A2 Biology | Post your doubts here

[angelgirl:)]

..which is why i used the word beneficial/favourable..
Advantage, beneficial/favourable..they all mean the same thing..don't they??

lol...

 

[hassam]

well cn somebody quote more examples on interaction of environment and phenotype....plzzz

 

[user]

Aoa wr wb!
-How captive breeding programmes in zoos may help in the protection of endangered species?

(J’07 Q:1)​

1. fewer animals need to be caught (for zoos) ;
2. ref. becoming pregnant ; e.g. IVF / finding a mate
3. reintroduction into the wild ;
4. research easier with captive animals / AW ;
5. ref. increase in numbers ;
6. ante or postnatal care ;

Can anyone plz help me frame the answer?

 

[aliya_zad]

well cn somebody quote more examples on interaction of environment and phenotype....plzzz

SCA in malarial areas is one example..
another can be coat colur of rabbits in the poles to be protected from their enemies..(white coat colour becomes a selective Advantage)

 

[user]

well cn somebody quote more examples on interaction of environment and phenotype....plzzz

Explain, with examples, how the environment may affect the phenotype. (N’07 Q:11 b)

1. phenotypic variation results from interaction of genotype and environment / VP = VG
+ VE ;
2. environment may limit expression of gene(s) / AW ;
3. e.g. for size / mass / height ;
4. because, food / nutrients / ion, missing / malnutrition ;
5. named, nutrient / ion / mineral, missing ;
6. environment may, trigger / switch on, gene ;
7. ref. low temperature and change in animal colour ;
8. ref. high temperature and, curled wing in Drosophila / gender in crocodiles ;
9. ref. UV light and melanin production ;
10. ref. wavelength of light and, flowering / germination / fruit colour ;
11. other named trigger plus example ;
12. environment effect usually greater on polygenes / ora ;
13. environment may induce mutation affecting phenotype ;

Phenotypic variation results from the interaction of the genotype and the environment. Environment may limit the expression of the genes in an individual. Consider human height. If the individual has the number of alleles for tallness, he will have the potential to grow tall. However, if his diet is poor and the required proteins, for example, are missing in his diet, he will not be able to grow tall. Environment may trigger the genes, for example, hair colour in cats.They have many genes that influence their hair colour. They do this by coding for the production of enzymes. For example, in a particular type of cat, they have a gene that codes for the production of an enzyme which is sensitive to temperatures. It produces dark hair in regions where the temperature is lower eg: paws, ears and tail, and light hair in warmer parts of the body. Environment usually show greater effects on polygenes. Another example is the effect of UV light on melanin production. Area where people are exposed to sunlight for a longer time will have slightly higher melanin production [due to more UV] and hence have darker complexion.
^Not sure if this helps..
[Source: Notes uploaded by XPFMember]

 

[omair tahir]

..which is why i used the word beneficial/favourable..
Advantage, beneficial/favourable..they all mean the same thing..don't they??

I agreed wid u i didnt mean tht i dont agree

 

[angelgirl:)]

Aoa wr wb!
-How captive breeding programmes in zoos may help in the protection of endangered species?

(J’07 Q:1)​

1. fewer animals need to be caught (for zoos) ;
2. ref. becoming pregnant ; e.g. IVF / finding a mate
3. reintroduction into the wild ;
4. research easier with captive animals / AW ;
5. ref. increase in numbers ;
6. ante or postnatal care ;

Can anyone plz help me frame the answer?

to carry out captive breeding u need very few animals which r under extenction and then they r interbreeded or ivf method is carried out....as the animals r in captivity which r under the reserchers control so its easy for them to carry out any kind of research they want on them..they r given a good postnatal care so due to these processes their numbers r increased and are reintroduced back in the wild...

 

[hassam]

well tell answer to why variation is important for natural selction?

 

[aliya_zad]

I agreed wid u i didnt mean tht i dont agree

I was just Kidding..yeah ur rite too!!

 

[angelgirl:)]

wat r steroid hormones and explain y they can pass through the plasma membrane while protein hormones cant?

 

[angelgirl:)]

wat r steroid hormones and explain y they can pass through the plasma membrane while protein hormones cant?

ohh i got it...steroid hormones r the 1 which is not made of protein eg. testosterone, the plasma memebrane is a bilayer of phospholipids so steroid hormone can dissolve in it and can pass through...but protein hoermone such as insuline cant pass through these bilayers...

 

[omair tahir]

The concept of hydrophobic to be applied here i think angelgirl

 

[angelgirl:)]

The concept of hydrophobic to be applied here i think angelgirl

ya dats how its disolved in it...

 

[omair tahir]

ohh i got it...steroid hormones r the 1 which is not made of protein eg. testosterone, the plasma memebrane is a bilayer of phospholipids so steroid hormone can dissolve in it and can pass through...but protein hoermone such as insuline cant pass through these bilayers...

Totally
I just saw ur msg after posting

 

[angelgirl:)]

???
means totally agree or not

oh ok...

 

[omair tahir]

Totally agreed

 

[user]

to carry out captive breeding u need very few animals which r under extenction and then they r interbreeded or ivf method is carried out....as the animals r in captivity which r under the reserchers control so its easy for them to carry out any kind of research they want on them..they r given a good postnatal care so due to these processes their numbers r increased and are reintroduced back in the wild...

JazakAllahu khairen kaseeran [may Allah reward u loadz]

 

[angelgirl:)]

Totally agreed

lol ok...

 

[user]

Explain why variation is important in selection;

​

1. ref. continuous / discontinuous variation ;​

2. genetic / inherited variation ;​

3. variation in phenotype / characteristics / AW ;​

4. (can be due to) interaction of genotype and environment ;​

5. e.g. of characteristic that influences survival ;​

6. ref. intraspecific competition / struggle for existence ;​

7. those with favourable characteristics survive / AW ;​

8. pass on favourable characteristics to offspring ;​

9. those with disadvantageous characteristics die ;​

Variation means the presence of different characteristics or traits. There will be genetic variation within the population. The interaction of the genotype and environment results in phenotypic variation. Variation results in different survival rates of organism, which ultimately leads to reproductive success or failure. Organisms with most suitable traits and those that are best adapted to a stable environment have a survival advantage. Those surviving better get more chances of reproduction. They pass on their favourable characteristics to their offsprings and their number further increases. Whereas, those with disadvantageous characteristics, cannot survive, and die.
^need this answer to be improved a bit... hassam angelgirl:)

 

[user]

thanks but plz pray for me as i get really nervous as soon as i get the paper in my hand nd i forget everything...so my hardword is always lost just like that...i need every1s prayer plz plz...

we all need them..!! each of us gotta pray 4 everyone