题干

果蝇是常用的遗传学研究的实验材料,据资料显示,果蝇体细胞中约有104对基因,现有一黑腹果蝇的野生种群,约有107个个体,请分析回答以下问题:

(1)通过果蝇和其他生物的群体遗传学等的研究,可得出生物进化的基本单位是种群,该种群的全部个体所含有的全部基因统称为种群的____ ,在生物进化过程中,____ 使种群的基因频率定向改变并决定生物进化的方向.该种群中果蝇有多种多样的基因型,主要是通过有性生殖过程中的____ (突变/基因重组)而形成的.

(2)随机从种群中抽取100只果蝇,测知基因型AA(灰身)35只,Aa(灰身)60只,aa(黑身)5只,A的基因频率为____ .

上一题 下一题 0.0难度 选择题 更新时间:2019-05-18 01:29:10

答案(点此获取答案解析)

基因库,自然选择,基因重组,0.65

同类题2

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    Taking good notes is a time-saving skill that will help you to become a better student in several ways. ____ Second, your notes are excellent materials to refer to when you are studying for a test. Third, note-taking offers variety to your study time and helps you to hold your interest.

    You will want to take notes during classroom discussions and while reading a textbook or doing research for a report. ____ Whenever or however you take notes, keep in mind that note-taking is a selective process. ____

The following methods may work best for you.

●Read the text quickly to find the main facts and ideas in it.

●Carefully read the text and watch for words that can show main points and supporting facts.

●Write your notes in your own words.

____

●Note any questions or ideas you may have about what was said or written.

    As you take notes, you may want to use your own shorthand(速记). When you do, be sure that you understand your symbols and that you use them all the time. ____

A. Use words, not complete sentences.

B. There are three practical note-taking methods.

C. You must write your notes on separate paper.

D. Otherwise, you may not be able to read your notes later.

E. You will also want to develop your own method for taking notes.

F. That means you must first decide what is important enough to include in your notes.

G. First, the simple act of writing something down makes it easier for you to understand and remember it.