Phylogenies

Question 1

phylogeny

Answer 1

the history of descent of a group of organisms from a common ancestor

Question 2

phylogenetic tree

Answer 2

comparison of traits, individuals with common traits placed together

Question 3

trait

Answer 3

one form of a character

e.g. blue flower colour

Question 4

character

Answer 4

a feature of an organism

e.g. flower colour

Question 5

homologous traits

Answer 5

traits inherited from a common ancestor

Question 6

derived traits

Answer 6

traits that differ from ancestor

Question 7

homoplasies

Answer 7

similar character in 2 or more taxa that are not derived from a common ancestor

Question 8

example of a homoplasy

Answer 8

wings - found in insects, mammals (bats) and birds

Question 9

monophyletic taxa

Answer 9

include ALL descendents of common ancestor

Question 10

paraphyletic taxa

Answer 10

include SOME, but not all, descendent of a common ancestor

Question 11

polyphyletic taxa

Answer 11

includes members with MORE THAN ONE recent common ancestor

Question 12

outgroup

Answer 12

a lineage closely related to the focal group

Question 13

convergent evolution

Answer 13

independent evolution of similar traits due to similar selection pressure

Question 14

parallel evolution

Answer 14

independent evolution of common trait in organisms sharing distant relatives

Question 15

traits used in phylogenies

Answer 15

• morphology and developmental

- molecular

Question 16

advantages of molecular traits

Answer 16

• directly reflect underlying process of evolution
• vast number of potential traits
• can detect difference between very closely related organisms
• not affected by the environment
• mutations random with specific probabilities, number of mutations can be used to calibrate evolutionary time (molecular clocks)

Question 17

molecular clocks

Answer 17

mutations random with specific probabilities, number of mutations can be used to calibrate evolutionary time

Question 18

disadvantages of molecular traits

Answer 18

• can’t get DNA from too far back

- complexity - duplicates of the same gene

Question 19

transition

Answer 19

purine -> purine

pyrimidine -> pyrimidine

Question 20

transversion

Answer 20

purine -> pyrimidine

pyrimidine -> purine

Question 21

non-coding DNA located in…

Answer 21

introns

Question 22

coding DNA located in…

Answer 22

exons

Question 23

examples of non-coding DNA

Answer 23

repetitive sequences, pseudogenes

Question 24

synonymous

Answer 24

DO NOT change amino acid

more commonly fixed in evolution

Question 25

non-synonymous

Answer 25

DO change amino acid

Question 26

nonsense

Answer 26

prematurely terminate genes

Question 27

mitochondrial gene example for analysis (evolution)

Answer 27

cytochrome C - highly conserved gene

Question 28

calibration of molecular clock

Answer 28

alpha-globin

Question 29

What is the C-value?

Answer 29

the weight of the genome (in grams)

Question 30

explaining the C-paradox

Answer 30

1 - genomes differ in the amount of repetitive DNA 2 - some species have more than 2 copies of each chromosome (polyploidy)

Question 31

polyploidy

Answer 31

more than 2 copies of the haploid chromosome

Question 32

Single or Low-Copy sequences

Answer 32

- genes including promoters, exons and introns | - pseudogenes

Question 33

Repetitive DNA

Answer 33

middle-repetitive and highly-repetitive - multiple copy genes - increased expression -> more of gene product produced - telomeres - facilitate accurate copying of linear DNA molecule

Question 34

Mobile elements

Answer 34

transposons and retrotransposons

Question 35

transposons

Answer 35

mobile DNA elements that can move from one place to another

Question 36

retrotransposons

Answer 36

can increase in copy number via the production of an RNA intermediate followed by insertion of a DNA copy into the genome

Question 37

what are SSRs?

Answer 37

Simple sequence repeats - short sequence - 1-5 bp AKA micro-satellites

Question 38

why is number of repeats not well copied?

Answer 38

slippage

Question 39

________ contain large tracts of micro-satellites.

Answer 39

Centromeres

Question 40

mutation will normally lead to loss of function

Answer 40

(to) pseudogenes

Question 41

accumulated gene duplication leads to...

Answer 41

gene clusters

Question 42

euploidy

Answer 42

containing a chromosome number that is a multiple of the haploid number

Question 43

aneuploidy

Answer 43

extra or fewer copies of one chromosome or part of a chromosome guides

Question 44

chromosomal rearrangements

Answer 44

inversions and translocations