Unit 4 10C: Evidence of evolutionary relationships Flashcards
Structural morphology
the study of an organism’s features and form to determine the evolutionary relationship of species
Homologous structures
A structure within a group of species that performs a different fucntion yet has the same underlying structure
Divergent evolution
Where two or more species form from a single ancestral species over time
Vestigial Structure
A structure within an organism that is no longer functional but served a purpose in a common ancestor
Primates
The order consisting of all current and extinct humans, apes and monkeys, characterised by having dexterous hands with opposable thumbs and a relatively large and developed brain
Molecular homology
The analysis of DNA and amino acid sequences as evidence of evolutionary relationships
What two fundamental ideas is molecular homology based off
- The greater the similarily in the DNA or amino acid sequences between the species, the less time that has passed, and therefore the more recently these species shared a common ancestor.
The greater the differences in these sequences between species, the more time that has elapsed for these changes to accumulate and, hence, the further back in time a common ancestor was shared.
Relatedness
Refers to how recently species split from a common ancestor
Phylogeny
A branch of science that studies the evolutionary relationships between a group of species
Phylogenic tree
A branching diagram used to represent the evolutionary relationships between species
advantages of using Mitochondrial DNA over nuclear DNA when used as a molecular clock to determine evolutionary relationships
-Only passed through maternal lineage, no recombination with other parents’ DNA
-Large amounts of mitochondria within cell
Limitation of using MtDNA for determining relatedness
MtDNA only inherited from the maternal line, and therefore
Does not compare relatedness of organism to different parental species
