Question

Animal eggs are significantly larger than animal sperm. Mature endosperm contains 2 female genomes, but only one paternal genome. What similarities do you see among egg production in animals, endosperm production in angiosperms, and the costs of embryo development? How might those similarities be explained?

Answer 1

Animal egg (female games) is having different cells division (not as completed as male); remember metaphase II), significantly fewer in number and egg cell contain all required content for the initial development of the zygote, when male fuses with female gametes. That’s why we observe larger egg as compared to sperm. Endosperm contains 2 female gemones but only one paternal, which alters the genomic contribution from maternal and paternal counter part (ration of two) and effect the development of the endosperm.

In case of animals, both male and female contribute equally and as a result it produces diploid zygote (2n) and in endosperm the condition is triploid (3n, in most of the angiosperms, 2 maternal and 1 paternal. So, in animal egg, fusion take place inside the cells and similarly happens inside the endosperms and both nurture further for the development of the embryo.