Question

Describe and contrast the different mechanisms by which sperm are transported to the egg in ferns and in pine trees. Please be as much clear as you can.

Answer 1

Life cycle of Fern

A fertilized egg or zygote grows into a new sporophyte. The diploid sporophyte produces spores by meiosis. The haploid spores fall to the ground and grow into haploid gametophytes. Fern gametophytes produce gametes by mitosis- eggs in archegonia and sperm in antheridia. Sperm swim to archegonia and fertilize the eggs inside them.

Life cycle of pines

In pines, as in all plants, a diploid zygote results from sexual reproduction. The zygote develops into an embryo, which then becomes dormant (inactive). The embryo and the surrounding tissues form a seed. When their seeds are mature, seed cones open, and the seeds fall out. When conditions are favorable for growth, the seeds grow into new sporophytes. An adult pine tree produces both male and female cones. Spores form by meiosis, which occurs inside immature cones. The spores grow into gametophytes, which produce eggs and sperm by mitosis. After pollination, a pollen tube begins to grow from each pollen grain toward the eggs inside an ovule. Fertilization occurs as a sperm fuses with an egg, forming a zygote that will grow into a new sporophyte.