3- classification

Question 1

classification

Answer 1

the naming and organising of organisms in groups based on their characteristics

Question 2

classification system hierarchy

Answer 2

domain, kingdom, phylum, class, order, family, genus, species

Question 3

binomial naming system

Answer 3

• binomial names are italicised
• first part- genus is capitalised
• second part- species is lowercase

Question 4

species

Answer 4

a group of organisms with similar characteristics that are all potentially capable of interbreeding to produce fertile offspring

Question 5

morphological species model

Answer 5

group based on the degree of similarity and difference in their physical characteristics

Question 6

morphological species model disadvantages

Answer 6

• there can be variation within closely related organisms
• when there is sexual dimorphism, different sexes could be considered different species

Question 7

reproductive species model/ mate recognition species model

Answer 7

• group based on whether they are capable of producing fertile offspring
• group based on their fertilisation systems, including mating behaviour

Question 8

reproductive species model/ mate recognition species model disadvantages

Answer 8

• organisms may not interbreed due to geographical isolation
• cross breeding between species can result in fertile offspring
• many species have never been observed mating
• many species do not reproduce sexually
• fossil organisms cannot reproduce but still need to be classified

Question 9

ecological species model

Answer 9

group based on the ecological niche they occupy

Question 10

ecological species model disadvantages

Answer 10

• niche definitions vary
• many species occupy more than one niche

Question 11

genetic species model

Answer 11

grouped based on dna evidence

Question 12

genetic species model disadvantages

Answer 12

• scientists have not decided on the amount of genetic difference needed to consider organisms to be seperate species
• dna collection is difficult and takes a lot of time and money
• fossil organisms do not in most cases have accessible dna

Question 13

evolutionary species model

Answer 13

grouped based on shared evolutionary relationships between species

Question 14

disadvantages of evolutionary species model

Answer 14

there are not always clear evolutionary pathway for organisms

Question 15

molecular phylogeny

Answer 15

a branch of biology where the genetic differences among organisms are analysed to distinguish between species and determine their evolutionary relationships

Question 16

gel electrophoresis process

Answer 16

1) make wells in agarose jelly
2) extract the dna, and cut it into fragments with restriction endonuclease enzymes
3) dye the DNA with florescent dye
4) turn on a current to seperate the DNA by electrophoresis- DNA is (-) and moves to the anode
5) different bands represent different amino acids, they can be compared to known fragments

Question 17

dna sequencing

Answer 17

a technique used to find the exact sequence of nucleotides in a dna molecule, thus highlighting similarities and differences in the genetic data of organisms

Question 18

bioinformatics

Answer 18

an interdisciplinary field that used computational methods and software tools to analyse and compare genetic data between organisms

Question 19

analysis of genetic data

Answer 19

• genetic sequences can be used to establish evolutionary relationships among species
• the degree of similarity in sequences can indicate how closely related the species are

Question 20

role of scientific journals

Answer 20

scientific journals serve as platforms for researchers to publish their findings and contribute to the existing body of knowledge in a field

Question 21

peer review process

Answer 21

other scientists, experts in the same field, critically evaluate the evidence, methodology and results of a study. this adds credibility and validation to the findings

Question 22

scientific conferences

Answer 22

these events allow scientists to present their research, debate, and evaluate data. they also provide an opportunity for potential errors to be spotted and rectified

Question 23

3 domain model of classification

Answer 23

archaea, bacteria and eukaryotes

Question 24

basis for the three domain model

Answer 24

• Woese sequenced bacterial RNA and DNA, observed that methanogens lacked sequences characteristic of bacteria and proposed they belonged in a new domain; archae
• archae lack peptidoglycan in their cell walls, have different phospholipids in their cell membranes, and show differences in membrane structure, proteins and organelles when compared to other bacteria

Question 25

differences between the three domain and five kingdom systems

Answer 25

the three domain system gives less importance to eukaryotic groups, reflecting the greater diversity within prokaryotes by separating Archaea from other bacteria