Livestock Breeding System Vocab
... crossbred offspring exceed the average of the two parental breeds Homozygous identical pairs of genes Inbreeding mating of related individuals in which the sire and dam share at least one ancestor ...
... crossbred offspring exceed the average of the two parental breeds Homozygous identical pairs of genes Inbreeding mating of related individuals in which the sire and dam share at least one ancestor ...
Frog Reproduction
... When female approaches, the male climbs onto her back. He grasps her firmly. This embrace is called an amplexus. The female releases her eggs and the male deposits his sperm on top of them. Direct external fertilization is achieved. ...
... When female approaches, the male climbs onto her back. He grasps her firmly. This embrace is called an amplexus. The female releases her eggs and the male deposits his sperm on top of them. Direct external fertilization is achieved. ...
Reproductive suppression
Reproductive Suppression involves the prevention or inhibition of reproduction in otherwise healthy adult individuals. It includes delayed sexual maturation (puberty) or inhibition of sexual receptivity, facultatively increased interbirth interval through delayed or inhibited ovulation or spontaneous or induced abortion, abandonment of immature and dependent offspring, mate guarding, selective destruction and worker policing of eggs in some eusocial insects or cooperatively breeding birds, and infanticide (see also infanticide (zoology)), and infanticide in carnivores) of the offspring of subordinate females either by directly killing by dominant females or males in mammals or indirectly through the withholding of assistance with infant care in marmosets and some carnivores.The Reproductive Suppression Model argues that “females can optimize their lifetime reproductive success by suppressing reproduction when future [physical or social] conditions for the survival of offspring are likely to be greatly improved over present ones”. When intragroup competition (competition between individuals belonging to the same group) is high it may be beneficial to suppress the reproduction of others, and for subordinate females to suppress their own reproduction until a later time when social competition is reduced. This leads to reproductive skew within a social group, with some individuals having more offspring than others. The cost of reproductive suppression to the individual is lowest at the earliest stages of a reproductive event and reproductive suppression is often easiest to induce at the pre-ovulatory or earliest stages of pregnancy in mammals, and greatest after a birth. Therefore, neuroendocrine cues for assessing reproductive success should evolve to be reliable at early stages in the ovulatory cycle.Reproductive suppression occurs in its most extreme form in eusocial insects such as termites, hornets and bees and the mammalian naked mole rat which depend on a complex division of labor within the group for survival and in which specific genes, epigenetics and other factors are known to determine whether individuals will permanently be unable to breed or able to reach reproductive maturity under particular social conditions, and cooperatively breeding fish, birds and mammals in which a breeding pair depends on helpers whose reproduction is suppressed for the survival of their own offspring. In eusocial and cooperatively breeding animals most non-reproducing helpers engage in kin selection, enhancing their own inclusive fitness by ensuring the survival of offspring they are closely related to. Wolf packs suppress subordinate breeding.