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two questions in biology... please help

Genetics as it applies to evolution, molecular biology, and medical aspects.

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two questions in biology... please help

Postby hate-BIO » Sat Nov 18, 2006 6:40 pm

Hi all!

I am very happy to participate in such forums.... :lol:

I am distance learner.. I have homework in biology... would you help me answe these two questions... how would you answer them.. :roll:


Question # 1

An island, located in a local river, does not have any mice populations but has abundant food and shelter. A pair of mice are introduced onto the island and survive to reproduce. A team of researchers follows the population size for several years. Discuss what you would predict as a population growth curve and the factors that would contribute to this type of curve. Provide a drawing of your predicted growth curve.



Question # 2

Hemophilia is a sex-linked trait on the X chromosome. A normal female with a colorblind father marries a normal male. What are the chances of a male offspring being colorblind? A female offspring being colorblind? Show the genetic crossings used to derive your answers.


please respond to me as soon as possible.... :?:


Thanks
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Re: two questions in biology... please help

Postby Dr.Stein » Sun Nov 19, 2006 4:30 am

hate-BIO wrote:please respond to me as soon as possible.... :?:

later ok? I am busy now :twisted:

:lol:
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Postby hate-BIO » Tue Nov 21, 2006 5:39 am

Where R U?


:roll:
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Postby Dr.Stein » Tue Nov 21, 2006 8:24 am

While waiting, please write your answer here then we will check yours. I need to do my research now ;)
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Postby AstusAleator » Tue Nov 21, 2006 9:19 am

Aye, we're not going to do your homework for you :)
But we'll check it, or critique your answers...
maybe give you hints....
Like population growth usually being sigmoidal....
Or hemophilia being passed from mother to son...
:)
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Postby rob3 » Mon Nov 27, 2006 11:58 am

You are unlikely to get much help from a biology forum full of people who enjoy biology, if your screen name is: hate-BIO
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HERE ARE MY ANSWERS

Postby hate-BIO » Mon Nov 27, 2006 10:30 pm

1) An island, located in a local river, does not have any mice populations but has abundant food and shelter. A pair of mice are introduced onto the island and survive to reproduce. A team of researchers follows the population size for several years. Discuss what you would predict as a population growth curve and the factors that would contribute to this type of curve. Provide a drawing of your predicted growth curve.

ANSWER:
Actually, in an island with enough and appropriate food and shelter where a pair of mice is introduced; they would begin to reproduce quickly. In spite of the fact they would begin reproduction fast, the mice population would grow gradually. Then it will reach a point of exponential growth which will continue until the population reaches the environmental carrying aptitude. Later on, the mice populations would settle down or decrease to some extent. Year by year the mice population size would change with changing environmental and living circumstances. The growth curve would be represented by a sigmoid or logistic growth curve.

2) Hemophilia is a sex-linked trait on the X chromosome. A normal female with a colorblind father marries a normal male. What are the chances of a male offspring being colorblind? A female offspring being colorblind? Show the genetic crossings used to derive your answers.

ANSWER:

Note: XH = normal, Xh = hemophilia.

According to the questions we would understand that the normal female would have at least one XH (normal) chromosome. If the female’s father was colorblind his genotype would be XhY. Also, in the male there is only one X chromosome so the phenotype reflects the X chromosome. Therefore, the normal female should have received Xh from her father and XH from her mother building her heterozygous XHXh. This female XHXh mates with a normal male XHY. We can sum up that the chances of a male being colorblind is 50% (the male produced ½ would be colorblind.), but none of the females would be colorblind.
Here is the crossing required:

XH Y
XH XHXH XHY
Xh XHXh XhY
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Postby hate-BIO » Mon Nov 27, 2006 10:31 pm

PLEASE tell me what do you think about my answers, what additions you have????

Thanks
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