The first bite: The beginnings of predator-prey interactions on our planet

            In Where the Wild Things Were, Stolzenburg discusses the very first predator, which was most likely part of the “primordial soup” that generated multicellular organisms. I imagine during this time there were intense and viscous predator-prey interactions. Cells were being engulfed entirely (eating your neighbor whole!) or sucked up by some sort of apparatus or appendage. See this quote from Stolzenburg...

            “It was a natural step or two beyond that for predator and prey to add  spermlike tails and fluttering cilia of rudimentary self- propulsion, the first glimpses of the chase.”

One of the best (in my opinion) endosymbiotic diagrams 
from Keeling (2010) The endosymbiotic origin, diversification and fate of plastids 

            Scientists have discovered evidence of this predation.  Plastids contain relict prey membranes, still present and observed in most all plastid-bearing organisms. For example, early glaucophytes (a small group of algae) retain an extra membrane containing peptidoglycan (only found in the cell walls of bacteria). This wall is likely a remnant of the cyanobacteria that was preyed upon by early glaucophytes. It is fascinating that we are able to trace this sort of ancient predator-prey interaction.

           

            It is interesting to think about what sort of environmental pressures led to the first predation of one single celled organism upon another. Even further, what steps led to the permanent integration of this prey cell? What sorts of genes were transferred and how many millions of years did it take? Was the beginning of multicellularity ultimately driven by predator- prey interactions? I believe that scientists are just beginning to answer these questions with the amazing advances in genomics.

Didinium preying upon Paramecium (sciencephoto.com)

            Can you imagine what the first endosymbiotic event looked like? Are there any examples of predation that we can compare it to today? I imagine it looked something like one of the experiments that Stolzenburg describes with Didinium preying upon Paramecium. Gause, a microbiologist from the 30s, added Didinium to colonies of Paramecium and watched as the Didinium devoured every last Paramecium. He then added sediment to the bottom of the jar. Didinium again consumed most Paramecium, however a few were able to take refuge in the sediment. This simple experiment is interesting from a predator-prey perspective for several reasons. It shows how environment also plays a role in these interactions. Also, how predators drive niche specialization by causing prey to take refuge in different environments.

WATCH Didinium hunt and eat Paramecium.....

http://www.youtube.com/watch?v=HlHihxqqXOE

or...

http://www.youtube.com/watch?v=rZ7wv2LhynM

            

Ancient shipwrecks

 Weisman illustrates the counter attack of nature if humans where to disappear. He also describes areas of the planet where humans once existed, but nature prevailed, as if we really did disappear. Shipwrecks can be eerie, remind us of the power of nature, and also gives us a glimpse in the past.

One of the most rare shipwrecks ever discovered is the Kyrenia Ship, an ancient Greek ship that was discovered off the coast of Northern Cyrpus. Wiesman describes the watery scene in detail. It is amazing what can be preserved in the absence of oxygen; the Kyrenia ship is the only example of a perfectly in tact merchant ship.

The ship’s hull was discovered by Andreas Cariolou perfectly intact, although the wood needed to be injected with polymers or else it would disintegrate when exposed to air. The hull was constructed of the Aleppo pine, a pine that is native to the Mediterranean and held together by copper nails, resistant to rust. 

The Kyrenia ship was known to carry wine, olives, and almonds. Interestingly, scientists were able to carbon date the almond seeds and date the ship to over 2,300 years old. I wonder if there will ever be a time in the future when someone will carbon date the seeds agriculturalists use today.  Will future humans even need seeds? It is interesting to imagine current humans as an ancient population and what future generations would think of us.

How did this ship go down you might wonder? It is difficult to determine the fate of this ship because it was found underwater in pristine condition. There were no signs of battle wounds. Scientists speculate that piracy or simply old age might have contributed to the sinking of this fascinating ship. The Kyrenia ship is considered an archeological treasure, still giving us much information about the past. To learn more about this ship check out the BBC documentary. 

The Power of Fungi

While it is interesting to imagine the world without humans, I want to take a moment to image the world without fungi. This would be a world where humans would not want to live. Plants would die because of their inability to take up proper water and nutrients from the soil without mycorrhizal fungi. The animals that eat those plants would die, and the predatory animals that eat those animals would die. Ultimately, we would be left with piles and piles of dead plants and animals that would never decay. We would be buried up to our ears. Fungi are incredible decomposers; there are very few substrates that hyphae cannot penetrate (fungi are known to decompose even rocks). We are lucky that fungi retain this amazing ability and keep our lives clutter free.

 

Imagine once again that humans have mysteriously vanished from the earth. This is a world where fungi would reign, decomposing all of what we left behind. Basically, fungi in a world without us would have a field day. The antifungal treatments we use when building will eventually succumb to the power of mold. See this passage from Weisman...

"As gravity increases tension on the trusses, the ¼ inch pins securing their now-rusting connector plates pull free from the wet wood, which now sports a fuzzy coating of greenish mold...the same thing is happening to the floors inside...as the wood continues to rot, trusses start to collapse against each other...eventually the walls lean to one side, and finally the roof falls in.”

All the precautions we take to stop fungus from decaying all of our possessions would seize to work.  Since spores are mere microns in size, they have no trouble finding a way into the smallest of crevices. It only takes one teeny tiny spore (we probably inhale hundreds of them which each breath) to start a rampant fungal colony. As Weisman states...

"No matter how hermetically you’ve sealed your temperature –tuned interior from the weather, invisible spores penetrate anyway, exploding in sudden outbursts of mold- awful when you see it, worse when you don’t, because its hidden behind a painted wall, munching paper sandwiches of gypsum board, rotting studs and floor joints.”

It is estimated that there are in excess of 13 million species of fungi in the world, each of which plays an equally important role in allowing us to live our lives. It is unusual that someone places value in fungi, but lets not forget that penicillin saves millions of lives each year. We would also be without three highly valued food products including bread, cheese, and wine. This is just a small review of the many, many luxuries that fungi provide us with. A world without fungi is a place that I would not want to live.