B14 Variation and evolution

Question 1

allele

Answer 1

different form of the same gene

Question 2

phenotype

Answer 2

set of observable characteristics of an individual

Question 3

why does speciation happen

Answer 3

result of evolution
mutations create new alleles and two populations diverge
average phenotypes diverge so much they no longer produce fertile offspring

Question 4

survival of fittest

Answer 4

individual w better suited genes/adaptation to environment will survive and produce offspring
most likely to breed successfully
better adapted characteristics more likely to be passed on to next generation

Question 5

evolution

Answer 5

gradual change of inherited characteristics of biological populations over time

Question 6

selective breeding

Answer 6

promotes genetic characteristics seen as desirable
choose + breed parents which strongly display desired characteristic
choose and breed offspring which most strongly show desired characteristic
repeat process until all offspring show desired characteristic

Question 7

selective breeding in crops

Answer 7

disease resistance increase yield
flowers based on visual criteria eg. size or colour
animals that produce most meat/milk for yield

Question 8

disadvantages of selective breeding

Answer 8

lead to inbreeding- susceptible to disease or defects
reduces variation so its harder to adapt to environmental change

Question 9

genetic engineering

Answer 9

modifying an organism’s genome by introducing a gene from another organism to produce a desired characteristic

Question 10

GE process

Answer 10

enzymes used to ‘cut’ desired gene out of chromosome
enzyme used to cut vector
vector used to insert gene into required cell
all cells in developed organism will have gene and show characteristic

Question 11

uses of GM

Answer 11

treat type 1 diabetes by mass producing insulin
GM crops resistant to disease,insects or herbicides produce larger better fruits
sheep have had genomes modified so their milk contains drugs used to treat human diseases

Question 12

advantages of GM

Answer 12

prevent inherited diseases
improve food production efficiency
increase crop yields
better nutritional value

Question 13

disadvantages of GM

Answer 13

reduce biodiversity
long term effect on human health unknown
genes could escape into natural environment
some view it as unethical to create new life forms