1. Importance of Meiosis
• The sperm cells and egg cells produced after
gametogenesis are haploid cells.
haploid (n) + haploid (n) = diploid (2n)
• The process of meiosis is an important event because
it produces genetic variations among sexually
reproducing organisms.
2. Genetic variations are the reasons why no two
individuals are identical. Because of these genetic
variations, every individual is unique when
compared to others.
The parts of genetic information that give specific
traits are called genes, which are found at
specific locations on the chromosomes called loci.
3. Three mechanisms contribute to
genetic variation:
Independent Assortment – takes place during the
alignment of the homologous chromosomes during
metaphase I.
Crossing-over – or the exchange of genetic material
between homologous chromosomes, adds even more
variations.
Random fertilization – more complicated process. During
the process of fertilization, the fusion of sperm cell and
egg cell (both gametes independently produced) involves
a random process.
4. Life Cycle and Gamete Formation in Plants
Plants undergo an alternation of generations to
perpetuate their own kind.
In animal life cycle, meiosis is the first step in the
production of gametes.
The plant life cycle is composed of two distinct phases
namely diploid and haploid generations which
alternate give rise to each other.
5. Because of the strong connection, the plant life
cycle is known as alternation of generation –
diploid generation known as sporophyte alternating
with haploid generation known as gametophyte.
Exercise:
Describe the life cycle of a non-flowering and
flowering plant.
