Edexcel 6BIO2 ~ 3rd June 2013 ~ AS Biology

what causes founder effect? what is founder effect, what causes genetic drift? what causes it? any possible ways of reducing them?
what causes inbreeding depression?
and why is it bad? how can we reduce inbreeding depression apart from selective mating, studbooks?
do we need to know these things?

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hi, just to let you know there is an updated version of this revision note on page 4 of this thread.

The founder effect is when a small group of people from a larger population establish a colony of their own; as a result the genetic variety is drastically reduced as the gene pool is smaller.
Genetic drift is any change in the frequency of an allele; so the founder effect and bottlenecking may cause genetic drift, (bottle necking is when natural disasters- storm, earthquake, tsunami etc drastically reduce population size and thus decrease genetic variety)
These two cause genetic drift as the change in the gene pool and reduction in genetic variety will ofc change and reduce the frequencies of certain alleles in the gene pool

Inbreeding depression is the reduced fitness of a population due to inbreeding, this is bad because inbreeding will reduce genetic variety of a population thus if there is a selective pressure change, they are less likely to possess an allele that may serve a selective advantage- so less likely to survive, risk of extinction etc etc.
Other than the preventative methods you've mentioned, I'm not sure we need to know any other methods- tjhose are usually the ones on the mark sheme.

its going ok, and you? today im going to go over all papers from jan 2010 and go over my notes.
i have chemistry and statistics 2 left, what about you?

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Tha Realest Hey!
so what core practical u r expecting? tensile one also?

Thanks for this ... What's your prediction ?

Anatomical is more about physical features. Physiological is more on the way the body works. So, anatomy deals with the structure of an organism, so skeleton, organ system, tissue structure, and even cell structure, whereas physiology looks at function, so how these organs work, how cell metabolism works, how enzymes work.
Does this help?

If the totipotency is the practical with the agar, I doubt it will come up because in came up in the January 2013 exam : /

P.S. Do we need to know water uptake in detail?

I need around 110 ums in this paper, how many marks would i need to get roughly?

Yep mostly about the pathways (apoplast and symplast) and transpiration You also need to learn about the environmental factors that affect the rate of transpiration (i.e. light intensity, temperature, humidity etc...), how water enters the xylem vessels and root pressure that's pretty much it!

No you don't - Even transpiration is not on the spec.

Question: What is a benefit of using pluripotent stem cells rather then totipotent for the treatment of type 1 diabetes?