Prospective kin

Organisms treat their mates better than average conspecifics - even before they have had any offspring with them.

It isn't hard to think of reasons for this, but many of of those reasons invoke the idea of prospective kin - unborn children.

Most children have a probability of becoming an ancestor - and it is possible to extend this idea to children that haven't been born - and to children that haven't been even conceived.

Pretty standard kin selection models can thus be applied to courtship behaviour, bower construction, nuptual gifts - and so forth. These are cases where cooperative behaviour without relatedness occurs. In fact, there is relatedness - relatedness to unborn children.

Kin recognition is what kin selection does

One thing I learned from reading "Social Bonding and Nurture Kinship" was that there was a debate over whether kin recognition and other adaptations related to kin selection are really all that different. I had previously absorbed (from the literature on the topic) the idea that "kin recognition" was a subset of "kin discrimination". Looking at another individual and seeing that they are similar to you and other family members is called "kin recognition". Helping nestmates (regardless of whether they resemble you) is called "kin discrimination".

However, another camp holds that kin recognition is what kin selection does. From this perspective dividing "kin recognition" from "kin discrimination" isn't carving nature at the joints. It's trying to make a distinction where there isn't really much of a difference:

I suggest that group or individual recognition systems might well qualify as kin recognition regardless of the cues used, provided that the groups or individuals so recognised are routinely kin and that the fitness benefits associated with recognition typically flow among kin. Grafen's insistence that kin recognition be a function of genetically based cues and that no individual or group recognition system should qualify excludes many recognition systems that may well function to associate kin in a fitness enhancing context. Kin recognition is an inherently functional concept and any definition or restriction that relies too much on a particular mechanisms or source of cues is problematic. (Stuart 1991).

I've warmed up to this. "Kin recognition" and "kin discrimination" is too much terminology for what is basically one type of effect. "Kin recognition" is the more popular term (by a factor of five). The "kin discrimination" category is surely the more useful one. I think we should just refer to "kin discrimination" as "kin recognition".

Clade selection

"Kin selection" and "group selection" are common terms for the way that organisms help organisms which are similar to themselves. I've proposed the term "similarity selection". Another contender is "clade selection". This term came from George C. Williams (1992).

Dawkins said of this:

Williams efficiently disposed of “group selection,” which never recovered (except as a muddled version of kin selection). But in Natural Selection: Domains, Levels and Changes (1992), where he gathered many threads of thought, he developed the important and superficially similar idea (foreshadowed in Adaptation and Natural Selection) of “clade selection” to explain, not “altruism” but macroevolutionary patterns of diversity and - as I would put it - “the evolution of evolvability.”

"Clade selection" seems like better terminology than "group selection" - in some respects. Like the term "kin selection" it puts an explicit emphasis on relatedness. Group selection only works - in the sense of producing group-level adaptations - when relatedness is involved. So: why not use the term clade selection?

Alas, I think there's a good reason not to use the term "clade selection". A clade consists of an organism and all its descendants. The problem is with the "all". You can still have group selection that works without it being clade selection - by the fitness delta involved not affecting all the descendants.

The "all" in "clade" makes "clade selection" a confusing term. Not worthless, perhaps, but I don't think I can endorse the term.