Codium fragile, known as green sea fingers, dead man's fingers, felty fingers, forked felt-alga, stag seaweed, sponge seaweed, green sponge, green fleece, oyster thief, is a species of seaweed in the family Codiaceae. It originates in the Pacific Ocean near Japan and has become an invasive species on the coasts of the Northern Atlantic Ocean; this siphonous green alga is dark green in color. It appears as a fuzzy patch of tubular fingers; these formations hang down from rocks during low tide, hence the nickname "dead man's fingers". The "fingers" are branches up to a centimeter wide and sometimes over 30 centimeters long. Codium fragile occurs in the low intertidal zone, subtidal on high-energy beaches, it has no asexual stage, male and female gametes are both produced on separate plants. Subspecies of C. fragile can only be distinguished microscopically. Codium fragile subsp. Atlanticum is known to have arrived in the southwest of Ireland around 1808. From there it may have spread by floating in the sea.
30 years it was found in Scotland. It is thought to have come from the Pacific Ocean near Japan. Since 1840, when it was first discovered in Scotland, it has spread the entire length of Britain, including Shetland. Between 1949 and 1955 it is known to have spread between Berwick-upon-Tweed and St. Andrews, Fife, a distance of 80 km. Populations of this algae occur in northern Britain. Elsewhere in Europe it is found in several places, including the Norway, France and the Azores; this species displaces the native Codium tomentosum. Codium fragile subsp. Atlanticum is used as food in the Far East; the subspecies Codium fragile subsp. Tomentosoides, occurs along nearly the whole coastline of the eastern United States, from the Gulf of St. Lawrence in Canada to North Carolina, it is a spreading invasive species. It originated in the Pacific Ocean around Japan, was introduced into New York from Europe in 1957, its presence was first recorded in 1964 in the Gulf of Maine at Boothbay. This is a dominant subspecies in the subtidal zone, attaching to any hard surface.
This results in increased maintenance labor for aquaculturists and reduces the productivity of cultured marine life. In established shellfish beds, this species can become a nuisance; this was the inspiration for the common name "oyster thief". This subspecies was introduced from Asiatic coasts of the Pacific to Norway, to Denmark in 1919; this subspecies is found in the low intertidal to subtidal zones around New Zealand at the North Island, South Island, Chatham Islands, Stewart Island, Auckland Island, Campbell Island as well as around the Falkland Islands
Kelp forests are underwater areas with a high density of kelp. They are recognized as one of dynamic ecosystems on Earth. Smaller areas of anchored kelp are called kelp beds. Kelp forests occur worldwide throughout temperate and polar coastal oceans. In 2007, kelp forests were discovered in tropical waters near Ecuador. Physically formed by brown macroalgae, kelp forests provide a unique, three-dimensional habitat for marine organisms and are a source for understanding many ecological processes. Over the last century, they have been the focus of extensive research in trophic ecology, continue to provoke important ideas that are relevant beyond this unique ecosystem. For example, kelp forests can influence coastal oceanographic patterns and provide many ecosystem services. However, the influence of humans has contributed to kelp forest degradation. Of particular concern are the effects of overfishing nearshore ecosystems, which can release herbivores from their normal population regulation and result in the overgrazing of kelp and other algae.
This can result in transitions to barren landscapes where few species persist. The implementation of marine protected areas is one management strategy useful for addressing such issues, since it may limit the impacts of fishing and buffer the ecosystem from additive effects of other environmental stressors; the term kelp refers to marine algae belonging to the order Laminariales. Though not considered a taxonomically diverse order, kelps are diverse structurally and functionally; the most recognized species are the giant kelps, although numerous other genera such as Laminaria, Lessonia and Eisenia are described. A wide range of sea life uses kelp forests including fish. In the North Pacific kelp forests rockfish, many invertebrates, such as amphipods, marine snails, bristle worms, brittle stars. Many marine mammals and birds are found, including seals, sea lions, sea otters, terns, snowy egrets, great blue herons, cormorants, as well as some shore birds. Considered an ecosystem engineer, kelp provides a physical substrate and habitat for kelp forest communities.
