B13 Variation and Evolution

Question 1

What is DNA?

Answer 1

DNA is a chemical found in nucleus of cells. It is the genetic material of an organism.

Question 2

Describe the structure of DNA.

Answer 2

DNA is a polymer made up of two strands
forming a double helix.

Question 3

Define the term ‘gene’.

Answer 3

A gene is a small section of DNA on a chromosome. Each gene codes
for a particular sequence of amino acids, to make a specific protein.

Question 4

What is variation?

Answer 4

Variation is the differences in the characteristics of individuals in a population.

Question 5

What causes variation (hint there are 3 causes).

Answer 5

• The genes they have inherited (genetic causes)
• The conditions in which they have developed (environmental
  causes)
• A combination of genes and the environment.

Question 6

What are mutations?

Answer 6

Mutations are any changes to the DNA sequence which may cause a change to the protein.

Question 7

Define an allele.

Answer 7

An allele is a variant form of a gene, which arises due to mutations and leads to differences in inherited traits.

Question 8

Explain the term ‘homozygous’.

Answer 8

Homozygous refers to an individual having two identical alleles for a particular gene, either both dominant or both recessive.

Question 9

What does heterozygous mean?

Answer 9

Heterozygous describes an individual possessing two different alleles for a particular gene, one dominant and one recessive.

Question 10

Define genotype.

Answer 10

Genotype refers to the genetic makeup of an organism, represented by the combination of alleles present for a particular gene.

Question 11

Explain the term ‘phenotype’.

Answer 11

Phenotype refers to the observable characteristics of an organism, which result from the interaction between its genotype and the environment.

Question 12

What is genetic variation?

Answer 12

Genetic variation refers to the diversity of alleles and genotypes within a population or species, which arises due to mutations, meiosis, and sexual reproduction.

Question 13

Define evolution.

Answer 13

Evolution is the process by which species gradually change over time, typically through natural selection, and mutation, leading to the emergence of new species.

Question 14

What is natural selection?

Answer 14

Natural selection is the process whereby organisms better adapted to their environment tend to survive and produce more offspring, while those less adapted tend to be eliminated.

Question 15

Who developed the theory of natural selection?

Answer 15

Charles Darwin

Question 16

Why did people find it hard to believe Darwin’s theory of natural selection?

Answer 16

His theory challenged the idea that God made all living things on earth.

There was insufficient evidence at the time the theory was published to convince Scientists at the time.

The mechanism of inheritance/genes was not known until 50 years after his theory was published.

Question 17

Why Darwin’s theory the most widely accepted now?

Answer 17

It explains a wide range of observations

It has been discussed and tested by a wide range of Scientists all over the world.

Question 18

What is a species?

Answer 18

A species is a group of similar organisms capable of interbreeding to produce fertile offspring.

Question 19

What is selective breeding?

Answer 19

Selective breeding is the process whereby humans deliberately choose organisms with desirable traits to breed, in order to produce offspring with those desired traits. It occurs over many generations.

Question 20

Describe the goal of selective breeding.

Answer 20

The goal of selective breeding is to produce offspring with specific characteristics that are desirable for humans, such as increased yield, disease resistance, or certain physical traits.

Question 21

What is meant by artificial selection?

Answer 21

Artificial selection is a type of selective breeding where humans intentionally choose which organisms will breed based on desired traits, rather than allowing natural selection to determine reproductive success.

Question 22

Give an example of selective breeding in agriculture.

Answer 22

One example of selective breeding in agriculture is the breeding of crops with high yield or resistance to pests and diseases, such as wheat varieties bred for disease resistance or dairy cattle bred for higher milk production.

Question 23

What are some potential ethical considerations of selective breeding?

Answer 23

Ethical considerations of selective breeding include concerns about animal welfare, loss of genetic diversity, and unintended consequences for ecosystems.

Question 24

How does selective breeding differ from genetic engineering?

Answer 24

Selective breeding involves the breeding of organisms with desired traits to produce offspring with those traits, while genetic engineering involves directly altering an organism’s genetic material.

Question 25

What are the disadvantages of selective breeding?

Answer 25

Selective breeding can lead to ‘inbreeding’ where some breeds are particularly prone to disease or inherited defects.

Because of the smaller genetic pool selective bred organisms are more likely to pass on harmful recessive alleles.

There they are more likely to be susceptible to diseases.

Question 26

What is genetic engineering?

Answer 26

Genetic engineering is the process of manipulating an organism’s DNA to introduce or modify specific traits, often by inserting genes from another organism.

Question 27

Give an example of a genetically engineered crop.

Answer 27

Examples of a genetically engineered crop, are corn or soybeans, which have been altered to exhibit traits like herbicide resistance or increased yield.

Question 28

What is the purpose of a vector in genetic engineering?

Answer 28

A vector is a carrier molecule, such as a plasmid or a virus, used to transfer foreign genetic material into a host organism during genetic engineering.

Question 29

What are some applications of genetic engineering in medicine?

Answer 29

Applications of genetic engineering in medicine include the production of pharmaceuticals, gene therapy for genetic disorders, and the development of genetically engineered organisms for medical research.

Question 30

Discuss some of the disadvantages of genetic engineering

Answer 30

• Inserted genes may have unwanted side effects.
• Possible harm when eaten by human/other animals
• Concerns over the effect on populations of wild flowers and insects.
• GM animals might escape and breed with wild animals