"of September to January. Eggs are soft-shelled when laid, but become hardened and brittle when exposed to the air. These eggs are usually deposited under rocks, inside animal burrows, or inside logs. Each female only produces 1 clutch per year. Females on Barrow Island reproduce by parthenogenesis, a form of asexual reproduction where the growth and development of the embryo occurs without fertilisation by a male. The Bynoe's gecko is mainly active at night. It leaves its shelter and hunts various invertebrates including moths and grasshoppers throughout the night. It hunts among leaf litter or in bare open spaces and"
"Asexual reproduction Asexual reproduction is a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only; it does not involve the fusion of gametes, and almost never changes the number of chromosomes. Asexual reproduction is the primary form of reproduction for single-celled organisms such as archaea and bacteria. Many plants and fungi sometimes reproduce asexually. While all prokaryotes reproduce without the formation and fusion of gametes, mechanisms for lateral gene transfer such as conjugation, transformation and transduction can be likened to sexual reproduction in the sense of genetic recombination in meiosis."
"families. Asexual reproduction covers all those modes of multiplication of plants where normal gamete formation and fertilization does not take place making these distinctly different from normal seed production crops. In the absence of sexual reproduction, the genetic composition of plant material being multiplied remains essentially the same as its source plant. Clones of mother plants can be made with the exact genetic composition of the mother plant. Superior plants are selected and propagated vegetatively; the vegetative propagated offspring are used to develop stable varieties without any deterioration due to segregation of gene combinations. This unique characteristic of asexual reproduction"
"form of reproduction in unisexual organisms, that is often associated with species that are also capable of gynogenetic reproduction. In this reproductive mode unisexual females mate with sympatric males of related species, and genetic material in the paternal line recombines with the maternal DNA and thus is passed on. This mode of reproduction can be seen in numerous, though not all, species of unisexual salamander, particularly salamanders in the genus ""Ambystoma"", and is implicated in the exceptional genetic diversity that exists in those animals. Parthenogenesis in amphibians Parthenogenesis is a form of reproduction where eggs develop without fertilization, resulting in"
"the pollen contributes no genetic material to the developing offspring. Other forms of apomixis occur in plants also, including the generation of a plantlet in replacement of a seed or the generation of bulbils instead of flowers, where new cloned individuals are produced. Asexual reproduction is a type of reproduction where the offspring comes from one parent only, thus, inheriting the characteristics of the parent. A rhizome is a modified underground stem serving as an organ of vegetative reproduction; the growing tips of the rhizome can separate as new plants, e.g., polypody, iris, couch grass and nettles. Prostrate aerial stems,"
"a very small number of species, the eggs are retained in the coelom where they develop viviparously, later emerging through ruptures in the body wall. In some species of crinoid, the embryos develop in special breeding bags, where the eggs are held until sperm released by a male happens to find them. One species of seastar, ""Ophidiaster granifer"", reproduces asexually by parthenogenesis. In certain other asterozoans, the adults reproduce asexually for a while before they mature after which time they reproduce sexually. In most of these species, asexual reproduction is by transverse fission with the disc splitting in two. Regrowth"
"Parthenogenesis in amphibians Parthenogenesis is a form of reproduction where eggs develop without fertilization, resulting in unisexual species. This phenomenon is closely related with reproductive modes such as hybridogenesis, where fertilization occurs, but the paternal DNA is not passed on. Among amphibians, it is seen in numerous frog and salamander species, but has not been recorded in caecilians. Haploid parthenogenesis has been achieved experimentally in amphibians, through approaches that could be considered artificial gynogenesis. Oscar Hertwig first achieved artificial parthenogenesis in frogs in 1911, using eggs fertilized by irradiated sperm. The radiation destroyed the DNA within the sperm, but nearly"
"or female gonads. These individuals are called gonozooids. Fertilized eggs produce slightly different individuals, featuring nine muscle bands, no gonads, and two stalks growing from each individual's body: the shorter one at the ventral side, and the longer one growing from the dorsal edge of the posterior siphon. These asexual individuals are informally called ""nurses"", and each one produces an astonishing number of mature progeny asexually; such progeny include both sexual and asexual zooids in three sequential ""generations"". The nurse produces buds (which grow into new zooids) in its ventral stalk, but the buds grow and mature on its dorsal"
"species of snakes. ""True"" parthenogenesis is a form of asexual reproduction in all-female species that produce offspring without any male involvement. There are at least eight parthenogenetic species of Caucasian rock lizard in the genus ""Lacerta"". This genus is unique in containing the only known monoclonal parthenogenetic species, ""Lacerta rostombekovi,"" where the entire species originates from a single hybridization event. In all other cases of unisexual reptilian species that have been examined, multiple separate asexual lineages are present. As true parthenotes, Lacerta do not require stimulation from sperm to reproduce. The best-known and perhaps most evolutionarily derived example of parthenogenesis"
"Arrhenotoky Arrhenotoky (from Greek -τόκος ""-tókos"" ""birth of -"" + ἄρρην ""árrhēn"" ""male person""), also known as arrhenotokous parthenogenesis, is a form of parthenogenesis in which unfertilized eggs develop into males. Typically, females are the offspring in parthenogenesis, hence the important distinction. The set of processes included under the term arrhenotoky depends on the author. Arrhenotoky may be restricted to the production of males that are haploid, or include diploid males that permanently inactivate one set of chromosomes (parahaploidy) or be used to cover all cases of males being produced by parthenogenesis (e.g. aphids where the males are XO diploids)."
