Number of Chromosomes: 3 only; 0 or 3; 0 or 6; 2 or 4; 0, 3, or 6; 2, 3, 4
<span>Situations: </span>
<span>1.) Meiosis occurs normally (no nondisjunctions) </span>
<span>2.) Nondisjunction of one chromosome pair in meiosis I </span>
<span>3.) Nondisjunction of all three chromosome pairs in meiosis </span>
<span>4.) Nondisjunction in one chromosome of one daughter cell in meiosis II </span>
<span>5.) Nondisjunction of all three chromosomes of one daughter cell in meiosis II </span> Below is the answer:
Just draw out daughter cells in Meiosis I and II if you get confused. <span>1. Regular meiosis is 2n --> n, so each daughter cells has 3 chromsomes </span> <span>2. After Meiosis I, 1 daughter cell will have 4 chromosomes, and the other 2. If disjunction occurs normally in Meiosis II, end result is 2 daughter cells with 4 chromsomes, and 2 daughter cells with 2 chromosomes. (4,4,2,2) </span> <span>3. After Meiosis I, 1 daughter cell has 6 chromosomes, and the other 0. After Meiosis II, 2 daughter cells with 6, and 2 daugther cells with 0. (6,6,0,0). </span> <span>4. After Meiosis I, both daughter cells has 3 chromsomes. After Meiosis II, 2 daughter cells will have 3 chromosomes, and 1 daugter cell will have 4, and 1 daughter cell will have 2. (3,3,4,2) </span> <span>5. After Meiosis I, both daughter cells has 3 chromosomes. Non-disjuction occurs in both daughter cells in Meiosis II, so it would be 3,0,3,0</span>
The Precambrian represents the time period, right from the beginning of the earth to about 540 million years back. It is divided into 3 parts, namely the Hadean, the Archean and the Proterozoic. Throughout this geological time, vast changes have taken place on earth. The first life forms of about 3.8 billion years old, that existed on earth were the simple unicellular organisms, whose traces were only found at some particular places. These organisms were very small and are comprised of soft bodies, so they were affected by the earth's dynamic processes. The organisms in order to get fossilized must contain hard parts. Due to the presence of soft bodies, the organisms were not fossilized and so it took a long time to demarcate that the late Precambrian organisms were animal-like life.
En el reino monera se encuentran todos los organismos unicelulares, procariotas. Son los únicos seres cuyas células no tienen núcleo definido y contienen el material genético más simple de la naturaleza.
