How did the first cells form? Evolution and Biology

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a cell: an irregular gray blob with smaller light and dark blobs and lines inside it: like the first cells

A very simple cell (seen through a microscope) like the first cells

RNA and lipid membranes

Sometime around four billion or 3.5 billion years ago, lipid membranes and RNA or DNA got together to form the earliest living cells on Earth. Nobody understands exactly how this happened. But somehow some RNA or DNA molecules, or both, got into the water that was inside the bubbles of lipid membranes. It probably happened accidentally at first, when RNA and DNA molecules just happened to be in the water where a lipid membrane was forming. But being inside lipid membranes turned out to be helpful to the RNA and DNA molecules, because the lipid membranes protected the molecules from water currents and other things and helped keep them from breaking apart. These were the first cells.

Natural selection favors the first cells

So natural selection caused more of the RNA and DNA that was inside bubbles to survive, while more of the RNA and DNA that was outside bubbles died. After a while most of the RNA and DNA was inside lipid membrane bubbles – inside cells.

How these cells reproduced

Like the RNA and DNA that were inside them, these simple cells were able to reproduce themselves. One cell could become two new cells. The cell began by using RNA molecules to make a copy of the cell’s DNA. Then, with one copy of the DNA in each half of the cell, the cell’s membrane would pinch itself in the middle and split apart, making two new cells, each pretty much the same as the old cell (except if copying mistakes had happened during the copying of the DNA).

Did you find out what you wanted to know about the first cells? Let us know in the comments!

Learn by doing – looking at a cell
More about cells

Bibliography and further reading about cells:

Cells
Biology
Chemistry
Math
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By |2018-04-04T21:31:15+00:00May 28th, 2017|Biology|10 Comments
Cite this page: Carr, K.E. How did the first cells form? Evolution and Biology. Quatr.us Study Guides, May 28, 2017. Web. October 17, 2018.

About the Author:

Dr. Karen Carr is Associate Professor Emerita, Department of History, Portland State University. She holds a doctorate in Classical Art and Archaeology from the University of Michigan. Follow her on Instagram, Pinterest, or Facebook, or buy her book, Vandals to Visigoths.

10 Comments

  1. Francine Mayer September 8, 2018 at 8:30 pm - Reply

    Hello Dr. Karen,

    People either believe or don’t believe. The first life was formed with the elements of the earth. The earth was born out of the stars and the stars out of the BIG BANG.. Someone or something created the BANG where everything came out of. It might be the ‘Great Creator’, which some call God, or Allah etc. which started it all.
    But for now no one really knows. And we are not even close to knowing.

    Sincerely,
    Francine Mayer

    • Karen Carr September 9, 2018 at 5:28 am

      People either know and understand the facts, or they don’t. Believing is not part of science; that’s religion. It is not God that created the Big Bang, but physical forces, even if we don’t understand them perfectly yet.

    • Muhammad Muzammil September 18, 2018 at 8:24 am

      dude where is the first “Cell” com FROM????!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
      DNA OR RNA whatever
      where is first nucleus com form
      if you find awnser reply me at : onemuzamil@gmail.com

    • Karen Carr September 18, 2018 at 8:27 am

      Our best answer to that is on this page, Muhammed: RNA molecules found themselves inside a lipid membrane, where they were safer. Scientists are still working to find a more detailed answer; when they do, we will report it here.

  2. Ronald July 6, 2018 at 5:34 am - Reply

    “If what you mean is that only God could have created life, then most scientists disagree with you.” (Karen Carr’s reply to Greg).

    I would guess there are many, many people out there who don’t accept evolution theory as the most plausible (or even probable) explanation for life in all it’s complexity as we see and experience it to this very day. Automatically these people get categorized as being stupid, ignorant, etc. As if the idea of ‘random mutations’ and ‘natural selection’ leading to utterly complex systems (like human beings) isn’t laughable at all… Why is that the ‘holy houses’ of science are not to be doubted by anyone without quickly being labeled as ‘stupid’, ‘ignorant’ (or worse)?’ This not only goes for evolution theory, but for all the ‘pillars’ our contemporary world paradigm rests upon (germ theory, biomedical model, and all the other reductionist theories that have led to the multinational corporations dominating our world today). Ever wondered why the mainstream media hardly ever has anything negative to say about evolution theory, the biomedical model, vaccination, chemotherapy, etc.? Not realizing the extend as to how the public is being manipulated to accept all kinds of ‘scientific’ theories/models that are mainly good for business is truly an example of ignorance…

    • Karen Carr July 6, 2018 at 8:50 am

      I’m sure there are lots of people who think that the earth is flat, that the moon is made of green cheese, and that storks bring babies. But all of those things are wrong, no matter how many people think them. Majority votes elect (some) governments, but they do not decide what is true. Similarly, your assertion that the media are corrupt and hiding the truth about chemotherapy is not founded in facts. That is probably why you don’t offer any evidence to support your ideas.

  3. Rosemarie Markell May 21, 2018 at 9:03 pm - Reply

    You do not say how the dna was formed. We now know that the dna strand is a language. A code. A single cell contains more information than a library of encyclopedias. Cells like bacteria. The 1st cells formed. No matter how many tries, how many times i throw a bunch of letters in the air, it isnt going to form an encyclopedia! It makes sense that an eternally present creator organized the dna code. And probably let things evolve from there.

    • Karen Carr May 21, 2018 at 9:32 pm

      Hi Rosemarie! Thanks for stopping by! I’m not sure how you got from not knowing how DNA forms to assuming the existence of God, but you might like to read how scientists think it happened on our page about RNA: https://quatr.us/biology/rna-cell-biology-evolution.htm. Of course you are free to believe that God created everything if you prefer.

  4. Greg April 4, 2018 at 3:44 pm - Reply

    You seem to just casually mention that ” But somehow some RNA or DNA molecules, or both, started hanging out in the water inside the bubbles of lipid membranes.” but the production of amino acids to proteins to DNA is not casual at all and to just try to assemble all of the improbable if not impossible events under the umbrella of “somehow” is just plain ridiculous .

    •Think of DNA as the cell’s library, and RNA as a book that can be checked out of the library. A kind of RNA checks out information from the DNA to line up left handed amino acids in the exact order required for each individual protein.

    •Next the correctly ordered left-handed amino acids are linked together by a “molecular machine.” This machine is made up of another kind of RNA working together with several specialized proteins. The machine links the properly ordered left-handed amino acids one to another to make proteins.
    •Amino acids do not concentrate in the ocean; they disperse and break down.

    •Amino acids will not link together in nature to form proteins; not even when scientists help them by buying all left-handed amino acids from a chemical supply house to make the perfect “organic soup.”

    •If proteins could form, they could not get together with DNA because DNA does not form outside of living cells either.
    If it were so easy to create living cells by just floating in the ocean while being protected by a lipid membrane then science would be able to have figured out how to duplicate the process by now and as far as I know, that has not happened.
    Thank You for your time

    • Karen Carr April 4, 2018 at 8:52 pm

      If what you mean is that only God could have created life, then most scientists disagree with you. There are many seemingly easy things that today’s scientists can’t do yet. Science is still only just beginning to understand how life works – remember that only 150 years ago, many doctors still believed that bloodletting would cure illnesses. The ideas I present here may turn out to be wrong, of course, and then I will be happy to change my ideas. But this is the most convincing story we have right now.

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