The fact that the chromosomal number is split during meiosis means that there are several possibilities of contribution from each parent that will come together. This refers to independent assortment of the chromosomes during meiosis 1 and random fertilization. The pairs of chromosomes are arranged independently and randomly along the metaphase plate for when they split during meiosis 1 this result in many combinations then they fertilize and combine with other gametes leaving endless possibilities for genes.
What are the distinct features of Meiosis?
Homolog pair during Meiosis 1 in mitosis sister chromatids are attached and they split. The kinetochore behavior is also unique because in meiosis both kineticores of the homolog pair attach to the same pole of the microtubles. In Mitosis the sister chromatids are attached to by cohesion, in meiosis the pairs are linked by the chaisma and then use the cohesion to keep the sister chromatids together until they spilt during meiosis 2.
What are the benefits and disadvantages of sexual reproduction?
The advantage is that there is more room for variation and therefore adaptation. With sexual reproduction organisms are not the same as their parents, which creates variety. In asexual reproduction parents make exact replicas of themselves, they do not need a second person to contribute this is an advantage, because it makes asexual reproduction easier to occur since they do not have to find a mate. This means though that if something in the environment changes an entire species of asexual reproducing organisms could die off, where sexually reproducing organisms would have certain people with enough variation for some to survive most likely. A disadvantage to sexual reproduction is also though that it is so variant because if a species is successful with certain characteristics their offspring may not have those same beneficial traits.
Five Facts:
-A locus is a gene’s specific location on a chromosome
-Karyotyping involves mapping chromosomes
-Haploid cells are gametes and they contain half the chromosomes of diploid also known as somatic cells they make up the majority of the organism
-All sexual reproduction involves meiosis
- Meiosis halves the chromosome number so that offspring do not have double the genes of their parents.
This diagram shows the steps of meiosis. Essentially chromosomes replicate like they would in mitosis but instead of separating once they pair off into homologs cross over with other pairs and then separate. Then the sister chromatids which are still attached but may have some pieces from another chromosome separate halving the chromosome number.
Summary: In sexual reproduction offspring inherit half their chromosomes from each parent this creates variation and quicker adaptations. In asexual reproduction one parent exactly duplicates themselves. In somatic cells there are 2n chromosomes in gametes there are n chromosomes. Gametes are produced by meiosis and they combine with gametes from the opposite sex of the same organism to form a zygote, which is diploid and continues to replicate. Because of the genetic variation caused by crossing over and independent assortment with meiosis evolution is far more efficient.