In algae, the body of an individual organism is known as a thallus rather than as a plant. The morphological structure of a kelp thallus is defined by three basic structural units: The holdfast is a root-like mass that anchors the thallus to the sea floor, though unlike true roots it is not responsible for absorbing and delivering nutrients to the rest of the thallus; the stipe is analogous to a plant stalk, extending vertically from the holdfast and providing a support framework for other morphological features. The fronds are leaf- or blade-like attachments extending from the stipe, sometimes along its full length, are the sites of nutrient uptake and photosynthetic activity. In addition, many kelp species have pneumatocysts, or gas-filled bladders located at the base of fronds near the stipe; these structures provide the necessary buoyancy for kelp to maintain an upright position in the water column. The environmental factors necessary for kelp to survive include hard substrate, high nutrients, light.
Productive kelp forests tend to be associated with areas of significant oceanographic upwelling, a process that delivers cool, nutrient-rich water from depth to the ocean’s mixed surface layer. Water flow and turbulence facilitate nutrient assimilation across kelp fronds throughout the water column. Water clarity affects the depth. In ideal conditions, giant kelp can grow as much as 30–60 cm vertically per day; some species, such as Nereocystis, are annuals, while others such as Eisenia are perennials, living for more than 20 years. In perennial kelp forests, maximum growth rates occur during upwelling months and die-backs correspond to reduced nutrient availability, shorter photoperiods, increased storm frequency. Kelps are associated with temperate and arctic waters worldwide. Of the more dominant genera, Laminaria is associated with both sides of the Atlantic Ocean and the coasts of China and Japan; the region with the greatest diversity of kelps is the northeastern Pacific, from north of San Francisco, California, to the Aleutian Islands, Alaska.
Although kelp forests are unknown in tropical surface waters, a few species of Laminaria have been known to occur in tropical deep waters. This general absence of kelp from the tropics is believed to be due to insufficient nutrient levels associated with warm, oligotrophic waters. One recent study spatially overlaid the requisite physical parameters for kelp with mean oceanographic conditions has produced a model predicting the existence of subsurface kelps throughout the tropics worldwide to depths of 200 m. For a hotspot in the Galapagos Islands, the local model was improved with fine-scale data and tested; this suggests that their global model might be accurate, if so, kelp forests would be prolific in tropical subsurface waters worldwide. The importance of this contribution has been ack
The brown algae, comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Most brown algae live in marine environments, where they play an important role both as food and as habitat. For instance, Macrocystis, a kelp of the order Laminariales, may reach 60 m in length and forms prominent underwater kelp forests. Kelp forests like these contain a high level of biodiversity. Another example is Sargassum, which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Many brown algae, such as members of the order Fucales grow along rocky seashores; some members of the class, such as kelps, are used by humans as food. Between 1,500 and 2,000 species of brown algae are known worldwide; some species, such as Ascophyllum nodosum, are important in commercial use because they have become subjects of extensive research in their own right.
They have environmental significance as well, through carbon fixation. Brown algae belong to the group Heterokontophyta, a large group of eukaryotic organisms distinguished most prominently by having chloroplasts surrounded by four membranes, suggesting an origin from a symbiotic relationship between a basal eukaryote and another eukaryotic organism. Most brown algae contain the pigment fucoxanthin, responsible for the distinctive greenish-brown color that gives them their name. Brown algae are unique among heterokonts in developing into multicellular forms with differentiated tissues, but they reproduce by means of flagellated spores and gametes that resemble cells of other heterokonts. Genetic studies show their closest relatives to be the yellow-green algae. Brown algae exist in a wide range of forms; the smallest members of the group grow as tiny, feathery tufts of threadlike cells no more than a few centimeters long. Some species have a stage in their life cycle that consists of only a few cells, making the entire alga microscopic.
