17.2.7

Artificial Selection

Test yourself on Artificial Selection

Test your knowledge with free interactive questions on Seneca — used by over 10 million students.

Artificial Selection - Example

Artificial selection happens when humans choose animals and crops to breed, based on their genetic characteristics. The process of the artificial selection of big cows proceeds as follows:

1) Parent selection and breeding

1) Parent selection and breeding

  • Choose parents who most strongly display the desired characteristic.
    • Breed the chosen parents.
2) Offspring selection and breeding

2) Offspring selection and breeding

  • From the resultant offspring (children), choose the offspring that best display the desired characteristic.
    • Breed these chosen offspring.
3) Repeat

3) Repeat

  • Repeat this process of breeding and re-selection over many generations until all the offspring show the desired characteristic.
History of artificial selection

History of artificial selection

  • Humans have done this in farming for thousands of years (with both crops and animals) to promote the genetic characteristics that we view as desirable.

Uses of Selective Breeding

Usefulness and appearance are the two most common reasons for a characteristic being considered desirable. Some useful examples are:

Crops

Crops

  • Disease resistance in food crops like wheat and rice is a useful characteristic because it improves yield (food production productivity).
  • Mutant alleles for gibberellin synthesis can be selectively bred into plants to produce dwarf varieties.
    • This increases crop yield as more energy is used to grow the grain rather than grow the plant taller.
  • Maize crops have been hybridized & inbred to produce uniformity in groups.
    • Hybridization involves crossbreeding different species of corn that each have desirable characteristics.
Animals

Animals

  • In farming, animals that produce more milk or meat are also useful for yield-related reasons.
  • This has been done with dairy cows. Cows have the amount of milk they produce (yield) recorded.
    • This allows identification of bulls that produce female offspring with high yield.
  • Eggs from high-yield female cows are inseminated by such bulls. The resulting embryos are placed in surrogate cows.
  • This process is repeated over many generations to produce high milk yield cows.
Dogs

Dogs

  • Gentle-natured domestic dogs are useful as these animals must co-exist (live with) with humans.

Dangers of Artificial Selection

Artificial selection can create some issues:

Inbreeding

Inbreeding

  • Artificial selection can lead to inbreeding. Here, some breeds become particularly susceptible to disease or inherited defects.
    • For example, French bulldogs have been selectively bred to have flat faces, but that causes them breathing problems.
Reduced variation

Reduced variation

  • Artificial selection can reduce variation (differences in characteristics) within a population, making it harder for a species to adapt to environmental change.
Jump to other topics
1

Cell Structure

2

Biological Molecules

3

Enzymes

4

Cell Membranes & Transport

5

The Mitotic Cell Cycle

6

Nucleic Acids & Protein Synthesis

7

Transport in Plants

8

Transport in Mammals

9

Gas Exchange

10

Infectious Diseases

11

Immunity

12

Energy & Respiration (A2 Only)

13

Photosynthesis (A2 Only)

14

Homeostasis (A2 Only)

15

Control & Coordination (A2 Only)

16

Inherited Change (A2 Only)

17

Selection & Evolution (A2 Only)

18

Classification & Conservation (A2 Only)

19

Genetic Technology (A2 Only)

Practice questions on Artificial Selection

Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
Answer all questions on Artificial Selection

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium