- Compatible fish
- Reviews 0
- Questions about the product 0
Clownfish family (Amphiprionidae)
A small family of bright coral fish, numbering only 2 genera and about 30 species. They all inhabit the warm tropical waters of the Indian and Pacific Oceans, inhabiting exclusively coral reefs. Amphiprio live in symbiosis with anemones - large sea anemones. The poisonous tentacles of these anemones are not dangerous for clowns, between them they hide from predators. And for protection, the amphiprion pays for the anemones with pieces of food. Usually, the union of clown fish and anemone is species-specific - fish of certain species settle only in certain anemones.
They are small fish with a massive body, from 9 to 17 centimeters in length. Amphiprionaceae differ from their close relatives, the pomacentrae, with which they are often combined into one family, by small scales and a serrated outer edge of the operculum. Their laterally flattened body has an oval shape, at the end of a rounded muzzle there is a small mouth. Well-developed pectoral fins are rounded, always brightly colored, in contrast to the pomacenter fins, the pectoral fins of which are practically transparent. The color is usually bright, combining red, black, white. The pattern consists of wide contrasting light transverse stripes, sometimes only one thin stripe remains against the general bright background. Many species have different color variations, and age-related dimorphism is also common.
Clowns are without doubt one of the most popular coral fish in marine aquariums. They are small, non-aggressive, and the only necessary condition for their life is the presence of a suitable type of anemone. In a spacious aquarium, you can keep both clowns of the same species, as well as several different species. They get along well with other fish, as they are reliably protected from encroachments by their poisonous hosts. When kept in pairs, clowns often even breed in captivity. Many species have long been introduced into crops, and there are mainly bred animals on sale.
- 1 (current)
- 1 (current)
Number of species in "sister" taxa
|genus||Honeydew variegated||Bolemoreus||Nyári & Joseph||2011|
|suborder / suborder||Singers||Oscines|
|detachment / order||Passerines||Passeriformes|
|superorder / superorder||New Sky Birds (Typical Birds)||Neognathae||Pycroft||1900|
|infraclass||Real birds (Fan-tailed birds)||Neornithes||Gadow||1893|
|subclass||Cilegrud Birds (Fantail Birds)||Carinatae Ornithurae (Neornithes) Ornithurae (Neornithes)||Merrem||1813|
|subtype / subdivision||Vertebrates (Cranial)||Vertebrata (Craniata)||Cuvier||1800|
|type / department||Chordates||Chordata|
|section||Bilaterally symmetrical (Three-layer)||Bilateria (Triploblastica)|
Rainforest passerines skip the breeding season if it falls in a dry year
Thomas E. Martin and James C. Mouton of the University of Montana analyzed the reproduction and survival data of 38 rainforest passerine bird species in normal and dry years. The material was collected in Venezuela (from 2002 to 2008, the dry year was 2008) and Malaysia (from 2009 to 2018, the dry year was 2016).
Observations have shown that drought significantly reduces the level of bird reproduction in tropical forests on both continents. In the 18 studied species from Venezuela, it decreased on average by 51.9 percent, and in 20 species from Malaysia - by 36.3 percent. For example, in a normal year, Martin and Mouton found 65 used nests of gray-breasted forest wrens (Henicorhina leucophrys) in the model area in Venezuela, and only seven in a year with a lack of rainfall. At the same time, the number of adult individuals of different bird species in the studied territories in different years remained approximately the same, which indicates the refusal of some individuals from reproduction during a drought.
Male birds have to choose between attractive coloration and beauty of the song.
Sexual selection, which is based on the struggle for reproductive success, can potentially act as a powerful factor in speciation. This role is supported by mathematical models and individual works, but many attempts at a broader analysis did not reveal the expected relationship. A team of British bird watchers asked the question: Is it always correct in such studies to assess the power of sexual selection? It is generally assumed that sexual selection will affect all traits associated with mate competition and fertility. Often, sexual dimorphism in color is used as an indicator of sexual selection - differences in the color of males and females. However, the visual channel is not the only one that can be used to attract a partner. Thus, in many birds, acoustic signals serve this purpose. Using the order of Passeriformes (Passeriformes) as an example, the authors of the new study demonstrated that there is a compromise between the development of the two systems for attracting a partner: the dignity of males is mainly manifested either in vocalization or in appearance. This means that it is simply impossible to assess the role of sexual selection based on only one group of traits.
