Ep 80: When eyes are a problem
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When eyes are a problem Sometimes, evolution can take it back. Many cave dwelling animals have lost their eyes. Theories as to why this happen range from genetic drift, to mutations that improve other senses interfering with the proper development of eyes, to the energy cost of growing and maintaining vision. I suspect that it …
Ep 79: Be afraid
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Be afraid Sometimes, you feel like something is wrong. Most of the time, it’s just a feeling; it doesn’t mean anything. But, every now and then, something is wrong, you really are in danger, you really should be afraid. Here are some articles on how humans can react to the unconsciously sensed smell of fear …
Ep 78: Eyes
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Eyes “ To suppose that the eye, with all its inimitable contrivances… could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree… Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its …
Ep 77: The Cambrian explosion
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The Cambrian explosion Between 520 and 550 million years ago, a sudden explosion of animal types appear in the fossil record. This example of rapid evolution is known as the Cambrian explosion. Theories of how and why it occurred range from the notion that it didn’t happen at all, to a spike in oxygen levels, …
Ep 76: We’re upside-down?
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We’re upside-down? In today’s rather short episode, we talk about the first creatures to have developed a centralized nervous system, though not a central nervous system as of yet. It was a simple worm like creature, with a nerve cord running along the length of its body, and an extra-large bundle of nerves toward its …
Ep 75: Electricity life and Frankensteinean experiments
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Electricity life and Frankensteinean experiments A stun gun works by passing electricity through your muscles, causing uncontrollable contractions. An electric eel, which is actually a type of fish, can do the same thing. There is a single celled creature that can conduct electrons from hydrogen sulfide in the soil, to oxygen dissolved in the water. …
Ep 74: side-stepping inheritance
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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 …
Ep 73: Why go multicellular?
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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 …
Ep 72: The one become many, and the many are one
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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 …