In fact, your parents, and you, would not be distinguishable as male or female. Your mother would not have produced the egg cell destined to produce the other half. If, however, we lived like some plants, your father would not have produced the sperm cell destined to provide half of your genes, although there would be such a sperm cell. We may give birth to other individuals by producing eggs or sperm, but only if they join with other sperm or eggs to produce new, separate lives. Each of us has a unique identity that we keep throughout our entire lives, until death marks our end. None of us would doubt that we have changed significantly since we began as single cells. Now, through mitosis and the miracle of development, we are made of trillions of cells organized into tissues, organs, and organ systems, which make us complex, amazing, active, individual beings. Each of us, of course, began as that single cell made when a sperm united with an egg. You also know that meiosis in your own ovaries or testes produces haploid eggs or sperm, which must join in fertilization to become a new individual. You know that humans develop, or gradually change, from infants to quite different, sexually mature adults. If you think about this analogy, you may begin to realize that many plants, which appear so inert to our roving eyes and active minds, actually lead secret lives of surprising variety. Imagine that human life cycles resembled those of the earliest plants.

Common characteristics of plants