Sexual reproduction
From Wikipedia, a free encyclopedia written in simple English for easy reading.
Sexual reproduction is a way of reproduction of some animals and plants. Some protists and fungi also reproduce this way. Organisms that reproduce sexually have two different sexes: male and female. Offspring is made by a cell from the male and a cell of the female.
Different steps are involved in the process. Each of the two cells has a complete set of chromosomes. Something therefore needs to be done to make sure that the resulting cell does not have two sets of them, but only one. This process is called meiosis. The second step is called fertilization. In it, the two cells merge into one. During meiosis, cross over occurs. This makes it possible to get genetic recombination. This means, that for each copying step involved, there is a certain probability of failure. This leads to more diversity in the genome.
[edit] Sexual reproduction of Animals
In animals, a male's sperm and a female's ovum form a zygote. Some animals keep the zygote in their bodies until it is a full-grown baby. The time between the forming of the zygote and the baby's birth is called pregnancy. Other animals do not keep the zygote in their bodies, but lay an egg. The zygote grows inside the egg until it is ready and hatches.