Agriculture

Question 1

What are contact action pesticides?

Answer 1

Kill plants by damaging their tissues. Contact insecticides kill insects that are sprayed directly or come into contact with the pesticide on the crop. (May be washed off by rain)

Question 2

Describe hormone pesticides

Answer 2

Kill pests through their biochemical action, kill insects by increasing/starting natural processes. Low persistence and are quite specific.

Question 3

What are examples of cultural pest control methods?

Answer 3

Companion crops, crop rotation, pest predator habitats, biological control, predator/pathogen species introduction

Question 4

How can temperature be controlled in agriculture?

Answer 4

Smudge pots in apple orchards to prevent frost

Question 5

Briefly outline what pheromone traps are

Answer 5

Used to indicate presence of pest so that pesticides may be sprayed. Can also be used to trap all of one gender of a species so that they can’t breed

Question 6

Name three pros and one con of using antibiotics in agriculture

Answer 6

Increase livestock mass, prevent disease spread, treat infections in livestock
Although can lead to development of antibiotic resistant pathogens

Question 7

Why is topography important in agriculture?

Answer 7

Terraced slopes
Contour ploughing to reduce soil erosion
Levelling undulating fields for eg rice padis

Question 8

How can soil ph be controlled and what ph is optimal for agriculture?

Answer 8

Crushed limestone if too acidic
Sulphur powder if too alkaline
5.5-7 optimal

Question 9

Define the term genetic manipulation

Answer 9

To control the inherited features of crop/livestock

Question 10

Discuss the pros and cons of asexual reproduction/vegetative cloning

Answer 10

Produces genetically identical individuals
No genetic variation in offspring so no improvement in characteristics

Question 11

Discuss the pros and cons of cloning in animals? 3 pros one con

Answer 11

Cloning not yet generally possible in animals
Potential advantages include replacement of animals with desirable features
Produce more individuals with the same desirable characteristics
Replace herds culled for disease control

Question 12

How can cloning be useful in plants

Answer 12

Cultivation of cuttings or runners eg strawberries

Question 13

Explain the term crossbreeding

Answer 13

Breeding between different varieties of crop or livestock breeds. Each parent has different desirable characteristics. Offspring may have a combination of the desired characteristics.

Question 14

Name three improved breeding techniques involving genetic control

Answer 14

Artificial insemination, (AI)
Embryo transfer
F1 hybrids

Question 15

Explain the process of artificial insemination

Answer 15

Semen sample inserted into a female. No need for animals to meet. Semen can be froze for later use

Question 16

Explain the process of embryo transfer

Answer 16

Eggs are removed from female with desirable characteristics, then they are fertilised with semen. Embryos transferred into surrogate females. Original female can produce many offspring. Embryos can be stored frozen.

Question 17

Explain the term F1 hybrids

Answer 17

True breeding varieties are homozygous for all genes
Offspring produced by breeding between two true breeding varieties
Characteristics inherited are often predictable
Genetic uniformity produces same characteristics and makes management easier-same growth rate, nutrient requirements etc

Question 18

Explain Genetic engineering/transgenics

Answer 18

Genes are artificially transferred between organisms, often of different species. It produces characteristics that couldn’t be produced by natural breeding.

Question 19

Name two examples of genetic engineering/transgenics

Answer 19

Golden rice in the Philippines
Increases vitamin A content
Genes transferred from daffodil and a bacterium.
Bt crops, genes transferred from a bacterium that releases a toxin. Bt crops are toxic to insect pests

Question 20

Define the term productivity

Answer 20

A measure of yield per unit area of land

Question 21

Define the term efficiency

Answer 21

A measure of yield per unit of input

Question 22

What is food conversion ratio

Answer 22

The ratio of the mass of food needed to produce a given mass of animal biomass