UNIT 4 DAY 4 - RECONSTRUCTING EVOLUTIONARY HISTORY

Question 1

phylogeny

Answer 1

• evolutionary history of a group of species
• history of organismal lineages as they change through time

Question 2

classification

Answer 2

categorised list of all species in a group

Question 3

taxonomy

Answer 3

scientific discipline of naming species and placing them in a classification

Question 4

taxon (taxa)

Answer 4

general term for a species or higher category

Question 5

created a phylogeny according to shared homologies

Answer 5

• translate the phylogeny into a classification –>lists all species in the group within a nested hierarchy of larger group

Question 6

homologies

Answer 6

shared similarities

Question 7

constructing phylogenies

Answer 7

• all phylogenies are simple hypotheses about actual historical events

Question 8

structure of phylogenies

Answer 8

• represents 1 possible hypothesis about evolutionary relationship of 6 taxa
  –> tells us 6 different species exist, hypothesis that 6 species are related by 4 hypothetical ancestors

Question 9

branch points

Answer 9

• lines leading back from where the taxa joins
  –> represents hypothesised common ancestor which taxa diverged from

Question 10

sister taxa

Answer 10

any 2 taxa connected at branch point

Question 11

dichotomy

Answer 11

2 lines emerging from branch points

Question 12

unresolved polytomy

Answer 12

more than 2 lines emerging from a branching point

Question 13

3 main taxa all living things are placed in

Answer 13

1. Eubacteria (“true bacteria”, mitochondria, chloroplasts)
2. Archaea (protists, plants, fungi, animals etc)
3. Eukaryotes (methanogens, halophiles, sulfolobustrelatives)

Question 14

homologies

Answer 14

structures that are similar due to some cause other than shared ancestry

Question 15

convergent evolution

Answer 15

process by which unrelated organisms independently evolve similarities when adapting to similar environments

Question 16

distinguish homology from homoplasy

Answer 16

• complex structures that are similar in detail, likely to be a result of common ancestry because alternate that they evolved the same structural complex independently
• certain kind of traits, readily molded by natural selection, expected to evolve repeatedly by convergent evolution

Question 17

2 categories of homologies

Answer 17

• derived: newly evolved characters that can tell us, because newly evolved, which taxa are most closely related within group under study
• ancestral: present in ancestor of group - all members should have it

Question 18

which homologus characters should one use?

Answer 18

• only shared derived homologies are used to construct phylogenies
• shared ancestral homologies should be ignored

Question 19

ingroup

Answer 19

group under of the study

Question 20

outgroup

Answer 20

a taxon that is outside the in group up shares a relatively recent common ancestry with it

Question 21

monophyletic group

Answer 21

includes ancestor of the group and all its descendants

Question 22

paraphyletic group

Answer 22

includes ancestor of group but not all of its descendants

Question 23

polyphyletic group

Answer 23

includes 2 groups that don’t share a recent common ancestor

Question 24

picture a scientist: Riley Black

Answer 24

• vertebrate palaeontologist and science writer
• passionate about sharing science with the public, writes about her experiences as transgender woman in palaeontology

Question 25

when constructing a phylogeny, which sorts of characters should be used?

Answer 25

shared derived homologies

Question 26

only type of group that should be used to construct a classification is

Answer 26

monophyletic group

Question 27

sister group of animals

Answer 27

fungi