Negative aspects of selective breeding:
1. Other important and necessary aspects may be lost over time.
2. The other animals or plants become redundant and un-necessary.
3. Could cause genetic problems and the animal may become sick easier.
4. If it is a plant that needs more water then it would be creating an environmental issue.
5. Disrupts the food chain and the natural order of life, there is already a law of nature in place to choose the best aspects (survival of the fittest)
6. Some selectively bred animals are more likely to become extinct.
7. Some animals may be lost as the selectively bred ones are preferred (dogs from wolves, wolves would eventually become extinct in preference to dogs).
Selective breeding allows humans to control evolution, and this is the process which has created the Cow from the Aurochs, and Dogs from Wolves. Selective breeding has many good qualities: Dogs are much more obedient than wolves and Cows are easier to milk than Aurochs. One problem is that people will sometimes breed animals in such a way that makes them weaker and more vulnerable to extinction. The Turkey for example has been selectively bread for producing meat, but this has resulted an animal which would quickly die if humans did not take care of it.
The negatives of selective breeding are that recessive genes are inherited in a double dose ,ie from both parents. Most recessive genes are mutations and most mutations are harmful. We can see this a lot in pedigree dog breeding where most breeds are now disease specific and many pedigree dogs suffer the terrible consequences of inbreeding.
Because it brings together in individuals two copies of a mutated recessive gene. Because most mutations are harmful and even lethal then selectively bred species, ie dogs, suffer from breed specific traits/diseases.
The disadvantages of mankinds artificial selection methods are that mutated bad recessive genes are passed onto the offspring is double doses, ie the same disease causing recessive genes come as a pair in the created individuals as both parents,being related (OVER AND OVER AGAIN) are both carriers for the same familial mutation///. Another good example is the white coat colour and deafness. Because the alleles ( paired genes) for white coat colour and for deafness lie in the same locus ( area) or the dog genome then during the recombination of parental chromosomes, the break ( exchange of chromosomal material) does not always happen between the colour and deafness alleles and so they are often inherited together as a package so to speak . So lets say that the breeder wants white dogs ( the so called desired trait) he/she also gets the so called undesirable trait, deafness because of selection of white coat colour. Hope this has answered your query/ Intensified selective breeding obviously brings along more familial mutations ,causing the individual many health problems. This is what has happened of recent years because the breed clubs , ie Crufts in London England, have brought in so called Standards. This is not compatable with animal welfare.
Selective breeding is bad because it disrupts the food chain
Hi I have just done this topic and it may a few years down the line wipe most pure bred animals as they wont be needed and people wont want them
My family is inbred leave them alone you bully's
Plant breeding is changing