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Nuptial Gift
A nuptial gift is a nutritional gift given by one partner in some animals' sexual reproduction practices. Formally, a nuptial gift is a material presentation to a recipient by a donor during or in relation to sexual intercourse that is not simply gametes in order to improve the reproductive fitness of the donor. Often, such a gift will improve the fitness of the recipient as well. This definition implies neutral gifts, costly gifts and beneficial gifts regarding the fitness of the recipient. Nuptial gifting is at the intersection of sexual selection, nutritional ecology, and life history theory, creating a link between the three. Edible and inedible nuptial gifts Many nuptial gifts are a source of nutrition for the recipient. In many species of animals, including birds, insects, and spiders, this takes the form of a food item that is transferred from a male to a female just prior to copulation. This is a behavior known as courtship feeding. Inedible tokens may include items ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes ( diploid). This is typical in animals, though the number of chromosome sets and how that number changes in sexual reproduction varies, especially among plants, fungi, and other eukaryotes. Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. Sexual reproduction also occurs in some unicellular eukaryotes. Sexual reproduction does not occur in prokaryotes, unicellular organisms without cell nuclei, such bacteria and archaea. However, some process in bacteria may be considered analogous to sexual reproduction in that they incorporate new genetic information, including bacterial conjugation, transform ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermatophore
A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores may additionally contain nourishment for the female, in which case it is called a nuptial gift, as in the instance of bush crickets. In the case of the toxic moth '' Utetheisa ornatrix'', the spermatophore includes sperm, nutrients, and pyrrolizidine alkaloids which prevent predation because it is poisonous to most organisms. However, in some species such as the Edith's checkerspot butterfly, the "gift" provides little nutrient value. The weight of the spermatophore transferred at mating has little effect on female reproductive output. Arthropods Spermatophores are the norm in arachnids and several soil arthropods. In various insects, such as bush crickets, the spermatophore is often surrounded by a proteinaceous spermatophyla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mate Choice
Mate choice is one of the primary mechanisms under which evolution can occur. It is characterized by a "selective response by animals to particular stimuli" which can be observed as behavior.Bateson, Paul Patrick Gordon. "Mate Choice." Mate Choice, Cambridge University Press, 1985 In other words, before an animal engages with a potential mate, they first evaluate various aspects of that mate which are indicative of quality—such as the resources or phenotypes they have—and evaluate whether or not those particular trait(s) are somehow beneficial to them. The evaluation will then incur a response of some sort. These mechanisms are a part of evolutionary change because they operate in a way that causes the qualities that are desired in a mate to be more frequently passed on to each generation over time. For example, if female peacocks desire mates who have a colourful plumage, then this trait will increase in frequency over time as male peacocks with a colourful plumage will hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extended Phenotype
''The Extended Phenotype'' is a 1982 book by the evolutionary biologist Richard Dawkins, in which the author introduced a biological concept of the same name. The main idea is that phenotype should not be ''limited'' to biological processes such as protein biosynthesis or tissue growth, but ''extended'' to include all effects that a gene has on its environment, inside or outside the body of the individual organism. Dawkins considers ''The Extended Phenotype'' to be a sequel to ''The Selfish Gene'' (1976) aimed at professional biologists, and as his principal contribution to evolutionary theory. Summary Genes as the unit of selection in evolution The central thesis of ''The Extended Phenotype,'' and of its predecessor by the same author ''The'' ''Selfish Gene'', is that individual organisms are not the true units of natural selection. Instead, the gene — or the ‘active, germ-line replicator’ — is the unit upon which the forces of evolutionary selection and adaptatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insects
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Their blood is not totally contained in vessels; some circulates in an open cavity known as the haemocoel. Insects are the most diverse group of animals; they include more than a million described species and represent more than half of all known living organisms. The total number of extant species is estimated at between six and ten million; In: potentially over 90% of the animal life forms on Earth are insects. Insects may be found in nearly all environments, although only a small number of species reside in the oceans, which are dominated by another arthropod group, crustaceans, which recent research has indicated insects are nested within. Nearly all insects hatch from eggs. Inse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lizards
