An example of AI coherence and ability to meaningfully and correctly answer qeustions about the state of knowledge

I asked Google Bard some questions about the origin of photosynthesis, and whether this was a one-off or might have occurred more than once in the history of life. Also, I asked it the same thing about C4 photosynthesis, which is a modified chemical pathway first appearing about 35 million years ago, and used by some plants, including corn (but not wheat) that make them more efficient at converting sunlight to living matter. This was its response, which I think you will agree is pretty stunningly coherent (and also, to my knowledge, quite accurate). 

Your questions delve into the fascinating history of photosynthesis on Earth, and here's what we know:

 

Origin of Photosynthesis:

• The current consensus is that oxygen-producing photosynthesis (oxygenic photosynthesis), the dominant form responsible for Earth's oxygenated atmosphere, evolved only once. Evidence points to a common ancestor of cyanobacteria, from which all other oxygenic photosynthetic organisms (including plants containing chloroplasts descended from cyanobacteria) are ultimately derived.

• However, older, simpler forms of photosynthesis that don't produce oxygen (anoxygenic photosynthesis) might have evolved multiple times independently in different ancient bacterial lineages. These simpler forms use various electron donors besides water and typically don't contribute significantly to atmospheric oxygen.

Krebs Cycle and Water Splitting:

• The specific features of oxygenic photosynthesis you mentioned, the Krebs cycle for carbon fixation and water splitting for oxygen production, are indeed shared by all organisms using this process. This further supports the single origin hypothesis for oxygenic photosynthesis.

C4 Photosynthesis:

• C4 photosynthesis is a specialized adaptation within some plant lineages (monocots and dicots) to improve photosynthetic efficiency, particularly in hot and dry conditions.

• Evidence suggests that C4 photosynthesis has evolved independently multiple times in several unrelated plant lineages, both monocots and dicots. This highlights the convergent evolution phenomenon, where similar adaptations arise in different groups facing similar environmental pressures.

In summary:

• Oxygenic photosynthesis: Likely evolved once, with all organisms using it sharing key features like the Krebs cycle and water splitting.

• Anoxygenic photosynthesis: May have evolved independently multiple times in different bacterial lineages.

• C4 photosynthesis: Evolved independently several times in both monocot and dicot plant lineages.

The field of evolutionary biology continues to unravel the intricate history of life on Earth, and further research might shed light on the exact number of independent appearances of different photosynthetic pathways and their adaptations.

I do find that it uses phrases like "x is a fascinating question" and "In summary,...." too much. (Especially in view of the admitted fact that "fascination," whatever it is, is not within the purview of AI, which has no self-awareness or emotional capability. But that a machine can process (and "seem" to understand) a detailed series of questions and almost instantly prepare a meaningful answer is pretty damn remarkable, I'd say. 

By the way, just playing around with it, after having done much the same thing with ChatGPT, I find Google's ability to accurately represent facts is better. It did fall down on things like identifying Bach as a "17th century composer" because he was born in the 17th century, but when I pointed that out, it readily corrected its answer.