Reproduction

thumb|350px|right|Production of new individuals along a leaf margin of the miracle leaf plant (Kalanchoe pinnata). The small plant in front is about 1 cm (0.4 in) tall. The concept of "individual" is obviously stretched by this asexual reproductive process. Reproduction (or procreation or breeding) is the biological process by which new individual organisms – offspring – are produced from their parent or parents. There are two forms of reproduction: asexual and sexual.

reproduction process that creates a new organism by combining the genetic material of two organisms

thumb|300px|Spores produced in a sporic life cycle thumb|300px|Fresh snow partially covers rough-stalked feather-moss (Bryopsida|Brachythecium rutabulum), growing on a thinned hybrid black poplar (Populus x canadensis). The last stage of the moss lifecycle is shown, where the [[sporophytes are visible before dispersion of their spores: the calyptra (1) is still attached to the capsule (3). The tops of the gametophytes (2) can be discerned as well. Inset shows the surrounding, black poplars growing on sandy loam on the bank of a kolk, with the detail area marked.]]

assisted reproductive technology procedure (ART)

period involving all different generations of a species succeeding each other through means of reproduction

Amenorrhea or amenorrhoea is the absence of a menstrual period in a female organism which has reached reproductive age. Physiological states of amenorrhea are most commonly seen during pregnancy and lactation (breastfeeding). In humans, it is where a woman or girl who has reached reproductive age and who is not on birth control does not menstruate.

reproductive strategy

right|thumb|A frog in frogspawn In biology, offspring () are the young creation of living organisms, produced either by sexual or asexual reproduction. Collective offspring may be known as a brood or progeny. This can refer to a set of simultaneous offspring, such as the chicks hatched from one clutch of eggs, or to all offspring produced over time, as with the honeybee. Offspring can occur after mating, artificial insemination, or as a result of cloning.

single organism composed of two or more different populations of genetically distinct cells

portion of a life cycle in which an organism is capable of sexual reproduction

thumb|Different forms of anisogamy: A) anisogamy of motile cells, B) oogamy ([[egg cell and sperm cell), C) anisogamy of non-motile cells (egg cell and spermatia).|283x283px]]

[[File:Isogamy.svg|thumb|Different forms of isogamy:

evolutionary mechanism for speciation

sex change as part of the normal life cycle of a species

movement of individuals (animals, plants, fungi, bacteria, etc.) from their birth site to their breeding site, as well as the movement from one breeding site to another

animal offspring

thumb|Light micrograph of a whole-mount slide of gametangia of [[Equisetum]] A gametangium (: gametangia) is a sex organ or cell in which gametes are produced that is found in many multicellular protists, algae, fungi, and the gametophytes of plants. In contrast to gametogenesis in animals, a gametangium is a haploid structure and formation of gametes does not involve meiosis.

Autogamy or self-fertilization refers to the fusion of two gametes that come from one individual. Autogamy is predominantly observed in the form of self-pollination, a reproductive mechanism employed by many flowering plants. However, species of protists have also been observed using autogamy as a means of reproduction. Flowering plants engage in autogamy regularly, while the protists that engage in autogamy only do so in stressful environments.

In biology, gonochorism is a sexual system where there are two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric.

thumb|Microscopic photo of spores (in red) of Selaginella. The large three spores at the top are megaspores whereas the numerous smaller red spores at the bottom are microspores.

Superfecundation is the fertilization of two or more ova from the same menstrual cycle by sperm from the same or different males, whether through separate acts of intercourse or during a single sexual encounter with multiple males. This can result in twin babies that have different biological fathers.

device able to make copies of itself

Allogamy or cross-fertilization is the fertilization of an ovum from one individual with the spermatozoa of another. By contrast, autogamy is the term used for self-fertilization. In humans, the fertilization event is an instance of allogamy. Self-fertilization occurs in hermaphroditic organisms where the two gametes fused in fertilization come from the same individual. This is common in plants (see Sexual reproduction in plants) and certain protozoans.

