For these reasons, viruses are not generally considered to be alive. However, not everyone agrees with this conclusion, and whether they count as life remains a topic of debate. Some even simpler molecules, such as proteins—like the that cause mad cow disease—and “prions” RNA enzymes, also have some, but not all, of the properties of life. Moreover, all of the properties of life we have discussed are characteristic of life on earth. If extraterrestrial life exists, it may or may not share the same definition that is a characteristics. Indeed, NASA’s working “life system capable of opens the door to many Darwinian evolution” more possibilities than the criteria defined superscript, 3, end superscript. However, this definition also makes it hard to quickly decide whether something is alive! As more types of biological entities are discovered, on Earth or beyond, they may demand that we re-think what it means for something to be alive. Future discoveries may call for revisions and extensions of the definition of life. What do think? you How would you define life? Would you add something to the list of properties above, subtract something, or use an entirely different definition? Can you think of exceptions or special cases that covered by the list? aren’t Share your ideas in the comments section below!
For these reasons, viruses are not generally considered to be alive. However, not everyone agrees with this conclusion, and whether they count as life remains a topic of debate. Some even simpler molecules, such as proteins—like the “prions” that cause mad cow disease—and RNA enzymes, also have some, but not all, of the properties of life. Moreover, all of the properties of life we have discussed are characteristic of life on earth. If extraterrestrial life exists, it may or may not share the same characteristics. Indeed, NASA’s working definition that “life is a system capable of Darwinian evolution” opens the door to many more possibilities than the criteria defined superscript, 3, end superscript. However, this definition also makes it hard to quickly decide whether something is alive! As more types of biological entities are discovered, on Earth or beyond, they may demand that we re-think what it means for something to be alive. Future discoveries may call for revisions and extensions of the definition of life. What do you think? How would you define life? Would you add something to the list of properties above, subtract something, or use an entirely different definition? Can you think of exceptions or special cases that aren’t covered by the list? Share your ideas in the comments section below!
What%20is%20alive.docx