• 2 Posts
  • 11 Comments
Joined 1 year ago
Cake day: July 12th, 2023
  • mononomi@feddit.nltoNo Stupid Questions@lemmy.world•How does DNA decide the shape of the body?
    2·
    2 months ago

    I recently had a course in developmental biology and this is what I can remember the best:

    From the moment of fertilization, the egg has a ‘polarity’, thus a direction like up and down, left and right etc. This can be established by e.g. the entry point of the sperm or protein produced by the mother in one side of the egg. From here on out protein gradients and interactions on cell membranes specify where cells are and thus what kind of tissue they should become

    This early polarity leads to a certain pattern of cell division. An important part of this is the folding in of tissue layers called gastrulation, creating the beginning for the gastrointestinal tract.

    In vertebrates a streak starts to form in the embryo. This is the start of the vertebrae and the neural tube in it. Also blocks of cells called somites start to form. These blocks are very important for all kinds of tissues in the body.

    Hox genes make the cells in somites get an identity like head, arm etc. So in the end Hox genes are probably what you are looking for. If leg Hox genes are expressed where fruitfly normally have antennae, you get this horror:

    Fruitfly with legs instead of antennae

  • mononomi@feddit.nltoNo Stupid Questions@lemmy.world•How can I prove myself that my brain isn't just creating images so I can experience life?
    25·
    6 months ago

    The philosophical question you’re raising is known as solipsism, which is the idea that one can only be sure of the existence of their own mind and not of anything external to it. While it’s an interesting concept to explore, proving the absolute reality of the external world can be challenging.

    Philosophers have debated these questions for centuries, and there isn’t a definitive answer. However, there are some common responses and arguments:

    Pragmatism: While you might not be able to prove the absolute reality of the external world, it is generally more practical and beneficial to assume its existence. The way we navigate and interact with the world is based on the assumption that it is real.

    Consensus Reality: The fact that multiple people can agree on the existence of certain things suggests a shared reality. If others can perceive and interact with the same objects or events as you do, it adds weight to the argument that there is an external reality.

    Scientific Method: Science provides a systematic way of understanding the world through observation, experimentation, and verification. While it may not provide absolute certainty, the scientific method has proven to be a reliable way to gain knowledge about the external world.

    Testability: While you may question the authenticity of your perceptions, you can still make predictions and test them against your experiences. For example, if you drop an object, you can predict that it will fall, and when it does, it provides some validation of the external reality.

    Regarding your doubt about whether people are real or if the responses are from AI, the same principles can apply. If there is consistency in responses, coherence in conversations, and a shared understanding among users, it adds credibility to the reality of the interaction.

    It’s important to note that these responses don’t necessarily provide absolute certainty but offer practical and reasonable ways to engage with the external world. The nature of reality is a complex and debated topic in philosophy, and there may never be a conclusive answer.