Difference Between a Food Chain, Food Web, and Energy Pyramid
Chains, Webs, and Pyramids are About Inter-Relationships
The terms “food chain” “food web” and “food pyramid” are shorthand ways of illustrating some important food information. “Food chain” and “food web” relate to the ecological cycle of life in which one species eats another to survive. A “food pyramid” is used to describe the ideal balanced diet for a human being.
Diagrams and images like these are used by governments to deliver important nutritional messages. Many people have difficulty understanding complex scientific information and so these diagrams have been devised to summarize key facts.
What Is a Food Chain?
A food chain shows how energy is transferred within the natural world. Just like the links in a chain, each part of the process takes energy from one source and transfers it to the next.
The term “food chain” is used to describe an ecological concept. It shows how everything in nature relies on the entirety of the energy transfer system for its own survival. Starting with energy from the sun, creatures exist by eating plants, bacteria or other creatures. The predator becomes the predated.
An example of a food chain would be as follows. Grass grows using photosynthesis to convert the sun’s energy into nutrients. Fields of grass are eaten by cows. Herds of cows are raised on these fields to provide food for human beings.
The Food Chain
What Is a Food Web?
A food web is a more complex diagram than a food chain. The pattern of energy transfer looks more like a spider’s web than a straight line. A food web is a better representation of what really happens in nature. The ecological system of the natural world is more complex than a simple straight line food chain would suggest. For example, there can be many predators for each prey species.
How to Draw a Food Web
Example of a Food Web for Fish-Eating Bird Species
The diagram below shows how top predator birds such as the Osprey and Bald Eagle rely on phytoplankton, aquatic vegetation and land based vegetation for their survival. Before the concept of a food web was fully understood, it was assumed that so long as their food source (fish and duck) was available Osprey and Bald Eagle would continue to thrive.
Scientists are now aware that when primary converters of the sun’s energy (e.g. phytoplankton) are not working properly there is a knock-on effect for species further up in the food web. This has resulted in a change of focus when tackling the issue of species extinction. In recent years there has been more emphasis on conserving not just an individual species, but also its habitat so that a complete food web for animal life is maintained.
Underground Soil Food Web
Key parts of many food webs take place underground. This is illustrated in the diagram below. Plants which photosynthesize the sun’s energy into green leaves also produce roots. These roots eventually rot and are broken down by bacteria to provide food for fungi, worms and beetles. These in turn provide food for birds and small animals. And these in turn become prey for larger predators.
What Is a Food Pyramid?
In 1974 the Swedish government wanted to promote a message of healthy eating. They devised a simple diagram to illustrate how much of each food type people should aim to eat. The foods which should be eaten in small quantities were at the top of the pyramid, whilst those which should form the bulk of a healthy diet were at the base of the pyramid.
Over 25 countries have since adopted the idea of a healthy eating food pyramid but it's the one produced by US Department of Agriculture (USDA) in 1992 that is familiar to many people due to the global influence of America.
Do you eat a healthy diet?
Harvard University Food Pyramid
It's alleged the original USDA food pyramid was influenced by major food producers to give a greater emphasis to grains than is appropriate for health. So Harvard University School of Public Health devised the food pyramid shown below. The weightings in the diagram rely on peer-reviewed nutritional recommendations for a healthy diet. The key difference between this pyramid and the US government’s food pyramid is that there is a new emphasis on exercise being part of a healthy diet. There is also a reduced emphasis on whole grains in their recommended diet.
Latest Advice on Oils and Fats in a Healthy Diet
There is a continuing debate in the medical and academic communities about the role of oils and fats in a healthy diet. Some nutritionists argue that there should be a greater distinction between healthy and unhealthy oils and fats. For example, Omega-3, considered a healthy oil, is found in fish and so more fish should be in your diet; while animal fats such as butter are usually considered unhealthy and so the amount eaten should be reduced.
In the video clip below, Dr. Brian Royer discusses some of the drawbacks with the current dietary recommendations. He mentions the influence the lobby groups of major agricultural industries (e.g. sugar, wheat and pork producers,) have on government advice.
Dr Brian Royer Discusses The New Food Pyramid
Healthy Diet and Regular Exercise For Energy
The Choose My Plate campaign is based on the idea is that it is easier to visually divide your dinner plate in front of you, than struggle with abstract concepts.
- Eat more vegetables
- Half your plate should be filled with vegetables
- Quarter of your plate should be fruit or grains
- Quarter of your plate is for protein
- Drink plenty of water
- Control portion size
- Take regular exercise
Eating a healthy diet and exercising regularly should make you feel better and more energized. If you are struggling to maintain a healthy weight, you should seek appropriate advice from a qualified medical practitioner or nutritionist.
Food Webs and Energy Pyramids: Bedrocks of Biodiversity
What is an Energy or Trophic Pyramid?
The primary producer of energy on our planet earth is the sun. An energy pyramid is a way of illustrating the flow of this energy between organisms. At the base of the pyramid are producer organisms such as plankton, algae and bacteria. They can access the sun's energy directly using processes like photosynthesis.
On the next levels of the trophic pyramid are consumer organisms; herbivores (plant eaters), carnivores (meat-eaters), and predators at the top. These higher-level organisms cannot synthesise energy directly from the sun for themselves. They need to consume animals and plants from lower down the eco-system as their energy source.
Energy pyramids are an important concept in ecology. Understanding the inter-relationships of trophic producers and consumers can help humans maintain sustainable habitats for endangered wildlife species.