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side-stepping inheritance Darwin originally published “On the Origins of Species” in 1859. At the time, the mechanism of inheritance wasn’t well understood. Inheritance and the implication that lifeforms could change over time stood in contrast to the popular notion that God had created all things in perfect and unchanging forms. His theory only considered traits …
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Why go multicellular? Bacteria are very successful. They’ve been around for billions of years, as compared to hundreds of millions for multicellular creatures. They have survived mass extinctions that wiped out things like the dinosaurs and others. Today, we look at salpingoeca rosetta, which can live as either a single celled creature, or in a …
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The one become many, and the many are one How did life move from simple single celled forms, into more complex multicellular ones? In today’s episode, we talk about an experiment that induced that transition in the laboratory. Here’s a link to an article on the experiment. Multicellular Life Evolves in Laboratory And here’s a …
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How to make a mind—part3 Take life, put it in the right environment, and give it between 3.5 and 4 billion years. We take the time to review what we’ve covered since “How to make a mind—part1,” episode 35; and “How to make a mind—part2,” episode 59. This sets us up nicely to talk about …
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Death There are creatures that do not seem to have a natural limit on their life span. They only die when they are killed by accident or the action of sickness parasites and pathogens. Other creatures are apparently programmed to die at a given time, and under a given set of conditions. So why do …
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Sex This episode turned out to be both long and hard. Feel free to snicker at this point. It was long because I couldn’t resist the numerical pun. To match this episode’s number with its subject, I had to squish together the development of eukaryotes with the development of sexual reproduction. Fortunately, they may both …
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An environmental catastrophe Sometimes, a new species will come into being, and explode across the planet. The population increases drastically within a short time period as they learn to use new materials and new forms of energy. Sometimes, they produce material that is poisonous to forms of life that previously hadn’t encountered such substances. Many …
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Don’t let the headlines fool you. Nobody knows how life started This is probably the least coherent episode to date. Though the precursors of life can apparently be produced by processes taking place anywhere from the deep sea to deep space, how to get from those starting chemicals to a living cell is still unknown. …
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When worlds literally collide It is theorized that our moon was formed when our planet was struck a glancing blow by an object roughly the size of Mars. The notion is known as the giant impact hypothesis. If such a large impact happened to our planet, what about the other planets. How common are giant …
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Our big, beautiful moon According to the rare Earth hypothesis, see episode 59, a large moon is needed for the development of complex life. Our moon isn’t the biggest moon in our solar system; but the moons that are bigger are orbiting much larger planets. Our moon is the largest as a percentage of the …