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia although some lizards are more closely related to these two excluded groups than they are to other lizards. Lizards range in size from chameleons and geckos a few centimeters long to the 3-meter-long Komodo dragon. Most lizards are quadrupedal, running with a strong side-to-side motion. Some lineages (known as " legless lizards"), have secondarily lost their legs, and have long snake-like bodies. Some such as the forest-dwelling ''Draco'' lizards are able to glide. They are often territorial, the males fighting off other males and signalling, often with bright colours, to attract mates and to intimidate rivals. Lizards are mainly carnivorous, often being sit-and-wait predators; many smaller species eat insects, while the Komodo eats mammals as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birds
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimmin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodents
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are native to all major land masses except for New Zealand, Antarctica, and several oceanic islands, though they have subsequently been introduced to most of these land masses by human activity. Rodents are extremely diverse in their ecology and lifestyles and can be found in almost every terrestrial habitat, including human-made environments. Species can be arboreal, fossorial (burrowing), saltatorial/richochetal (leaping on their hind legs), or semiaquatic. However, all rodents share several morphological features, including having only a single upper and lower pair of ever-growing incisors. Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, and hamsters. Rabbits, hares, and pikas, who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Grey Shrike
The great grey shrike (''Lanius excubitor'') is a large and predatory songbird species in the shrike family (Laniidae). It forms a superspecies with its parapatric southern relatives, the Iberian grey shrike (''L. meridionalis''), the Chinese grey shrike (''L. sphenocerus'') and the American loggerhead shrike (''L. ludovicianus''). Males and females are similar in plumage, pearly grey above with a black eye-mask and white underparts. Breeding takes place generally north of 50° northern latitude in northern Europe and Asia. Most populations migrate south in winter to temperate regions.Harris & Franklin (2000): pp. 152–153 The great grey shrike is carnivorous, with rodents making up over half its diet. Taxonomy and systematics The species was first scientifically described by Carl Linnaeus in his 1758 edition of ''Systema Naturae'' under the current binomial name. His description is – "a shrike with a wedge-shaped white-bordered tail, back grey, wings black with white ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phoreticovelia Disparata
''Phoreticovelia disparata'', also called the Zeus bug, is a species of semi-aquatic bug from the family Veliidae (tribe Microveliini) with a unique form of sexual dimorphism. It is endemic to Australia (Queensland).Polhemus, D. A. & Polhemus, J. T. (2000)Additional new genera and species of Microveliinae (Heteroptera: Veliidae) from New Guinea and adjacent regions.nbsp;— Tijdschrift voor Entomologie 143, 91-123 (2000). Biology ''Phoreticovelia disparata'' live near tropical rivers. They are 1–2 mm in length. It is the only known species (aside from its sister species '' Phoreticovelia rotunda'') where the female feeds the male a nuptial gift. They are sexually dimorphic; the female mating form has a special glandular area on the dorsal surface of the body. The half-sized male (about 1 mm long) clings to her, feeding on the secretions of a pair of glands, sitting on his partner for several days. Both adult males and females have wings, but females are wingless at th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pisaura Mirabilis
The nursery web spider ''Pisaura mirabilis'' is a spider species of the family Pisauridae. Description Striking characteristics of ''Pisaura mirabilis'' are its long legs (the fourth one being the longest) and its slender abdomen ( opisthosoma). The male is between 10 and 13 mm, while the female is 12 to 15 mm. After final ecdysis, the male spiders weigh on average 54 mg and females 68 mg. The prosoma ( cephalothorax) is variable in color, ranging from light to reddish brown and from gray to black. A lighter stripe is visible down the middle of the prosoma. The opisthosoma (abdomen) is long and narrow and tapered towards the rear end. The female spiders has a dark patch ( epigyne) on the underside of her abdomen that includes the copulatory organs. Male genital openings can be found at the same location, but remain inconspicuous. Patterning and coloration varies due to polymorphism. These patterns, which can be caused by hair and pigments, change with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every land habitat. , 50,356 spider species in 132 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900. Anatomically, spiders (as with all arachnids) differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax or prosoma, and the opisthosoma, or abdomen, and joined by a small, cylindrical pedicel, however, as there is currently neither paleontological nor embryological evidence that spiders ever had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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