classification

Question 1

define classification

Answer 1

the sorting of organisms into smaller sub-groups based on shared similarities

Question 2

define taxonomy

Answer 2

the study of sorting organisms into different groups based on shared similarities

Question 3

why is classification important

Answer 3

1) make the study of living organisms more manageable
2) support ideas of evolution
3) allow scientists to communicate with each other

Question 4

what is the modern classification system called

Answer 4

the phylogenetic hierarchy

Question 5

define the phylogenetic hierarchy

Answer 5

the sorting of organisms into smaller and smaller sub-groups based off of shared similarities to reflect evolutionary relatedness

Question 6

what are the current groupings of taxa used for classification

Answer 6

1) kingdom
2) phylum
3) class
4) order
5) family
6) genus
7) species

Question 7

define a species

Answer 7

a group of organisms which can interbreed together and produce fertile offspring

Question 8

what are the five kingdoms of classification

Answer 8

1) animalia
2) fungi
3) protocista
4) prokaryotae
5) plantae

Question 9

what are the three domains of classification

Answer 9

1) eubacteria
2) archae
3) eukaryotes

Question 10

what are some issues with any classification system

Answer 10

1) places divisions in what is a series of continuous evolutionary trends
2) has to comprise between an accurate representation of evolutionary relatedness and what is convenient
3) new discoveries may require new groups to be set up

Question 11

what are the different methods used to classify organisms

Answer 11

1) similar morphology- homologous/ analogous features
2) biochemical methods- DNA hybridisation, immunology techniques, protein electrophoresis
3) fossil record

Question 12

what are the different biochemical ways of studying evolutionary relatedness

Answer 12

1) protein electrophoresis
2) DNA hybridisation
3) fossil records

Question 13

what is the difference between homologous and analogous features

Answer 13

1) a consequence of divergent evolution where organisms shared a similar ancestor and as a result have similar external structures but used for different functions
2) a consequence of convergent evolution where organisms have no common ancestor and therefore different external structures however they share the same or similar functions

Question 14

outline DNA hybridisation

Answer 14

1) two single strands of DNA from different species are joined together to produce a double hybrid helix
2) the double helix is then heated and the temp at which separation of the two strands is recorded
3) species which are more related will share similar base sequences, therefore have increased complementary base pairs and hydrogen bonds, therefore higher temps are needed to separate them so temps will be closer to 86 degrees
4) species less related will have less compilatory base pairs so have less hydrogen bonds so requires less energy for separation

Question 15

outline how protein electrophoresis can be used as a biochemical method for studying relatedness or species

Answer 15

measures the proportion of genes and therefore protein shared between species to estimate relatedness by separating proteins in a gel

Question 16

out line the biochemical method of immunology techniques in discovering species relatedness

Answer 16

1) human proteins are injected into a rabbit causing an immune responce and the production of specific complementary antibodies to that human protein
2) blood is removed from the rabbit and antibodies are purified
3) antibodies are mixed with the human protein in a test tube so antibody-protein complexes form creating lots of precipitated
4) The same protein from different species will have different amino acid sequences so will have a different tertiary structure so antibodies wont bind so less precipitate formed
5) the amount of precipitate formed is proportional to the degree of similarity between protein molecules

Question 17

outline how fossil records can be used to determine evolutionary relatedness

Answer 17

• layers of sedimentary rocks contain fossils
• new layers cover old ones creating a record overtime
• fossils within layers show the different successions o species which populated earth