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56-702: Perch , pike , lenok , grayling , taimen and whitefish are also found in the waters of the Tsipa. The Tsipa is a western, left tributary of the Vitim. It has its sources in a tarn of the Southern Muya Range , in the area where this range merges with the Ikat Range . It is known as "Upper Tsipa" (Верхняя Ципа) in its upper course until its mouth in lake Baunt in the Baunt Depression in

112-455: A ZW sex-determination system , the W chromosome carries factors responsible for female development, and default development is male. In this case, ZZ individuals are male and ZW are female. It is the female gamete that determines the sex of the offspring. This system is used by birds, some fish, and some crustaceans . The majority of butterflies and moths also have a ZW sex-determination system. Females can have Z, ZZW, and even ZZWW. In

168-418: A plant species, the diploid organism produces a type of haploid spore by meiosis that is capable of undergoing repeated cell division to produce a multicellular haploid organism. In either case, the gametes may be externally similar ( isogamy ) as in the green alga Ulva or may be different in size and other aspects ( anisogamy ). The size difference is greatest in oogamy , a type of anisogamy in which

224-448: A spermatozoon (produced in vertebrates within the testes ), is a small cell containing a single long flagellum which propels it. Spermatozoa are extremely reduced cells, lacking many cellular components that would be necessary for embryonic development. They are specialized for motility, seeking out an egg cell and fusing with it in a process called fertilization . Female gametes are egg cells. In vertebrates, they are produced within

280-414: A byproduct of these processes, may provide long-term advantages in those sexual lineages that favor outcrossing . The biological cause of an organism developing into one sex or the other is called sex determination . The cause may be genetic, environmental, haplodiploidy , or multiple factors. Within animals and other organisms that have genetic sex-determination systems, the determining factor may be

336-460: A common name, to be considered a true perch, the fish must be of the family Percidae. Most authorities recognize three species within the perch genus: Perch have a long and round body shape which allows for fast swimming in the water. True perch have "rough" or ctenoid scales. Perch have paired pectoral and pelvic fins , and two dorsal fins , the first one spiny and the second soft. These two fins can be separate or joined. The head consists of

392-444: A group becomes female; when a dominant female is absent, then her partner changes sex from male to female. In many wrasses the opposite is true: the fish are initially female and become male when they reach a certain size. Sequential hermaphroditism also occurs in plants such as Arisaema triphyllum . Many reptiles , including all crocodiles and most turtles , have temperature-dependent sex determination . In these species,

448-453: A male and a female gamete fuse to form a zygote , which develops into an offspring that inherits traits from each parent. By convention, organisms that produce smaller, more mobile gametes ( spermatozoa , sperm ) are called male , while organisms that produce larger, non-mobile gametes ( ova , often called egg cells) are called female . An organism that produces both types of gamete is hermaphrodite . In non-hermaphroditic species,

504-409: A more brown-red colored urogenital opening compared to females. The esophagus is a flexible tube that goes from the mouth to the stomach. The stomach is connected to the intestine via the pyloric sphincter . The intestines of perch consist of the small intestine and large intestine ; the intestines have many pyloric caeca and a spiral value , the small intestine consists of a part called

560-431: A partner of the opposite sex for mating . Animals which live in the water can mate using external fertilization , where the eggs and sperm are released into and combine within the surrounding water. Most animals that live outside of water, however, use internal fertilization , transferring sperm directly into the female to prevent the gametes from drying up. In most birds, both excretion and reproduction are done through

616-758: A popular sport fish species. They are known to put up a fight, and to be good for eating. They can be caught with a variety of methods, including float fishing, lure fishing, and legering . Fly fishing for perch using patterns that imitate small fry or invertebrates can be successful. The record weight for this fish in Britain is 2.81 kg (6 lb 3 oz), the Netherlands 3.05 kg (6 lb 11 + 1 ⁄ 2  oz), and in America 2.83 kg (6 lb 4 oz). The biggest recorded catch in Sweden

