B14 - Variation and Evolution

Question 1

What is variation

Answer 1

• Difference in characteristics/pheotypes
• in a population (organism of same specie in a habitat)

Question 3

What is variation caused by

Answer 3

• Genetic causes
• Environmental causes
• combination of genes and environment

Question 4

How common is variation

Answer 4

• Usually lots of genetic variation within a population
  • organisms of same species in a habitat

Question 5

Mutations: frequency and result

Answer 5

• Occur continuously
• Lead to new genetic variants
• Often have no effect on phenotype but can happen
• If phenotype makes organism better suited in it environment it will become more common

Question 6

Natural selection Theory

Answer 6

• All species have evolved from simple life forms
• which first developed more than 3 billion years ago

Question 7

Natural Selection (6 markers) –> Base

Answer 7

• Describe variation caused by random mutation
• Explain which is better adapted
• State who is more likely to survive and reproduce
• Explain what alleles will be passed on more frequently
• Frequency of alleles will increase over generations = natutral selection

Question 8

What is selective breeding

Answer 8

• Humans breed plants and animals
• for particular genetic characteristics

Question 9

What classififies a species

Answer 9

When they can produce fertile offspring

Question 10

Steps involved in selecive breeding

Answer 10

• Parents with desired characteristic are chosen
• They are bred together
• Select best offspring and breed them together
• Repeat over many generations until all offspring show desired characteristics

Question 11

Which characteristics are often choosen

Answer 11

• Disease resistance in crops
• Animals which produce more milk or meat (higher yield)
• Domestic animals with gentle nature
• Asthetic reasons
• Large or unusual flowers

Question 12

Negatives of selective breading

Answer 12

• Reduced gene pool
• due to inbreeding
• which can lead to genetic defects
• and increased risk of disease of health problems

Question 13

Genetic engeeniring

Answer 13

• Modifying the genome of an organism
• By introducing a gene from another organism
• for desired characteristic

Question 14

Why are crops GM

Answer 14

• Resistant to disease
• Resistant to pest
• Resistant to herbicide
• Produe bigger and better fruits (increased yield)
• Have more nutritional value

Question 15

Negatives of GM plants

Answer 15

• Effect on population of wild flowers and insects
• Effect of GM plants on humans hasn’t been fully explored

Question 16

GM in medicine

Answer 16

• Cure inherited disorders
• Transferring normal genes into patients so correct protein is produced

Question 17

Bacterial cell GM

Answer 17

• produce useful substances
• Such as human insulin

Question 18

Describe main stages of Genetic Engineering

Answer 18

• Enzyme are used to cut gene from bacteria
• Gene is inserted into a vector usually a bacterial plasmid or virus
• Vector is used to insert the gene into required cell
• Gene are transferred to cell at an early stage of development
• So cells w/gene can divide and developed desired characteristic

Question 19

What is a clone

Answer 19

an individual that has been produced asexually

Question 20

What are the two methods for cloning plants

Answer 20

• Cuttings
• Tissue culture

Question 21

Cuttings

Answer 21

Cuttings from a parent can be used to make identical plants

• Stem cut from plants
• Cutting dipped in rooting power
• Planted

Question 22

Tissue Cultures

Answer 22

What

• Commercial uses in nurseries
• preserving rare plant species

How

• Sample of small groups of cells
• from parent plant
• are used to grow new identical plants

Question 23

What the 2 ways to clone animals

Answer 23

• Adults cell cloning
• Embryo transplants

Question 24

Adult Cell cloning

Answer 24

• Remove nucleus from body cell (contains same DNA as egg cell) of the desired animal
• Remove egg cells from donor animal
• Insert nucleus of body cell into empty egg cell
• Electric shock to allow cells to divide
• insert uterus of surrogate

Question 25

Embryo transplant

Answer 25

- Remove developing embryos (before specialisation) - Separate cells and grow for a while in lab - transport into host mother