According to my interpretation of this sentence, it stops short of telling us that in our reality all species–man, animals, and plant life (and viruses and bacteria too, for that matter)–developed from a single primordial living source. Evolutionary theory maintains that such a source spontaneously came into being, riding upon various protein molecules (or certain other kinds of molecules) that had themselves chemically–and miraculously–evolved out of nonliving matter, then demonstrated the ability to duplicate themselves.
Proteins, for instance, are very complex chains of amino acids, and consist of nitrogen, oxygen, hydrogen, carbon, and or certain other elements. They exist in great variety in all animal and vegetable matter; in the body each protein supports a very definite function. But the the view that all life had a common origin, that by pure chance it originated on the earth–just once–without the aid of God, or any sort of designer, is today accepted by most scientist in biology and related disciplines. Such thinking stems from the work done in the 19th century by the English naturalist Charles Darwin and Alfred Wallace.
I believe that at most the “facts of evolution” make up a working hypothesis–or unproven proposition–only, for many of evolution’s tenets, especially those involving energy/entropy are open to serious challenge. There’s plenty of evidence around for changes occurring within species, but the “upward” transmission of one species into another has not been scientifically proven from the index fossil record, nor has it been experimentally verified. The arguments about evolution can get very technical.