Question

What does it mean when scientists say that living organisms share a universal genetic code?

Answer 1

All living organisms shared an ancestor in the past. All of life originated from one prokaryotic organism that developed in early earth's primordial soup millions of years ago. Later as time went on some prokaryotic cellular organisms absorbed other prokaryotic organisms (i.e. Chloroplast and Mitochondria) to preform essential functions within eventually turning eukaryotic cells. These cells eventually evolved into all animals and plants you see today, that are classified as such.