Why does biomass decrease in a food chain

Many chemoautotrophs in hydrothermal vents use hydrogen sulfide H 2 S , which is released from the vents, as a source of chemical energy. This allows chemoautotrophs to synthesize complex organic molecules, such as glucose, for their own energy and in turn supplies energy to the rest of the ecosystem. Chemoautotrophs : Swimming shrimp, a few squat lobsters, and hundreds of vent mussels are seen at a hydrothermal vent at the bottom of the ocean.

Heterotrophs function as consumers in the food chain; they obtain energy in the form of organic carbon by eating autotrophs or other heterotrophs. They break down complex organic compounds produced by autotrophs into simpler compounds, releasing energy by oxidizing carbon and hydrogen atoms into carbon dioxide and water, respectively. Unlike autotrophs, heterotrophs are unable to synthesize their own food. If they cannot eat other organisms, they will die.

Productivity, measured by gross and net primary productivity, is defined as the amount of energy that is incorporated into a biomass. Explain the concept of primary production and distinguish between gross primary production and net primary production. Productivity within an ecosystem can be defined as the percentage of energy entering the ecosystem incorporated into biomass in a particular trophic level.

Biomass is the total mass in a unit area at the time of measurement of living or previously-living organisms within a trophic level. Ecosystems have characteristic amounts of biomass at each trophic level.

The productivity of the primary producers is especially important in any ecosystem because these organisms bring energy to other living organisms by photoautotrophy or chemoautotrophy. Photoautotrophy is the process by which an organism such as a green plant synthesizes its own food from inorganic material using light as a source of energy; chemoautotrophy, on the other hand, is the process by which simple organisms such as bacteria or archaea derive energy from chemical processes rather than photosynthesis.

The rate at which photosynthetic primary producers incorporate energy from the sun is called gross primary productivity. An example of gross primary productivity is the compartment diagram of energy flow within the Silver Springs aquatic ecosystem. Energy flow in Silver Springs : This conceptual model shows the flow of energy through a spring ecosystem in Silver Springs, Florida. Notice that the energy decreases with each increase in trophic level. Because all organisms need to use some of this energy for their own functions such as respiration and resulting metabolic heat loss , scientists often refer to the net primary productivity of an ecosystem.

The net productivity is then available to the primary consumers at the next trophic level. Large amounts of energy are lost from the ecosystem between one trophic level and the next level as energy flows from the primary producers through the various trophic levels of consumers and decomposers.

The main reason for this loss is the second law of thermodynamics, which states that whenever energy is converted from one form to another, there is a tendency toward disorder entropy in the system. In biologic systems, this means a great deal of energy is lost as metabolic heat when the organisms from one trophic level are consumed by the next level. The measurement of energy transfer efficiency between two successive trophic levels is termed the trophic level transfer efficiency TLTE and is defined by the formula:.

The low efficiency of energy transfer between trophic levels is usually the major factor that limits the length of food chains observed in a food web. The fact is, after four to six energy transfers, there is not enough energy left to support another trophic level. In the Lake Ontario ecosystem food web, only three energy transfers occurred between the primary producer green algae and the tertiary, or apex, consumer Chinook salmon.

Food web of Lake Ontario : This food web shows the interactions between organisms across trophic levels in the Lake Ontario ecosystem. Primary producers are outlined in green, primary consumers in orange, secondary consumers in blue, and tertiary apex consumers in purple. Arrows point from an organism that is consumed to the organism that consumes it. Notice how some lines point to more than one trophic level. For example, the opossum shrimp eats both primary producers and primary consumers.

Ecologists have many different methods of measuring energy transfers within ecosystems. Some transfers are easier or more difficult to measure depending on the complexity of the ecosystem and how much access scientists have to observe the ecosystem.

In other words, some ecosystems are more difficult to study than others; sometimes the quantification of energy transfers has to be estimated. Another main parameter that is important in characterizing energy flow within an ecosystem is the net production efficiency. Net production efficiency NPE allows ecologists to quantify how efficiently organisms of a particular trophic level incorporate the energy they receive into biomass.