"as that of the parent producing the spores. However, mitotic sporogenesis is an exception and most spores, such as those of plants, most Basidiomycota, and many algae, are produced by meiosis. Fragmentation is a form of asexual reproduction where a new organism grows from a fragment of the parent. Each fragment develops into a mature, fully grown individual. Fragmentation is seen in many organisms. Animals that reproduce asexually include planarians, many annelid worms including polychaetes and some oligochaetes, turbellarians and sea stars. Many fungi and plants reproduce asexually. Some plants have specialized structures for reproduction via fragmentation, such as ""gemma"""
"ovum with a full set (two sets of genes) provided solely by the mother. Thus, a male is not needed to provide sperm to fertilize the egg. This form of asexual reproduction is thought in some cases to be a serious threat to biodiversity for the subsequent lack of gene variation and potentially decreased fitness of the offspring. Some invertebrate species that feature (partial) sexual reproduction in their native range are found to reproduce solely by parthenogenesis in areas to which they have been introduced. Relying solely on parthenogenetic reproduction has several advantages for an invasive species: it obviates the"
"has consequences much like those of parthenogenesis, and the females are not actually pregnant on hatching but become pregnant before emerging into free living. Telescoping generations Telescoping generations can occur in parthenogenetic species, such as aphids or other life forms that have the ability to reproduce without ovum fertilization. This occurrence is characterized by a viviparous female having a daughter growing inside her that is also parthenogenetically pregnant with a daughter cell. This pattern of reproduction can also occur in certain mites that are not parthenogenetic, e.g. ""Adactylidium"", in which the young hatch and mate within the mother, eating her"
"of parthenogenesis is gynogenesis. In this type of reproduction, offspring are produced by the same mechanism as in parthenogenesis, however, the egg is stimulated to develop simply by the ""presence"" of sperm - the sperm cells do not contribute any genetic material to the offspring. Because gynogenetic species are all female, activation of their eggs requires mating with males of a closely related species for the needed stimulus. The Amazon molly, (pictured), reproduces by gynogenesis. The elkhorn sculpin (""Alcichthys elongatus"") is a marine teleost with a unique reproductive mode called “internal gametic association”. Sperm are introduced into the ovary by"
"range of reproductive modes, including sexual reproduction, facultative sexuality (in which most, but not all, generations reproduce asexually), and both meiotic and mitotic parthenogenesis. The genus ""Mesorhabditis"" exhibits an unusual form of parthenogenesis, in which sperm-producing males copulate with females, but the sperm do not fuse with the ovum. Contact with the sperm is essential for the ovum to begin dividing, but because no fusion of the cells occurs, the male contributes no genetic material to the offspring, which are essentially clones of the female. Different free-living species feed on materials as varied as algae, fungi, small animals, fecal matter,"
"sometimes used in a restrictive sense to refer to types of agamospermy in which the endosperm is fertilized but the embryo is not (see Pseudogamous apomixis, below). A better term for the restrictive sense is centrogamy. Apomixis in flowering plants (angiosperms) includes some types of vegetative reproduction and also agamospermy, which is asexual reproduction through seeds (see apomixis for more information). Agamospermy can occur through many different mechanisms, some of which require pollination (pseudogamy), and some of which do not (autonomous apomixis). Many flowering plants with pseudogamous apomixis require fertilization to produce the endosperm of the seed. However, it has"
"or identical copies of themselves without the contribution of genetic material from another organism. Bacteria divide asexually via binary fission; viruses take control of host cells to produce more viruses; Hydras (invertebrates of the order ""Hydroidea"") and yeasts are able to reproduce by budding. These organisms often do not possess different sexes, and they are capable of ""splitting"" themselves into two or more copies of themselves. Most plants have the ability to reproduce asexually and the ant species Mycocepurus smithii is thought to reproduce entirely by asexual means. Some species that are capable of reproducing asexually, like hydra, yeast (See"
"Budding Budding is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. The small bulb like projection coming out from the yeast cell is called a bud. The new organism remains attached as it grows, separating from the parent organism only when it is mature, leaving behind scar tissue. Since the reproduction is asexual, the newly created organism is a clone and is genetically identical to the parent organism. Organisms such as hydra use regenerative cells for reproduction in the process of budding. In hydra,"
"(e.g., aphids) while the production of males by parthenogenesis is referred to as arrhenotoky (e.g., bees). When unfertilized eggs develop into both males and females, the phenomenon is called deuterotoky. Parthenogenesis can occur without meiosis through mitotic oogenesis. This is called ""apomictic parthenogenesis"". Mature egg cells are produced by mitotic divisions, and these cells directly develop into embryos. In flowering plants, cells of the gametophyte can undergo this process. The offspring produced by apomictic parthenogenesis are ""full clones"" of their mother. Examples include aphids. Parthenogenesis involving meiosis is more complicated. In some cases, the offspring are haploid (e.g., male ants)."
