Evolution by artificial selection is a common way by which people breed plants and animals to have characteristics that we find desirable.
Imagine that you are working in a lab where scientists are trying to breed a strain of apple that has much higher sugar content. How might the scientists attempt to do this?
In order to breed a strain of apple with higher sugar content, scientists can use a process known as artificial selection. Here's how they might attempt to do it:
1. Start with a diverse population: Scientists would gather a diverse collection of apple trees that exhibit a range of sugar content. This variability is crucial to have a starting point for the selection process.
2. Measure sugar content: The scientists would measure the sugar content of the apples from each tree in their collection. This can be done using laboratory techniques such as chromatography or spectroscopy.
3. Select high sugar content individuals: Based on the sugar content measurements, scientists would choose the trees with the highest sugar content to be the parents of the next generation. These individuals are the ones that exhibit the desirable characteristic of high sugar content.
4. Crossbreeding: The selected individuals are crossbred to produce offspring. This can be done by manually transferring pollen from the selected tree's flowers to ensure controlled mating.
5. Grow and evaluate the offspring: The offspring, known as F1 generation, would be grown and their sugar content measured. This step helps in understanding the inheritance patterns of sugar content and identifying potential individuals with even higher sugar content.
6. Repeat the process: The individuals with the highest sugar content from the F1 generation would be selected as the parents for the next generation (F2 generation). This process is repeated for several generations, selecting individuals with progressively higher sugar content each time.
7. Monitor genetic diversity: Throughout the breeding process, scientists would consider genetic diversity to avoid inbreeding depression. It is essential to periodically introduce new genetic material into the breeding population to maintain a healthy and diverse gene pool.
8. Continuous improvement: The process of artificial selection would continue for multiple generations, each time selecting individuals with the highest sugar content. Over time, this iterative process can lead to the development of a strain of apples with significantly higher sugar content.
It is important to note that this process requires careful record-keeping, scientific expertise, and long-term commitment. It can take several years or even decades to achieve significant improvements in sugar content through artificial selection.