These viruses – known as phages – attach to the surface of bacterial cells, inject their genetic material, and use the cells' enzymes to multiply while destroying their hosts. To defend against a phage attack, bacteria have evolved a variety of immune systems
The complete statement made by Stephen Hawking is: "though much of its behaviour through out history, has been pretty stupid, and not calculated to aid the survival of the species."
If one looks at our history, there are some events that defy our capacity for logical thinking. One would think that, as we possess this capacity, we would be able to direct our decisions towards the survival of the human species.
However, in many cases greed and the desire for personal gain have taken precedence. One good example was the burning of the great library of Alexandria, one of the most significant libraries in the ancient world. This magnificent collection was lost during the siege of Alexandria, when Julius Caesar set on fire the ships in the harbor.
Another example is the atomic bomb, when science has been used to invent one of the most destructive weapons known to us. Atomic warfare is still a threat that may end all life on Earth.
Furthermore, the greed of some corporations has led to multiple ecological catastrophes that endanger not only other species but our own future as well. One example is the Bhopal gas leak in India, where in 1984, due to poor maintenance, the chemical plant released 30 metric tons of methyl isocyanite into the atmosphere.
Answer:
Ecology is the branch of biology that deals with the relations of organisms to one another and to their physical surroundings.
The units of genetic distance derived from bacterial conjugation studies are called minutes. Bacterial conjugation is the process by which a bacterium transfers genetic materials to another through direct contact. One bacterium serves as a donor of the genetic material and the other serves as the recipient.
