4.3.3 evidence used in classification

Question 1

what’s convergent evolution

Answer 1

2 unrelated species could adapt in similar ways & thus, look similar

Question 2

how can we determine the differences between animals seen today is evolution

Answer 2

by assuming the earliest living things all had identical versions of these molecules (certain large biological molecules in all living things)

Question 3

evidence for organisms not evolving separately for long

Answer 3

if they have similar molecules

Question 4

how can we determine organisms have evolved separately for longer

Answer 4

if they have very different versions of the molecule

Question 5

what do the differences between these molecules in different species reflect

Answer 5

evolutionary relationships

Question 6

what can we also use biological molecules in classification for

Answer 6

to clarify & correct relationships we are unsure about

Question 7

what’s cytochrome c

Answer 7

protein used in respiration which all living organisms who respire must have (but not identical in all species)

Question 8

what can be compared within cytochrome c to compare between species

Answer 8

the amino acid sequences

Question 9

what certain conclusions can be drawn when comparing amino acid sequences in cytochrome c

Answer 9

• if sequences same = 2 species must be closely related
• if sequences different = 2 species aren’t closely related
• more differences found between sequences = less closely related the species are

Question 10

how can DNA be used to classify organisms

Answer 10

• found in all living organisms
• genetic code same for all organisms = universal
• changes to sequence of DNA = mutations
• comparison of DNA sequences can be used to classify species
• more similar sequence in section of DNA = more closely related 2 species

Question 11

who created the 3-domain system

Answer 11

1990 carl woese

Question 12

components of the 3-domain system

Answer 12

• eukaryotes
• prokaryote = bacteria & archaeae

Question 13

structural differences of bacteria compared to archaeae & eukaryotes

Answer 13

• diff. cell membrane structure
• flagella w/ diff. internal structure
• diff. enzymes (RNA polymerase) for synthesising RNA
• no proteins bound to genetic material
• different mechanisms for DNA replication & synthesising RNA

Question 14

features archaeae share with eukaryotes

Answer 14

• similar enzymes (RNA polymerase) for synthesising RNA
• similar mechanisms for DNA replication & synthesising RNA
• production of some proteins that bind to DNA

Question 15

what did woese argue

Answer 15

• that the differences between bacteria & archaea are fundamental
• he suggested these 2 groups are more different than archaea & eukaryotes
• thus, an accurate classification system must reflect difference