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672-536: A single X chromosome develop as male, while those with two develop as female. In the nematode Caenorhabditis elegans , most worms are self-fertilizing hermaphrodites with an XX karyotype, but occasional abnormalities in chromosome inheritance can give rise to individuals with only one X chromosome—these XO individuals are fertile males (and half their offspring are male). In the ZO sex-determination system , males have two Z chromosomes whereas females have one. This system

728-418: A single posterior opening, called the cloaca —male and female birds touch cloaca to transfer sperm, a process called "cloacal kissing". In many other terrestrial animals, males use specialized sex organs to assist the transport of sperm—these male sex organs are called intromittent organs . In humans and other mammals, this male organ is known as the penis , which enters the female reproductive tract (called

784-419: A small, motile gamete combines with a much larger, non-motile gamete. In anisogamic organisms, by convention, the larger gamete (called an ovum , or egg cell) is considered female, while the smaller gamete (called a spermatozoon, or sperm cell) is considered male. An individual that produces large gametes is female, and one that produces small gametes is male. An individual that produces both types of gamete

840-490: A species may be physically alike (sexual monomorphism) or have physical differences ( sexual dimorphism ). In sexually dimorphic species, including most birds and mammals, the sex of an individual is usually identified through observation of that individual's sexual characteristics . Sexual selection or mate choice can accelerate the evolution of differences between the sexes. The terms male and female typically do not apply in sexually undifferentiated species in which

896-410: A stage of genetic recombination via chromosomal crossover , in which regions of DNA are exchanged between matched pairs of chromosomes, to form new chromosomes, each with a new combination of the genes of the parents. Then the chromosomes are separated into single sets in the gametes. When gametes fuse during fertilization, the resulting zygote has half of the genetic material of the mother and half of

952-439: A two-chambered heart consisting of four compartments: the sinus venous , one atrium , one ventricle , and conus . Perch have a swim bladder that helps control buoyancy or floating within the water, the swim bladder is only found in bony fish. In perch, the duct connecting the swim bladder to the pharynx is closed so air is unable to pass through from the mouth, these fish are called physoclists . Specifically in perch,

1008-493: Is 3.15 kg (6lb 15oz) in 1985. Perch grow to around 50 cm (20 in) and 2.3 kg (5 lb) or more, but the most common size caught are around 30 cm (1 ft) and 450 g (1 lb) or less and anything over 40 cm (16 in) and 900 g (2 lb) is considered a prize catch. Sex Sex is the biological trait that determines whether a sexually reproducing organism produces male or female gametes . During sexual reproduction,

1064-433: Is a hermaphrodite . In some species, a hermaphrodite can self-fertilize and produce an offspring on its own. Most sexually reproducing animals spend their lives as diploid, with the haploid stage reduced to single-cell gametes. The gametes of animals have male and female forms— spermatozoa and egg cells, respectively. These gametes combine to form embryos which develop into new organisms. The male gamete,

1120-491: Is a stub . You can help Misplaced Pages by expanding it . This article related to a river in the Russian Far East is a stub . You can help Misplaced Pages by expanding it . Perch Perch is a common name for freshwater fish from the genus Perca , which belongs to the family Percidae of the large order Perciformes . The name comes from Greek : πέρκη , romanized :  perke , meaning

1176-430: Is absent. About 99% of vertebrates are gonochoric, and the remaining 1% that are hermaphroditic are almost all fishes. The majority of plants are bisexual , either hermaphrodite (with both stamens and pistil in the same flower) or monoecious . In dioecious species male and female sexes are on separate plants. About 5% of flowering plants are dioecious, resulting from as many as 5000 independent origins. Dioecy

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1232-403: Is also the first step towards sexual dimorphism and influenced the evolution of various sex differences. It is unclear whether anisogamy first led to the evolution of hermaphroditism or the evolution of gonochorism , and the evolution of sperm and eggs has left no fossil evidence. A 1.2 billion year old fossil from Bangiomorpha pubescens has provided the oldest fossil record for

