genes
Sexual Reproduction Sexual reproduction is the combination of usually haploid reproductive cells from two individuals to form a third usually diploid unique offspring. Sexual reproduction produces offspring with novel combinations of genes. This can be an adaptive advantage in unstable or unpredictable environments. As humans, we are used to thinking of animals as having two separate sexesmale and femaledetermined at conception. However, in the animal kingdom, there are many variations on this theme. Hermaphroditism Hermaphroditism occurs in animals where one individual has both male and female reproductive parts. Invertebrates such as earthworms, slugs, tapeworms and snails, shown in Figure 43.5, are often hermaphroditic. Hermaphrodites may selffertilize or may mate with another of their species, fertilizing each other and both producing offspring. Self fertilization is common in animals that have limited mobility or are not motile, such as barnacles and clams.