47-560: The gymnosperms ( / ˈ dʒ ɪ m n ə ˌ s p ɜːr m z , - n oʊ -/ JIM -nə-spurmz, -noh- ; lit. ' revealed seeds ' ) are a group of seed-producing plants that include conifers , cycads , Ginkgo , and gnetophytes , forming the clade Gymnospermae . The term gymnosperm comes from the composite word in Greek : γυμνόσπερμος ( γυμνός , gymnos , 'naked' and σπέρμα , sperma , 'seed'), and literally means 'naked seeds'. The name
94-406: A clade of gymnosperms , with the gnetophytes in or near the conifers. For example, one common proposed set of relationships is known as the gne-pine hypothesis and looks like: (flowering plants) [REDACTED] Cycads [REDACTED] Ginkgo [REDACTED] Pinaceae (the pine family) [REDACTED] Gnetophytes [REDACTED] other conifers [REDACTED] However,
141-444: A phanerogam (taxon Phanerogamae ) or a phaenogam (taxon Phaenogamae ), is any plant that produces seeds . It is a category of embryophyte (i.e. land plant) that includes most of the familiar land plants, including the flowering plants and the gymnosperms , but not ferns , mosses , or algae . The term phanerogam or phanerogamae is derived from the Greek φανερός ( phanerós ), meaning "visible", in contrast to
188-414: A female. Hangingflies (Bittacidae) provide a nuptial meal in the form of a captured insect prey, such as a caterpillar, bug, or fly. The male attracts a female with a pheromone from vesicles on his abdomen; he retracts these once a female is nearby, and presents her with the prey. While she evaluates the gift, he locates her genitalia with his. If she stays to eat the prey, his genitalia attach to hers, and
235-505: A few areas, some species are the first insects to arrive at a cadaver , making them useful in forensic entomology . Mecopterans vary in length from 2 to 35 mm (0.1 to 1.4 in). There are about six hundred extant species known, divided into thirty-four genera in nine families. The majority of the species are contained in the families Panorpidae and Bittacidae . Besides this there are about four hundred known fossil species in about eighty-seven genera, which are more diverse than
282-414: A gymnosperm involves alternation of generations , with a dominant diploid sporophyte phase, and a reduced haploid gametophyte phase, which is dependent on the sporophytic phase. The term "gymnosperm" is often used in paleobotany to refer to (the paraphyletic group of) all non-angiosperm seed plants. In that case, to specify the modern monophyletic group of gymnosperms, the term Acrogymnospermae
329-554: A long labium , long mandibles and fleshy palps , which resemble those of the more primitive true flies . Like many other insects, they possess compound eyes on the sides of their heads, and three ocelli on the top. The antennae are filiform (thread-shaped) and contain multiple segments. The fore and hind wings are similar in shape, being long and narrow, with numerous cross-veins, and somewhat resembling those of primitive insects such as mayflies . A few genera, however, have reduced wings, or have lost them altogether. The abdomen
376-404: A now-extinct family with members which (in an example of convergent evolution ) resembled the modern butterflies that arose far later. All gymnosperms are perennial woody plants , Unlike in other extant gymnosperms the soft and highly parenchymatous wood in cycads is poorly lignified, and their main structural support comes from an armor of sclerenchymatous leaf bases covering the stem, with
423-468: A refractory period during which the female does not mate with other males: all of these increase the number of offspring the male is likely to have. The female lays the eggs in close contact with moisture, and the eggs typically absorb water and increase in size after deposition. In species that live in hot conditions, the eggs may not hatch for several months, the larvae only emerging when the dry season has finished. More typically, however, they hatch after
470-505: A relatively short period of time. The larvae are usually quite caterpillar -like, with short, clawed, true legs, and a number of abdominal prolegs . They have sclerotised heads with mandibulate mouthparts. Larvae possess compound eyes, which is unique among holometabolous insects. The tenth abdominal segment bears either a suction disc, or, less commonly, a pair of hooks. They generally eat vegetation or scavenge for dead insects, although some predatory larvae are known. The larva crawls into
517-548: A system to guide the pollen to the seed. Runcaria was followed shortly after by plants with a more condensed cupule, such as Spermasporites and Moresnetia . Seed-bearing plants had diversified substantially by the Famennian , the last stage of the Devonian. Examples include Elkinsia , Xenotheca , Archaeosperma , " Hydrasperma ", Aglosperma , and Warsteinia . Some of these Devonian seeds are now classified within
