Selective Breeding Flashcards
All 6 cards in this deck
What is selective breeding (artificial selection)?
The process by which humans breed plants and animals for particular genetic characteristics.
What are the steps of selective breeding?
e.g. breeding cows for a high milk yield
- Choose parents with the desired characteristic from a mixed population: cows with the highest milk yield.
- Breed them together and select the offspring showing the characteristic most: the calves giving most milk.
- Breed these offspring together, repeating over many generations until all offspring show it.
Give three characteristics that plants and animals are selectively bred for.
Disease resistance in food crops, larger or more unusual flowers, animals that produce more meat or milk, and domestic dogs with a gentle nature.
What is the problem of inbreeding caused by selective breeding?
Some breeds become particularly prone to disease or to inherited defects, because the gene pool is reduced.
True or false? Selective breeding increases the genetic variation in a population.
False. It reduces variation (a smaller gene pool), which can leave a breed vulnerable to disease or new conditions.
In a breeding programme, the mean mass of fruit rises over ten successive generations. What does this show?
That large fruit mass is being selected for and passed on to offspring, so the selective breeding is working.