Question

. The following quote is from Mallet J (2006) What does Drosophila genetics tell us about speciation? Trends in Ecology & Evolution 21:386-393

“Studies [in] Drosophila have given insight into the genetic changes that result in reproductive isolation. Here, I survey some extraordinary and important advances in Drosophila speciation research. However, ‘reproductive isolation’ is not the same as ‘speciation’, and this Drosophila work has resulted in a lopsided view of speciation.”

Focus in on the last sentence in this quote and answer the following questions:

a. What is speciation? (4 points)

b. What is reproductive isolation? (4 points)

c. Define species according to the Biological Species Concept (BSC). (4 points)

d. Given the BSC, what does the author mean that speciation and reproductive isolation are not synonymous? (4 points)

e. In any event, species concepts are difficult to deal with. The definitions we have for species do not often work for all species. Give an example of how the Biological Species Concept “breaks down” in some cases. (4 points)

Answer 1

a) specation- 1) It is the evolutionary process by which populations evolved to became distinct species.2) occurs when groups in a species became reproductively isolated and diverge.3) new species are form. 4) it is a lineage splitting event.

b) Reproductive isolation- 1) It is the condition where different species live in the same area, but the properties of indviduals prevent them from interbreeding. 2) inability of a species to breed successfully with related species.3) it leads to evolution of species.

c) Species- Acc to BSC, It is a group of individuals that can breed together. they cannot breed with other groups. 2) species are reproductive community, a gene pool, a genetic system.

d) It is so because specation involves reproductive isolated groups with in original population. 2) accumulation of genetic differences between the two groups.

In reproductive isolation, divergence occurs without geographical barrier.

e) When a female horse and male donkey mate, they produce hybrid offspring called mules.