Accessory glands become depleted with repeated matings (Rogers et al., 2006), and the amount of sperm stored by a female is correlated to the testis size of the male that she mates with (Fry, 2006). A similar pattern of co-variation between male eyespan and the size of the testes ...
Gametes are sperm and egg cells. When the sperm fertilizes the egg, their genetic material is joined to form a new cell called a zygote. Because both the sperm and egg cells have half the number of chromosomes as in normal body cells, the zygote will have the full number of chromosomes...
In flowering plants, a mature seed consists of the embryo, endosperm and seed coat. Seed development starts with double fertilisation. One sperm cell fuses with the egg cell to form the embryo, and another sperm cell fuses with the central cell to generate the endosperm. Thus, the embryo ...
Sperm limitation may be an important selective force influencing gamete traits such as egg size. The relatively inexpensive extracellular structures surrounding many marine invertebrate eggs might serve to enhance collision rates without the added cost of increasing the egg cell. However, despite decades ...
Thus, we cannot rule out age as a confounding parameter in the generation of size differences. We analyzed the size distribution within each clutch; each female lays eggs within a restricted range of sizes, supporting a genetic contribution in determining egg size. Commercial Xenopus laevis sources...
Woodlice also grew relatively fast but achieved a decreased asymptotic body mass in response to warm conditions; the oxygen did not affect growth. Under hypoxia, growing females developed larger lungs compared to under normoxia, but only in the late stage of development. Among mature animals, this...
Marshall DJ, Keough MJ (2003) Sources of variation in larval quality for free-spawning marine invertebrates: egg size and the local sperm environment. Invertbr Reprod Dev 44:63–70Marshall DJ, Keough MJ. 2003b. Sources of variation in larval quality for free-spawning marine invertebrates: Egg...
This is why it takes several million guy sperm cells, each one wriggling in its own direction, totally confident it knows where it is going, to locate a female egg, despite the fact that the egg is, relative to them, the size of Wisconsin." - Copy to Clipboard -- Dave Barry Listed...
They looked at diversity at three levels — allozyme, nuclear DNA and mtDNA — expecting all to show the same patterns as a result of population size: invertebrates should have more polymorphism than vertebrates; marine species more than terrestrial or freshwater species; and large animals more ...
CELL WALL ELASTICITYEvolutionary games of sperm competition in which two males mate with the same female have previously considered sperm size to be fixed at some (small) constant level. Although male gametes in multicellular organisms are typically small compared with ova, they vary greatly both ...