In an ocean ecosystem, many types of fish and turtles are herbivores that eat algae and seagrass. In kelp forests, seaweeds known as giant kelp provide shelter and food for an entire ecosystem. Sea urchins are powerful primary consumers in kelp forests. These small herbivores eat dozens of kilograms pounds of giant kelp every day.

Secondary consumers eat herbivores. They are at the third trophic level. In a desert ecosystem, a secondary consumer may be a snake that eats a mouse. In the kelp forest , sea otters are secondary consumers that hunt sea urchins. Tertiary consumers eat the secondary consumers. They are at the fourth trophic level. In the desert ecosystem, an owl or eagle may prey on a snake. There may be more levels of consumers before a chain finally reaches its top predator.

Top predators, also called apex predators, eat other consumers. They may be at the fourth or fifth trophic level. They have no natural enemies except humans. Lions are apex predators in the grassland ecosystem.

In the ocean, fish like the great white shark are apex predators. In the desert, bobcats and mountain lions are top predators. Detritivores and Decomposers Detritivores and decomposers make up the last part of food chains.

Detritivores are organisms that eat nonliving plant and animal remains. For example, scavengers such as vultures eat dead animals. Dung beetles eat animal feces. Decomposers, like fungi and bacteria, complete the food chain. Decomposers turn organic wastes, such as decaying plants, into inorganic materials, such as nutrient-rich soil. They complete the cycle of life, returning nutrients to the soil or oceans for use by autotrophs.

This starts a whole new series of food chains. Food Chains Food webs connect many different food chains, and many different trophic levels. Food webs can support food chains that are long and complicated, or very short.

For example, grass in a forest clearing produces its own food through photosynthesis. A rabbit eats the grass. A fox eats the rabbit. When the fox dies, decomposers such as worms and mushrooms break down its body, returning it to the soil where it provides nutrients for plants like grass. This short food chain is one part of the forest's food web.

Another food chain in the same ecosystem might involve completely different organisms. A caterpillar may eat the leaves of a tree in the forest. A bird such as a sparrow may eat the caterpillar. A snake may then prey on the sparrow. An eagle, an apex predator , may prey on the snake. Yet another bird, a vulture, consumes the body of the dead eagle. Finally, bacteria in the soil decompose the remains. Algae and plankton are the main producers in marine ecosystems.

Tiny shrimp called krill eat the microscopic plankton. The largest animal on Earth, the blue whale, preys on thousands of tons of krill every day. Apex predators such as orcas prey on blue whales.

As the bodies of large animals such as whales sink to the seafloor, detritivores such as worms break down the material. The nutrients released by the decaying flesh provide chemicals for algae and plankton to start a new series of food chains. Biomass Food webs are defined by their biomass. Biomass is the energy in living organisms. Autotrophs, the producers in a food web, convert the sun's energy into biomass.

Biomass decreases with each trophic level. There is always more biomass in lower trophic levels than in higher ones. Because biomass decreases with each trophic level, there are always more autotrophs than herbivores in a healthy food web. There are more herbivores than carnivores. An ecosystem cannot support a large number of omnivores without supporting an even larger number of herbivores, and an even larger number of autotrophs.

A healthy food web has an abundance of autotrophs, many herbivores, and relatively few carnivores and omnivores. This is then transferred to the locusts when they eat the plant.

Therefore, biomass is transferred from the maize to the locusts. Some of the biomass in the locust is then transferred to the lizards when the lizard eats the locusts and so on.

Not all of the biomass is passed from the maize plants to the locusts. Translation 8: Metabolism 1. Metabolism 2. Cell Respiration 3. Photosynthesis 9: Plant Biology 1. Xylem Transport 2. Phloem Transport 3. Plant Growth 4. Plant Reproduction Genetics 1. Meiosis 2. Inheritance 3.

Speciation Animal Physiology 1. Antibody Production 2.