Other groups of brown algae grow to much larger sizes. The rockweeds and leathery kelps are the most conspicuous algae in their habitats. Kelps can range in size from the two-foot-tall sea palm Postelsia to the giant kelp Macrocystis pyrifera, which grows to over 45 m long and is the largest of all the algae. In form, the brown algae range from small crusts or cushions to leafy free-floating mats formed by species of Sargassum, they may consist of delicate felt-like strands of cells, as in Ectocarpus, or of foot-long flattened branches resembling a fan, as in Padina. Regardless of size or form, two visible features set the Phaeophyceae apart from all other algae. First, members of the group possess a characteristic color that ranges from an olive green to various shades of brown; the particular shade depends upon the amount of fucoxanthin present in the alga. Second, all brown algae are multicellular. There are no known species that exist as single cells or as colonies of cells, the brown algae are the only major group of seaweeds that does not include such forms.
However, this may be the result of classification rather than a consequence of evolution, as all the groups hypothesized to be the closest relatives of the browns include single-celled or colonial forms. Whatever their form, the body of all brown algae is termed a thallus, indicating that it lacks the complex xylem and phloem of vascular plants; this does not mean that brown algae lack specialized structures. But, because some botanists define "true" stems and roots by the presence of these tissues, their absence in the brown algae means that the stem-like and leaf-like structures found in some groups of brown algae must be described using different terminology. Although not all brown algae are structurally complex, those that are possess one or more characteristic parts. A holdfast is a rootlike structure present at the base of the alga. Like a root system in plants, a holdfast serves to anchor the alga in place on the substrate where it grows, thus prevents the alga from being carried away by the current.
Unlike a root system, the holdfast does not serve as the primary organ for water uptake, nor does it take in nutrients from the substrate. The overall physical appearance of the holdfast differs among various brown algae and among various substrates, it may be branched, or it may be cup-like in appearance. A single alga has just one holdfast, although some species have more than one stipe growing from their holdfast. A stipe is a stalk or stemlike structure present in an alga, it may grow as a short structure near the base of the alga, or it may develop into a large, complex structure running throughout the algal body. In the most structurally differentiated brown algae, the tissues within the stipe are divided into three distinct layers or regions; these regions include a central pith, a surrounding cortex, an outer epidermis, each of which has an analog in the stem of a vascular plant. In some brown algae, the pith region includes a core of elongated cells that resemble the phloem of vascular plants both in structure and function.
In others, the center of the stipe is hollow and filled with gas that serves to keep that part of the alga buoyant. The stipe may be flexible and elastic in species like Macrocystis pyrifera that grow in strong currents, or may be more rigid in species like Postelsia palmaeformis that are exposed to the atmosphere at low tide. Many algae have a flattened portion that may resemble a leaf, this is termed a blade, lamina, or frond; the name blade is most applied to a single undivided structure, while frond may be
Sargassum is a genus of brown macroalgae in the order Fucales. Numerous species are distributed throughout the temperate and tropical oceans of the world, where they inhabit shallow water and coral reefs, the genus is known for its planktonic species. Most species within the class Phaeophyceae are predominantly cold-water organisms that benefit from nutrients upwelling, but the genus Sargassum appears to be an exception. Any number of the benthic species may take on a planktonic pelagic existence after being removed from reefs during rough weather; the Atlantic Ocean's Sargasso Sea was named after the algae, as it hosts a large amount of Sargassum. Sargassum was named by the Portuguese sailors who found it in the Sargasso Sea after the wooly rock rose that grew in their water wells at home, and, called sargaço in Portuguese; the Florida Keys and its smaller islands are well known for their high levels of Sargassum covering their shores. Gulfweed was observed by Columbus. Although it was thought to cover the entirety of the Sargasso Sea, making navigation impossible, it has since been found to occur only in drifts.
