Have you ever noticed how much we love symmetry? It’s everywhere—in art, buildings, and even in the way we solve math problems. This makes sense because our bodies are pretty symmetrical too. We have two eyes, two ears, two arms, and two legs, much like a paper doll. But, if we take a closer look inside, things aren’t as symmetrical as they seem on the outside.
Most of us have one heart, and it’s on the left side of our body. Our stomach and spleen are also on the left, while the liver is on the right. Even organs that look symmetrical, like our lungs, have differences. The right lung has three sections, but the left lung only has two. In our brains, the parts that help us talk are usually found on the left side.
It’s not just humans who have this internal asymmetry. Animals like starfish also show similar patterns. What’s really interesting is that most of us share the same internal layout. However, about 1 in 20,000 people have a condition called situs inversus, where their organs are flipped. Surprisingly, this doesn’t usually cause any health problems.
In 1972, singer Donny Osmond had a burst appendix, but the pain was on the wrong side of his body. Doctors found his appendix on the opposite side and removed it just in time. Other famous people with situs inversus include Enrique Iglesias and Catherine O’Hara.
If people can live healthy lives with reversed organs, why aren’t there more of them? And why do we look so symmetrical on the outside? One idea is that symmetry has been important for survival and reproduction throughout evolution. For example, female barn swallows often choose mates with symmetrical tails, which might suggest better genes for their offspring.
When humans form relationships, we look for more than just physical symmetry. The way our organs are arranged might be due to how we develop as embryos. At first, embryos are symmetrical. Then, tiny hair-like structures called cilia start moving together, creating a flow that helps decide where organs will go.
It’s fascinating that our bodies are arranged this way, and for most people, this is how it is. This topic is part of a series about the human body. If you’re curious to learn more, check out the other parts of the series!
Explore your surroundings and find examples of symmetry and asymmetry. Take photos or draw sketches of at least five objects or structures. Share your findings with the class and discuss why symmetry might be appealing or functional in each case.
Create a puzzle using cutouts of human organs. Arrange them on a body outline to reflect their actual positions. Then, try rearranging them to mimic situs inversus. Discuss how this condition affects the body and why it doesn’t usually cause health problems.
Research different animals and their symmetry or asymmetry. Choose one animal and create a poster or digital presentation showing its symmetrical and asymmetrical features. Present your findings to the class, highlighting how these features benefit the animal.
Create a piece of art that uses symmetry as a central theme. You can draw, paint, or use digital tools. Consider how symmetry can create balance and harmony in your artwork. Share your creation with the class and explain your artistic choices.
Participate in a class debate on the importance of symmetry in evolution. One side will argue that symmetry is crucial for survival and reproduction, while the other side will argue that asymmetry can be just as beneficial. Use examples from the article and your own research to support your arguments.
Sure! Here’s a sanitized version of the transcript, removing any informal language and ensuring clarity while maintaining the original meaning:
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[music] We appreciate symmetry. It is evident in our art and architecture, and we even balance equations based on it. Our affinity for symmetry is understandable, as we are symmetrical beings—two eyes, two ears, two arms, and two legs. Our bodies resemble paper dolls in their symmetry. However, this external beauty is superficial. When we examine the internal structure, we find that symmetry is not as prevalent.
Unless one is from Gallifrey, individuals typically have one heart located on the left side of the body, along with the stomach and spleen, while the liver is situated on the right. Even organs that initially appear symmetrical often exhibit some degree of asymmetry. For instance, the right lung is divided into three lobes, whereas the left lung has only two. Additionally, in the brain, two areas essential for speech and language are usually found only in one lobe, typically the left.
Interestingly, animals as distantly related as starfish also exhibit similar internal asymmetry. What is noteworthy is not just that our bodies are asymmetrical, but that we all share the same patterns of asymmetry. An exception exists for approximately 1 in 20,000 individuals who have a genetic condition known as situs inversus, where the internal organs are inverted from left to right. Generally, these individuals experience no adverse effects from their reversed organs.
In 1972, singer Donny Osmond was hospitalized due to pain in the left side of his abdomen, which is typically indicative of appendicitis. However, the pain was in the incorrect location. The doctors proceeded with surgery and successfully removed his burst appendix from the opposite side of his body, just in time. Other notable individuals with situs inversus include Enrique Iglesias and Catherine O’Hara.
If people can lead healthy lives with inverted organs, one might wonder why we do not see more individuals with such conditions. Furthermore, if being asymmetrical internally does not cause harm, why do we exhibit such pronounced symmetry externally? One theory suggests that throughout evolution, external appearance has played a significant role in reproductive success. For example, female barn swallows appear to select mates based on the symmetry of their long forked tails. Highly symmetrical bodies in animals may indicate superior genetic quality, leading to better offspring.
When humans form relationships, we consider various forms of symmetry and look for more than just physical balance. The orientation of our organs may simply be a result of developmental processes. In the early stages of embryonic development, left and right are symmetrical. Recent research has shown that hairlike cilia on a specific group of cells begin to beat in unison, directing the development of what will become the left side of the embryo. This creates a current that influences the expression of a gene determining the placement of organs.
It is intriguing that this arrangement does not have to be the case, but for most individuals, it is. This video is part of a three-part series focused on the human body. If you wish to learn more about the organization of your body, please explore the other videos in this series.
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This version maintains the informative content while ensuring clarity and professionalism.
Symmetry – Symmetry in biology refers to the balanced distribution of duplicate body parts or shapes within the body of an organism. – Many animals, such as humans and butterflies, exhibit bilateral symmetry, where their left and right sides are mirror images of each other.
Asymmetry – Asymmetry in biology refers to the lack of symmetry or balanced proportions in the body structure of an organism. – Sponges are an example of organisms that display asymmetry, as their body shapes do not have any specific pattern or symmetry.
Organs – Organs are collections of tissues that perform specific functions necessary for the survival of an organism. – The heart and lungs are vital organs that work together to circulate blood and oxygen throughout the body.
Lungs – Lungs are respiratory organs in many animals that are responsible for the exchange of oxygen and carbon dioxide with the environment. – The human lungs are essential for breathing, allowing oxygen to enter the bloodstream and carbon dioxide to be expelled from the body.
Heart – The heart is a muscular organ that pumps blood throughout the body, supplying oxygen and nutrients to tissues and removing carbon dioxide and other wastes. – The human heart beats approximately 100,000 times a day to maintain circulation and support life.
Spleen – The spleen is an organ involved in the production and removal of blood cells and is part of the immune system. – The spleen helps filter blood and plays a role in fighting infections by producing white blood cells.
Liver – The liver is a large organ that processes nutrients, detoxifies harmful substances, and produces bile for digestion. – The liver is crucial for metabolizing drugs and breaking down fats in the digestive system.
Embryos – Embryos are early developmental stages of an organism, following fertilization and before becoming a fetus. – During the embryonic stage, cells rapidly divide and differentiate to form the basic structures of the organism.
Evolution – Evolution is the process by which different kinds of living organisms develop and diversify from earlier forms during the history of the Earth. – Charles Darwin’s theory of evolution explains how species adapt over time through natural selection.
Cilia – Cilia are small hair-like structures on the surface of some cells that help with movement and the transport of materials. – In the human respiratory system, cilia help move mucus and trapped particles out of the airways.