1288-714: Is carried by wind to neighboring plants. Some flowering plants have heavier, sticky pollen that is specialized for transportation by insects or larger animals such as hummingbirds and bats , which may be attracted to flowers containing rewards of nectar and pollen. These animals transport the pollen as they move to other flowers, which also contain female reproductive organs, resulting in pollination . Most species of fungus can reproduce sexually and have life cycles with both haploid and diploid phases. These species of fungus are typically isogamous , i.e. lacking male and female specialization. One haploid fungus grows into contact with another, and then they fuse their cells. In some cases,

1344-423: Is common in gymnosperms , in which about 65% of species are dioecious, but most conifers are monoecious. It is generally accepted that isogamy was ancestral to anisogamy and that anisogamy evolved several times independently in different groups of eukaryotes, including protists, algae, plants, and animals. The evolution of anisogamy is synonymous with the origin of male and the origin of female . It

1400-439: Is exclusive to eukaryotes . Genetic traits are encoded in the deoxyribonucleic acid (DNA) of chromosomes . The eukaryote cell has a set of paired homologous chromosomes , one from each parent, and this double-chromosome stage is called " diploid ". During sexual reproduction, a diploid organism produces specialized haploid sex cells called gametes via meiosis , each of which has a single set of chromosomes. Meiosis involves

1456-408: Is found in other organisms, including insects like the common fruit fly , and some plants. In some cases, it is the number of X chromosomes that determines sex rather than the presence of a Y chromosome. In the fruit fly individuals with XY are male and individuals with XX are female; however, individuals with XXY or XXX can also be female, and individuals with X can be males. In birds, which have

1512-411: Is found in several species of moths. For many species, sex is not determined by inherited traits, but instead by environmental factors such as temperature experienced during development or later in life. In the fern Ceratopteris and other homosporous fern species, the default sex is hermaphrodite, but individuals which grow in soil that has previously supported hermaphrodites are influenced by

1568-421: Is often distinct from sex differentiation . Sex determination is the designation for the development stage towards either male or female while sex differentiation is the pathway towards the development of the phenotype . Humans and most other mammals have an XY sex-determination system : the Y chromosome carries factors responsible for triggering male development, making XY sex determination mostly based on

1624-409: Is used by some insect species to inseminate females through a wound in the abdominal cavity—a process detrimental to the female's health. Like animals, land plants have specialized male and female gametes. In seed plants , male gametes are produced by reduced male gametophytes that are contained within pollen which have hard coats that protect the male gamete forming cells during transport from

1680-509: The XO sex-determination system , males have one X chromosome (XO) while females have two (XX). All other chromosomes in these diploid organisms are paired, but organisms may inherit one or two X chromosomes. This system is found in most arachnids , insects such as silverfish ( Apterygota ), dragonflies ( Paleoptera ) and grasshoppers ( Exopterygota ), and some nematodes, crustaceans, and gastropods. In field crickets , for example, insects with

1736-399: The anthers to the stigma . The female gametes of seed plants are contained within ovules . Once fertilized, these form seeds which, like eggs, contain the nutrients necessary for the initial development of the embryonic plant. The flowers of flowering plants contain their sexual organs. Most flowering plants are hermaphroditic, with both male and female parts in the same flower or on

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1792-403: The duodenum . The spleen is located after the stomach and before the spiral value. The spleen is connected to the circulatory system , not part of the digestive tract . The liver is composed of three lobes: one small lobe (includes the gall bladder) and two large lobes. Perch have long and narrow kidneys that contain clusters of nephrons which empty into the mesonephric duct . They have

1848-401: The ovaries . They are large, immobile cells that contain the nutrients and cellular components necessary for a developing embryo. Egg cells are often associated with other cells which support the development of the embryo, forming an egg . In mammals, the fertilized embryo instead develops within the female, receiving nutrition directly from its mother. Animals are usually mobile and seek out

1904-421: The pheromone antheridiogen to develop as male. The bonelliidae larvae can only develop as males when they encounter a female. Some species can change sex over the course of their lifespan, a phenomenon called sequential hermaphroditism . Teleost fishes are the only vertebrate lineage where sequential hermaphroditism occurs. In clownfish , smaller fish are male, and the dominant and largest fish in

