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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 has to do with how easily injured eyes are when they don’t work. I’ve never seen that brought up by scientists; maybe you have to go blind to get it.

Here’s an article on the kiwi bird and how it may be losing its sight as a species. Special thanks to @seeingwithsound for the article and pointing me to this topic.

New Zealand’s iconic kiwi birds may be losing their sight

Here’s an article on changes in the brains of sightless animals.

Thanks to evolution, blind cave-dwellers are rapidly losing the visual parts of their brains

Here’s a paper on animals that have given up eyes, and how and why they may have done so.

Evolution of eye development in the darkness of caves: adaptation, drift, or both?

Here’s an article on blind cave fish that includes a video.

How This Cave-Dwelling Fish Lost Its Eyes to Evolution

And an article on how the offspring of blind cave fish can regain their sight.

Blind Cavefish Can Produce Sighted Offspring

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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 in the perspiration of others.

Humans Can Sense ‘Smell Of Fear’ In Sweat, Psychologist Says

The smell of fear is real and it’s contagious

Study Says Humans Can Smell Fear, Emotion Is Contagious

Here’s a paper on the human reaction to putrescine, a chemical associated with death and decay. Even when we don’t consciously notice the smell, we’re instinctively made nervous by its presence.

The smell of death

Here’s a talk by a woman who felt unexplained feelings of dread within her new home. At first, she thought it was a ghost, but eventually she discovered it was something far more deadly.

A scientific approach to the paranormal

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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. Almost every living cell has an electric charge. Multicellular life has found a way to use electricity to send long distance messages from one part of the organism to another. Today, we talk about electricity, life, and some slightly grotesque experiments that have been done with the relationship between the two.

Here’s an article on electric currents applied to recently deceased human body’s, that caused them to move.

1800s doctors conducted weird electrical experiments on corpse brains

Here are a couple of articles about single celled life and nanowires that they grow to conduct electricity.

Bacteria buzzing in the seabed

Biological wires carry electricity thanks to special amino acids

Here’s an article about experiments done that altered the electrical properties of cells that changed the way the organism grew. This included eyes on the tales of tadpoles, and hints of being able to regrow severed limbs in creatures that do not normally possess such a capacity.

It’s Electric: Biologists Seek to Crack Cell’s Bioelectric Code

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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.