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How do scientists use models to illustrate how photosynthesis transforms light energy into stored chemical energy?

If you were wondering how Gigi Hadid and Gisele Bundchen help us understand the process of photosynthesis, we’re sorry to inform you that we’re talking about different types of models!

There are all kinds of processes scientists use to better understand natural phenomena. Models are the tools they use to both learn about and explain different events, like photosynthesis.

But what are scientific models, anyway?

Scientific models are visual, physical, and/or mathematical approximations of different events that are very difficult to see and examine in real life. They allow scientists to understand and even predict chemical, physical, ecological, and biological processes that occur in different situations and conditions. However, scientific models are only representations of the processes and events – they do not replicate them exactly. Models are always being improved and even altered as scientists’ understanding of their subjects changes, and as modeling technology – computer representations, for example – becomes more advanced.

Photosynthesis is one of the complex natural processes that scientists cannot easily observe and record precisely in real time, so modeling is used to explain the different stages, such as the transformation of light energy into chemical energy.

To better understand the process of photosynthesis, here are a few commonly used terms you should learn:

Biomass: The total mass of organic material within an ecosystem, including all living organisms.

Cellular Respiration. This describes the chemical reaction that occurs when the cells from an organism use oxygen to convert their food supply – sugars, fatty acids, and amino acids – into usable chemical energy to sustain life.

Consumer. A consumer is an organism that uses other living organisms as its food supply. Consumers are divided into different categories, most notably primary consumers, secondary consumers, and tertiary consumers. Primary consumers are the organisms that eat only plants (they are also known as herbivores). Secondary consumers eat plants and primary consumers (they are also known as omnivores). Tertiary consumers eat primary and secondary consumers and are also considered apex predators because they aren’t actively hunted for food by other organisms.

Decomposer. An organism that survives by sourcing energy from dead and/or decaying organic matter or animal waste. Examples of decomposers include worms, fungi, and bacteria.

Ecological Pyramid. This is a type of scientific model that illustrates how the different organisms use and transfer energy. These models are also known as energy pyramids.

Food Web. This is a type of scientific model that demonstrates how energy and matter are transferred throughout an ecosystem across food chains.

Photosynthesis. The capture of light energy from the sun creates chemical energy in photosynthetic organisms like green plants, algae, and cyanobacteria. This stored energy is held in carbohydrates within the organism and released through cellular respiration.

Producer. An organism that uses non-organic elements to create its own food supply. Plants are the most commonly known type of producer, but algae and certain single-celled bacteria are also producers.

Trophic Level. This is the position of an organism or series of organisms within a food web. There are five trophic levels within an ecosystem representing different organisms’ positions to the main energy source: Decomposers, producers, primary consumers, secondary consumers, and tertiary consumers/apex predators.


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The Transfer of Energy and Matter in Ecosystems

It’s important to remember that energy and matter move through ecosystems in different ways. Physical matter cycles through ecosystems, but energy flows through them.

When producers – organisms that create their own food supply using non-organic elements like sunlight – undergo the process of photosynthesis, energy is brought into an ecosystem. During photosynthesis, plants use sunlight, water, and carbon dioxide to facilitate the process. These are the inputs of photosynthesis. The resulting chemical energy, oxygen, and glucose are known as the outputs.

That energy is stored within its cellular structure and is released during the process of cellular respiration, or continually stored as biomass.

Once energy enters an ecosystem, it flows through the different trophic levels through the consumption of different organisms. In addition to the energy being released during cellular respiration or stored as biomass, it can also be released as waste, which is an energy source for decomposer organisms. The decomposer organisms use the energy, then generate inorganic matter which is recycled back into the ecosystem.

Energy enters the ecosystem as light from the sun, then flows throughout the biomass as heat. The matter that stores the energy is continually cycled and recycled as consumers and decomposers consume the material.


Food Webs Illustrate the Transfer of Matter and Energy

One of the most common and accessible scientific models showing how matter and energy move through ecosystems is the food web. Food webs show the different relationships between organisms within a particular ecosystem, namely what-eats-what.

When organisms eat other organisms, the energy stored within the cells of the consumed organism is absorbed by the consumer organism, along with the physical matter. This is clearly shown in food web models by the arrows pointing from one organism to another. For example, in a food web where an arrow is pointing from a mouse to an owl, the mouse is eaten by the owl, and the energy stored within the cells of the mouse is transferred to the owl.

Ecological Pyramids Illustrate Energy Loss

Ecological pyramids, also called energy pyramids, are also scientific models. They estimate the volume of energy and matter within an ecosystem’s trophic levels and detail the amount of energy that is used to maintain a trophic level and how much is transferred to the next trophic levels. It is estimated that approximately 10 percent of all the energy within any trophic level is transferred to another level; the remaining energy is either used or stored within that level.

The different volumes of energy transferred between trophic levels are represented by the volume of organisms within different trophic levels within the pyramid. The largest portion of an ecological pyramid represents the producers, which account for millions of producer plants and organisms. The level above the producers – the primary consumer level – has significantly fewer organisms. The level above the primary consumer level has fewer organisms, and so on, with the very top of the pyramid representing the fewest organisms.

However, it’s important to recognize that organisms can exist in more than one trophic level, as different animals can consume both producers and other consumers.

These are only a few of the models that help us understand matter and energy transfer. Models can change over time as we discover new processes and scientific methods, and the tools become more accurate and refined. The technology we use is constantly updated and improved, so new models may supersede the ones we commonly use today!

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