Determining relatedness between species

Question 1

Comparison of DNA

Answer 1

• directly comparing DNA sequences of genes of different species.
• DNA hybridisation

Question 2

Comparison of amino acid sequences

Answer 2

the more similar the sequnces of amino acids are, the more clsely related the species are.

Question 3

mtDNA comparison

Answer 3

• contains a few highly conserved genes that encode for essential proteins required for cellular respiration
• the rest is hypervariable, mening the regions can accumulate mutation without affecting celular functioning.
• similar mtDNA indicate a closer relationship.

Question 4

master genes

Answer 4

• switch
• control expression of many other genes
• regulate the activity of other genes in a coordinated way
• produce transcription factors (DNA binding genes= bind to target genes= turns them on or off).

Question 5

Effect of high BMP in finches and cichilids

Answer 5

high beak width and depth.

short robust lower jaw

Question 6

Effect of low BMP in finches and cichilids

Answer 6

low beak width and depth

elongated jaw, and large well spaced out teeth

Question 7

How can comparisons of DNA sequences be used to determine which species are the most closely related?

Answer 7

BMPThe greater the similarities in DNA, the less time that’s been available for mutations to accumalate. Therefore, they must share a more common ancestor.

Question 8

BMP4 role in finches?

Answer 8

• low= long, arrow beaks.

- high= wide, deep beak.

Question 9

BMP4 role in cichlids?

Answer 9

• low= longer, slender sucking jaws

- high= strong, heavy bitting jaws with powerful muscles. “robust”

Question 10

Extinctoin definition

Answer 10

when a speicies ceases to exist, or a particular variation no longer exists (eradication of an allele)

Question 11

Causes of extinction?

Answer 11

• change in environment is too rapid to allow for the species to adapt.
• only small inbreeding populations are present, meaning there is little variation and are more likely to suffer the adverse effects of suuden environmental change (eg disease)
• human action (eg habitat destruction, introductio of feral species, global warming)

Question 12

What is the molecular clock?

Answer 12

The measurement of the rate of accumulation of random genetic changes in the genomes of different organisms.