Earwax, Butt Hair, and Other Weird Human Things

SciShow2 minutes read

Earwax helps moisturize and protect the ear canal, evolving as a self-cleaning mechanism. Excessive buildup can lead to hearing loss, easily treated with removal kits or by a doctor without using cotton swabs.

Insights

  • Earwax, composed of oils, skin cells, dirt, and microbes, acts as a natural self-cleaning mechanism for the ear canal, preventing dryness and protecting against invaders.
  • Human evolution, impacted by changes in diet and lifestyle, has led to anatomical adaptations like jaw shrinkage due to softer foods and the development of the human butt through running for obtaining food and increasing brain development.

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Recent questions

  • What is earwax made of and why is it important?

    Earwax, or cerumen, is composed of oils, dead skin cells, dirt, dust, and microbes. It serves to moisturize, waterproof, and protect the ear canal. The structure of the ear canal makes it difficult for old skin cells to shed naturally, leading to the formation of earwax as a self-cleaning mechanism. Sebaceous glands produce sebum to lubricate the ear canal, while ceruminous glands release lipids and antimicrobial proteins, combining with dead skin cells to form earwax. This substance naturally works its way out of the ear canal as you talk or chew, preventing dryness, capturing dust or microbes, and protecting the ear from invaders.

  • How can excessive earwax buildup affect hearing?

    Excessive earwax buildup can lead to hearing loss. While earwax is essential for the health of the ear canal, an overabundance can block the passage of sound waves, hindering the ability to hear properly. It is crucial to address excessive earwax buildup promptly to prevent any negative impact on hearing.

  • What is the purpose of deciduous teeth in humans?

    Deciduous teeth, also known as baby teeth, start to erupt around six months old and play a vital role in evenly biting and chewing. They ensure proper jaw growth and alignment, preparing the mouth for the eventual eruption of permanent teeth. Deciduous teeth are eventually replaced by the permanent set of adult teeth, aiding in the development and function of the oral cavity.

  • How has the evolution of agriculture impacted human teeth?

    The evolution of agriculture has led to changes in human jaw size and shape, causing issues such as overcrowding and crooked teeth. This change occurred due to a mismatch between the size of the jaw and the number of teeth, resulting in dental problems. Modern human diets, characterized by softer cooked foods, may have contributed to jaw shrinkage, leading to orthodontic issues like crowded teeth.

  • What role does the appendix play in the human body?

    The appendix, often considered vestigial, actually plays a role in immunity by housing immune cells and gut bacteria. It potentially provides emergency gut bacteria during infections like clostridium difficile. Despite its historical perception as a non-functional organ, recent research suggests that the appendix serves a purpose in supporting the body's immune system and maintaining gut health.

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Summary

00:00

Earwax, Teeth, and the Appendix: Human Evolution.

  • Earwax, or cerumen, is a unique substance made up of oils, dead skin cells, dirt, dust, and microbes that helps moisturize, waterproof, and protect the ear canal.
  • The ear canal's structure makes it difficult for old skin cells to naturally shed, leading to the formation of earwax as a self-cleaning mechanism.
  • Sebaceous glands produce sebum to lubricate the ear canal, while ceruminous glands release lipids and antimicrobial proteins, combining with dead skin cells to form earwax.
  • Earwax naturally works its way out of the ear canal as you talk or chew, preventing dryness, capturing dust or microbes, and protecting the ear from invaders.
  • Excessive earwax buildup can lead to hearing loss, but it can be easily removed with earwax removal kits or by a doctor, avoiding the use of cotton swabs that can push wax in or cause infections.
  • Humans, like most mammals, are diphiodonts, growing two sets of teeth in their lifetime: a deciduous set of baby teeth and a permanent set of adult teeth.
  • Deciduous teeth, starting to erupt around six months old, help in evenly biting and chewing, ensuring proper jaw growth, and are eventually replaced by permanent teeth.
  • The evolution of agriculture led to changes in human jaw size and shape, causing overcrowding and crooked teeth due to a mismatch between jaw size and the number of teeth.
  • Modern human diets, with softer cooked foods, might have contributed to jaw shrinkage, leading to orthodontic issues like crowded teeth.
  • The appendix, often considered vestigial, actually plays a role in immunity by housing immune cells and gut bacteria, potentially providing emergency gut bacteria during infections like clostridium difficile.

12:36

Evolution of Human Butt and Running

  • Gluteus maximus is crucial for running, stabilizing the body and pulling it back.
  • Bones and muscles' functions are interrelated, aiding in inferring evolution from fossils.
  • Homo erectus had a human-like pelvis around two million years ago, possibly indicating a human-like butt.
  • Human evolution for running involved long Achilles tendons, short toes, and long legs.
  • Distance running helped in obtaining food, leading to the evolution of the human butt.
  • Butt evolution coincided with a diet increase in protein, aiding in brain development.
  • Theories on butt hair's purpose include evolutionary pressure, scent communication, and friction prevention.
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