Parallel Evolution

[akira88]

What is the proper definition of it? I've heard so many different versions- Heinemann claims that it occurs when a species diverge from a common ancestor and THEN share common features because of the similar environments they live in :\ Another thing I've heard is that parallel evolution happens when two unrelated species live in similar environmental conditions (but can be on different continents etc) and develop common features. Also, it is very difficult to find examples of it. Not to mention, parallel evolution isn't even mentioned on the study design.... so we don't have to know it?

Also another question: Could someone clarify the second theory of how modern humans arose? I understand the "Out-of-Africa" one but the other theory sounds so implausible (in the Heinemann book). Thanks a whole lot!

[onerealsmartass]

yeah i am also intrested in finding out a good definition of parallel evolution.
ive heard that they diverge from a common ancestor and due to common selection pressures they develop similar features that the common ancestor didnt have... - not too sure on the last part

[jasoN-]

This one is just out of the Nature of biology textbook:
Parallel evolution is the response of species with a common evolutionary heritage to similar environmental demands through the evolution of structural similarities.
Examples of parallel evolution in closely related species that share structural similarities because of their similar way of life include:
-the backward-opening pouches in the Australian native marsupials, the marsupial mole (Notoryctes typhlops) and the bilby (Macrotis lagotis), which reflect their burrowing behaviours.
-the large ears seen in the Australian microbats, which reflect their use of echolocation to locate prey.

From the Heinemann textbook:
Parallel evolution occurs when related species evolve similar features independently.


I assume we don't need to know it as it is not even mentioned in my school's textbook (Nelson)

[akira88]

Yeah I hope we don't need to know it! Thanks anyways
Can anyone answer my second question? About the second theory of where modern humans originated from?

[Russ]

Out of Africa is generally accepted hypothesis because it has the most supporting evidence and the least contradictory evidence.

The multiregional hypothesis has faded recently, especially since mitochondrial Eve was established. Basically, we're all the same species and (millions of years ago) spread out over the world but continued to develop simultaneously due to constant (in)breeding.

I doubt you'll be asked a direct question about either model, but just remember that OoA is by far the preferred model.

[simpak]

You do need to know it.

[akira88]

Does the second theory propose that modern humans arose from evolving from the homo erectus (which was for some reason were all around the world), leading to the different origins of humans? Sorry if that doesn't make any sense.

[lexitu]

You don't need to know about parallel evolution. Forget about the textbook, what matters is what VCAA says. If you look at this document they are very unambiguous about what they want. In the study design proper it is also not mentioned.

PDF alert: http://www.vcaa.vic.edu.au/vce/studies/biology/keyknowmap.pdf