Can mushrooms be created asexually? If not, then how is it that the 'largest organism on the planet' (the giant fungus in Oregon)is generating its own mushrooms from the ground?
Certainly. There are many fungi that reproduce asexually, sexually, and even by fragmentation. They are among the most diverse lifeforms on the planet.
The largest organism by weight is an aspen colony in Utah, weighing some 6,000 tons and over 80,000 years old.
That said, can they be transported naturally from one planet to another via debris from a catastrophic collision?
Possibly - if they can survive the intense heat of the collision, which is probably unlikely. And the intense cold of space which would freeze and burst any living cells.
Spores are not living cells, and I understand they can survive the vacuum of space (but not so much, UV radiation). Surviving Space: How Bugs Might Travel Between Planets
Eh? You're trying to say that spores are inanimate objects (like grains of sand) that can somehow spring to life under the right conditions?? I believe you are thinking of something like a virus. Non-living genetic material.
Spores are haploid cells, produced by diploid cells that have undergoine meiosis. They can withstand long periods of dessication, during which they have virtually no metabolic activity. However, technically, they are 'alive', just as frozen eggs or sperms are 'alive' even if not undergoing metabolic activity, because they can 'spring back to life' when placed in the right conditions, and do not need a host cell (unlike viruses, which need host cells in order to replicate).
OK I wasn't really sure. Anyway, their advantage is they don't contain as much nutrients, so the fungus can make many of them. The more there are out there, the greater the chance they will find favorable conditions.
Lets not forget Tardigrades. Please Register or Log in to view the hidden image! These amazing creatures are multicellular but can withstand the freezing cold and deadly radiation of space, at least for a while.
Yes, quite correct. 'Bacterial spores' are an entirely different category, being prokaryotic. I don't usually consider them to be 'spores' along the lines of fern, mushroom, liverwort, and other eukaryotic organisms that regularly reproduce by spores. Here's a good link about 'bacterial spores': http://www.daviddarling.info/encyclopedia/B/bacspores.html
I'm reading a section on endospores at the moment and it seems that some of the oldest known spores were found in the stomach of an ancient bee preserved in amber. It is estimated to be around 25-40 million years old. Necessary precautions were taken to prevent any pathogenic outbreak from occurring and the bacteria were revived in a basic growth medium. (Cano, R. J., and M. K. Borucki. 1995. Revival and identification of bacterial spores in 25- to 40-million-year-old Dominican Amber. Science 268: 1060-1064)
If you go to the link I posted, you will see that fact referenced in the body of the text. Below is a link that is even more interesting of endospores that were reported to be 250,000,000 years old, preserved in salt crystals, that were viable. See: http://www.spaceref.com/news/viewnews.html?id=231
Thank you for that link WLW. A quarter of a billion years and they say this, "The implications of this discovery are rather profound - both for the prospects of life upon other worlds - but also for the possibility of life being swapped between worlds." Now I have two questions. Where does that put those bacteria in the evolutionary time table on Earth, and how early in our known universe could such life have evolved elsewhere given our understanding of the possible existence of hospitable planets in the early galaxies. Could such life have originated somewhere in the early universe (after say a few billion or five to ten billion years) long before the 13 billion years that the Carlsbad spores were trapped in the salt crystals here on Earth?
Bacteria are believed to have arisen some 3,000 million years ago or thereabouts; so certainly it is plausible that if we know they can survive 250 million years trapped in salt crystals, they could survive far longer; so the idea of panspermia is quite viable with those discoveries.