"reproduction is a major puzzle for biologists. The two-fold cost of sexual reproduction is that only 50% of organisms reproduce and organisms only pass on 50% of their genes. Sexual reproduction typically requires the sexual interaction of two specialized organisms, called gametes, which contain half the number of chromosomes of normal cells and are created by meiosis, with typically a male fertilizing a female of the same species to create a fertilized zygote. This produces offspring organisms whose genetic characteristics are derived from those of the two parental organisms. Asexual reproduction is a process by which organisms create genetically similar"
"It is sometimes also used to describe reproduction modes in hermaphroditic species which can self-fertilize. Sexual reproduction is a biological process that creates a new organism by combining the genetic material of two organisms in a process that starts with meiosis, a specialized type of cell division. Each of two parent organisms contributes half of the offspring's genetic makeup by creating haploid gametes. Most organisms form two different types of gametes. In these anisogamous species, the two sexes are referred to as male (producing sperm or microspores) and female (producing ova or megaspores). In isogamous species, the gametes are similar"
"Eggs develop inside the body and are shed in capsules. Weeks later, the eggs hatch and grow into adults. In asexual reproduction, the planarian detaches its tail end and each half regrows the lost parts by regeneration, allowing neoblasts (adult stem cells) to divide and differentiate, thus resulting in two worms. Some researchers claim that the products derived from bisecting planaria are similar to the products of planarian asexual reproduction; however, debates about the nature of asexual reproduction in planaria and its effect on the population are ongoing. Some species of planaria are exclusively asexual, whereas some can reproduce both"
"asexual reproduction through the production of motile diploid zoospores. These zoospores form in plurilocular sporangium, and can mature into the sporophyte phase immediately. In a representative species ""Laminaria"", there is a conspicuous diploid generation and smaller haploid generations. Meiosis takes place within several unilocular sporangium along the algae's blade, each one forming either haploid male or female zoospores. The spores are then released from the sporangia and grow to form male and female gametophytes. The female gametophyte produces an egg in the oogonium, and the male gametophyte releases motile sperm that fertilize the egg. The fertilized zygote then grows into"
"female offspring through asexual reproduction. Some clones even develop into hermaphrodites. Sexual reproduction in the well-studied ""Aiptasia pallida"" and ""Aiptasia pulchella"", is dioecious, meaning that individual ""Aiptasia"" are of separate sexes. During spawning, anemones release their gametes into the water where fertilization occurs. The resulting zygote becomes a free swimming planula larva which eventually settles onto a suitable substrate where it undergoes metamorphosis to become a small polyp. Newly produced larvae are aposymbiotic meaning they do not contain symbionts. The larvae or newly settled polyps can acquire symbiotic algae from the environment. External factors affect the method of reproductions. Asexual"
"Telescoping generations Telescoping generations can occur in parthenogenetic species, such as aphids or other life forms that have the ability to reproduce without ovum fertilization. This occurrence is characterized by a viviparous female having a daughter growing inside her that is also parthenogenetically pregnant with a daughter cell. This pattern of reproduction can also occur in certain mites that are not parthenogenetic, e.g. ""Adactylidium"", in which the young hatch and mate within the mother, eating her from the inside and then escaping; in some species the males never escape, and in others they die shortly afterwards. However, the resulting inbreeding"
"Anisogamy Anisogamy (also called heterogamy) is the form of sexual reproduction that involves the union or fusion of two gametes, which differ in size and/or form. (The related adjectives are ""anisogamous"" and ""anisogamic""). The smaller gamete is considered to be male (sperm cell), whereas the larger gamete is regarded as female (egg cell). There are several types of anisogamy. Both gametes may be flagellated and therefore motile. Alternatively, both of the gametes may be non-flagellated. The latter situation occurs in some algae and plants. In the red alga ""Polysiphonia"", non-motile eggs are fertilized by non-motile sperm. In flowering plants, the"
