investigating diversity Flashcards
What is the natural classification system based on
Evolutionary relationships between organisms and their ancestors
Classifies species using shared homologous features
Arranges groups into a hierarchy
Which limbs have 5 digits
Pentadactyl line
What techniques can scientists use now to help them to determine evolutionary relationships
Genome sequencing
Immunology
What is the type of classification called when only observations are used
Artificial
How could genome sequencing be used to clarify evolutionary relationships between organisms?
The order of the nucleotides on one of the strands of DNA can be sequenced
This sequence can then be compared to the sequence of other species
Organisms with DNA sequences that have the same DNA nucleotides in the same order are more closely related than those that do not
Why does the DNA sequence of genes change over time
Mutations
Who do changes in a gene allow you to relate organisms to each other
The more recently they shared a common ancestor the less time has lapsed for changes between the gene for those species
Why must the same gene be compared for all species
Base sequence will be similar/ some bases in common
These bases will bind together/ hydrogen bonds/ complementary pairs
Why might comparing mRNA also be used to investigate evolutionary relationships between organisms
By comparing the mRNA between 2 species it shows similarities / differences between which genes are expressed
Why might cytochrome be a better protein to use as acomparison compared to haemoglobin
Haemoglobin can only be compared in organisms that contain this molecule in their blood
Cytochrome may be a better protein
