Week3a+-+Answers

1) To begin, we are doing better in the number of posts, but FAR from what is expected! Guys, the schedule here, unlike with paper assignments, is strict! You MUST post your answers no later than Sundays at 9:00 pm, or we will never move forward. I will try to send reminder emails, but some might consider that an unnecessary nagging. It is a lose-lose situation. Technical problems with the internet at home are NOT an excuse. Today there are plenty of options, especially during the work days. And you can always email me directly f you have a special problem. OK, Speech over., NOW..
 * 01.29.12 SUMMRY of WEEK3: **

2) Now, to the ANSWER KEY (several students rightfully complained that they don't know if their answers were right or wrong. so here we go!).... For the most part, the quotations that students found were relevant to evidence in the article, though rarely did a students quote more than one part. As an example, allow me to quote Patty Cruz (period 2)
 * QUESTION 1: ** **"What was the experimental evidence**?",

"I think that **"Fluorescent antibodies that latch on to proteins involved in meiosis allowed the researchers to see how the process happens. Hassold and his colleagues had already examined the earliest phase of meiosis in men and found that it follows the steps laid out in every biology textbook: a chromosome finds its match and the two pair up, gluing themselves together. Then the chromosomes swap some genetic information, a process known either as recombination or crossing over. Next, the chromosomes go through two rounds of division to form four sperm, each with one copy of each chromosome" from the article describes the evidence about men's chromosomes."** It says they EXAMINED meiosis in men and that the chromosomes properly completed meiosis while women's do differently. These chromosomes divide, cross over, divide again**."** //And then Patty continued to:// "Another piece of evidence I forgot to put in was what the scientists saw (since they said saw in the article and not see, this must be evidence). This helps show even more how women's chromosomes cary from mens and thus alter the crossing over aspect in their systems.

"**In men, chromosome pairs zip themselves tightly together all along their length. But in women, Hassold saw “split ends” and “bubbles” where the chromosomes were not tightly joined. And women’s chromosomes had fewer recombination points than expected. About 5 percent of the chromosome 21 pairs the researchers examined had no evidence of recombination**."

So, thank you, Patty for verbalizing how you actually used my guidance for identifying evidence! And cudos for finding more than one quote, one more technical about their method, and the other, describing what they saw.


 * Question 2: What is the advantage of crossing over **?

Most people posted the right answers, a few kept forgetting to mention genetic variations. Here is a quote form Louisa Chilian (period 2):
 * Crossing over is a huge advantage because __it provides genetic variation__. It makes family units small so that the parents can focus on all their, for example, 3 offspring rather than care poorly for like 10**.

Here, of course, there is not right answer, but there were several interesting ones. A. Requests to get the answers to the questions, B. To make it more clear. I will do my best! But keep on coming with suggestions, so that it will really be OUR wikispaces, not just my own.
 * Question 3: What do you think about wiki? **