Variation and Evolution

Question 1

list the three causes of variation

Answer 1

1. Genetic Variation
   - based on the alleles the individual has inherited
2. Environmental Variation
   - based on the environment an individual grows up in
3. Genetic and Environmental Variation
   - based on the alleles the individual has inherited and whether the environment they live in can contribute

Question 2

define mutations

Answer 2

random changes to DNA

Question 3

define evolution

Answer 3

the change in the inherited characteristics of a population over time through a process of natural selection

Question 4

what is the main problem with selective breeding?

Answer 4

inbreeding - if we breed together closely related animals or plants, they can be prone to disease

Question 5

define genetic engineering

provide some examples

Answer 5

when genes are cut out from one organism and transferred to the next

e.g. INSULIN - bacteria have been genetically modified to contain the human insulin gene for people with type 1 diabetes

*e.g. GENETICALLY MODIFIED CROPS - can be made resistant to disease or insect attack

Question 6

what are the main steps in genetic engineering? (4)

Answer 6

• identify that gene that is going to be transferred
• isolate that gene using enzymes
• transfer the gene into a small circle of DNA (a plasmid) or a virus
• then, the desired gene is transferred into the cells of the target organism

Question 7

how could bacteria become resistant to antibiotics? (4)

Answer 7

through a mutation; when the antibiotic is killed, all other bacteria are killed but the resistant bacteria remains

• this antibiotic resistant strain then reproduces without any competition from other bacteria
• under the right conditions, bacteria can reproduce every 30 minutes
• the resistant strain now spreads; this is because people are not immune to it and there’s no effective treatment

Question 8

describe the three ways in which antibiotic resistant strains can be reduced in development

Answer 8

1. doctors should prescribe antibiotics appropriately
   - there’s no point using antibiotics for a virus because they have no effect on them
2. patients should always complete their course of antibiotics to make sure all the bacteria are killed
3. restrict the use of antibiotics in farming

Question 9

who was carl linnaeus

Answer 9

the first to start classifying species into different categories

Question 10

what is each organism named from?

Answer 10

their genus and species
it’s known as their binomial name

Question 11

who was carl woese

Answer 11

he developed the three domain system

Question 12

what does the three domain system consist of?

Answer 12

ARCHAE - primitive bacteria
TRUE BACTERIA - the kind that live in the human digestive system
EUKARYOTA - animals, plants, fungi, protists