Sargassum species ares cultivated and cleaned for use as an herbal remedy. Many Chinese herbalists prescribe powdered Sargassum—either the species S. pallidum, or more hijiki, S. fusiforme—in doses of 0.5 gram dissolved in warm water and drunk as a tea. It is called 海藻. Species of this genus of algae may grow to a length of several metres, they are brown or dark green in color and consist of a holdfast, a stipe, a frond. Oogonia and antheridia occur in conceptacles embedded in receptacles on special branches; some species have berrylike gas-filled bladders that help the fronds float to promote photosynthesis. Many have a rough, sticky texture that, along with a robust but flexible body, helps it withstand strong water currents. Large, pelagic mats of Sargassum in the Sargasso Sea act as one of the only habitats available for ecosystem development; the Sargassum patches act as a refuge for many species in different parts of their development, but as a permanent residence for endemic species that can only be found living on and within the Sargassum.
These endemic organisms have specialized patterns and colorations that mimic the Sargassum and allow them to be impressively camouflaged in their environment. In total, these Sargassum mats are home to over 100 different species. There is a total of 81 fish species that reside in the Sargassum or utilize it for parts of their life cycles. Other marine organisms, such as young sea turtles, will use the Sargassum as shelter and a resource for food until they reach a size at which they can survive elsewhere; this community is being affected by humans due to overfishing and other types of pollution, boat traffic, which could lead to the demise of this diverse and unique habitat. Below is a list of organisms. Organisms found in the pelagic Sargassum patches, Arthropods Amphipods Skeleton shrimp Crabs Copepods Shrimp Sea Spiders Worms Annelid worms Flatworms Mollusks Nudibranchs Snails Squid Fish Sargassum fish Porcupinefish Triplefin Plainhead filefish Others Sea turtlesSargassum is found in the beach drift near Sargassum beds, where they are known as gulfweed, a term that can mean all seaweed species washed up on shore.
Sargassum species are found throughout tropical areas of the world and are the most obvious macrophyte in near-shore areas where Sargassum beds occur near coral reefs. The plants grow subtidally and attach to coral, rocks, or shells in moderately exposed or sheltered rocky or pebble areas; these tropical populations undergo seasonal cycles of growth and decay in concert with seasonal changes in sea temperature. In tropical Sargassum species that are preferentially consumed by herbivorous fishes and echinoids, a low level of phenolics and tannins occurs. Sargassum muticum is a large brown seaweed of the class Phaeophyceae, it grows attached to rocks by a perennial holdfast up to 5 cm in diameter. From this holdfast the main axis grows to a maximum of 5 cm high; the leaf-like laminae and primary lateral branches grow from this stipe. In warm waters, it can grow to 12 m long, however in British waters it gives rise to a single main axis with secondary and tertiary branches that the plant sheds annually.
Numerous small 2–6 mm stalked air vesicles provide buoyancy. The reproductive receptacles are stalked, develop in the axils of leafy laminae, it is self-fertile. The Gulf has the second largest concentration of sargassum of any body of water in the world. A fair amount of it washes out through the Straits of Florida in the Gulf Stream and ends up in the Sargasso Sea in the Atlantic Ocean off the East Coast of the United States. We rounded Hatteras in fair weather, saw the line between the brilliant blue Gulf Stream full of gulf weed and the muddy grayish shore water as defined as that between the sidewalk and the roadway in a street. In summer 2015, large quantities of different species of Sargassum accumulated along the shores of many of the countries on the Caribbean Sea; some of the affected islands and regions include the Caribbean coast of Mexico, the Dominican Republic and Tobago. Another large outbreak
Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them; some animals may scale trees only but others are arboreal. The habitats pose numerous mechanical challenges to animals moving through them and lead to a variety of anatomical and ecological consequences as well as variations throughout different species. Furthermore, many of these same principles may be applied to climbing without trees, such as on rock piles or mountains; the earliest known tetrapod with specializations that adapted it for climbing trees was Suminia, a synapsid of the late Permian, about 260 million years ago. Some animals are arboreal in habitat, such as the tree snail. Arboreal habitats pose numerous mechanical challenges to animals moving in them, which have been solved in diverse ways; these challenges include moving on narrow branches, moving up and down inclines, crossing gaps, dealing with obstructions. Moving along a narrow surface poses special difficulties to animals.
