Cross a non-floppy-eared male to a floppy-eared female and observe if males offspring have the floppy ear trait
Explanation:
Mammals (e.g. dogs) have two sex chromosomes: X and Y. In the XY sex-determination system, the female gamete (i.e., the ovum) contributes to an X chromosome, while the male gamete (i.e., the sperm) contributes either an X chromosome or a Y chromosome: normal females are XX and normal males are XY. In consequence, a male always inherits its X chromosome from the mother and its Y chromosome from the father. In this case, the presence of the floppy ear trait in all males F1 offspring obtained by crossing a non-floppy-eared male to a floppy-eared female indicates that this trait is linked to the X chromosome because males inherit the floppy ear trait from the mother.
So there's a simple explanation for the Great Oxidation Event. It was the cyanobacteria, pumping out unwanted oxygen, that transformed Earth's atmosphere. ... That means the cyanobacteria were busy pumping out oxygen for at least half a billion years before oxygen started appearing in the air.
