The Lab Demo

Ep 73: Why go multicellular?

By thelabwithbradbarton | October 19, 2017

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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 multicellular colonial form. We compare that to the experimentally evolved multicellular colonies of yeast we introduced in the previous episode, episode 72; and examine how the multicellular creatures came about, and how and why they are no longer able to return to a single celled lifestyle.

Here’s an article about work by Nicole King, that introduced me to salpingoeca rosetta.

How Life Made the Leap From Single Cells to Multicellular Animals

Here’s an article that examines genetic ratcheting, the tendency for evolution to take steps that it cannot take back.

How Did Multicellular Life Evolve?

Ep 72: The one become many, and the many are one

By thelabwithbradbarton | October 18, 2017

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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 link to the research paper, which happens to be freely available online.

Experimental evolution of multicellularity

Ep 71: How to make a mind—part3

By thelabwithbradbarton | October 17, 2017

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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 the way we evolved from simple creatures, into the oh so very complicated animals we are today.

Ep 70: Death

By thelabwithbradbarton | October 13, 2017

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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 we die? What is death for?

Ep 69: Sex

By thelabwithbradbarton | October 12, 2017

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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 have come about because of interactions taking place within microbial mats. It was hard because the subject turns out to be more complicated than I had thought.
…

Ep 68: An environmental catastrophe

By thelabwithbradbarton | October 11, 2017

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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 species can be pushed to the edge of extinction and beyond. This happened approximately 2.5 billion years ago, with the rise of cyanobacteria. The toxic material that was being produced was oxygen. Though it was catastrophic at the time, the presence of oxygen allowed for a new form of life, which could use the free oxygen as an energy source. This allowed for the arrival of the animals, and eventually, us.

Ep 67: Don’t let the headlines fool you. Nobody knows how life started

By thelabwithbradbarton | October 10, 2017

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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. Rather than a lack of theories, there are just too damn many of them, all of them seemingly at least plausible, and little or no way to decide between one or another. Perhaps they all happened. Perhaps none of them. Perhaps the actual process has yet to be described. Perhaps pieces of the puzzle simply took too long, or require temperatures and pressures that cannot be reproduced in a laboratory.

Here’s a link to a Nova special on this subject that covers it much better than I have. Mind you, they had 45 minutes to do it in, rather than the 9 minutes and change I had.

Origin of Life – How Life Started on Earth

Ep 66: When worlds literally collide

By thelabwithbradbarton | October 6, 2017

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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 impacts within our solar system? From the loss of the outer layers of Mercury, to the two-faced appearance of Mars, to the tipped over condition of Uranus, it seems that about half our planets were struck hard enough, by large enough objects, to have a major effect on how the planets appear today.

Ep 65: Our big, beautiful moon

By thelabwithbradbarton | October 5, 2017

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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 planet it orbits. Measured in that way, no other moon comes close. So how rare is such a large moon? Where did our big beautiful moon even come from?

Here are some articles about our moon and where it may have come from.

Where did the Moon come from?

Giant Moon-Forming Impact On Early Earth May Have Spawned Magma Ocean

New Moon-Formation Theory Also Raises Questions About Early Earth

Ep 64: Why do big ones orbit so strangely?

By thelabwithbradbarton | October 4, 2017

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Why do big ones orbit so strangely?

Today, we consider all the large planets orbiting stars other than our sun, and their tendency to adopt eccentric orbits. The possible reasons include close encounters with other stars, interactions between the planets themselves, and different ways the large planets may have formed.

Here’s an article on the large size of Jupiter, and the core accretion model, versus disk instability as possible explanations.

How Jupiter Got Big

Here are several articles on computer simulations of planet to planet interaction, which could cause orbits to become eccentric, or planets to adopt a short-term nearly circular orbit, or even flip over.

Mystery Solved: How The Orbits Of Extrasolar Planets Became So Eccentric

The Architecture of Planetary Systems

Orbit Flips in Exoplanet Systems

Toward the end of the episode, I referenced a couple of earlier episodes. Here are links to said episodes.

Ep 55: The search for Planet 9

Ep 59: How to make a mind—part2