Which evolved first...

[~nerd~]

Spider or lizard? Why?

[AzurePhoenix]

Well, invertebrates emerged onto the land far earlier than vertebrates (and initially evolved first and far earlier anyway), and had a chance to diversify, with spiders something like 400 million years ago. Verts on the otherhand evolved much later, then made it to land.... eh... not sure when lizards evolved, but it was many millions of years later.

[~nerd~]

Hope you don't mind, I just quoted you for my homework

[AzurePhoenix]

If I'd known that I woulda written something more than an rudimentary shrug

 

Question of my own; what's the angry face about?

[~nerd~]

Haha, the question makes me angry. I've been doing Biology homework for the last two hours ~getting sick of it~ and I don't believe in evolution so the section annoys me... By any chance do you know a lot about Biology, because I have three questions that are bugging the crap out of me!

[AzurePhoenix]

By any chance do you know a lot about Biology, because I have three questions that are bugging the crap out of me!

meh, bio's my field, so ask your questions. Whether me or someone else, you'll probably get good help, but now that I know it's homework, I myself might not be eager to give you straight out answers.

[~nerd~]

It ain't so much homework as it is what my teacher gave us to do because she wasted all of our class time lecturing immature children... Here are my questions:

(1) How might I explain the genetic basis of a disorder that occurs with equal frequency among both sexes and that doesn't follow basic patterns of Mendel inheritance??????

 

(2) Explain the idea of heterozygote superiority with respect to human genetic disorders.

 

(3) In a rare form of colour blindness, a person cannot distinguish the colour blue. This abnormality, when it does occur, affects both males and females and in equal numbers. Explain this pattern of inheritance and compare it to that involved in red-green colour blindness.

[AzurePhoenix]

Hmm, I'm better versed on the macro-scale of biology, but I'll take a shot (soemone please correct me where I'm wrong )

 

(1) How might I explain the genetic basis of a disorder that occurs with equal frequency among both sexes and that doesn't follow basic patterns of Mendel inheritance??????

Eh, different ways. The gene might only occur on the Y chrom. which is only found in males, but it'd have to be dominant I think. Alternatively it could be a recessive trait that occurs only on the x chromosome, meaning it would need two so only females would get it. There are also organisms that are polyploidal, with more than two sets of chromosomes.

 

(2) Explain the idea of heterozygote superiority with respect to human genetic disorders.

As in the advantage of being heterozygote for sickle cell anemia? I won't go into the deatils about why it works (I'm short for time) but being heterozygote protects the person from being fatally vulnerable to malaria. In regions where malaria is a prevalent problem, the risk for a child born homozygous for sickle-cell is outweighed by the benevent of being invulnerable to malaria.

 

(3) In a rare form of colour blindness, a person cannot distinguish the colour blue. This abnormality, when it does occur, affects both males and females and in equal numbers. Explain this pattern of inheritance and compare it to that involved in red-green colour blindness.

I couldn't answer this one without more information; you'll need to draw in someone better at micro-bio than I am.

[ecoli]

Red-green color blindness is a sex-linked trait, so the expression of which is a lot 'easier' for males then females (because the y-chom) can't mask the X.

[~nerd~]

Thank you, I really appritiate all the help.

 

And thank you ecoli for the help on that last one.

 

in a bit i may have a couple more questions, dont know.

 

so up to you to stick around or not

 

1) Compare Amniocentesis with chronic villus biopsy.

 

2)Why are transfusion useful in treatin people with sickle-cell anemia?

 

ok i got the first one but i cant seem to find the second one, can ya help me out plz?

[chuinhen]

the most obvious different is the sample .

In Amniocentesis , the sample is the amniotic fluid containing sheded skin of the fetus .

 

So the target is the DNA in the sheded skin cell .

However the fetus shed its 1st skin after 2 - 3 months after fertilisation .

 

 

In chronic villus biopsy , the target is the chorionic cells which have the same genome with the fetus .

The chorion develops just after the implantation .

 

In conclusion , The biggest difference is :

 

The fetus's genome can be determine earlier by using chronic villus biopsy.

[Cloud]

1) Compare Amniocentesis with chronic villus biopsy.

 

2)Why are transfusion useful in treatin people with sickle-cell anemia?

 

1) No idea. Don't even know what that is. Not going to look it up. Lazy.

 

2) Transfusion is useful because sickle cell anemia is a deformity of red blood cells greatly reducing the capacity of oxygen transported to cells. A blood transfusion provides a fresh batch of healthy cells with normal oxygen capacity and the patient is relieved (to some extent).

 

How's that?

[FreeThinker]

and I don't believe in evolution so the section annoys me.

 

If you don’t know how to answer these questions, how can you "no believe” in evolution. Shouldn't you first learn the basics of evolution before you start not believing it?