1960-427: The skull (formed from loosely connected bones), eyes , mouth , operculum , gills , and a pair of nostrils (which has no connection to the oral cavity). They have small brush-like teeth across their jaws and on the roof of their mouth. The gills are located under the operculum on both sides of the head and are used to extract oxygen molecules from water and expel carbon dioxide; the gills have gill rakers inside

2016-475: The type species of this genus, the European perch ( P. fluviatilis ). Many species of freshwater game fish more or less resemble perch, but belong to different genera. In fact, the exclusively saltwater-dwelling red drum (which belong to a different order Acanthuriformes ) is often referred to as a "red perch", though by definition perch are freshwater species. Though many fish are referred to as perch as

2072-450: The vagina ) to achieve insemination —a process called sexual intercourse . The penis contains a tube through which semen (a fluid containing sperm) travels. In female mammals, the vagina connects with the uterus , an organ which directly supports the development of a fertilized embryo within (a process called gestation ). Because of their motility, animal sexual behavior can involve coercive sex. Traumatic insemination , for example,

2128-530: The United States in freshwater ponds, lakes, streams, or rivers. These fish can be found in freshwater all over the world, and are known to inhabit the Great Lake region, in particular Lake Erie . These fish inhabit bodies of water where vegetation and debris is readily accessible. In the spring when the perch chooses to spawn , they use vegetation to conceal their eggs from predators. Perch are

2184-420: The carpel, where it delivers male gamete nuclei to fertilize an ovule that eventually develops into a seed. Some hermaphroditic plants are self-fertile, but plants have evolved multiple different self-incompatibility mechanisms to avoid self-fertilization, involving sequential hermaphroditism , molecular recognition systems and morphological mechanisms such as heterostyly . In pines and other conifers ,

2240-406: The carpels are ovules which develop into seeds after fertilization. The male parts of the flower are the stamens : these consist of long filaments arranged between the pistil and the petals that produce pollen in anthers at their tips. When a pollen grain lands upon the stigma on top of a carpel's style, it germinates to produce a pollen tube that grows down through the tissues of the style into

2296-481: The differentiation of male and female reproductive types and shown that sexes evolved early in eukaryotes. Studies on green algae have provided genetic evidence for the evolutionary link between sexes and mating types . The original form of sex was external fertilization . Internal fertilization , or sex as we know it, evolved later and became dominant for vertebrates after their emergence on land . The most basic role of meiosis appears to be conservation of

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2352-411: The father. The combination of chromosomal crossover and fertilization , bringing the two single sets of chromosomes together to make a new diploid zygote , results in a new organism that contains a different set of the genetic traits of each parent. In animals , the haploid stage only occurs in the gametes, the sex cells that fuse to form a zygote that develops directly into a new diploid organism. In

2408-604: The fusion is asymmetric, and the cell which donates only a nucleus (and no accompanying cellular material) could arguably be considered male. Fungi may also have more complex allelic mating systems, with other sexes not accurately described as male, female, or hermaphroditic. Some fungi, including baker's yeast , have mating types that determine compatibility. Yeasts with the same mating types will not fuse with each other to form diploid cells, only with yeast carrying another mating type. Many species of higher fungi produce mushrooms as part of their sexual reproduction . Within

2464-408: The gas bladder can vary from 12% to 25% of oxygen and 1.4% to 2.9% of carbon dioxide gas. Perch reproductive organs include either a pair of testes (sperm-producing) or a pair of ovaries (egg-producing). Perch are classified as carnivores , choosing waters where smaller fish, shellfish , zooplankton, and insect larvae are abundant. The yellow perch can be found in the central parts of

2520-412: The individuals are isomorphic (look the same) and the gametes are isogamous (indistinguishable in size and shape), such as the green alga Ulva lactuca . Some kinds of functional differences between individuals, such as in fungi , may be referred to as mating types . Sexual reproduction, in which two individuals produce an offspring that possesses a selection of the genetic traits of each parent,

