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Reproductive Coevolution In Ficus
The genus ''Ficus'' is composed of 800 species of vines, shrubs, and trees, defined by their syconiums, the fruit-like vessels that either hold female flowers or pollen on the inside. In addition to being cultivated by humans for thousands of years, ''Ficus'' is also known for their reproductive mutualism with the fig wasp. Fig trees either produce hermaphrodite fruit known as caprifigs, or female figs; only the female figs are palatable to humans. In exchange for a safe place for their eggs and larvae, fig wasps help pollinate the ficus by crawling inside the tiny hole in the apex of the fig, called the ostiole, without knowing whether they crawled into a caprifig or a fig. If the female wasp crawls into the caprifig, she can successfully lay her eggs and die. The males hatch first, mate with the females, dig tunnels out of the caprifig, and die. The females, now covered in fig pollen from the caprifig, fly out to begin the cycle again. If the female wasp crawls into a female fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ficus
''Ficus'' ( or ) is a genus of about 850 species of woody trees, shrubs, vines, epiphytes and hemiepiphytes in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extending into the semi-warm temperate zone. The common fig (''F. carica'') is a temperate species native to southwest Asia and the Mediterranean region (from Afghanistan to Portugal), which has been widely cultivated from ancient times for its fruit, also referred to as figs. The fruit of most other species are also edible though they are usually of only local economic importance or eaten as bushfood. However, they are extremely important food resources for wildlife. Figs are also of considerable cultural importance throughout the tropics, both as objects of worship and for their many practical uses. Description ''Ficus'' is a pantropical genus of trees, shrubs, and vines occupying a wide variety of ecological niches; most are evergreen, bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or more rare within a population. The evolutionary pressures that determine whether a characteristic is common or rare within a population constantly change, resulting in a change in heritable characteristics arising over successive generations. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms, and molecules. The theory of evolution by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cospeciation
Cospeciation is a form of coevolution in which the speciation of one species dictates speciation of another species and is most commonly studied in host-parasite relationships. In the case of a host-parasite relationship, if two hosts of the same species get within close proximity of each other, parasites of the same species from each host are able to move between individuals and mate with the parasites on the other host. However, if a speciation event occurs in the host species, the parasites will no longer be able to "cross over" because the two new host species no longer mate and, if the speciation event is due to a geographic separation, it is very unlikely the two hosts will interact at all with each other. The lack of proximity between the hosts ultimately prevents the populations of parasites from interacting and mating. This can ultimately lead to speciation within the parasite. According to Fahrenholz's rule, first proposed by Heinrich Fahrenholz in 1913, when host-parasit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Host Switch
In parasitology and epidemiology, a host switch (or host shift) is an evolutionary change of the host specificity of a parasite or pathogen. For example, the human immunodeficiency virus used to infect and circulate in non-human primates in West-central Africa, but switched to humans in the early 20th century. All symbiotic species, such as parasites, pathogens and mutualists, exhibit a certain degree of host specificity. This means that pathogens are highly adapted to infect a specific host - in terms of but not limited to receptor binding, countermeasures for host restriction factors and transmission methods. They occur in the body (or on the body surface) of a single host species or – more often – on a limited set of host species. In the latter case, the suitable host species tend to be taxonomically related, sharing similar morphology and physiology. Speciation is the creation of a new and distinct species through evolution and so unique differences exist between all life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Species
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same taxonomic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harvard University
Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher learning in the United States and one of the most prestigious and highly ranked universities in the world. The university is composed of ten academic faculties plus Harvard Radcliffe Institute. The Faculty of Arts and Sciences offers study in a wide range of undergraduate and graduate academic disciplines, and other faculties offer only graduate degrees, including professional degrees. Harvard has three main campuses: the Cambridge campus centered on Harvard Yard; an adjoining campus immediately across Charles River in the Allston neighborhood of Boston; and the medical campus in Boston's Longwood Medical Area. Harvard's endowment is valued at $50.9 billion, making it the wealthiest academic institution in the world. Endowment inco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ficus Wassa
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''Ficus wassa'' is a species of fig in the family Moraceae found in Malesia. References wassa The Wasa are Akan people who live predominantly in Ghana Ghana (; tw, Gaana, ee, Gana), officially the Republic of Ghana, is a country in West Africa. It abuts the Gulf of Guinea and the Atlantic Ocean to the south, sharing borders with I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostiole
An ''ostiole'' is a small hole or opening through which algae or fungi release their mature spores. The word is a diminutive of "ostium", "opening". The term is also used in higher plants, for example to denote the opening of the involuted syconium (fig inflorescence) through which fig wasps enter to pollinate and breed. Sometimes a stoma In botany, a stoma (from Greek ''στόμα'', "mouth", plural "stomata"), also called a stomate (plural "stomates"), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange. The pore is bor ...tal aperture is called an "ostiole"."Synergistic Pectin Degradation and Guard Cell Pressurization Underlie Stomatal Pore Formation", See also * Ostium (other) References Fungal morphology and anatomy Plant anatomy {{botany-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproductive Isolation
The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring are sterile. These barriers maintain the integrity of a species by reducing gene flow between related species.Strickberger, M. 1978. ''Genética''. Omega, Barcelona, España, p.: 874-879. .Futuyma, D. 1998. ''Evolutionary biology'' (3ª edición). Sinauer, Sunderland. The mechanisms of reproductive isolation have been classified in a number of ways. Zoologist Ernst Mayr classified the mechanisms of reproductive isolation in two broad categories: pre-zygotic for those that act before fertilization (or before mating in the case of animals) and post-zygotic for those that act after it.Mayr, E. 1963. ''Animal species and evolution''. Harvard University Press, Cambridge. The mechanisms are genetically controlled and can appear in species whose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygote
A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicellular organisms, the zygote is the earliest developmental stage. In humans and most other anisogamous organisms, a zygote is formed when an egg cell and sperm cell come together to create a new unique organism. In single-celled organisms, the zygote can divide asexually by mitosis to produce identical offspring. German zoologists Oscar and Richard Hertwig made some of the first discoveries on animal zygote formation in the late 19th century. Humans In human fertilization, a released ovum (a haploid secondary oocyte with replicate chromosome copies) and a haploid sperm cell (male gamete) combine to form a single diploid cell called the zygote. Once the single sperm fuses with the oocyte, the latter completes the division of the second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syconium
Syconium (plural ''syconia'') is the type of inflorescence borne by figs (genus ''Ficus''), formed by an enlarged, fleshy, hollow receptacle with multiple ovaries on the inside surface. In essence, it is really a fleshy stem with a number of flowers, so it is considered both a multiple and accessory fruit. Etymology The term ''syconium'' comes from the Ancient Greek word (''sykon''), meaning "fig". Morphology The syconium is an urn-shaped receptacle which contains between 50 and 7000 (depending on the species) highly simplified uniovulate flowers or florets on its inner surface. It is closed off from most organisms by the ostiole, fringed by scale-like bracts. Syconia can be monoecious or functionally dioecious: the former contain female flowers with variable style length and few male flowers, and produce seeds and pollen. The latter have male and female forms in different plants: seed figs contain female flowers with long styles and produce seeds; gall figs contain female ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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