Chromosomes are parts of a cell that carries genetic information inform of genes, they contain DNA molecules packaged around histone proteins. Diploid number of chromosomes means that a cell has both sets of homologous chromosomes while haploid is used to refer to a cell that has one set of chromosomes and therefore a single set of genes.Mitosis is a type of cell division that takes place in the somatic cells (body cells) resulting to two daughter cells with the same number of chromosomes as the parent cell (diploid). Therefore, in this case a somatic cell will have 48 chromosomes (diploid number 2n).
Genetic drift is change in allele frequencies in a population from generation to generation that occurs due to chance events
The genetic drift occurs due to random fluctuation of any allele in a gene pool and is more efficient in small population
The founder effect and the bottleneck effect are cases in which a small population is formed from a larger population which means they may experience strong drift for generations
In founder effect a genotype from a homogeneous gene pool migrate to a newer habitat and colonize there and form a newer community which leads to the genetic drift to the original population, speciation which occurs in this effect is the peripatric speciation
In bottleneck effect the elimination of inferior genotype from a homogeneous gene pool occurs due to the strong selection pressure and changing environmental conditions which leads to genetic drift and a only a few most adapted genotype survives and flourish
Natural Selection
Natural selection is a selection pressure which operates in a population and allow the best fitted genotype to survive in changing environmental conditions and eliminate the other genotype which are not fit
Genetic drift, mutation and sexual selection are important causes of natural selection
Directional natural selection favours the superior genotype and eliminate the inferior and intermediate genotype, in the history of evolution the most common natural selection is directional natural selection
Stabilizing natural selectionfavours the intermediate genotype but eliminates the extreme genotype
Bidirectional natural selection favours the extreme genotypes but eliminate the intermediate genotypes
