Higher Biology - Unit 3 - Part 2 - Plant and Animal Breeding

Question 1

What traits do breeders try to improve in their crops and animals ?

Answer 1

• higher food yields,
• higher nutritional values,
• pest and disease resistance
• ability to thrive in particular environmental conditions.

Question 2

In designing field trials what should be taken into account?

Answer 2

• The selection of treatments (to ensure fair comparisons);
• the number of replicates (to take account of the variability within the sample) &
• the randomisation of treatments (to eliminate bias when measuring treatment effects).

Question 3

Animals and cross-pollinating plants are naturally….

Answer 3

outbreeding

Question 4

In inbreeding, selected plants or animals are bred for several generations until the population breeds true to the desired type due to the elimination of ________

Answer 4

heterozygotes

Question 5

Inbreeding depression is the accumulation of …

Answer 5

recessive, deleterious homozygous alleles.

Question 6

Self-pollinating plants are naturally inbreeding and less susceptible to inbreeding depression due to the
elimination of deleterious alleles by …..

Answer 6

natural selection

Question 7

In outbreeding species, inbreeding depression is avoided by selecting for the desired characteristic while maintaining an otherwise genetically ________ population.

Answer 7

diverse

Question 8

In animals, individuals from different breeds may produce a new crossbreed population with _________ characteristics.

Answer 8

improved

Question 9

F1 hybrids often have increased

Answer 9

vigour and yield

Question 10

Test crosses can be used to identify unwanted

individuals with heterozygous recessive ________.

Answer 10

alleles

Question 11

Using genetic transformation techniques a single ____ can be inserted into a genome which can then be used in breeding programmes.

Answer 11

gene

Question 12

The F2 generation is genetically variable and of little use for further production although it can provide
a source of ____________

Answer 12

new varieties

Question 13

If a Blue Faced Leicester Ram and a Black Faced Sheep produce a “Scotch Mule” lamb, the lamb is referred to as a …….

Answer 13

an F1 hybrid or crossbreed as its parents are both pure breeds

Question 14

Pea plants normally self fertilize. They are natural _________

Answer 14

inbreeders