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#1732868638500564-422: Is an integumented megasporangium surrounded by a cupule. The megasporangium bears an unopened distal extension protruding above the mutlilobed integument . It is suspected that the extension was involved in anemophilous (wind) pollination . Runcaria sheds new light on the sequence of character acquisition leading to the seed. Runcaria has all of the qualities of seed plants except for a solid seed coat and
611-438: Is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants ( angiosperms ), which are enclosed within an ovary . Gymnosperm seeds develop either on the surface of scales or leaves , which are often modified to form cones , or on their own as in yew , Torreya , and Ginkgo . The life cycle of
658-404: Is cylindrical with eleven segments, the first of which is fused to the metathorax . The cerci consist of one or two segments. The abdomen typically curves upwards in the male, superficially resembling the tail of a scorpion , the tip containing an enlarged structure called the genital bulb. The caterpillar -like larvae have hard sclerotised heads with mandibles (jaws), short true legs on
705-506: Is low, with Trinidad, Taiwan and Japan, where they are found, having had recent land bridges to the nearest continental land masses. The European scorpionfly was named Panorpa communis by Linnaeus in 1758 . The Mecoptera were named by Alpheus Hyatt and Jennie Maria Arms in 1891. The name is from the Greek , mecos meaning long, and ptera meaning wings. The families of Mecoptera are well accepted by taxonomists but their relationships have been debated. In 1987, R. Willman treated
752-432: Is monophyletic, sister to Siphonaptera: Diptera (true flies) [REDACTED] Pistillifera (scorpionflies, hangingflies, 400 spp .) [REDACTED] Boreidae (snow scorpionflies, 30 spp.) [REDACTED] Nannochoristidae (southern scorpionflies, 8 spp.) [REDACTED] (fleas, 2500 spp.) [REDACTED] All the families were formerly treated as part of a single order, Mecoptera. The relationships between
799-561: Is sometimes used. The gymnosperms and angiosperms together constitute the spermatophytes or seed plants. The spermatophytes are subdivided into five divisions , the angiosperms and four divisions of gymnosperms: the Cycadophyta , Ginkgophyta , Gnetophyta , and Pinophyta (also known as Coniferophyta). Newer classification place the gnetophytes among the conifers. Numerous extinct seed plant groups are recognised including those considered pteridosperms/seed ferns , as well other groups like
846-476: Is the flowering plants , also known as angiosperms or magnoliophytes, the largest and most diverse group of spermatophytes: In addition to the five living taxa listed above, the fossil record contains evidence of many extinct taxa of seed plants, among those: By the Triassic period, seed ferns had declined in ecological importance, and representatives of modern gymnosperm groups were abundant and dominant through
893-819: Is the most basal, and the relationships of the rest are not completely clear. Nannochoristidae Boreidae (snow scorpionflies) [REDACTED] Siphonaptera (fleas) [REDACTED] Eomeropidae (mainly fossil ( Triassic to present), 1 extant sp.) [REDACTED] (?) Bittacidae (hangingflies) Meropeidae (earwigflies) [REDACTED] Choristidae (Australian scorpionflies) [REDACTED] Apteropanorpidae (Tasmanian snow scorpionflies) (?) Bittacidae (hangingflies) [REDACTED] Panorpodidae (short-faced scorpionflies) Panorpidae ( Jurassic to present, common scorpionflies) [REDACTED] Mecoptera are small to medium-sized insects with long beaklike rostra , membranous wings and slender, elongated bodies. They have relatively simple mouthparts, with
940-555: The Greek : mecos = "long", ptera = "wings") is an order of insects in the superorder Holometabola with about six hundred species in nine families worldwide. Mecopterans are sometimes called scorpionflies after their largest family, Panorpidae , in which the males have enlarged genitals raised over the body that look similar to the stingers of scorpions , and long beaklike rostra . The Bittacidae , or hangingflies, are another prominent family and are known for their elaborate mating rituals, in which females choose mates based on
987-911: The Permochoristidae , to the Middle Triassic . During the Late Triassic through the Middle Jurassic , Aneuretopsychina species were gradually replaced by species from the Parachoristidae and Orthophlebiidae. Modern mecopteran families are derived from the Orthophlebiidae. Mecoptera have special importance in the evolution of the insects. Two of the most important insect orders, Lepidoptera (butterflies and moths) and Diptera (true flies), along with Trichoptera (caddisflies), probably evolved from ancestors belonging to, or strictly related to,
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#17328686385001034-988: The Siphonaptera (fleas) are inside that clade, so that the traditional "Mecoptera" taxon is paraphyletic. However the earlier suggestion that the Siphonaptera are sister to the Boreidae is not supported; instead, there is the possibility that they are sister to another Mecopteran family, the Nannochoristidae . The two possible trees are shown below: (a) Mecoptera (clades in boldface) is paraphyletic, containing Siphonaptera: Diptera (true flies) [REDACTED] Pistillifera (scorpionflies, hangingflies, 400 spp .) [REDACTED] Boreidae (snow scorpionflies, 30 spp.) [REDACTED] Nannochoristidae (southern scorpionflies, 8 spp.) [REDACTED] Siphonaptera (fleas, 2500 spp.) [REDACTED] (b) Mecoptera
1081-645: The Bennettitales. By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes ( Gnetum , Ephedra and Welwitschia ), and Ginkgo biloba (a single living species). About 65% of gymnosperms are dioecious , but conifers are almost all monoecious . Some genera have mycorrhiza , fungal associations with roots ( Pinus ), while in some others ( Cycas ) small specialised roots called coralloid roots are associated with nitrogen-fixing cyanobacteria . Over 1,000 living species of gymnosperm exist. It
1128-938: The Mecoptera as a clade , containing the Boreidae as sister to the Meropeidae, but in 2002 Michael F. Whiting declared the Mecoptera so-defined as paraphyletic, with the Boreidae as sister to another order, the Siphonaptera (fleas). Among the earliest members of the Mecoptera are the Nannochoristidae of Upper Permian age. Fossil Mecoptera become abundant and diverse during the Cretaceous , for example in China, where panorpids such as Jurassipanorpa , hangingflies (Bittacidae and Cimbrophlebiidae), Orthophlebiidae, and Cimbrophlebiidae have been found. Extinct Mecoptera species may have been important pollinators of early gymnosperm seed plants during
1175-449: The Mecoptera. Evidence includes anatomical and biochemical similarities as well as transitional fossils , such as Permotanyderus and Choristotanyderus , which lie between the Mecoptera and Diptera. The group was once much more widespread and diverse than it is now, with four suborders during the Mesozoic . It is unclear as of 2020 whether the Mecoptera form a single clade, or whether
1222-551: The clade Aneuretopsychina . Their lengths range from 3 mm (0.12 in) in Parapolycentropus burmiticus to 28 mm (1.1 in) in Lichnomesopsyche gloriae . The proboscis could be as long as 10 mm (0.39 in). It has been suggested that these mecopterans transferred pollen on their mouthparts and head surfaces, as do bee flies and hoverflies today, but no such associated pollen has been found, even when
1269-470: The eggs may not hatch until the wet season arrives. The larvae are caterpillar-like and mostly feed on vegetable matter, and the non-feeding pupae may pass through a diapause until weather conditions are favorable. Early Mecoptera may have played an important role in pollinating extinct species of gymnosperms before the evolution of other insect pollinators such as bees. Adults of modern species are overwhelmingly predators or consumers of dead organisms. In
1316-494: The end of the Cretaceous , when the angiosperms radiated. A whole genome duplication event in the ancestor of seed plants occurred about 319 million years ago . This gave rise to a series of evolutionary changes that resulted in the origin of modern seed plants. A middle Devonian (385-million-year-old) precursor to seed plants from Belgium has been identified predating the earliest seed plants by about 20 million years. Runcaria , small and radially symmetrical,
1363-895: The exception of species with underground stems. There are no herbaceous gymnosperms and compared to angiosperms they occupy fewer ecological niches , but have evolved both parasites ( Parasitaxus ), epiphytes ( Zamia pseudoparasitica ) and rheophytes ( Retrophyllum minus ). Conifers are by far the most abundant extant group of gymnosperms with six to eight families, with a total of 65–70 genera and 600–630 species (696 accepted names). Most conifers are evergreens . The leaves of many conifers are long, thin and needle-like, while other species, including most Cupressaceae and some Podocarpaceae , have flat, triangular scale-like leaves. Agathis in Araucariaceae and Nageia in Podocarpaceae have broad, flat strap-shaped leaves. Cycads are
1410-561: The families are, however, a matter of debate. The cladogram, from Cracraft and Donoghue 2004, places the Nannochoristidae as a separate order, with the Boreidae, as the sister group to the Siphonaptera, also as its own order. The Eomeropidae is suggested to be the sister group to the rest of the Mecoptera, with the position of the Bittacidae unclear. Of those other families, the Meropeidae
1457-437: The family Panorpidae occurs, such as the eastern United States, these scorpionflies can be the first insects to arrive at a donated human cadaver, and remain on a corpse for one or two days. The presence of scorpionflies thus indicates that a body must be fresh. Scorpionflies are sometimes described as looking "sinister", particularly from the male's raised "tail" resembling a scorpion 's sting. A popular but incorrect belief
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1504-404: The female lowers herself into an upside-down hanging position, and eats the prey while mating. Larger prey result in longer mating times. In Hylobittacus apicalis , prey 3 to 14 millimetres (0.12 to 0.55 in) long give between 1 and 17 minutes of mating. Larger males of that species give prey as big as houseflies, earning up to 29 minutes of mating, maximal sperm transfer, more oviposition, and
1551-519: The insects were finely preserved in Eocene Baltic amber . They likely pollinated plants such as Caytoniaceae , Cheirolepidiaceae , and Gnetales , which have ovulate organs that are either poorly suited for wind pollination or have structures that could support long-proboscid fluid feeding. The Aneuretopsychina were the most diverse group of mecopterans in the Latest Permian, taking the place of
1598-424: The larvae being able to jump like fleas . Hangingflies, family Bittacidae, occur in forests, grassland and caves with high moisture levels. They mostly breed among mosses, in leaf litter and other moist places, but their reproductive habits have been little studied, and at least one species, Nannochorista philpotti , has aquatic larvae. Adult mecopterans are mostly scavengers , feeding on decaying vegetation and
1645-548: The late Devonian period around 383 million years ago. It has been suggested that during the mid-Mesozoic era, pollination of some extinct groups of gymnosperms was by extinct species of scorpionflies that had specialized proboscis for feeding on pollination drops. The scorpionflies likely engaged in pollination mutualisms with gymnosperms, long before the similar and independent coevolution of nectar-feeding insects on angiosperms. Evidence has also been found that mid-Mesozoic gymnosperms were pollinated by Kalligrammatid lacewings ,
1692-538: The late Middle Jurassic to mid– Early Cretaceous periods before other pollinating groups such as the bees evolved. These were mainly wind-pollinated plants, but fossil mecopterans had siphon-feeding apparatus that could have fertilized these early gymnosperms by feeding on their nectar and pollen . The lack of iron enrichment in their fossilized probosces rules out their use for drinking blood. Eleven species have been identified from three families, Mesopsychidae , Aneuretopsychidae , and Pseudopolycentropodidae within
1739-685: The living members of the order. The group is sometimes called the scorpionflies, from the turned-up "tail" of the male's genitalia in the Panorpidae. Distribution of mecopterans is worldwide; the greatest diversity at the species level is in the Afrotropic and Palearctic realms , but there is greater diversity at the generic and family level in the Neotropic , Nearctic and Australasian realms . They are absent from Madagascar and many islands and island groups; this may demonstrate that their dispersal ability
1786-1254: The next most abundant group of gymnosperms, with two or three families, 11 genera, and approximately 338 species. A majority of cycads are native to tropical climates and are most abundantly found in regions near the equator. The other extant groups are the 95–100 species of Gnetales and one species of Ginkgo . Today, gymnosperms are the most threatened of all plant groups. Ginkgo Cycas Dioon Bowenia Macrozamia Encephalartos Lepidozamia Ceratozamia Stangeria Microcycas Zamia Ephedra Gnetum Welwitschia Larix Pseudotsuga Pinus Cathaya Picea Cedrus Abies Keteleeria Pseudolarix Nothotsuga Tsuga Araucaria Agathis Wollemia Halocarpus Pectinopitys Prumnopitys Sundacarpus Lepidothamnus Phyllocladus Parasitaxus Lagarostrobos Manoao Saxegothaea Microcachrys Pherosphaera Seed plant A seed plant or spermatophyte ( lit. ' seed plant ' ; from Ancient Greek σπέρματος ( spérmatos ) 'seed' and φυτόν (phytón) 'plant'), also known as
