Not so much a post as a question

5 07 2007

I’m not sure why I started thinking about it (I think it has something to do with parental care in dinosaurs), but I wonder how precocial and altricial development patterns in different animals evolved. I’m sure other people have thought about it before, but I do wonder about the interplay between behavior and development, especially the physiology of altricial young that cannot care for themselves. I would imagine that parental care as a behavior would develop first, but given that, how did this influence the physiology and development of offspring? If I find any answers, you can bet I’ll write about it.




3 responses

6 07 2007
Zach Miller

Good question. Altricial babies get more parental care, so they tend to have a better survival rate. But there’s certainly an advantage to precocial babies, too, because they can get along just fine on their own and their parents can focus on spending energy on making more babies.

6 07 2007
Cory Tucholski

I’m assuming that I’m the last of your regular readers that you expected to comment on this entry. But you have raised an interesting question that has spiritual implications as well. It’s also relevant to any number of leadership issues.

Precocial employees result in higher turnover. But if management spends more time with the employee during his formative days with the company (an altrical employee!), then that employee has a higher rate of job satisfaction and thus is far more likely to stay with your organization longer.

Precocial employees tend to learn their jobs more quickly, I’ve noticed. But they develop their own methods and are highly resistant to being told the correct company procedures. (I work in fast food, and procedures are absolutely paramount–as I’m sure they are in your science lab)

Anyway, very interesting thoughts.

6 07 2007

Zach; thanks for the input. That’s what I figured out at first, but what I’m really wondering is how parental behavior might change the development of the offspring, i.e. how did altricial dinosaurs like Maiasaura come to be (I would assume that the most ancestral condition for young would be precocial). Initially I thought that better parental care would allow weaker offspring to survive, thus spreading their genes through the population, but I’m not so sure such a hypothesis would work (what about healthier offspring?). Crocs and birds are probably going to be my focus as I do a lit. search on this, being that crocs have a very rudimentary parental care system (amounting more to protection than help) while baby birds require much care from their parents.

Cory; you’re right that “precocial” employees are likely to have a much higher turnover rate depending on the type of job, although such situations are not life-or-death (and altricial employees don’t show up unable to walk with big, oil-drop eyes that make the managers want to protect them from others, etc., hah).

For ourselves, we essentially have to be altricial young; if we developed further in the womb, we simply would not be able to get out. Just like birds and reptiles, the bones of our skulls are not fused when we’re born, but if they were more mothers and children would die in childbirth (barring a c-section). Indeed, Carl Sagan draws a loose connection between this and the Biblical “price for intelligence” (pain in childbirth) in that humans mothers experience so much pain in childbirth because of the way the reproductive system has to twist to accommodate our big ol’ heads, pain that does not seem to be experienced by most other animals that I’ve seen give birth.

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