It just stands to reason that higher forms of life are more complex than “lower” forms of life.
One way to guess the intelligence and complexity of an organism is to look at how many genes it has in its genome. It just stands to reason that simple forms of life don’t need as many genes and more complex forms.
For example, the virus that causes mononucleosis has a measly 80 genes (sorry for the pun, but measles are viruses, too).
A fruit fly has 13,379 genes, fewer than a round worm which has approximately 21,000 genes.
A mouse has about 23,000 genes.
We humans have approximately 25,000 genes. I think that puts us pretty near the top of the animal kingdom. I don’t know about whales and dolphins. Maybe we better not find out.
What about plants?
Rice has about 28,000 genes.
A cottonwood tree? 45,000 genes.
That’s why I listen to trees.
They might have something worthwhile to say to us....
More about the mononucleosis virus: Epstein-Barr virus (EBV)
More about the fruit fly: Drosophila melanogaster
More about human genes: Here