B14

Question 1

Two types of variation

Answer 1

Genrtic variation and environmental variation

Question 2

Variation

Answer 2

Its how organisms can vary in appearance, size, eye colour……….

Question 3

Our characteristics are determined by

Answer 3

Our genes inherited by parents

Question 4

The combining of genes from two parents causes

Answer 4

Genetic variation - no two of the soecies are genetically identical (other than identical twins)

Question 5

Environmental variation

Answer 5

The envrionment including the conditions that organisms live and grow in, causes difference brtween members of the same species.
- it covers a range of sifferences from losing toes, getting a tan, to yellow leaves and dark leaves

Question 6

Mutations

Answer 6

Changes to the sequence of bases in DNA. Mutations lead to changes in protein that a gene codes for.
- most mutations have no effect on the protein genes code for, so phenotype is barely affected.
- some very slightly influence characterisitics
- if environment changes, and the new phenotype makes an individual more suited to the new environment.

Question 7

Theory of Evolution

Answer 7

All of today’s species have evolved from simple life froms that fursf started to develop over three billion years

Question 8

Evolution

Answer 8

How species have developed over millions of years

Question 9

The species on earth today have

Answer 9

Evolved over millions of years

Question 10

The process of evolution started with _____ organisms which lived in ______, over time these evolved to become ________. This eventually produced the animals of the ____ and _____ we observe today. Most of the evidence for evolution comes from ________

Answer 10

Unicellular, water, multicellular. Air, land, fossils

Question 11

Survival of the fittest

Answer 11

Organisms with the most suitable characteristics for the environment would be more successful competitors and would be more likely to survive

Question 12

Natural selection

Answer 12

Organisms with the most suitable characteristics for the environment would be more successful competitors and would be more likely to survive

Question 13

Selective breeding

Answer 13

When humans artificially select the plants/animaks that are giing to breed si that the genes for particular characteristics remain in the population

Question 14

Organisms are selectively bred to develop certain features…..

Answer 14

• animals that produce meat/milk
• crops with disease resistance
• dogs with good/gentle temperament
• decorative plants with big/unsusual flowers

Question 15

Selective breeding process:

Answer 15

• from exisiting stock, select ones sith desriable characteristics
• breed them together
• select best offspring, breed them together
• do this over several generations, and desirable traits gets stronger and stronger
• eventually all will have the characterisitics.

Question 16

Drawbacks of SELECTIVE BREEDING

Answer 16

• reduces the gene pool (num of different alleles in a populatio)
• this is because farmers breed the best animals togehter which are usually always closely related (inbreeding)
• causes health problems as more chance of organisms inhering harmful genetic defects as gene pool is limited
• serious problems if new disease appears, as not much variation in the population.
• as they are all closely related, if one dies to it, the others are also likely to succumb it.

Question 17

Advantages of Selective breeding:

Answer 17

• Higher economic gains
• eliminating disease
• create new varieties of crops
• does not involve genetic modification
• ## produces fitter, stronger animals

Question 18

Disadvantages of selective breeding

Answer 18

• animal discomfort
• loss of variety and variation (inbreeding)
• no control of genetic mutations
• can lead to loss of traits
• it can change the evolution of a species

Question 19

Genetic engineering is a process which involves

Answer 19

modifying the genome of an organism by introducing a gene from another organism to give a desired characte

Question 20

Plant crops have been genetically engineered to be

Answer 20

resistant to diseases or to produce bigger better fruits.

Question 21

Bacterial cells have been genetically engineered to produce

Answer 21

useful substances such as human insulin to treat diabetes.

Question 22

In genetic engineering, genes from the chromosomes of humans and other organisms can be

Answer 22

‘cut out’ and transferred to cells of other organisms.

Question 23

The main steps in genetic engineering:

Answer 23

• 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 desired characteristics.

Question 24

Genetic modification (bacteria, crops, sheep, inherited disease

Answer 24

• Bacteria have been GM to produce human insulin thst can be used to treat diabetes
• GM crops have had their genes modified to improve suze/auality of their fruit, make them resistant to disease/insects/herbicides.
• sheep have been genetically engineered to produce substances, like drugs, in their milk that csn be used to treat human diseases.
• scientists are researching GM treatmentsfor inherited diseases caused by faulty genes. (By inserting working genes into people with the disease (gene therapy).

Question 25

Pros of GM crops:

Answer 25

• the characteristics chosen for GM crops can increase the yield, making more food.
• in developing nations = often lack of nutrients in their diets = GM crops can be engineered to contain missing nutrients
• GM crops are being grown in places, often no problems

Question 26

Cons of GM CROPS:

Answer 26

• Growing GM crops affect the number of wikd flowers that kune in/around crops - reducing BIODIVERSITY
• not all people convinced that GM crops are safe and concerned that we don’t fully understand the affects of eating them on human health
• A big concern is that transplanted genes may get out into the natural environment.

Question 27

Concerns about genetic engineering

Answer 27

• Genetic engineering is a very new science-no one can be sure about the long term effects.
• Insects may become pesticide-resistant if they eat a constant diet of pesticide-forming plants.
• Genes from GM plants and animals might spread into the wildlife countryside. This might affect wild flowers and insects.

Question 28

Three advantages of GE in agriculture

Answer 28

• improved plant growth rates of plants
• increased crop food value
• ability to grow crops in adverse conditions

Question 29

Genetic engineering may one day be used to dure human genetic disorders. How

Answer 29

• ‘healthy’ genes could be inserted into affected cells.
  • the affected cells could then begin to work properly
  • advances in science may mean we can alter peoples genes
  • Scientists would then be able to change the affected gene so they no longer have the disorder

Question 30

Plants can be cloned by tissue culture and from cuttings

Answer 30

Tissue Culture:
- Where a few plant cells are put in a growth medium with hormones, they grow into new plants - clones of the parent plant
- some plants can be made very quickly, in little space grown all year.
-Tissue culture preserves rare plants that are hard to reproduce naturally and by plants nurseries to produce lots of stock quickly.
Cuttings:
- Gardeners take cuttings from good parent plants, then plant them to produce genetically identical copies of the parent plant.
- These plants can be produced quickly and cheaply. Older, simpler method thsn tissue culture.

Question 31

A species is a group of similar

Answer 31

Organisms that can reproduce to give fertile offspring.

Question 32

Speciation is

Answer 32

The development of a new species

Question 33

Speciation occurs when

Answer 33

Populations of the same species become so different thst they csn no longer successfully interbreed to produce fertile offspring.

Question 34

Animal clones using Embryo Transplants:

Answer 34

• sperm cells taken from a bull and egg cekls are from cow.
• the sperm are used to artificially fertilise an egg cell. The embryo that develops then splits manu times before any cells become slecialised.
• cloned embryos can then be implanted into lots of other cows where they grow into baby calves.

Question 35

Adult cell cloning is another way to make a clone….