During locomotion on the ground, the location of the center of mass may swing from side to side, but during arboreal locomotion, this would result in the center of mass moving beyond the edge of the branch, resulting in a tendency to topple over. Additionally, foot placement is constrained by the need to make contact with the narrow branch; this narrowness restricts the range of movements and postures an animal can use to move. Branches are oriented at an angle to gravity in arboreal habitats, including being vertical, which poses special problems; as an animal moves up an inclined branch, they must fight the force of gravity to raise their body, making the movement more difficult. Conversely, as the animal descends, it must fight gravity to control its descent and prevent falling. Descent can be problematic for many animals, arboreal species have specialized methods for controlling their descent. Due to the height of many branches and the disastrous consequences of a fall, balance is of primary importance to arboreal animals.
On horizontal and sloped branches, the primary problem is tipping to the side due to the narrow base of support. The narrower the branch, the greater the difficulty in balancing a given animal faces. On steep and vertical branches, tipping becomes less of an issue, pitching backwards or slipping downwards becomes the most failure. In this case, large-diameter branches pose a greater challenge since the animal cannot place its forelimbs closer to the center of the branch than its hindlimbs. Branches are not continuous, any arboreal animal must be able to move between gaps in the branches, or between trees; this can be accomplished by gliding between them. Arboreal habitats contain many obstructions, both in the form of branches emerging from the one being moved on and other branches impinging on the space the animal needs to move through; these obstructions may be used as additional contact points to enhance it. While obstructions tend to impede limbed animals, they benefit snakes by providing anchor points.
Arboreal organisms display many specializations for dealing with the mechanical challenges of moving through their habitats. Arboreal animals have elongated limbs that help them cross gaps, reach fruit or other resources, test the firmness of support ahead, in some cases, to brachiate. However, some species of lizard have reduced limb size that helps them avoid limb movement being obstructed by impinging branches. Many arboreal species, such as tree porcupines, green tree pythons, emerald tree boas, silky anteaters, spider monkeys, possums, use prehensile tails to grasp branches. In the spider monkey and crested gecko, the tip of the tail has either a bare patch or adhesive pad, which provide increased friction. Claws can be used to interact with rough substrates and re-orient the direction of forces the animal applies; this is what allows squirrels to climb tree trunks that are so large as to be flat, from the perspective of such a small animal. However, claws can interfere with an animal's ability to grasp small branches, as they may wrap too far around and prick the animal's own paw.
Adhesion is an alternative to claws. Wet adhesion is common in tree frogs and arboreal salamanders, functions either by suction or by capillary adhesion. Dry adhesion is best typified by the specialized toes of geckos, which use van der Waals forces to adhere to many substrates glass. Frictional gripping is used by primates. Squeezing the branch between the fingertips generates a frictional force that holds the animal's hand to the branch. However, this type of grip depends upon the angle of the frictional force, thus upon the diameter of the branch, with larger branches resulting in reduced gripping ability. Animals other than primates that use gripping in climbing include the chameleon, which has mitten-like grasping feet, many birds that grip branches in perching or moving about. To control descent down large diameter branches, some arboreal animals such as squirrels have evolved mobile ankle joints that permit rotating the foot into a'reversed' posture; this allows the claws to hook into the rough surface of the bark.
Many arboreal species lower their center of mass to reduce pitching and toppling movement when climbing. This may be accomplished by altered body proportions, or smaller size. Small size provides many advantages to arboreal species: such as increasing the relative size of branches
Ascophyllum nodosum is a large, common cold water seaweed or brown alga in the family Fucaceae, being the only species in the genus Ascophyllum. It is a seaweed that only grows in the northern Atlantic Ocean known in localities as feamainn bhuí, Norwegian kelp, knotted kelp, knotted wrack or egg wrack, it is common on the north-western coast of Europe including east Greenland and the north-eastern coast of North America, its range further south of these latitudes being limited by warmer ocean waters. A. nodosum has long tough and leathery fronds, irregularly dichotomously branched fronds with large, egg-shaped air bladders set in series at regular intervals along the fronds and not stalked. The fronds are attached by a holdfast to rocks and boulders; the fronds are olive-brown in color and somewhat compressed, but without a midrib. Its life history is of gametes; each individual plant is either female. The gametes are produced in the spring in conceptacles embedded in yellowish receptacles on short branches.
