Question

Most modern breeds of domestic dogs evolved through:
(a) Sexual selection
(b) Artificial selection
(c) Natural selection
(d) Isolation

Answer 1

Hint: Selective breeding is the selection of the desired characters (generally superior), in plant or animal breeding. The natural characters of the organism are manipulated in the controlled breeding environment by isolating and propagating the desired genotypes.

Complete answer:
Artificial selection is the method employed for breeding the modern breeds of domestic dogs. Economical and aesthetical qualities, useful for humans, rather than useful to the organism in its natural environment, is selected. The artificial selection is performed by choosing the male and female animals of the species to perform sexual reproduction and have offspring together. The domesticated animals are known as breeds and are bred by a professional breeder. The offspring of two animals (male and female) of different breeds are known as crossbreeds.
Different types of techniques are performed by humans in animal breeding:
- Inbreeding: Inbreeding is the production of offspring by mating or breeding the animals that are closely related to each other (genetically related) . Inbreeding results in homozygosity and helps in preserving the superior characters of male and female dogs.
- Linebreeding: This is a form of inbreeding in which crosses between individuals and their descendants or two cousins are performed. This method is used to increase a particular animal's contribution to the population. The line breeding technique is less likely to cause problems in the first generation than the inbreeding technique, but over time, linebreeding can reduce the genetic diversity of a population.
- Out- crossing or out- breeding: It is the technique of crossing between different breeds with different ancestors. This is the practice the animals with unrelated genetic material are introduced into the breeding line. It increases the hybrid vigor of the offspring, thus reducing the probability of an individual being subject to disease or genetic abnormalities.
- Sexual selection is a natural process where the animals choose their mates and compete with other species.
- The survival of an individual based on their phenotype differences and environment.
- Isolation is the process of preventing two biological species from producing their young ones through breeding.
So, the correct answer is, ‘Artificial selection.’

Note: Robert Bakewell introduced selective breeding as a scientific practice during the 18th century of The British Agricultural Revolution. He was able to quickly select large yet fine- boned sheep, with long, and lustrous wool by sheep breeding, or by using the native stock.