Evidence of Evolution Flashcards
What are the two main fields of evidence for evolution?
Comparative studies and palaeontology
What are the biochemical analysis areas of comparative studies?
1) Comparative genomics
2) Endogenous retroviruses
3) Protein sequences
4) Bioinformatics
What are comparative genomics?
Testing of DNA sequences, genes, gene order or other genomic structural biomarkers
Used to infer an evolutionary relationship between 2 species.
Greater the similarity in genome, more recent the common ancestor
What are the characteristics of Mitochondrial DNA (mtDNA)?
Small, circular molecules containing 37 genes (24 for tRNA, 13 for proteins needed for cell resp.)
Cells contain numerous mitochondria, so mtDNA can be found in large quantities.
What are endogenous retroviruses?
Sections of “junk DNA” which used to be viruses, which are inserted into the genome.
Enter host cells and copy their RNA genome into the DNA using reverse transcription.
Viral DNA enters the gametes, meaning the viral DNA is passed on to the next generation.
The more endogenous retroviruses two species share, the more recent their common ancestors is.
What are protein sequences?
Examining of the sequence of amino acids in proteins.
Ubiquitous proteins are examined (e.g cytochrome C, alpha-beta chains of haemoglobin)
More similar the protein sequence, more recent the common ancestor
What is bioinformatics?
Multidisciplinary field involving computer science, statistics, mathematics and engineering.
Analysing of DNA & proteins on larger scale to compare entire genomes.
Testing highlights the amount of similarity between species.
Why can mtDNA be used to trace ancestry?
mtDNA only inherited from mother
mtDNA mutates rapidly (compared to nuclear DNA)
How are bioinformatics used in evidence for evolution?
Greater the degree of similarity in bioinformatics profiles, more recent the common ancestor.
What are homologous structures?
Anatomical resemblances between organisms, which represent variations on a structural theme present in a common ancestor.
(e.g. pentedactyl limbs)
What are vestigial structures?
Remnants of structures that served important functions in the organism’s ancestors.
(e.g. wings on flightless birds)
What are analogous structures?
Superficial similarities reflecting on adaptation to a similar environment. Do NOT represent descent from a common ancestor.
(e.g. wings)
What is comparative embryology?
Comparison of embryos in early stages of development.
Common features in early embryos are
- 2-chambered heart
- well-developed tail
- gill pouches and arches
- similar brain development
What is the significance of gill pouches in early embryos?
Suggests evolution from aquatic organisms.
this is supported by the fossil record
