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Siblicide
Siblicide (attributed by behavioural ecologist Doug Mock to Barbara M. Braun) is the killing of an infant individual by its close relatives (full or half siblings). It may occur directly between siblings or be mediated by the parents, and is driven by the direct fitness benefits to the perpetrator and sometimes its parents. Siblicide has mainly, but not only, been observed in birds. (The word is also used as a unifying term for fratricide and sororicide in the human species; unlike these more specific terms, it leaves the sex of the victim unspecified.) Siblicidal behavior can be either obligate or facultative. Obligate siblicide is when a sibling almost always ends up being killed. Facultative siblicide means that siblicide may or may not occur, based on environmental conditions. In birds, obligate siblicidal behavior results in the older chick killing the other chick(s). In facultative siblicidal animals, fighting is frequent, but does not always lead to death of a sibling; th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue-footed Booby
The blue-footed booby (''Sula nebouxii'') is a marine bird native to subtropical and tropical regions of the eastern Pacific Ocean. It is one of six species of the genus '' Sula'' – known as boobies. It is easily recognizable by its distinctive bright blue feet, which is a sexually selected trait and a product of their diet. Males display their feet in an elaborate mating ritual by lifting them up and down while strutting before the female. The female is slightly larger than the male and can measure up to long with a wingspan up to . The natural breeding habitats of the blue-footed booby are the tropical and subtropical islands of the Pacific Ocean. It can be found from the Gulf of California south along the western coasts of Central and South America to Peru. About half of all breeding pairs nest on the Galápagos Islands. Its diet mainly consists of fish, which it obtains by diving and sometimes swimming under water in search of its prey. It sometimes hunts alone, but us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parent–offspring Conflict
Parent–offspring conflict (POC) is an expression coined in 1974 by Robert Trivers. It is used to describe the evolutionary conflict arising from differences in optimal parental investment (PI) in an offspring from the standpoint of the parent and the offspring. PI is any investment by the parent in an individual offspring that decreases the parent's ability to invest in other offspring, while the selected offspring's chance of surviving increases. POC occurs in sexually reproducing species and is based on a genetic conflict: Parents are equally related to each of their offspring and are therefore expected to equalize their investment among them. Offspring are only half or less related to their siblings (and fully related to themselves), so they try to get more PI than the parents intended to provide even at their siblings' disadvantage. However, POC is limited by the close genetic relationship between parent and offspring: If an offspring obtains additional PI at the expense of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spotted Hyena
The spotted hyena (''Crocuta crocuta''), also known as the laughing hyena, is a hyena species, currently classed as the sole extant member of the genus ''Crocuta'', native to sub-Saharan Africa. It is listed as being of least concern by the IUCN on account of its widespread range and large numbers estimated between 27,000 and 47,000 individuals. The species is, however, experiencing declines outside of protected areas due to habitat loss and poaching. The species may have originated in Asia, and once ranged throughout Europe for at least one million years until the end of the Late Pleistocene. The spotted hyena is the largest known member of the Hyaenidae, and is further physically distinguished from other species by its vaguely bear-like build, its rounded ears, its less prominent mane, its spotted pelt, its more dual-purposed dentition, its fewer nipples and the presence of a pseudo-penis in the female. It is the only placental mammalian species where females lack an external ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infanticide (zoology)
In animals, infanticide involves the intentional killing of young offspring by a mature animal of the same species. Animal infanticide is studied in zoology, specifically in the field of ethology. Ovicide is the analogous destruction of eggs. The practice has been observed in many species throughout the animal kingdom, especially primates ( primate infanticide) but including microscopic rotifers, insects, fish, amphibians, birds and mammals. Infanticide can be practiced by both males and females. Infanticide caused by sexual conflict has the general theme of the killer (often male) becoming the new sexual partner of the victim's parent, which would otherwise be unavailable. This represents a gain in fitness by the killer, and a loss in fitness by the parents of the offspring killed. This is a type of evolutionary struggle between the two sexes, in which the victim sex may have counter-adaptations that reduce the success of this practice. It may also occur for other reaso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Masked Booby
