Competition - post a photo you've taken of nature >>

BIOL4 Biology Unit 4 Exam - 13th June 2011

Scroll to see replies

Conservation is maintaining an ecosystem, it requires a lot of planning and the best way is used.
Niche is what an organism does in its environment?

Reply 721

Jing_jing

Original post by jonnyboy1993

if you know this notation for maths it is the same as 5C2. And in fact this generalises to nC2 for any n different alleles forming a diploid genotype.

Lies

5C2 is 10, you've got to take into account the genotypes where the alleles on each chromosome are the same

Reply 722

Rickesh

Keep the questions flowing guys

Reply 723

jonnyboy1993

Original post by Jing_jing

Lies

5C2 is 10, you've got to take into account the genotypes where the alleles on each chromosome are the same

Yeah, my bad :colondollar:

I've done so much biology recently that I've forgotten maths :tongue:

Reply 724

Black Butler

Original post by Rickesh

Shouldnt you say: Choose a plant variety that is the most pest resistant, then manage the environment correctly, i.e. provide suitable habitats, then monitor it for pests if there are pests then hand pick them, if there are too many then use biological control, if it exceeds and gets out of hand use pesticides?

Yeah sorry - what you've said is more correct. I think the main point when usng chemical control as a last resort is to use a small amount of pesticide.

Integrated control is hassle - trying to minimise damage to environment.

Reply 725

Rickesh

Original post by Black Butler

Yeah because pesticides are not good lol ! Got any other questions? These Q and A are good ?

Reply 726

Jing_jing

Original post by jonnyboy1993

Yeah, my bad :colondollar:

I've done so much biology recently that I've forgotten maths :tongue:

I have FP3 and C3 tomorrow as well so if I started to forget Maths I'd be in big trouble! :laugh:

Kudos to you for even attempting to use combinatorics though, I thought about it for about 5 seconds and then decided just to write out the possible combinations!

I've never really understood what a niche is? In my notes I have 'the role of an organism in the ecosystem and where it lives'?

Reply 727

arvin_infinity

2 units we need to know
1. kj m-2 year-1
2. cant remember (maybe was for biomass)

Defo 1:30 right?

Original post by arvin_infinity

2 units we need to know
1. kj m-2 year-1
2. cant remember (maybe was for biomass)

biomass is: gm-2

Reply 730

Black Butler

Original post by arvin_infinity

2 units we need to know
1. kj m-2 year-1
2. cant remember (maybe was for biomass)

biomass is kgm^-2

Reply 731

FatalError

Biomass in water is gm-3 and on land is gm-2 could also be KG.

Energy is obviously kj m-2 year-1 because its the energy per square meter over a period of time

Reply 732

Rickesh

Original post by Black Butler

biomass is kgm^-2

I thought it was g m-2?

Reply 733

SK-mar

Original post by Stratos

Modern intensive farming recognises the environmental dangers of the untrammelled use of pesticides, so is
adopting Integrated Pest Management (IPM). IPM attempts to bring together all forms of pest management
to benefit from the best of each. The aim is to reduce the effect of pesticides on the environment but
without compromising the goal of maximising crop yield. There are 4 stages, each one more powerful than
the one before:
1. Identify the pests and their population density at which they cause economic harm – the economic
threshold. Only take action against the pest if its population is above the threshold.
2. Use suitable cultural methods to prevent pests reaching their threshold.
3. If the pest population starts to exceed threshold the use biological control to bring it down.
4. If biological control doesn’t work then use chemical pesticides, but at low and carefully controlled dose,
and at the best time of year to minimise damage to other organisms while maximising effect on pest.
5. At each stage the effect of that treatment is evaluated before deciding to proceed to the next stage.

just out of question, what would be suitable cultural methods?

Reply 734

Rickesh

Why is haemophilia only in men?

Reply 735

FatalError

Why is haemophilia only in men?

You don't need to know about specific disorders i think. I don't think it's only in men is it?
They are more likely to suffer from it because their sex chromosomes are not the typical bivalent so they are less likely to have the dominant allele to override the recessive allele.