Sexual Reproduction
Plant Reproduction
Genes can be passed from one plant to another via asexual reproduction, sexual reproduction, and apomixis
I. Asexual reproduction:
- The world's heaviest living thing. L-2. Plant clones can be massive. The same genotype can cover large geographic areas. This has implications for long-term fitness.
- The garlic example. L-2. If there is no sexual reproduction, the only source of genetic variation will be mutation. Introduction of a sexual reproduction system into an asexually reproduction system opens new horizons for plant breeding.
II. Sexual reproduction:
A. Advantages and disadvantages of sexual reproduction
- Advantages : Environments are highly heterogeneous and unstable - sexual reproduction generates variability and variability is the basis for selection (natural and artificial).
- Disadvantages
- In a dioecious species, half the reproductive effort is wasted in producing males
- Meiosis will produce some "unfit" combinations of genes
- Cross-pollinated plants may be subject to environmental conditions unfavorable to pollination
- An in-depth look at the advantages of sexual reproduction. L-2. What is the Red Queen hypothesis?
B. Alternation of generations: In plants there is an alternation of the gametophytic (n) and sporophytic (2n) generations. The sporophytic generation may be diploid (2n = 2x) or polyploid (2n = _x).
- Alternation of generations. L-1. n vs. 2n, and getting ready for "x".