Thanks, darkz!
Hi guys!
I have a few questions I want to clarify.
1. Does allopatric speciation occur at the same time? Like, there was a question on checkpoints asking whether allopatric speciation occurred based on analysing a phylogenetic tree. I said no because the different bat species speciated at different times and not the same time, thus it wouldn't be allopatric speciation.
2. When asked to define gene pool, I said the total collection of genes present in a population. Checkpoints said that it is wrong to say this. Is it because it sounds like I'm talking about the number of genes and it doesn't focus on the variations of the gene(allele)?
3. Also, mitochondria DNA, is single stranded and circular right? Because it was thought to once be a prokaryote?
Thanks in advance!
1. Depends how many groups you're talking about. If you've only got two groups (which is the most common scenario) then they must speciate at the same time because when group A can no longer interbreed with group B, then group B also can't interbreed with group A, therefore they're different species.
If you're talking about more than two groups then they can speciate at different times - for example if three groups of the same species are separated onto three different islands, they each become their own species when they can no longer interbreed. So if group A can no longer interbreed with either group B or group C then it's a separate species, but if group B and group C can still interbreed then they're still the same species, and it might take longer for them to speciate. Generally the evidence you need to know that it's allopatric speciation is just to know that the speciation occurred due to geographical separation.
2. Say the total
variety of genes instead (also don't worry about having perfect definitions for the exam, you won't need them).
3.It's double stranded & circular