In organisms that reproduce sexually, each offspring gets half its chromosomes from its mother and half from its father. Therefore, except in the case of monozygous twins, the chances of chromosomally identical siblings are very low.
Crossing over of chromosomes in meiosis, independent assortment of chromosomes in meiosis, and the development of genetic mutations.
By crossing over during meiosis, followed by gametic union during fertilization.
From their parents.
Firstly, mutation. In a sexually reproducing population recombination ( independent orientation of chromosomes and crossing over in meiosis and random fertilization ) is also a source of variation in populations.
Through Meiosis
What could be said is that the offspring will not be identical, genetically or regarding appearance; there will be variation between offspring and their sexually reproducing parents.
Meiosis is a type of cell division that occurs in sexually reproducing organisms. It produces haploid cells, which are also known as gametes.
meiosisHuman recombination
recombination of alleles
b) sorting and recombining of genes
Mutation and the genetic recombination in sexually reproducing organisms.
If meiosis did not occur in sexually reproducing organisms, the chromosome number would double in each generation. Sexual reproduction results in new combinations of genetic traits.
From their parents.
recombination of alleles
The gametes.
the variations in genes, genes of sexually reproducing organisms will vary due to crossing-over of genes, mutations, and adaptations. In asexually reproducing organisms genes will vary through adaptations and mutations.
Variations arise due to recombinations(gene rearrangements) ,mutations etc.The former is the principal source of variation in sexually reproducing organisms and the latter is the source of variation in asexual organisms.According to Darwin variation arises due to chance since all the above mentioned process occur in nature spontanuously all organisms show variation
There will be no reproduction
Basic source of variation in all organisms is mutation .