The masked booby (''Sula dactylatra''), also called the masked gannet or the blue-faced booby, is a large seabird of the booby and gannet family, Sulidae. First described by the French naturalist René-Primevère Lesson in 1831, the masked booby is one of six species of booby in the genus '' Sula''. It has a typical sulid body shape, with a long pointed yellowish bill, long neck, aerodynamic body, long slender wings and pointed tail. The adult is bright white with black wings, a black tail and a dark face mask; at long, it is the largest species of booby. The sexes have similar plumage. This species ranges across tropical oceans, except in the eastern Atlantic and eastern Pacific. In the latter, it is replaced by the Nazca booby (''Sula granti''), which was formerly regarded as a subspecies of masked booby. Nesting takes place in colonies, generally on islands and atolls far from the mainland and close to deep water required for foraging. Territorial when breeding, the masked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nymphalis Antiopa
''Nymphalis antiopa'', known as the mourning cloak in North America and the Camberwell beauty in Britain, is a large butterfly native to Eurasia and North America. The immature form of this species is sometimes known as the spiny elm caterpillar. Other older names for this species include grand surprise and white petticoat. A powerful flier, this species is sometimes found in areas far from its usual range during migration. These butterflies have a lifespan of 11 to 12 months, one of the longest lifespans for any butterfly. It is also the state insect of the U.S. state of Montana, adopted in 2001. Etymology The specific epithet ''antiopa'' is thought to be derived from Antiope, a common name in Greek mythology. North American name "mourning cloak" In several European countries with Germanic languages, other than Britain, the name for this butterfly literally translates to "mourning cloak", such as German "Trauermantel", Dutch "rouwmantel", Swedish "sorgmantel", Finnish "su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wasps
A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. The wasps do not constitute a clade, a complete natural group with a single ancestor, as bees and ants are deeply nested within the wasps, having evolved from wasp ancestors. Wasps that are members of the clade Aculeata can sting their prey. The most commonly known wasps, such as yellowjackets and hornets, are in the family Vespidae and are eusocial, living together in a nest with an egg-laying queen and non-reproducing workers. Eusociality is favoured by the unusual haplodiploid system of sex determination in Hymenoptera, as it makes sisters exceptionally closely related to each other. However, the majority of wasp species are solitary, with each adult female living and breeding independently. Females typically have an ovipositor for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The larva's appearance is generally very different from the adult form (''e.g.'' caterpillars and butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs. By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles, adults are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Identical Twins
Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of TwinLast Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or ''dizygotic'' ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Since identical twins develop from one zygote, they will share the same sex, while fraternal twins may or may not. In rare cases twins can have the same mother and different fathers ( heteropaternal superfecundation). In contrast, a fetus that develops alone in the womb (the much more common case, in humans) is called a ''singleton'', and the general term for one offspring of a multiple birth is a ''multiple''. Unrelated look-alikes whose resemblance parallels that of twins are referred to as doppelgängers. Statistics The human twin birth rate in the United States rose 76% fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intrauterine Growth Restriction
Intrauterine growth restriction (IUGR), or fetal growth restriction, refers to poor growth of a fetus while in the womb during pregnancy. IUGR is defined by clinical features of malnutrition and evidence of reduced growth regardless of an infant's birth weight percentile. The causes of IUGR are broad and may involve maternal, fetal, or placental complications. At least 60% of the 4 million neonatal deaths that occur worldwide every year are associated with low birth weight (LBW), caused by intrauterine growth restriction (IUGR), preterm delivery, and genetic abnormalities, demonstrating that under-nutrition is already a leading health problem at birth. Intrauterine growth restriction can result in a baby being small for gestational age (SGA), which is most commonly defined as a weight below the 10th percentile for the gestational age. At the end of pregnancy, it can result in a low birth weight. Types There are two major categories of IUGR: pseudo IUGR and true IUGR With pseud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twin-to-twin Transfusion Syndrome
Twin-to-twin transfusion syndrome (TTTS), also known as feto-fetal transfusion syndrome (FFTS), twin oligohydramnios-polyhydramnios sequence (TOPS) and stuck twin syndrome, is a complication of monochorionic multiple pregnancies (the most common form of identical twin pregnancy) in which there is disproportionate blood supply between the fetuses. This leads to unequal levels of amniotic fluid between each fetus and usually leads to death of the undersupplied twin and, without treatment, usually death or a range of birth defects or disabilities for a surviving twin, such as underdeveloped, damaged or missing limbs, digits or organs (including the brain), especially cerebral palsy. The condition occurs when the vein–artery connections within the fetuses' shared placenta allow the blood flow between each fetus to become progressively imbalanced. It usually develops between week 16 and 25 of pregnancy, during peak placental growth. The cause of the developmental effects on a su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genes
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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