B14 Variation and Evolution

Question 1

What are inter-specific variation?

Answer 1

Variation between different species

Question 2

What is intra-specfic variation?

Answer 2

Variation between organisms of the same species.

Question 3

What is an example of inter-specific variations?

Answer 3

Humans and monkeys

Question 4

What is an example of intraspecifc variations?

Answer 4

Skin colour

Question 5

What factors can cause variations?

Answer 5

• genetic factors only
• enviromental factors only
• genetic and enviromental factors both

Question 6

Examples of genetics only variations?

Answer 6

• Blood type
• Skin colour
• Hair colour
• Attached earlobe
• Ability to roll tounge

Question 7

Examples of enviroment only variations?

Answer 7

• Accent
• Languages
• Music
• Scarring
• Sports

Question 8

Examples of genetic and enviromental variations?

Answer 8

• weight
• height
• skin tan colour
• intelligance
• life expectancy

Question 9

What is variation?

Answer 9

Variation is the differences between individuals of a population

Question 10

What does a mutation do?

Answer 10

Causes change to the protien that is expressed

Question 11

What is natural selection?

Answer 11

A process where organisms that are better adapted to an environment will survive and have more offspring. This means their genes are passed on to the future generations.

• This process is fundamental to the process of evolution

Question 12

What term did Charles Darwin give to explain natural selection and his theory of evolution?

Answer 12

Survival of the Fittest

Question 13

What is selective breeding?

Answer 13

An artificial process in which humans breed plants and animals for particular genetic characteristics.

Question 14

What are the steps for selective breeding?

Answer 14

1) Select parents with desired characteristics
2) Breed the parents (control pollination in plants)
3) Choose the best offsprings with desired characteristics to breed for the next generation
4) Repeat this process over many generations until all offsprings have desired characteristics

Question 15

Give examples of selective breeding being used in animals?

Answer 15

• Highland cows and Arberdeen Angus cows have been bred for their meat
• Friesian cows have been bred to produce large volumes of milk

Question 16

What are examples of desired characteristics in plants?

Answer 16

• disease resistance in food crops
• wheat plants that produce lots of grain
• large or unusual flowers

Question 17

What are examples of desired characteristics in animals?

Answer 17

• animals that produce lots of milk or meat
• chickens that lay large eggs
• domestic dogs that have a gentle nature

Question 18

How can we determine that two populations of a species has become to different species?

Answer 18

If the two species have become so different that they can’t interbreed to produce fertile offspring, then two new species has formed

Question 19

What are the risks of selective breeding?

Answer 19

• Reduced genetic variation can lead to attack by specific insects or disease, which could be extremely destructive
• Rare disease genes can be unknowingly selected as part of a positive trait, leading to problems with specific organisms, eg a high percentage of Dalmatian dogs are deaf
• Can create physical problems in specific organisms, eg large dogs can have faulty hips due to not being formed correctly

Question 20

What is genetic engineering?

Answer 20

The modification of the genome of an organism by introducing a gene from another organism to result in a desired characteristcs

Question 21

What are the steps of genetic engineering?

Answer 21

1) Enzymes are used to isolate the required gene, this gene is inserted into a vector, which is usually a bacterial plasmid or a virus.

2) The vector inserts the gene into required cells.

3) The genes are transferred to animal, plant or microorganism cells, during early development. This allows them to develop with the desired characteristics.

Question 22

Give an example of genetic engineering.

Answer 22

Insulin producing bacteria
Golden rice
Disease resistant crops

Question 23

What is an advantage of golden rice?

Answer 23

Populations where vitamin A deficiency is common can grow it to prevent blindness.

Question 24

What are the ethical issues concerned with genetic modifaction/engineeing?

Answer 24

• It may contain possible health risks, release of toxins or allergic reactions
• Others think it’s ethically wrong to create new life forms or to move genes between organisms

Question 25

Give a future use of genetic engineering?

Answer 25

In the future researchers are hoping to use genetic engineering to be able to overcome some inherited disorders, such as cystic fibrosis and Huntington's disease amongst others.

Question 26

What are the benefits of genetic engineering?

Answer 26

- Genetic modification is a faster and more efficient way of getting the same results as selective breeding. - Improve crop yields or crop quality, which may help reduce hunger around the world. - Introduce herbicide resistance, which results in less herbicides being used - Insect and pest resistance can be developed and inserted into the plants. The plant produces toxins, which would discourage insects from eating the crop. - Sterile insects could be created such as a mosquito. They would breed, which would lead to infertile offspring. This may help with spread of diseases, *such as malaria ans dengue fever*

Question 27

What are the risks of genetic engineering?

Answer 27

- Transfer of the selected gene into other species. What benefits one plant may harm another. - Some people believe it is not ethical to interfere with nature in this way. - GM crop seeds are often more expensive and so people in developing countries cannot afford them. - GM crops could be harmful, for example toxins from the crops have been detected in some people’s blood. - GM crops could cause allergic reactions in people. - Pollen produced by the plants could be toxic and harm insects that transfer it between plants.

Question 28

What is a clone?

Answer 28

An organism that is genetically identical to another organism.

Question 29

What are the different methods of cloning in plants?

Answer 29

- Cuttings - Tissue Culture

Question 30

How are cuttings used to clone plants?

Answer 30

1) A branch from the parent plant is cut off, its lower leaves are removed, and the stem is planted in damp compost. 2) Plant hormones are often used to encourage new roots to develop. The cutting is usually covered in a clear plastic bag to keep it moist and warm. After a few weeks, new roots develop and a new plant grows.

Question 31

What is another name for cloning in tissue culture?

Answer 31

micropropagation

Question 32

How can we use tissue culture in the cloning of plants?

Answer 32

1) Explants are placed in Agar growth medium containing nutrients and auxins 2) Samples develop into tiny plantlets 3) Plantlets planted into compost

Question 33

Why is cloning by tissue culture more expensive than cuttings?

Answer 33

They are growm in virto (in glassware) using sterile agar jelly that contain plant hormones and nutrients

Question 34

What are the different methods of cloning in animals?

Answer 34

- Embyro transplants - Adult cell cloning

Question 35

How can embryo transplants be used in animal cloning?

Answer 35

1) Sperm is taken from bull and artificially inseminated into cow 2) Zygotes develop into embryos in cow and then removed from the uterus 3) Embryos are split into several smaller cells before they become specialised, each of which can grow into a new calf 4) Identical embryos are transplanted into host mothers

Question 36

How can adult cell cloning be used in animal cloning?

Answer 36

1) The nucleus is removed from an unfertilised egg cell. 2) The nucleus from an adult body cell, such as a skin cell, is inserted into the egg cell. 3) An electric shock stimulates the egg cell to divide to form an embryo. 4) These embryo cells contain the same genetic information as the adult skin cell. 5) When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.