3.1 Classification

Question 1

give the order of the classification system

Answer 1

domain
kingdom
phylum
class
order
family
genus
species

Question 2

what are the three domains based on

Answer 2

molecular phylogeny

Question 3

describe eukarya

Answer 3

protists
fungi
plantae
animalia

Question 4

describe bacteria

Answer 4

eubacteria-true bacteria found in digestive system of many organisms

Question 5

describe archaea

Answer 5

archaebacteria - ancient bacteria

early relatives of the eukaryotes found in extreme conditions

Question 6

name the 3 domains

Answer 6

eukarya, bacteria, archaea

Question 7

what is the morphological species concept

Answer 7

if two organisms look similar, they are likely to be a similar species

Question 8

what are the limitations of the morphological species concept

Answer 8

• appearance of organisms can be affected by many factors
• may be a huge variation within a group of closely related organisms
• sexual dimorphism- great difference between males and females so different sexes could be seen as different species

Question 9

describe the reproductive species model

Answer 9

groups of organisms with similar characteristics that interbreed to produce fertile offspring

Question 10

give a limitation of the reproductive species model

Answer 10

if organisms of the species are geographically isolated, they cannot attempt to interbreed to produce fertile offspring

Question 11

define molecular phylogeny

Answer 11

the analysis of the genetic material of organisms to establish their evolutionary relationships

Question 12

give the process of gel electrophoresis

Answer 12

1. DNA is amplified in a polymerase chain reaction so multiple copies are made
2. DNA cut into fragments by restriction enzymes- fragments are then added to a dye so that it will glow under ultraviolet light
3. DNA fragments are loaded into wells in an agarose gel
4. buffer solution is added to maintain a constant pH - a potential difference is applied across gel
5. phosphate group in DNA gives it a slightly negative charge- moves towards anode. fragments separate bands and move based on mass and charge

Question 13

what do genetic differences tell us

Answer 13

evolutionary relationships

Question 14

where can genetic differences be found

Answer 14

in DNA sequences

in amino acid sequences

Question 15

define bioinformatics

Answer 15

electrophoresis, DNA sequencing and other molecular phylogeny techniques generate a vast amount of data so all data is analysed and organised on computer software

Question 16

what are the 3 key aspects of validating scientific evidence

Answer 16

scientific journal- work must be published
peer-review- paper must be original, significant, valid
scientific conferences- new ideas presented and challenged

Question 17

give 3 pieces of evidence for Darwin’s theory of evolution

Answer 17

• DNA molecule is the same in all organisms (supports Darwin’s idea of descent from common ancestor)
• DNA + protein have changes which can be identified and compared to see how closely related organisms in species are
• assessing speed of mutation shows species evolution over time

Question 18

describe the process of antibiotic resistance

Answer 18

1. original population has a variety of alleles caused by mutations
2. antibiotic is taken
3. bacteria with resistant mutation survive
4. new population has higher proportion of advantageous resistant mutation
5. antibiotic is taken again
6. only bacteria with resistant mutation survive
7. new population is almost entirely to antibiotics apart from new mutants.