Just in case you haven’t heard of these guys, let me tell you about a type of cellular slime mold that takes “working together” to the next level–Dictyostelium discoideum.
They’re frequently used in biological research because they grow quickly, are easy to store, and show very complex behavior for such simple organisms.
They start out like this
Individual amoebae, exploring the upper layer of soil snapping up bacteria. They’ll happily continue along in this state, building into a large population, until the overall bacteria population becomes dangerously low. Then they hop into action.
The individual cells begin to gather to a central location, sticking together as they bump into each other. Eventually they form into a large slug-like formation about 2-4 mm long, which can travel forward at a rate of 0.5 to 2 mm per hr. This slug sets out to travel towards light and heat, eating bacteria it encounters along the way.
When it finds a good place, the cells begin to stand up, gather in the base, and form into a fruiting body—the top producing spores that float on the wind to distribute individual cells.
They hopefully find areas rich and bacteria, and the life cycle starts again.
Here it all is:
A couple final twists
– Under certain conditions the cells can also reproduce sexually—if two of differing sexual types meet each other in the right conditions, they will fuse together, consume other nearby cells, and form a hard cellulose wall to protect themselves. Then they’ll reproduce, releasing offspring with a mixed genome.
– About 1/3 of Dicty colonies carry bacteria with them as they aggregate and send out spores, ensuring that the new colonies that are established have a source of food.
– This kind of slime mold and others are able to show complex behaviors like maze-solving, food scouting, and finding the most efficient paths without any nervous system to speak of. They use chemical cues to track where they’ve already been to know what to avoid.
Here’s a video of slime molds in action. Definitely worth checking out! http://youtu.be/bkVhLJLG7ug
(For more information, also look at http://dictybase.org/tutorial/)
I’ll be back in two weeks with an in-depth article of some kind.
(P.P.S. My second set of blogs on NOVA is in the process of going up! Past, Present, and Future of Cryptography (link to the first post).)