Several different varieties and forms of this species have been described. A. n. var. minor has been described from Larne Lough in Northern Ireland. Free-floating forms of this species are found in, for example, A. n. mackaii Cotton, found at sheltered locations, such as at the heads of sea lochs in Scotland and Ireland. A. nodosum is found on sheltered sites on shores in the midlittoral, where it can become the dominant species in the littoral zone. The species is found in a range of coastal habitats from sheltered estuaries to moderately exposed coasts, it dominates the intertidal zone. However, it is found on exposed shores, if it is found, the fronds are small and badly scratched; this seaweed grows quite 0.5% per day, carrying capacity is about 40 kg wet weight per square meter, it may live for 10–15 years. It may overlap in distribution with Fucus vesiculosus and Fucus serratus, its distribution is limited by salinity, wave exposure, temperature and general stress. It may take five years before becoming fertile.
Phlorotannins in A. nodosum act as chemical defenses against the marine herbivorous snail, Littorina littorea. Polysiphonia lanosa T. A. Christensen is a small red alga found growing in dense tufts on Ascophyllum whose rhizoids penetrate the host, it is considered by some as parasitic. This species has been recorded in Europe from Ireland, the Faroe Islands, Norway and Isle of Man and North America from the Bay of Fundy, Nova Scotia, Baffin Island, Hudson Strait and Newfoundland, it has been recorded as an accidental introduction near San Francisco and eradicated as a potential invasive species. A. nodosum is harvested for use in alginates and the manufacture of seaweed meal for animal and human consumption. It has long been used as an organic and mainstream fertilizer for many varieties of crops due to its combination of both macronutrients, micronutrients, it contains cytokinins, auxin-like gibberellins, mannitol, organic acids, amino acids, proteins which are all beneficial and used in agriculture.
Ireland and Norway have provided the world's principal alginate supply. A. Nodosum is used as packaging material for baitworm and lobster shipments from New England to various domestic and international locations. Ascophyllum itself has been introduced to California, several species found in baitworm shipments, including Carcinus maenas and Littorina saxatilis, may have been introduced to the San Francisco Bay region this way; because the age of the different parts of A. nodosum can be identified by its shoots, it has been used to monitor concentrations of heavy metals in seawater. A concentration factor for zinc has been reported to be of the order 104. A. nodosum contains the phlorotannins tetraphlorethol C and tetrafucol A. Controversy exists over impacts of commercial harvesting of A. nodosum for use in garden or crop fertilizers and livestock feed supplements in North America and Europe. Some research has been focused on impact on intertidal zone communities. Opponents of its wild harvest point to the algae's high habitat value for over 100 marine species, including benthic invertebrates, commercially important fish, wild ducks and seabirds.
Shoreland owners in Maine, as well as federal and local agencies in the United States, have placed their conservation lands off limits to rockweed removal. Rockweed harvesters point to the value of the seasonal jobs created by the harvest operation, highlight the differences in impact of different harvesting methods such as machine v hand harvesting; this article incorporates CC BY-2.5 text from the reference M. D. Guiry & G. M. Guiry. "Knotted wrack Ascophyllum nodosum". AlgaeBase: listing the world's algae. Galway: AlgaeBase. J. M. Hill & N. White. "Knotted wrack Ascophyllum nodosum". Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme. Plymouth: Marine Biological Association of the United Kingdom. O. Morton. "Ascophyllum nodosum — knotted wrack". Priority species in Northern Ireland. Ulster Museum. Retrieved 2007-01-30
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae and protozoa. Bacterial spores are not part of a sexual cycle but are resistant structures used for survival under unfavourable conditions. Myxozoan spores release amoebulae into their hosts for parasitic infection, but reproduce within the hosts through the pairing of two nuclei within the plasmodium, which develops from the amoebula. Spores are haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which goes on to produce gametes. Two gametes fuse to form a zygote; this cycle is known as alternation of generations. The spores of seed plants, are produced internally and the megaspores, formed within the ovules and the microspores are involved in the formation of more complex structures that form the dispersal units, the seeds and pollen grains.
