Asexual and Sexual Reproduction

Asexual reproduction

Asexual reproduction is a process resulting in the production of genetically identical offspring from one parent.
- Since they are genetically identical, there is little variation among offspring. Any variation is due to the effect of the environment (e.g. availability of nutrients and water determine growth of organism).
Binary fission is a form of asexual reproduction that is used by prokaryotes (e.g. bacteria) where a single cell divides into two identical daughter cells.
- EXAMPLE:Bacteria are microscopic organisms made up of one cell. THey do not have a nucleus, but a loop of DNA. When bacteria reproduce asexually, the DNA loop is duplicated so that there is some for each new cell. The bacterial cell divides into two by making a new cell wall.

Advantages	Disadvantages
Fast. Organisms can reproduce rapidly to spread and colonize areas where the parent plants grow. Plants grow more rapidly from tubers than seeds. Also only requires one parent and it saves time instead of looking for a mate, which uses energy.	Lack of genetic variation. All offspring are genetically identical clones. If a change in their environment occurs, everyone is vulnerable.
Rapid colonization. Populations can increase very quickly in a favorable, stable environment, allowing the species to outcompete others.	Risk of extinction. If a new disease or change in climate occurs, the lack of variation means no individuals may have the resistance needed to survive, potentially wiping out the population.
Succession/traits given to offspring. Favorable traits are passed on 100% of the time, ensuring that if the parent is well-adapted to the niche, the offspring will be too.	Overcrowding. A rapidly increasing population may result in lots of competition for essential things such as food, water, and space.

Advantages	Disadvantages
Uniformity. Every plant will have the same characteristics, making it easier for farmers to manage and harvest crops mechanically.	Vulnerability to disease. If a specific pest or pathogen attacks one plant, then the whole field will be affected due to lack of variation and no genetic resistance.
Speed to market. Asexually reproduced plants typically reach maturity faster than seeds, making harvesting faster.	Lack of adaptation. The crops can’t adapt to long-term changes in the soil or climate over generations.
Certainty of quality. If a parent plant has a high yield or tastes pleasant, these characteristics will be passed on to offspring.	Storage issues. Some asexually reproduced structures (like tubers) do not store as easily or as long as seeds, which are naturally dormant and resistant to dessication (the removal of moisture).

Sexual reproduction is a process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from each other.
In sexual reproduction, it requires two parents that have sex organs. The sex organs make gametes.
- Male gametes:
  - In animals, the male gametes are sperm cells.
  - In flowering plants, the male gametes are nuclei inside pollen grains.
- Female gametes:
  - In animals, the female gametes are egg cells.
  - In floweing plants, the female gametes are inside structures called ovules.
During sexual reproduction, the nuclei of the gametes fuse together at fertilization. The fertilized egg or zygote divides to form an embryo, which may grow into a new individual plant.
- Fertilization is the fusion of nuclei of gametes.
The nuclei of gametes are haploid and the nucleus of a zygote is diploid.
- A haploid nucleus contains two full sets of chromosomes.
- A diploid nucleus contains only one set of unpaired chromosomes.

Advantages	Disadvantages
Genetic variation. Offspring are genetically different to each other. This is the raw material for natural selection.	Time and energy waste. Individuals must find and attract a mate. This involves energy-intensive processes like building a nest, developing bright plummage, or fighting rivals.
Adaptation to changes. If the environment changes (e.g. new predator, climate shift, or disease), variation ensures that some individuals may possess advantageous traits to survive and reproduce.	Risk of predatation or disease. The process of searching for a mate or the act of mating can make individuals vulnerable to predators or the transmission of parasites.
Removal of harmful mutations. Sexual reproduction can help remove the population of harmful genetic mutations over many generations through recombination.	Slower population growth. Because only females can bear offspring (in most species) and a mate is required, the population increases much more slowly than asexual populations.