Post by Deleted on Apr 13, 2018 21:45:54 GMT
Its a continual shower by virii ...and its obvious they play a pivotal role in determining what is going to survive down below..
www.nytimes.com/2018/04/13/science/virosphere-evolution.html
Do viruses even fit the definition of something alive? While they are top predators of the microbial world, they lack the ability to reproduce and so must take over the cell of a host — called an infection — and use its machinery to replicate. The virus injects its own DNA into the host; sometimes that new genes are useful to the host and become part of its genome.
Researchers recently identified an ancient virus that inserted its DNA into the genomes of four-limbed animals that were human ancestors. That snippet of genetic code, called ARC, is part of the nervous system of modern humans and plays a role in human consciousness — nerve communication, memory formation and higher-order thinking. Between 40 percent and 80 percent of the human genome may be linked to ancient viral invasions.
Viruses and their prey are also big players in the world’s ecosystems. Much research now is aimed at factoring their processes into our understanding of how the planet works.
“If you could weigh all the living material in the oceans, 95 percent of it is stuff is you can’t see, and they are responsible for supplying half the oxygen on the planet,” Dr. Suttle said.
In laboratory experiments, he has filtered viruses out of seawater but left their prey, bacteria. When that happens, plankton in the water stop growing. That’s because when preying viruses infect and take out one species of microbe — they are very specific predators — they liberate nutrients in them, such as nitrogen, that feed other species of bacteria. In the same way, an elk killed by a wolf becomes food for ravens, coyotes and other species. As plankton grow, they take in carbon dioxide and create oxygen.
One study estimated that viruses in the ocean cause a trillion trillion infections every second, destroying some 20 percent of all bacterial cells in the sea daily.
Viruses help keep ecosystems in balance by changing the composition of microbial communities. As toxic algae blooms spread in the ocean, for example, they are brought to heel by a virus that attacks the algae and causes it to explode and die, ending the outbreak in as little as a day.
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While some viruses and other organisms have evolved together and have achieved a kind of balance, an invasive virus can cause rapid, widespread changes and even lead to extinction.
West Nile virus has changed the composition of bird communities in much of the United States, killing crows and favoring ravens, some researchers say. Multiple extinctions of birds in Hawaii are predicted as the mosquito-borne avipoxvirus spreads into mountain forests where it was once too cold for mosquitoes to live.
When species disappear, the changes can ripple through an ecosystem. A textbook example is a viral disease called rinderpest.
more at link..well worth it