Ughhhhh I'd have to break out my biology text book if you want a good answer that includes all of those terms, but I can't be bothered so I'll give you a brief overview.
In meiosis, the pairs of chromosomes in the gametes before the cell divides form pairs, called bivalents. The two pairs of chromosomes overlap one another, and in a process called crossing over, they exchange individual alleles. This creates genetic variation since the chromosomes now have a combination of alleles.
Independent assortment is also a way of creating variation. During meiosis after the pairs of chromsomes split they to go into the different cells. Since this movement of chromsomes is random, you get different chromsomes combinations in each new cell. This also happens in meiosis 2 where the individual chromatids randomly move to different cells.
Mutations can sometimes occur which produce completely new or altered genes in chromsomes which can lead to a new characteristic.
In meiosis, the pairs of chromosomes in the gametes before the cell divides form pairs, called bivalents. The two pairs of chromosomes overlap one another, and in a process called crossing over, they exchange individual alleles. This creates genetic variation since the chromosomes now have a combination of alleles.
Independent assortment is also a way of creating variation. During meiosis after the pairs of chromsomes split they to go into the different cells. Since this movement of chromsomes is random, you get different chromsomes combinations in each new cell. This also happens in meiosis 2 where the individual chromatids randomly move to different cells.
Mutations can sometimes occur which produce completely new or altered genes in chromsomes which can lead to a new characteristic.