I've been thinking as well that from some perspective a human being isn't actually a single life but rather itself a multitude of separate tiny-life forms that cooperate to survive (the cells). The voice in our head is the emerging consciouness that act as a captain, it's useful for the captain to think of itself as one being.
Now this said, I feel the article is jumping a bit too much on the Animism hippie bandwagon:
https://en.wikipedia.org/wiki/AnimismOf course, there is some intelligence in any life form behaviour, but if you want to say that a tomato plant is intelligent than you need to use another word or set of words for more advanced life forms. Putting in the same bag a tomato plant and a dolphin clearly makes the word intelligence so vague it loses almost every practical meaning.
To clarify also the part where it talks about earth being an organism.
I've thought of this as well, the whole universe could be a life form, each planet and star in it a cell in its body. It's a possibility.
Or maybe even our whole universe is just a cell in someone's body.
It's possible, but I fear there is little science in the people of that article and just old fashion Animism and protect "the mother earth" natural spiritual thinking that has existed for thousands of years.
Those people see the world as if they are druids in a fantasy novel. I see myself more as a wizard. We might have different opinions. I will take them seriously when they can LITERALLY speak with animals daily in useful manners and tell vines to move. Until then is just (a) Fantasy.
I can summon electricity and fireballs (with technology), if they want to say they are druids they better step up their enchantments. Telling "sit" to a dog and then writing long articles on how dogs are so intelligent doesn't cut it for me.