid is essential for quantifying available biomass at each trophic level.
The limitations of biomass are:
This requires a lot of initial setups.
Requires ample operating space.
Offers low efficiencies compared to fossil fuels.
Biomass energy helps protect the environment because the amount of carbon dioxide released when burning biomass-derived fuels is comparable to the amount captured by plants during photosynthesis. Therefore, it can be considered a carbon-neutral process. However, some pollutants are released during the conversion of biomass into bioenergy.
In terms of ecology, biomass can be defined as the various living organisms found in an ecosystem or environment. It consists of a producer, a list of consumers, and finally, the decomposers.