"eggs develop into males by converting one set of their chromosomes to heterochromatin and inactivating them. This is referred to as diploid arrhenotoky. Arrhenotoky Arrhenotoky (from Greek -τόκος ""-tókos"" ""birth of -"" + ἄρρην ""árrhēn"" ""male person""), also known as arrhenotokous parthenogenesis, is a form of parthenogenesis in which unfertilized eggs develop into males. Typically, females are the offspring in parthenogenesis, hence the important distinction. The set of processes included under the term arrhenotoky depends on the author. Arrhenotoky may be restricted to the production of males that are haploid, or include diploid males that permanently inactivate one set of"
"occur without fertilisation. Thelytoky is a particular form of parthenogenesis in which the development of a female individual occurs from an unfertilised egg. Automixis is a form of thelytoky, but there are different kinds of automixis. The kind of automixis relevant here is one in which two haploid products from the same meiosis combine to form a diploid zygote. Diploid ""Artemia parthenogenetica"" reproduce by automictic parthenogenesis with central fusion (see diagram) and low but nonzero recombination. Central fusion of two of the haploid products of meiosis (see diagram) tends to maintain heterozygosity in transmission of the genome from mother to"
"Human reproduction Human reproduction is any form of sexual reproduction resulting in human fertilization, typically involving sexual intercourse between a man and a woman. During sexual intercourse, the interaction between the male and female reproductive systems results in fertilization of the woman's ovum by the man's sperm. These are specialized reproductive cells called gametes, created in a process called meiosis. While normal cells contains 46 chromosomes, 23 pairs, gamete cells only contain 23 chromosomes, and it is when these two cells merge into one zygote cell that genetic recombination occurs and the new zygote contains 23 chromosomes from each parent,"
"biology given that asexual reproduction can reproduce by budding, fission, or spore formation not involving union of gametes, which reproduce at a much faster rate compared to sexual reproduction. 50% of offspring from sexual reproduction are males, unable to produce offspring themselves. Since hypotheses for the origins of sex are difficult to verify experimentally (outside of evolutionary computation), most current work has focused on the maintenance of sexual reproduction. Sexual reproduction must offer significant fitness advantages to a species because despite the two-fold cost of sex, it dominates among multicellular forms of life, implying that the fitness of offspring produced"
"new sporophyte without fertilization. It is important in ferns and in flowering plants, but is very rare in other seed plants. In flowering plants, the term ""apomixis"" is now most often used for agamospermy, the formation of seeds without fertilization, but was once used to include vegetative reproduction. An example of an apomictic plant would be the triploid European dandelion. Apomixis mainly occurs in two forms: In gametophytic apomixis, the embryo arises from an unfertilized egg within a diploid embryo sac that was formed without completing meiosis. In nucellar embryony, the embryo is formed from the diploid nucellus tissue surrounding"
"Ovoviviparity Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a mode of reproduction in animals in which embryos that develop inside eggs remain in the mother's body until they are ready to hatch. This method of reproduction is similar to viviparity, but the embryos have no placental connection with the mother and receive their nourishment from a yolk sac. In some species, this is supplemented by uterine secretions or other maternal provisioning. The young of ovoviviparous amphibians are sometimes born as larvae, and undergo metamorphosis outside the body of the mother, and in some insect species, such as the tachinid flies,"
"which eventually break away from the parent organism. Internal budding is a process of asexual reproduction, favoured by parasites such as ""Toxoplasma gondii"". It involves an unusual process in which two (""endodyogeny"") or more (""endopolygeny"") daughter cells are produced inside a mother cell, which is then consumed by the offspring prior to their separation. Also, budding (external or internal) is present in some worm like Taenia or Echinococci; these worm produce cyst and then produce (invaginated or evaginated) protoscolex with budding. Vegetative propagation is a type of asexual reproduction found in plants where new individuals are formed without the production"