Sexual reproduction is a general and fundamental mode of reproducing their young ones in animals, humans, and plants. Compared to asexual reproduction, sexual reproduction is lengthy and more complex. An organism that follows sexual reproduction has the specific reproductive organs. Both male and female have a different set of reproductive organs in their respective systems.
Stages of Sexual Reproduction
Pre-Fertilization: This stage involves the events prior to fertilization. Gamete formation (gametogenesis) and transfer of gamete are the two processes that take place during this stage. Gametes are sex cells, which are haploid (23 chromosomes) in nature and are distinct in males and females. The male gamete is called sperm whereas female gamete is called ovum or egg. In every organism, these gametes are formed within special structures. Since female gamete is immobile, male gametes need to be transferred for fertilization.
Fertilization: Fertilization is the fusion of haploid gametes- sperm with egg to produce the diploid zygote. It is the crucial stage of reproduction as, without fertilization, sexual reproduction is futile. This process is of two types.
- Internal fertilization: In internal fertilization, the fusion of sperm and egg takes place within the female parent. In this process, the sperms are released into the body of the females during copulation and the resulting zygote develops internally within the mother and gets its nourishment from her. This type of fertilization is found in all humans, and in most of the animals like cats, dogs, cows, lions, etc.
- External fertilization: In external fertilization, the fusion of sperm and egg is carried outside the female parent. This type of fertilization is found in minority of organisms. In this process, the female parent lay her eggs and later, these eggs are fused by the male parent by ejecting his sperms over the eggs.
Characteristics of Sexual Reproduction
- It takes a longer time than asuxual reproduction.
- The offspring produced in case of sexual reproduction are not simmilar to their parent plant genetically.
- The fusion of gametes from both male and female parts from the zygote, which further divides to grow into a new plant. The parts that are involved in reproduction get modified into fruit and seed of the plant.
- The process of reproduction required the contribution of boh sexes, whether from the same plant or a different plant.
- Produces genetic variation in the offspring
- The species can adapt to new environments due to variation, which gives them a survival advantage
- Disease is less likely to affect all the individuals in a population.
- Time and energy are needed to find a mate
- It is not possible for an isolated individual to reproduce