In addition to animals, plants, and fungi, other eukaryotes (e.g.the malaria parasite) also engage in sexual reproduction.
For instance, mate choice and sexual selection can accelerate the evolution of physical differences between the sexes.One of the basic properties of life is reproduction, the capacity to generate new individuals, and sex is an aspect of this process.Sexual reproduction in eukaryotes is a process whereby organisms form offspring that combine genetic traits from both parents.Chromosomes are passed on from one generation to the next in this process.Each cell in the offspring has half the chromosomes of the mother and half of the father.
Genetic traits are contained within the deoxyribonucleic acid (DNA) of chromosomes—by combining one of each type of chromosomes from each parent, an organism is formed containing a doubled set of chromosomes.
Among humans and other mammals, males typically carry XY chromosomes, whereas females typically carry XX chromosomes, which are a part of the XY sex-determination system.
Other animals have a sex-determination system as well, such as the ZW sex-determination system in birds, and the X0 sex-determination system in insects.
Sex comprises the arrangements that enable sexual reproduction, and has evolved alongside the reproduction system, starting with similar gametes (isogamy) and progressing to systems that have different gamete types, such as those involving a large female gamete (ovum) and a small male gamete (sperm).
In complex organisms, the sex organs are the parts that are involved in the production and exchange of gametes in sexual reproduction.
Many species, particularly animals, have sexual specialization, and their populations are divided into male and female individuals.