Is hybrid vigor a valid theory for humanity, animals, just plants or all lifeforms?

Answer 1

You can't hybridize humans. We are all the same species.
That said, yes, hybrid vigor is valid as long as the result is fertile.

Answer 2

All lifeforms.
Heterosis is increased strength of different characteristics in hybrids; the possibility to obtain a "better" individual by combining the virtues of its parents.
This is commonly known as hybrid vigor or outbreeding enhancement. It is often the opposite process of inbreeding depression, which increases homozygosity. Heterosis is an example of heterozygous advantage. The term often causes controversy, particularly in terms of domestic animals, because it is sometimes believed that all crossbred plants or animals are better than their parents; this is untrue. Rather, when a hybrid is seen to be superior to its parents, this is known as hybrid vigor. It may also happen that a hybrid inherits such different traits from their parents that make them unfit for survival. This is known as outbreeding depression, typical examples of which are crosses between wild and hatchery fish that have incompatible adaptations.
One study suggests that hybrid vigor may be associated with increased intelligence in humans. Nagoshi and Johnson (1986) found that children of Japanese-Caucasian cross-ethnic unions scored .26 SD higher on several cognitive tests than those from within-ethnic families, despite having virtually identical parental educational and occupational backgrounds

Answer 3

Valid as shown in animals, plants, and almost all living beings.
For humans it is not valid, since matings occur as a cultural outcome, mating is not something you do in order to strengthen your gene pool.

Answer 4

yes, for all lifeforms. Valid , yes. Definitive, no.

Answer 5

Yes.

Answer 6

y not we are animals...just highly specialized or so we think ; )