right|thumb|220px|During pregnancy, a two-way traffic of immune cells may occur through the placenta. Exchanged cells can multiply and establish long-lasting cell lines that are immunologically active even decades after giving birth. Microchimerism is the presence of a small number of cells in an individual that have originated from another individual and are therefore genetically distinct. This phenomenon may be related to certain types of autoimmune diseases although the responsible mechanisms are unclear. The term comes from the prefix "micro" + "chimerism" based on the hybrid Chimera of G

thumb|Spermatheca of Acanthoscurria geniculata (Brazilian Giant White Knee Tarantula) thumb|Variety of the structure of spermathecae in Phlebotominae (Diptera, Psychodidae) thumb|Female tarantula molt

In biology, polyspermy describes the fertilization of an egg by more than one sperm. Diploid organisms normally contain two copies of each chromosome, one from each parent. The cell resulting from polyspermy, on the other hand, contains three or more copies of each chromosome—one from the egg and one each from multiple sperm. Usually, the result is an unviable zygote. This may occur because sperm are too efficient at reaching and fertilizing eggs due to the selective pressures of sperm competition. Such a situation is often deleterious to the female: in other words, the male–male competition a

thumb|right|300px|Oospores of Hyaloperonospora parasitica, agent of the [[downy mildew (in the middle)]] An oospore is a thick-walled sexual spore that develops from a fertilized oosphere in some algae, fungi, and oomycetes. They are believed to have evolved either through the fusion of two species or the chemically induced stimulation of mycelia, leading to oospore formation.

thumb|A Lycaena phlaeas (small copper butterfly) perching on a plant

classes of possible reproductive strategies

Heterothallic species have sexes that reside in different individuals. The term is applied particularly to distinguish heterothallic fungi, which require two compatible partners to produce sexual spores, from homothallic ones, which are capable of sexual reproduction from a single organism.

branch of biology studying reproduction

Gametogamy is sexual fusion – copulation or fertlization – of two single-celled gametes of different sex and the union of their gamete nuclei (and corresponding extranuclear structures) giving the zygote nucleus, as well as whole zygotic content.

In fungi and algae, homothallism refers to the condition in which a single individual or thallus carries the genetic determinants (i.e., both mating types or sexes) required to undergo sexual reproduction without the need for a distinct mating partner. The opposite sexual functions are performed by different cells of a single mycelium.

thumb|250px|Amnon committed both rape and incest when he assaulted his half-sister Tamar Adelphogamy is a form of sexual partnership between sibling eukaryotes, especially in some species of fungi, flowering plants or ants, or in humans. In flowering plants, adelphogamy refers to sibling pollination: pollen and stigma belong to two individuals which derives from same mother plant.

thumb|right|Close-up of Gymnosporangium clavariiforme telia emerging from [[Juniperus communis bark]] thumb|right|Micrograph of two teliospores from telia of Gymnosporangium clavariiforme Telium, plural telia, are structures produced by rust fungi as part of the reproductive cycle. They are typically yellow or orange drying to brown or black and are exclusively a mechanism for the release of teliospores which are released by wind or water to infect the alternate host in the rust life-cycle. The telial stage provides an overwintering strategy in the life cycle of a parasitic heteroecious fungus

The creation of new life by other than the natural means available to an organism

Conflict with siblings for resources

terminology used with fungi

the unrestricted growth of populations resulting in the maximum growth of that population

procedure performed prior to in vitro fertilization

Sporogenesis is the production of spores in biology. The term is also used to refer to the process of reproduction via spores. Reproductive spores were found to be formed in eukaryotic organisms, such as plants, algae and fungi, during their normal reproductive life cycle. Dormant spores are formed, for example by certain fungi and algae, primarily in response to unfavorable growing conditions. Most eukaryotic spores are haploid and form through cell division, though some types are diploids or dikaryons and form through cell fusion.

providing future reproductive opportunities before a medical treatment with known risk of loss of fertility

means of choosing what type of sperm cell (X-chromosome or Y-chromosome) is to fertilize the egg cell

Apicomplexa life cycle

eusocial hymnopteran behavior where worker females eat or destroy eggs laid by other workers

biological term with multiple meanings

A quantitative ratio of sexually active population

external encapsulating structure part of the chorion. A single cone-shaped specialization that forms an opening in the chorion that allows sperm entry into the egg prior to fertilization

Megagametogenesis is the process of maturation of the female gametophyte, or megagametophyte, in plants. During the process of megagametogenesis, the megaspore, which arises from megasporogenesis, develops into the embryonic sac, in which the female gamete is housed. These megaspores then develop into the haploid female gametophytes. This occurs within the ovule, which is housed inside the ovary.