(Module 13)Variation and Evolution

Question 1

Definition of variation

Answer 1

Differences in the characteristics of individuals in a population

Question 2

What may cause variation

Answer 2

The genes the individual has inherited

The conditions in which they have been raised and developed (upbringing, environment)

Question 3

Definition of species

Answer 3

A group of similar organisms capable of interbreeding to produce fertile offspring

Question 4

Definition of a mutation

Answer 4

This is where the DNA (Genes) of an organism are changed/modified

Question 5

What is natural selection

Answer 5

This is where an organism that gains an advantage over another is more likely to survive and breed

Question 6

What is genetic screening

Answer 6

Genetic screening/testing involves undergoing tests to discover if a person/embryo/foetus has a genetic disorder or is carrying a faulty allele

Question 7

Give 3 ways embryos can be genetically scanned

Answer 7

Amniocentesis: takes sample of fluid around the baby (in the mums tummy)
Chorionic villus sampling: sample of tissue surrounding the baby
Analysing the foetus cells found in the mothers blood

Question 8

Advantages of genetic screening

Answer 8

Parents can decide whether or not to have children/continue with pregnancy
allows preparation for the parents to plan ahead, and could get treatment for the condition
They will know if there is a possibility of the child getting ill in the future

Question 9

Disadvantages of genetic screening

Answer 9

Risk of miscarriage/harm to the mother or foetus
Tests may be unreliable (false positive/false negative)
Screening can be very expensive
Ethically or morally wrong in some relegions

Question 10

Definition of selective breeding

Answer 10

This is the process by which humans breed plants or animals for particular genetic characteristics

Question 11

Show the steps of selective breeding (4 steps)

Answer 11

1. Choose two parents with the desired characteristics
2. Breed these two parents together
3. From the offspring, choose those with the desired characteristics and breed them together
4. Repeat this process over many generations until all the offspring show the desired characteristics

Question 12

Give 5 advantages of selective breeding

Answer 12

Can produce animals and plants with desirable characteristics
Increased milk/meat yield from cattle
Can create new varieties of good crops
Disease resistant in food crops or garden plants
Can produce domesticated animals with a gentle nature e.g labradoodles

Question 13

Give 5 disadvantages of selective breeding

Answer 13

Ethically or morally wrong in some religions
Inbreeding can occur
If a parent has a problem, it will be in all of its kin
A disease may occur which attacks the selected plants and could wipe them all out
Reduces variation
Unfair for animals without the desired characteristics

Question 14

What is genetic engineering

Answer 14

Genetic engineering is the the modification of the genetic material of an organism

Question 15

What are the basic steps of genetic engineering (4 steps)

Answer 15

1) Enzymes are used to isolate the required gene
2) This gene is inserted into a vector (usually a bacterial plasmid or a virus)
3) The vector is used to insert the gene into the required (host) cells
4) Genes are transferred to the cell of animals, plants or microorganisms at an early stage in development so that they can develop with the desired characteristics

Question 16

Give some advantages of Genetic engineering

Answer 16

Advantages:
Improves crop yield
Extends shelf life for products
Improves resistance to pesticides
Manufactures a certain chemical (e.g bacteria can manufacture insulin due to genetic engineering)
It is a convenience

Question 17

Give some disadvantages of genetic engineering

Answer 17

It may create unwanted side effects
Genetically modified animals could escape and mate with wild animals
(Can be Ethically or morally wrong in some religions)