The term spore derives from the ancient Greek word σπορά spora, meaning "seed, sowing", related to σπόρος sporos, "sowing," and σπείρειν speirein, "to sow." In common parlance, the difference between a "spore" and a "gamete" is that a spore will germinate and develop into a sporeling, while a gamete needs to combine with another gamete to form a zygote before developing further. The main difference between spores and seeds as dispersal units is that spores are unicellular, while seeds contain within them a multicellular gametophyte that produces a developing embryo, the multicellular sporophyte of the next generation. Spores germinate to give rise to haploid gametophytes, while seeds germinate to give rise to diploid sporophytes. Vascular plant spores are always haploid. Vascular plants heterosporous. Plants that are homosporous produce spores of the same type. Heterosporous plants, such as seed plants, spikemosses and ferns of the order Salviniales produce spores of two different sizes: the larger spore in effect functioning as a "female" spore and the smaller functioning as a "male".
Such plants give rise to the two kind of spores from within separate sporangia, either a megasporangium that produces megaspores or a microsporangium that produces microspores. In flowering plants, these sporangia occur within anthers, respectively. Fungi produce spores, as a result of sexual, or asexual, reproduction. Spores are haploid and grow into mature haploid individuals through mitotic division of cells. Dikaryotic cells result from the fusion of two haploid gamete cells. Among sporogenic dikaryotic cells, karyogamy occurs to produce a diploid cell. Diploid cells undergo meiosis to produce haploid spores. Spores can be classified in several ways: In fungi and fungus-like organisms, spores are classified by the structure in which meiosis and spore production occurs. Since fungi are classified according to their spore-producing structures, these spores are characteristic of a particular taxon of the fungi. Sporangiospores: spores produced by a sporangium in many fungi such as zygomycetes.
Zygospores: spores produced by a zygosporangium, characteristic of zygomycetes. Ascospores: spores produced by an ascus, characteristic of ascomycetes. Basidiospores: spores produced by a basidium, characteristic of basidiomycetes. Aeciospores: spores produced by an aecium in some fungi such as rusts or smuts. Urediniospores: spores produced by a uredinium in some fungi such as rusts or smuts. Teliospores: spores produced by a telium in some fungi such as rusts or smuts. Oospores: spores produced by an oogonium, characteristic of oomycetes. Carpospores: spores produced by a carposporophyte, characteristic of red algae. Tetraspores: spores produced by a tetrasporophyte, characteristic of red algae. Chlamydospores: thick-walled resting spores of fungi produced to survive unfavorable conditions. Parasitic fungal spores may be classified into internal spores, which germinate within the host, external spores called environmental spores, released by the host to infest other hosts. Meiospores: spores produced by meiosis.
Examples are the precursor cells of gametophytes of seed plants found in flowers or cones, the zoospores produced from meiosis in the sporophytes of algae such as Ulva. Microspores: meiospores that give rise to a male gametophyte. Megaspores: meiospores that give rise to a female gametophyte. Mitospores: spores produced by mitosis. Fungi in which only mitospores are found are called "mitosporic fungi" or "anamorphic fungi", are classified under the taxon Deuteromycota. Spores can be differentiated by. Zoospores: mobile spores that move by means of one or more flagella, can be found in some algae and fungi. Aplanospores: immobile spores that may potentially grow flagella. Autospores: immobile spores that cannot develop flagella. Ballistospores: spores that are forcibly discharged or ejected from the fungal fruiting body as the result of an internal force, such as buildup of pressure. Most basidiospores are ballistospores, another notable e