Reproduction

Reproduction is the biological process by which organisms produce new individuals of the same species, transmitting genetic material from one generation to the next. It enables continuation of populations and the evolution of life over time.

Reproduction is commonly categorized as sexual and asexual. Sexual reproduction involves the production and fusion of gametes (sperm and egg) from two organisms, producing a fertilized egg or zygote. Meiosis creates haploid gametes and introduces genetic recombination, producing offspring that are genetically distinct from the parents. Asexual reproduction produces offspring without genetic exchange, resulting in clones or near-clones. Methods include binary fission, budding, fragmentation, vegetative reproduction, and parthenogenesis.

At the cellular level, organisms reproduce by cell division. Mitosis enables growth and tissue maintenance, while meiosis reduces chromosome number for sexual reproduction and promotes variation. Fertilization combines genetic material from two gametes to form a zygote that develops into an offspring.

Reproduction patterns vary across life forms. In plants, many species alternate generations between haploid and diploid phases; fungi often release spores; animals rely on internal or external fertilization and various developmental paths from embryo to juvenile. Asexual strategies are common in some invertebrates, plants, and fungi, especially in stable environments.

Reproductive strategies are linked to ecology and evolution. Factors such as fecundity, parental investment, mating systems, and timing influence population dynamics and the fitness of offspring. Some species reproduce continually; others reproduce seasonally or sporadically.

Human reproduction involves complex biology and social considerations. Reproductive health, contraception, sterilization, and assisted reproductive technologies affect family planning and population dynamics. Ethics, policy, and education shape access to services and consideration of reproductive choices.