1833-540: The order Lyginopteridales . Seed-bearing plants are a clade within the vascular plants (tracheophytes). The spermatophytes were traditionally divided into angiosperms , or flowering plants, and gymnosperms , which includes the gnetophytes, cycads, ginkgo, and conifers. Older morphological studies believed in a close relationship between the gnetophytes and the angiosperms, in particular based on vessel elements . However, molecular studies (and some more recent morphological and fossil papers) have generally shown
1880-649: The quality of gift prey offered to them by the males. A smaller group is the snow scorpionflies, family Boreidae , adults of which are sometimes seen walking on snowfields. In contrast, the majority of species in the order inhabit moist environments in tropical locations. The Mecoptera are closely related to the Siphonaptera (fleas), and a little more distantly to the Diptera (true flies). They are somewhat fly-like in appearance, being small to medium-sized insects with long slender bodies and narrow membranous wings. Most breed in moist environments such as leaf litter or moss, and
1927-502: The relationships between these groups should not be considered settled. Other classifications group all the seed plants in a single division , with classes for the five groups: A more modern classification ranks these groups as separate divisions (sometimes under the Superdivision Spermatophyta ): Unassigned extinct spermatophyte orders, some of which qualify as "seed ferns": Mecoptera Mecoptera (from
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1974-431: The soft bodies of dead invertebrates. Panorpa raid spider webs to feed on trapped insects and even the spiders themselves, and hangingflies capture flies and moths with their specially modified legs. Some groups consume pollen , nectar , midge larvae, carrion and moss fragments. Most mecopterans live in moist environments; in hotter climates, the adults may therefore be active and visible only for short periods of
2021-445: The soil or decaying wood to pupate , and does not spin a cocoon. The pupae are exarate , meaning the limbs are free of the body, and are able to move their mandibles, but are otherwise entirely nonmotile. In drier environments, they may spend several months in diapause , before emerging as adults once the conditions are more suitable. Forensic entomology makes use of scorpionflies' habit of feeding on human corpses . In areas where
2068-484: The term "cryptogam" or " cryptogamae " (from Ancient Greek κρυπτός (kruptós) 'hidden'), together with the suffix γαμέω ( gaméō ), meaning "to marry". These terms distinguish those plants with hidden sexual organs (cryptogamae) from those with visible ones (phanerogamae). The extant spermatophytes form five divisions, the first four of which are classified as gymnosperms , plants that have unenclosed, "naked seeds": The fifth extant division
2115-533: The thorax, prolegs on the first eight abdominal segments, and a suction disc or pair of hooks on the terminal tenth segment. The pupae have free appendages rather than being secured within a cocoon (they are exarate). Mecopterans mostly inhabit moist environments although a few species are found in semi-desert habitats. Scorpionflies, family Panorpidae, generally live in broad-leaf woodlands with plentiful damp leaf litter. Snow scorpionflies, family Boreidae, appear in winter and are to be seen on snowfields and on moss;
2162-429: The year. Various courtship behaviours have been observed among mecopterans, with males often emitting pheromones to attract mates. The male may provide an edible gift such as a dead insect or a brown salivary secretion to the female. Some boreids have hook-like wings which the male uses to pick up and place the female on his back while copulating. Male panorpids vibrate their wings or even stridulate while approaching
2209-659: Was previously widely accepted that the gymnosperms originated in the Late Carboniferous period, replacing the lycopsid rainforests of the tropical region, but more recent phylogenetic evidence indicates that they diverged from the ancestors of angiosperms during the Early Carboniferous . The radiation of gymnosperms during the late Carboniferous appears to have resulted from a whole genome duplication event around 319 million years ago . Early characteristics of seed plants are evident in fossil progymnosperms of
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