Songbirds have an extra chromosome
In songbirds (suborder Passeri), most cells in the body contain 40 pairs of chromosomes. In 1998, an additional chromosome in the germ cells was found in zebra finches, and in 2014 in their relatives, Japanese finches. Then this find was viewed as a genetic curiosity. It was present in the germ cells of females, as well as in the precursors of the germ cells of males, but it was also "thrown out" from them during the maturation of sperm.
A group led by Pavel Borodin from the Novosibirsk Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences studied 14 species of songbirds from nine different families, as well as eight species of birds that do not belong to songbirds - geese, ducks, chickens, pigeons, gulls, swifts, falcons, parrots. In all singing species, an additional chromosome was found in the germ cells, while in other species it was not.
“We found that, unlike other birds and most other animals, all the species of songbirds studied contain a different number of chromosomes in somatic and germ cells. All of them, literally every bird studied, have an extra chromosome in the sex cells (COD). We have shown that the most common birds have an extra chromosome: siskins, swallows, tits, flycatchers, larks and rooks (the rook also belongs to songbirds). At the same time, the additional chromosome is absent in birds of all other orders, ”said Borodin N + 1.
He and his colleagues isolated and deciphered separate sections of additional chromosomes in the siskin, pale swallow, zebra finch and Japanese finch and found there numerous fragments of functional genes of the main genome. Simultaneously with Borodin's group, two independent groups of researchers discovered (1, 2) that the chromosomes in the germ cells of the zebra finch contain genes that are similar, but not identical to the genes of somatic cells. Some of these genes are present in multiple copies and produce RNA and proteins in the testes and ovaries of sexually mature birds.
“We hypothesize that COD emerged as an additional parasitic microchromosome in the common ancestor of all songbirds about 35 million years ago and underwent significant changes in size and genetic content, evolving from a 'genomic parasite' into an important component of the germ cell genome. We do not yet know why it is needed and what advantages it can give to its carriers. Perhaps it was she who allowed songbirds to become the most numerous suborder (more than 5 thousand out of a total of 9-10 thousand bird species), create many forms, beautiful and amazing, and capture many ecological niches on all continents, ”the scientist noted.
Scientists believe songbird COD can be seen as an evolutionary attempt to locally and temporarily increase the copy number of the desired genes without increasing the overall genome size and body weight. Birds need extra copies of genes in the germ cells during a short breeding period, just to make a lot of sperm and load the oocytes with a lot of proteins. And copies of these genes are not needed all year round and in all somatic cells.
“If we take into account that the COD of swallows, tits, warblers and many other small birds weighs about 0.1 picograms, and the entire genome is 1.2 picograms, it turns out to be a rather heavy burden to carry, and not just to carry, but also feed, water and multiply throughout life in all cells of the body. It is more convenient to store a set of genes for reproduction in a small toolbox, ”Borodin said.
Variegated, or Carolinian grebe (Podilymbus podiceps) found in temperate parts of North America, West Indies, throughout Central and significant parts of South America. This most common of American grebes lives mainly in shallow water bodies with stagnant water or weak currents: ponds, swamps, streams. It is rare in salty water bodies.
The characteristic features of this species are: a light, short and thick beak with a dark transverse stripe, a short metatarsus and the absence of any decorating feathers on the head. The upper side of this bird is brown, the lower is grayish-white, the head and neck are brownish-gray, with a black spot on the throat. The size of an adult is 31-38 cm, weight - 253-568 g. The small, tightly knit body of the variegated toadstool is in sharp contrast to its large head and rather massive beak. The beak resembles that of a chicken, its height is about half the length.
Variegated toadstool is mostly nocturnal. Her voice is a series of merging whistles. She arranges nests on the water. He rarely flies, in case of danger he prefers to dive under water. The Carolinian grebe feeds mainly on aquatic invertebrates, sometimes on small tailless amphibians.
Many variegated toadstools are sedentary - they spend both summer and winter in the same section of the reservoir. In winter, they can be seen in flocks, however, with the arrival of spring, the flocks break up into pairs, occupying separate territories. From the northern regions, where water bodies are covered with ice in winter, toadstools fly away to more southern regions or move to non-freezing areas near the sea coasts.