Dog Vomit: It Moves!

DvGuest article courtesy of the Lost Coast Interpretive Center by Eve Broughton. Eve lives in Whitethorn and was educated at UC Berkeley.

The first slime mold I saw frightened me. It was growing on a tree stump in our front yard, and I was at that time taking a course in fungal diseases.

It really is harmless. It decomposes vegetable matter.

The name is a good description of this weird organism. Although it looks like a mold, and it releases spores like a fungus, it moves. Slime molds are currently classified with the Protista, single-celled organisms like the amoeba or paramecium. But unlike them, it has a complicated life history which includes a colonial stage.

One stage of its life begins as a spore: single-celled with only 1 set of chromosomes. When ripe, the spore can either become amoeba-like, and move by bulging itself in a direction with the rest of the cell contents flowing behind (streaming). Or, it can grow a flagella, a moveable “tail” which can propel it forward. These swarm cells move about, ingesting the bacteria they encounter.

When food is scarce, if it meets another swarm cell of like kind (amoeboid or flagellated), the two will fuse together. They now have a paired set of chromosomes. This new creation then duplicates all chromosomes, again and again, and becomes a multi-nucleated organism within a single cell membrane. This is the stage we encounter, usually on a rotting log or tree.

It is now called a plasmodium, and it too can stream about like a very large amoeba, flowing over the surface as it seeks dead vegetation, bacteria, yeasts, and fungi. It can sense air-born chemicals, and direct its flow toward the source. It surrounds its food, and secretes enzymes to digest it, and then ingests the components.

750776349_8af1fdc09eSlime molds prefer damp shady areas with lots of organic matter. It tries to avoid light. However, if it is exposed to light, or if food gets scarce, the plasmodium can quickly change into a fruiting body. Stalks arise from its surface, bearing spores. When released, these spores can be spread by the wind. Spores can also remain dormant for years, until favorable conditions allow it to become a swarm cell. The spores absorb moisture in cool humid conditions, split and escape from the spore coat. The life-cycle now repeats itself.

DNA research has shed a light on the relationships of slime molds and their evolutionary history. They seem to be very ancient organisms, perhaps a billion years old, and may have been the first life to live on land, rather than in the oceans.

It also seems, perhaps, to have a form of intelligence. Research has claimed that P. polycephalum can find the shortest route through a maze when food was placed at the exit. The amoeba also makes a pattern of networks between several food sources, and cycles between them to achieve a balanced diet of protein and carbohydrate. Further research will show whether these claims are true.

Regardless, Dog Vomit is an interesting organism.

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6 comments

  • Mother Nature is soooo cool. It never ceases to amaze me. All of the antics. Such beautiful plants, birds, animals, and fishes. Even the ugly ones amaze me that they can exist. I wonder what the Earth will be like in another billion years?

    • Gods work is mysterious and nothing short of a miracle!
      It’s amazing that he was able to create so many wonderful things in such a short amount of time 7,000 years ago.
      He has a plan for all of this and there’s no way we can ever even begin to understand how or why.
      God bless!

      • Thank you for the blessing. It is easy to say that God created all these things. I guess that we will also never be able to figure out where God came from. The firmament is far more mysterious than “God made it”.

  • Wow – when I was in school there were two kingdoms of life, animal and vegetable. Now there are three, and animal and vegetable are subsets of one of them! http://en.wikipedia.org/wiki/Kingdom_%28biology%29

  • I think I came across this slime mold two summers ago while walking on my property and was so amazed because of its bright yellow color! I haven’t seen this very often , so, is this common to northern Ca?
    Thanks Eve…

  • Paul Stamets is the man!! Yes to the slime.
    https://www.youtube.com/watch?v=DAw_Zzge49c

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