Figure 5.8: During sexual reproduction, a sperm fertilizes an egg. ( 4 )bird’s cloaca to deposit sperm. Whatever method of fertilization is used, the net result is
the same: a zygote that contains DNA from both the male and female.
Figure 5.9: This fish guards her eggs, which will be fertilized externally. ( 15 )Plants also can reproduce sexually, but their reproductive organs are somewhat different
than animals’ gonads. Most plants are flowering plants, meaning their reproductive parts
are contained in a flower. The sperm is contained in the pollen, while the egg is contained in
the ovary deep within the flower. The sperm can reach the egg through several methods. In
self-pollination, the egg is fertilized by the pollen of same flower. Incross-pollination, the
sperm from the pollen from one flower fertilizes the egg of another flower. Cross-pollination
increases the genetic diversity of the population. Like other types of sexual reproduction,
cross-pollination allows new combinations of traits. Cross-pollination can be achieved when
pollen is carried by the wind to another flower, or many flowers rely on animal pollinators,
like honeybees, or butterflies (Figure5.10) to carry the pollen from flower to flower.