Studies are conducted with colonies experimentally lacking both the queen and brood, which results in the development of laying workers. Because they lack a functional sperm-storage organ and do not mate, these individuals can only lay haploid male eggs. Laying workers, like queens, have low JH...
Fertilization - Egg Activation, Sperm Fusion, Zygote: The acrosome reaction of spermatozoa is a prerequisite for the association between a spermatozoon and an egg, which occurs through fusion of their plasma membranes. After a spermatozoon comes in conta
Yes, there are egg laying mammals and they are known as monotremes. They are named so because of the presence of single cloacal opening in their bodies that serves as a passage for eggs or sperms, feces and urine. The tracts for urine, feces and sperms come straight to this cloaca a...
According to the size-advantage model (Ghiselin, 1969), protandry is favored in species in which: a) large females have more reproductive success than smaller females and similar-sized males and b) spawning occurs in pairs or small groups, and sperm competition is low. However, in contrast ...
Egg: Directed by Marianna Palka. With Christina Hendricks, Alysia Reiner, David Alan Basche, Anna Camp. Conceptual artist Tina (Reiner) introduces her eight-months-pregnant art-school rival (Hendricks) to her non-traditional surrogate Kiki (Camp). The tr
In this respect the egg and sperm are complementary structures; their union in syngamy thus restores to each the missing element necessary to further ... DL Kropf - 《Developmental Biology》 被引量: 159发表: 1994年 Changes in level of polymeric tubulin associated with activation and dorsoventral...
Do eggs and sperm arise by mitosis or meiosis? Mitosis happens when you want to grow, for example. You want all your new cells to have the same DNA as the previous cells. The goal ofmeiosis, however, is to produce sperm or eggs, also known as gametes. ...
Parental Care of Eggs 13 13 Please note that many pairs will not incubate their eggs unless at least three eggs are present in their nest. 13 Species foster parents Performing Nest Checks Candling Eggs on or after the fifth day of incubation ...
sperm competitionInteractions among eggs and sperm are often assumed to generate intraspecific variation in reproductive fitness, but the specific gamete-level mechanisms underlying competitive fertilization success remain elusive in most species. Sperm chemotaxis鈥搕he attraction of sperm by egg-derived ...
"Abalone was our system of choice for this investigation, as it is one of the few organisms where cognate egg coat and sperm proteins are known. Moreover, different species of abalone spawn in the open sea but, despite overlapping habitats and breeding seasons, hybrids rarely occur", says Pr...