Variation and Evolution

Question 1

Phenotype

Answer 1

Observable characteristics of an individual due to the interaction with their genes and their environment.

Question 1

Variation

Answer 1

Differences in the characteristics of individuals within a population

Question 2

Why is there so much genetic variation?

Answer 2

Mutation

Question 3

How can mutation be beneficial?

Answer 3

The organism is more likely to survive and reproduce and pass their genes (survival of the fittest)

Question 4

Natural selection

Answer 4

fittest individuals selected to survive

Question 5

Evolution

Answer 5

Inheritance of certain characteristics in a population, over multiple generations, could lead to a change in the whole species.

Question 6

Theory of evolution

Answer 6

All of today’s species have evolved from simple life forms that first started to develop over three billion years ago.

Question 7

Why did some people disagree against Darwin’s theory?

Answer 7

• Went against religious beliefs on how life on
  Earth developed
• Darwin couldn’t prove how useful
  characteristics were passed on; did not know
  anything about genes or mutations
• Wasn’t enough evidence to convince scientists
  as there weren’t a lot of other studies on
  evolution

Question 8

How has Darwin theory been proven?

Answer 8

• Fossil records
• Antibiotic Resistance

Question 9

Speciation

Answer 9

Over a long period, the phenotype of organism can change so much (natural selection) that a completely new species is formed.

Question 10

What are some reasons for extinction?

Answer 10

• Environment changes too quickly
  (deforestation)
• New predator kills them all (humans hunting)
• New disease kills them all
• Cannot compete with another species for food
• Catastrophic event that kills them all (collision
  with asteroid)

Question 11

Selective breeding

Answer 11

Humans artificially select organisms to breed together to develop features that are useful or attractive.

Question 12

What are examples of offspring from selective breeding

Answer 12

• Animals that produce more meat or milk
• Crops with disease resistance
• Dogs with a good, gentle temperament
• Decorative plants with big or unusual flowers

Question 13

Selective Breeding process

Answer 13

1. From existing stock, select ones with
   characteristics of your choice
2. Breed them together
3. Select best offspring and breed together
4. Continue this process over many generations
   for all the offspring to have the characteristics

Question 14

What is the main drawback of selective breeding?

Answer 14

It reduces the gene pool meaning inbreeding takes place

Question 15

Gene pool

Answer 15

The number of different alleles in a population

Question 16

inbreeding

Answer 16

• Can cause health problems because there’s
  more chance of organisms inheriting harmful
  genetic defects when the gene pool is limited.
• If new disease appear it would very serious as
  there is not variation in the population as all
  the stocks are closely related.

Question 17

Genetic Engineering

Answer 17

Transferring a gene thatcontains the desirable characteristics from one organism’s genome to another (modifying genome).

Question 18

Examples of genetic engineering

Answer 18

• Bacteria being genetic modified to produce
  human insulin to treat diabetes
• Sheep has been genetically engineered to
  produce drugs in their milk to treat human
  diseases
• gene therapy
• GM crops has improved size and quality of
  fruits or resistant to diseases

Question 19

Gene therapy

Answer 19

inserting working genes into people with the disease.

Question 20

How is Genetic Engineering carried out

Answer 20

1. A useful gene is isolated from one organism’s
   genome using enzymes and is inserted into a
   vector
2. Vector usually a virus or a bacterial plasmid
3. When the vector is introduced to the target
   organism, the useful gene is inserted into its
   cells.

Question 21

Genetic engineering drawbacks

Answer 21

• Small risk that GM could negatively affect our
  health
• if crops breed with wild plants they could
  spread their new genes and affect the gene
  pool

Question 22

What are the 2 methods that clones plants

Answer 22

• Tissue culture
• Cutting

Question 23

Tissue culture

Answer 23

A few plants are put in a growth medium with hormones and grow into new plants- clones of parent
- can be made very quickly in little space and all
year round

Question 24

Cutting

Answer 24

Gardeners take cutting from good parent plants and plant them to produce clones of parent plant
- can be produce quickly and cheap

Question 25

Embryo transplant

Answer 25

1. sperms cell are taken from animal 1 and egg
   cells are taken from animal 2
2. the sperm are then used to artificially fertilize
   and egg cell. the embryo then carries out
   mitosis before any cells become specialized
3. the clones embryos are then implanted into l
   its of other cows where they grow into babies
   which will be genetically identical to each
   other.

Question 26

Adult cell cloning

Answer 26

1. take an unfertilized egg cell and remove its
   nucleus
2. remove nucleus from an adult body cell and
   insert it into the empty egg cell
3. the egg cell is then stimulated by an electric
   shock making the egg to divide just like a
   normal embryo
4. when the embryo is a ball of cell it is then
   inserted into a womb of an adult female and
   grow into a genetically identical copy

Question 27

what are the issues surrounding cloning

Answer 27

• reduced gene pool (population will all die out)
• possible that cloned animals may not be as
  healthy as normal ones and make people
  afraid that cloning humans are next

Question 28

What are the benefits of cloning

Answer 28

• help to preserve endangered species
• better understanding of the development of embryos and of age related disorders