Sex for biologists
What makes a male… a male? And a female… a female? For humans, it might seem obvious. But what about a fish? Or a tree? How do biologists decide? For most sexually reproducing multicellular organisms the answer is anisogamy. Anisogamy comes from An - which means "not" Iso - which means "same" And gamy - which refers to the gametes, or sex cells. So basically anisogamy means unequal gametes. Females have big gametes… and males have small gametes. To help remember the characteristics of the different gametes we could say: Female gametes, which are called egg cells, are: Few — only a few are made. Fat — big and packed with resources. Fixed — they stay put. Male gametes, which are called sperm, are: Many — made in huge numbers. Mini — tiny and streamlined. Motile — they move to find the eggs! And this difference helps explain lots of behaviours... In many species, males have to compete to reach the scarce and valuable eggs… … and females are often very selective about ...