Variation and Evolution

Question 1

What is variation in biology?

Answer 1

Variation is defined as differences between individuals in an ecosystem.

Question 2

Give examples of genetic variation in humans.

Answer 2

blood group
eye colour
biological sex
ability to roll the tongue
free or fixed earlobes

Question 3

What factors contribute to environmental variation?

Answer 3

Environmental factors such as climate, diet, accidents, culture, and lifestyle contribute to environmental variation.

Question 4

How can genes and environment together affect a characteristic?

Answer 4

Genes give the characteristics we inherit, but the environment affects how these inherited characteristics develop.

For example, children of tall parents have the genetic potential to be tall, but poor diet can affect their growth.

Question 4

Give examples of environmental variation.

Answer 4

scarring from accidents

weight gain from diet and lifestyle

language and accent from being raised in a certain country

plant growing taller in the shade to reach more light

Question 5

What is genetic variation?

Answer 5

Genetic variation refers to differences in the DNA sequences of individuals within a population, leading to different traits or characteristics.

Question 6

What causes genetic variation within a species?

Answer 6

Genetic variation within a species is usually caused by mutations, which are random genetic changes that occur continuously.

Question 7

How do most mutations affect the phenotype?

Answer 7

Most mutations do not affect the phenotype because the protein produced by a mutated gene may function just as well as the protein from the non-mutated gene.

Question 7

Define mutation.

Answer 7

Mutations are random genetic changes that occur continuously.

Question 8

What influences the development of the phenotype of an organism?

Answer 8

The genome and its interaction with the environment influence the development of the phenotype of an organism.

Question 9

Define the term evolution.

Answer 9

Evolution is the change that occurs in populations over many generations. Natural selection is the mechanism by which this change occurs. This may result in the formation of a new species.

Question 9

What does the theory of evolution state about the origin of all living species on earth?

Answer 9

All species of living things have evolved from simple life forms that first developed more than three billion years ago.

Question 10

During the process of evolution, how is it possible to recognise the point at which two new species have evolved from one starting species?

Answer 10

Evolution has given rise to two new species at the point at which two populations of one species become so different in phenotype that they can no longer interbreed to produce fertile offspring.

Question 11

What is selective breeding in plants?

Answer 11

Selective breeding in plants involves the intentional breeding of plants with desirable traits to produce offspring with enhanced characteristics.

Question 12

What are some characteristics that plants are selectively bred for?

Answer 12

Disease resistance in food crops
The development of large or unique flowers
(The first two you need to specifically for your specification)
Increased crop yield
Tolerance to weather conditions such as drought or frost
Improved taste and nutritional quality of fruits

Question 12

What are two potential characteristics that animals are selectively bred for?

Answer 12

High milk or meat production in livestock such as cows, goats, and sheep
Docile temperament in domestic dogs
(The first two you need to know specifically for your specification)
High-quality wool in sheep
Large egg-laying capacity in chickens
Specific physical features or performance abilities in horses

Question 13

What are some potential problems associated with selective breeding?

Answer 13

Selective breeding can lead to inbreeding, which occurs when closely related individuals are bred together to perpetuate desired traits.

Inbreeding reduces the genetic diversity within a population, resulting in an increased risk of inheriting harmful genetic defects.

Additionally, the reduced genetic variation makes organisms more susceptible to new diseases, as there are fewer chances of possessing resistance alleles within the population.

Question 14

What is the significance of maintaining genetic diversity in selectively bred animal populations?

Answer 14

Resilience to disease
Good health
Adaptability of breeds over time

Question 14

What is selective breeding in animals?

Answer 14

Selective breeding (also known as artificial selection), involves the intentional mating of animals with desirable traits to produce offspring that inherit those characteristics.

Through careful selection and breeding of animals over successive generations, breeders aim to develop new breeds or strains that reliably exhibit the desired characteristics.

Question 15

True or False?

Selective breeding will yield success in just a few generations.

Answer 15

False.

Selective breeding occurs over many generations. Although, the process is much faster than natural selection as individuals with the desired characteristics are chosen to breed at the start of the process.

Question 16

Define the term genetic engineering.

Answer 16

Genetic engineering is a process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic.

Question 17

Why are plants crops genetically engineered?

Answer 17

Plant crops have been genetically engineered for several reasons, including to increase resistance to diseases or to produce bigger better fruits and vegetables.

Question 18

What are the main steps in the process of genetic engineering?

Answer 18

Enzymes are used to isolate the required gene

This gene is inserted into a vector, usually a bacterial plasmid or a virus

The vector is used to insert the gene into the required cells

Genes are transferred to the cells of animals, plants or microorganisms at an early stage in their development so that they develop with the desired characteristics

Question 19

Give an example of the use of bacteria in genetic engineering.

Answer 19

Bacterial cells have been genetically engineered to produce useful substances such as human insulin to treat diabetes.

Question 20

What are the potential benefits of genetic engineering in agriculture and medicine?

Answer 20

plants can be resistant to diseases GM crops generally show increased yields reduced use of pesticides and herbicides producing useful substances such as human insulin to treat diabetes overcoming some inherited disorders

Question 21

What are the potential risks of genetic engineering in agriculture and medicine?

Answer 21

the effect on populations of wildflowers and insects which may be reduced/reduced biodiversity herbicide-resistant GM crops are only effective on one type of herbicide, so there is increased dependency on this herbicide

Question 22

Define tissue culture.

Answer 22

Tissue culture is using small groups of cells from part of a plant which is used to grow identical new plants.

Question 22

What are genetically modified (GM) crops?

Answer 22

Crops that have had their genes modified by introducing a gene from another organism are called genetically modified (GM) crops.

Question 23

Why is tissue culture important?

Answer 23

Tissue culture is important to preserve rare plant species or for commercial benefit in nurseries.

Question 24

Define the term cutting in the context of plant cloning.

Answer 24

A cutting is a method used by gardeners to produce many identical new plants from a parent plant. Part of a plant off is cut and used to grow a new genetically identical plant.

Question 25

Define embryo transplant.

Answer 25

Embryo transplant is splitting apart cells from a developing animal embryo before they become specialised, then transplanting the identical embryos into host mothers.

Question 26

What are the steps of adult cell cloning?

Answer 26

The nucleus is removed from an unfertilised egg cell The nucleus from an adult body cell is inserted into the egg cell An electric shock stimulates the egg cell to divide to form an embryo The embryo cells contain the same genetic information as the adult body cell When the embryo has developed into a ball of cells, it is inserted into the uterus of an adult female to develop