|Life On Earth (from The Quick Guide To Creepy-Crawlies)|
Some of you may have noticed that there is a bit of a bug going around at the moment. It's OK, I'm not going to bang on about coronovirus, which you're all fed up to the back teeth reading about, but to have a more general look at the world of bacteria and viruses and try to answer the question, “what have they ever done for us?” The figure on the left (taken from my book The Quick Guide to Creepy-Crawlies) shows how life on Earth is classified into three sections (called Domains). All of the animals and plants that you can see with the naked eye (and many too small to see) fit into the bottom section, the Eukaryotes. The microscopic bacteria and the archaea between them, form a group called the Prokaryotes.
|bacteria colonies on beetroot|
Let's look at bacteria first. You're probably familiar with many of them: Escherichia coli (E. coli in common parlance), discovered by Theodore Escher in 1884 and the bane of butchers ever since; Staphylococcus aureus, the SA in MRSA that bedevils hospitals (the MR being multi-resistant [to antibiotics]); and Streptococcus pyogenes, the 'strep' in strep throat. But not all bacteria are bad. In fact, we couldn't live without them, they synthesize all the Vitamin B12 in the world for a start. They are responsible for the breakdown of organic material that returns nutrients to the soil, as these colonies of bacteria are doing to this beetroot.There are also an awful lot of them: between them, they weigh more than every animal and plant on the planet combined.
|Archaea providing a splash of colour|
The other half of the Prokaryotes are the archaea, with which you are probably not so familiar. These differ from bacteria (and ourselves for that matter) in their cell structure and basically, they are good guys. For instance, we couldn't digest our food without the help of an archaean with the zippy name of Methanobrevibacter smithii. When our gut bacteria have finished breaking down our meat and three veg. into stuff we can actually use to keep us alive, M. smithii mops up the bits that are left behind. They also bring a little colour into our lives as this picture of the of the Morning Glory Hot Spring in Yellowstone National Park, taken by ZYjacklin shows. The archaea are responsible for the bright yellow around the rim of the spring.
|Coronavirus (Alissa Eckert, MS; Dan Higgins, MAM / Public domain)|
So, where do viruses fit into all this? Awkwadly. Some say that they are a form of life (because they have genes and can reproduce) and some say that they are not (because they lack a cell structure). Personally, I go with Dr. Spock - “It's life Jim, but not as we know it.” They only come alive and reproduce when they are inside a host organism (plant, animal, bacteria or archaea), at all other times they exist as bits of genetic material in a protein coat floating about like teenagers looking for a party to crash. To continue the analogy, once they've found a party to crash, they trash the place by imparting a disease to the host (the SARS-CoV-2 virus currently spreading the COVID-19 disease around the world for example). They then move on to the next party through a variety of means; insects ferry them from plant to plant like Uber drivers; 'coughs and sneezes spread diseases' is an old adage which was made for them; poor toilet hygene (in the case of norovirus and rotavirus); or through intimate contact (such as HIV). Whether you consider them as living entities or not, Earth wouldn't be the same without them as they are the most numerous form of 'biological entity' on the planet. But what use are they?
Viruses spread most quickly when there is a high density of host organisms in one place and where there is a method of transportation between different groups of populations. This occurs most often when the population growth of a species spirals out of control. So, maybe we should consider viruses as nature's population control mechanism. A bit like brakes on a car; they don't make the car go any better, further or faster but they are a very necessary part of the over all design.
Talking of life, but not as we know it: I have a new novella out this week entitled The Eggs of Saramova which starts here in Greece and then moves somewhere further afield. It's a fast paced thriller, only available on Kindle at the moment (the paperback will be published in time for the summer) and you can read the first couple of chapters for free (or the whole book if you're enrolled with KDP Select) by following this link: http://viewbook.at/Saramova
The Eggs of Saramova
A science fiction novella for those who don't like science fiction. A fast-paced thriller that is, literally, out of this world (and it starts right here in Crete).
All you need to know to identify any type of insect, spider, worm or snail very simply and find out more about it.
A light-hearted look at life through the eyes of the fairer sex.
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