Which came first: pheromones or hormones?

[Bippitybop]

Which came in to use first, pheromones or hormones?

Hormone: any of various internally secreted compounds formed in endocrine glands, that affect the functions of specifically receptive organs or tissues when transported to them by the body fluids.
Origin: 1900–05; hormôn (prp. of hormân to set in motion, excite, stimulate) + -ōn, with ending assimilated to -one

Pheromone: any chemical substance released by an animal that serves to influence the physiology or behavior of other members of the same species.
Origin: 1959; phér(ein) (to bear, bring) + -o- + (hor)mone


This is a distinctly different question from, "which did we discover first?"

[BioWizard]

What's your thesis/hypothesis/argument or perhaps opinion?

[Paralith]

Well, I think that depends, really. Single celled organisms can and probably did, long before multicellularity and the evolution of animals, communicate between individuals via the secretion of specific molecules. (Communication being an attempt to influence another's behavior or physiology.) But do these count as pheromones since your listed definition clearly states animals? Even if we consider the earliest multi-cellular animals - they definitely had chemical communication between cells - they probably communicated chemically between individuals as well since they had no behavioral means to do so yet!

[BioWizard]

Well, I think that depends, really. Single celled organisms can and probably did, long before multicellularity and the evolution of animals, communicate between individuals via the secretion of specific molecules. (Communication being an attempt to influence another's behavior or physiology.) But do these count as pheromones since your listed definition clearly states animals? Even if we consider the earliest multi-cellular animals - they definitely had chemical communication between cells - they probably communicated chemically between individuals as well since they had no behavioral means to do so yet!

Not all chemical communication between cells is, afterall, hormonal/pheromonal. There's chemotaxis, cell adhesion signals, cytokines, etc. I suspect that for something to qualify as hormonal/pheromonal, it would require first the evolution of some faily complex multicellular organism.

[Bippitybop]

Point taken. Hormone use is only possible in a complex multicellular organism because you need glands to secrete them and a vascular system to transport them.

I had really been thinking about endogenous vs. exogenous chemical signals, and there are far many more types of endogenous signals than hormones. Let's broaden the question to, "which came first, pheromones or endocrine/autocrine/paracrine compounds?" aka "which came first, cell-to-cell signaling within an organism or cell-to-cell signaling between organisms?"

[Bippitybop]

What's your thesis/hypothesis/argument or perhaps opinion?

In my belief, pheromones. It was Bonnie Bassler's wickedly awesome (awesomely wicked) TED talk about bacterial communication in the form of quorum sensing molecules that made me think about it for the first time:

http://www.ted.com/talks/bonnie_bassler_on_how_bacteria_communicate.html

...and by "wicked" I don't mean to imply "evil." She seems like a super-nice lady.