ScienceShot: Dad's Odor Splits a Species

Key words: Sexual imprinting (male/female), (phenotype), speciation ,(species),ecological speciation, divergence (separating)

http://www.youtube.com/watch?v=cgPqmRNjoTEOctopus Garden

What is dad Stickleback doing in this picture?

He is guarding and caring for the eggs and fry as this deep-water form of stickleback is doing. The females of both types lay their eggs in an algae nest the male builds.

How does the Stickleback species change when divergence takes place?

Researchers studied two groups of the same species that ecologically separated. One lives in shallow water, the other in deep water. Evidence suggests ecological separation keeps species from mating. Some of the first evidence that sexual imprinting can drive speciation.

Girls, do you want a guy that looks like dear old dad?

Stickleback daughters want one who smells like him. Researchers have found that in two species of the fish from British Columbia's Paxton Lake, daughters learn who to choose as a mate based on their father's smell, a form of sexual imprinting.

Sexual imprinting

Offspring learn parental phenotypes and then select mates who are similar to their parents.

Speciation

“In any normal species there is some geographical variation through the range of the species. Some of this must be purely random variation, but typically geographic variation has some ecological pattern to it.”

Speciation

“In any normal species there is some geographical variation through the range of the species. Some of this must be purely random variation, but typically geographic variation has some ecological pattern to it.

Speciation

The Western meadowlark (left) and the Eastern meadowlark (right) appear to be identical, and their ranges overlap, but their distinct songs prevent interbreeding. (CalBerkley)

How might the dads be different in the deep water as compared to the dads in shallow water? Why won’t the daughters of the deep chose a mate from the males of the shallow and vice versa? Male imprinting?

Consider the different environments, adaptation as well as genetic traits over the generations.

Sexual imprinting

Offspring learn parental phenotypes and then select mates who are similar to their parents.

Now

• Let’s read part of the abstract from the researcher study to see if what they wrote makes sense.

Abstract (Genevieve M. Kozak1,*†, Megan L. Head2 and Janette W. Boughman3

• “Daughters imprinted on father odor and color during a critical period early in development. These traits have diverged between the species owing to differences in ecology. Therefore, we provide the first evidence that imprinting links ecological adaptation to sexual isolation between species. Our results suggest that imprinting may facilitate the evolution of sexual isolation during ecological speciation, may be especially important in cases of rapid diversification, and thus play an integral role in the generation of biodiversity. “

Speciation discussion on the Zonkey or Zedonk

How did this happen?

What about the Grolar?

How did this happen?

Is this real?

Speciation• For example, birds may vary their nesting habits according

to the trees available. Most geographic variation is the result of local adaptation to local environments, which in turn reflects some degree of genetic divergence between the separated populations. That genetic divergence will not lead to a species divergence, as long as genes flow (at some level) between the members of the species throughout their range. Gene flow is naturally much easier among individuals of a local population than between local populations, and much easier between adjoining populations than separated ones. Obviously, gene flow from neighboring populations acts against local adaptation.”

Speciation• “Suppose now that for some reason or other there is a

complete geographic separation between parts of the species range. Gene flow from the other parts of the range stops, and the separated populations evolve to suit their new, restricted environment. This encourages the genetic divergence of the separated populations, and might become so great that if the two populations were rejoined they would no longer be successful at interbreeding. [Even if limited interbreeding were still possible, the local adaptations might have become so advantageous that there would be strong selection for individuals to discriminate in order to mate preferentially with members of their local population, rather than with immigrant individuals.] The two sets of organisms have become new species because of the physical and genetic separation of the populations which, in theory leads to speciation.” http://mygeologypage.ucdavis.edu/cowen/historyoflife/speciationmode.html

Explore SpeciationWikipedia: Speciationhttp://en.wikipedia.org/wiki/Speciation

Understanding Evolution – Speciation:http://evolution.berkeley.edu/evosite/evo101/VSpeciation.shtml

TalkOrigins: Observed Instances of Speciationhttp://www.talkorigins.org/faqs/faq-speciation.html