Explain how the following prevents self pollination:
Protoandry
Self sterility
Advantages of cross pollination
State 2 disadvantages of sexual reproduction in animals
What is meant by: protoandry
Self sterility
Protoandry is a mechanism that prevents self pollination in plants. In protoandry, the male reproductive organs (stamens) mature before the female reproductive organs (pistils) in the same flower. This ensures that the pollen from the mature stamens is released before the pistils become receptive, thus reducing the chances of self-pollination.
Self sterility is another mechanism that prevents self pollination in plants. It refers to the inability of a plant to produce viable offspring through self-pollination. This can be due to various factors, such as the presence of mechanisms that promote cross-pollination or genetic barriers that prevent successful fertilization when pollen from the same plant is used.
The advantages of cross-pollination include:
1. Genetic diversity: Cross-pollination allows for the exchange of genetic material between different individuals of the same species. This results in the creation of genetically diverse offspring, which can increase their chances of survival by enhancing adaptability to changing environments and resisting diseases and pests.
2. Outbreeding depression prevention: Cross-pollination reduces the risk of inbreeding depression, which occurs when individuals with similar genetic traits mate. Inbreeding depression can lead to reduced fitness and increased susceptibility to genetic diseases.
Two disadvantages of sexual reproduction in animals are:
1. Energy expenditure: Sexual reproduction requires the investment of energy and resources in finding a mate, courtship rituals, and mating behaviors. This can be time-consuming and energetically demanding for animals, diverting resources away from other vital activities such as foraging or predator avoidance.
2. Reduced population growth rate: Compared to asexual reproduction, sexual reproduction usually results in fewer offspring being produced. This is because sexual reproduction involves the fusion of gametes (sperm and egg), which limits the number of offspring that can be produced compared to asexual reproduction, where individuals can reproduce on their own. This slower population growth rate can be a disadvantage in environments characterized by rapid environmental changes or high predation pressure.
Protoandry refers to the sequential maturation of male and female reproductive organs in plants, where the male organs mature first.
Self sterility refers to the inability of a plant to produce viable offspring through self-pollination due to genetic or physiological barriers.