2576-422: The integrity of the genome that is passed on to progeny by parents. The two most fundamental aspects of sexual reproduction , meiotic recombination and outcrossing , are likely maintained respectively by the adaptive advantages of recombinational repair of genomic DNA damage and genetic complementation which masks the expression of deleterious recessive mutations . Genetic variation , often produced as

2632-401: The mountains it turns again northeast and finally it meets the Vitim about 120 km (75 mi) southeast of Taksimo . Its main tributaries are the 329 km (204 mi) long Tsipikan and the 374 km (232 mi) long Amalat from the right. There are 3,227 lakes in the Tsipa basin, with a total area of 478 km (185 sq mi). This Buryatia location article

2688-400: The mouth. External anatomy can be used to determine the sex of perch in multiple ways. Perch have two posterior openings located on their abdomen, the anal and urogenital . In males, the shape of the urogenital opening is round and larger than the anal opening. In females, the urogenital opening is often a V- or U-shape which is a similar size to the anal opening. Also, males usually have

2744-455: The mushroom, diploid cells are formed, later dividing into haploid spores . A sexual system is a distribution of male and female functions across organisms in a species. Approximately 95% of animal species have separate male and female individuals, and are said to be gonochoric . About 5% of animal species are hermaphroditic. This low percentage is partially attributable to the very large number of insect species, in which hermaphroditism

2800-673: The northeastern part of the Vitim Plateau , near the Bolshoy Khapton Range. The river flows out of the lake in a NNE direction and slows down meandering across a swampy basin where there are many lakes, the largest of which is Busani . Then it makes a sharp bend to the west of the Bambuyka and turns south, crossing the Babanty Range through a narrow valley where it flows fast, forming rapids . After leaving

2856-432: The presence of a sex chromosome . In plants that are sexually dimorphic, such as Ginkgo biloba , the liverwort Marchantia polymorpha or the dioecious species in the flowering plant genus Silene , sex may also be determined by sex chromosomes. Non-genetic systems may use environmental cues, such as the temperature during early development in crocodiles , to determine the sex of the offspring. Sex determination

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2912-605: The presence or absence of the Y chromosome . It is the male gamete that determines the sex of the offspring. In this system XX mammals typically are female and XY typically are male. However, individuals with XXY or XYY are males, while individuals with X and XXX are females. Unusually, the platypus , a monotreme mammal, has ten sex chromosomes; females have ten X chromosomes, and males have five X chromosomes and five Y chromosomes. Platypus egg cells all have five X chromosomes, whereas sperm cells can either have five X chromosomes or five Y chromosomes. XY sex determination

2968-404: The same plant in single sex flowers, about 5% of plant species have individual plants that are one sex or the other. The female parts, in the center of a hermaphroditic or female flower, are the pistils , each unit consisting of a carpel , a style and a stigma . Two or more of these reproductive units may be merged to form a single compound pistil , the fused carpels forming an ovary . Within

3024-647: The sex of an individual is determined through one of several biological sex-determination systems . Most mammalian species have the XY sex-determination system , where the male usually carries an X and a Y chromosome (XY), and the female usually carries two X chromosomes (XX). Other chromosomal sex-determination systems in animals include the ZW system in birds, and the XO system in some insects. Various environmental systems include temperature-dependent sex determination in reptiles and crustaceans. The male and female of

3080-524: The sex organs are produced within cones that have male and female forms. Male cones are smaller than female ones and produce pollen, which is transported by wind to land in female cones. The larger and longer-lived female cones are typically more durable, and contain ovules within them that develop into seeds after fertilization. Because seed plants are immobile, they depend upon passive methods for transporting pollen grains to other plants. Many, including conifers and grasses, produce lightweight pollen which

3136-624: The temperature experienced by the embryos during their development determines their sex. In some turtles, for example, males are produced at lower temperatures than females; but Macroclemys females are produced at temperatures lower than 22 °C or above 28 °C, while males are produced in between those temperatures. Certain insects, such as honey bees and ants , use a haplodiploid sex-determination system . Diploid bees and ants are generally female, and haploid individuals (which develop from unfertilized eggs) are male. This sex-determination system results in highly biased sex ratios , as

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