phylogenetics

Question 1

universality of cell biology

Answer 1

• argues for one common ancestor
• genetic code based on DNA
• genetic code expressed via RNAs
• 20 AAs
• ATP use
  etc. ..

Question 2

Why is Classification important?

What tool do we use for classification?

Answer 2

• we use tree of life to help
• important because it insures biologists use the same terminology and nomenclature
• all organisms are placed in hierarchical system

Question 3

systematics

Answer 3

science of classification

-uses info to develop phylogenies

Question 4

phylogenies

Answer 4

• geneologies extended over evolutionary time

- view evolution as a descent from a common ancestor

Question 5

phylogenetic methods

Answer 5

• fossils
• organisms
• genes
• assesses similarities and differences
• all groups must be monophyletic clades

Question 6

uses of phylogenies

Answer 6

• find ancestor of a pathogen

- history of species

Question 7

cladogram

Answer 7

shows branching patterns and divergences from CA

-branch lengths are the same

Question 8

phylogram

Answer 8

conveys time and rate of evolutionary events with branch length

Question 9

characters

Answer 9

morphologic, anatomic, chemical, and genetic information

Question 10

homologous

Answer 10

derived from the same common ancestor

Question 11

analogous

Answer 11

similar, but not homologous

Question 12

homoplastic characters (homoplasies)

Answer 12

• shared by 2 groups but not possessed by all intervening ancestors
• from parallel or convergent evolution

Question 13

parallel evolution

Answer 13

• evolves independently in separate, but related groups
• e.g. winglessness in moths
• differs from convergent evolution because ancestors are more similar

Question 14

convergent evolution

Answer 14

• appears to show relatedness, but doesn’t

- e.g. eyes of vertebrates and cephalopods

Question 15

synapomorphies

Answer 15

-shared, derived characters

Question 16

symplesiomorphies

Answer 16

• shared, NOT derived characters

- trait is shown in common ancestor and throughout lineage

Question 17

apomorphic

Answer 17

derived

Question 18

plesiomorphic

Answer 18

same as ancestor

Question 19

autapomorphic

Answer 19

-UNSHARED, derived character

Question 20

How to separate plesiomorphic from apomorphic

Answer 20

• fossil evidence
• embryology
• USE AN OUTGROUP

Question 21

sister taxa

Answer 21

-share a common ancestor and diverged at the same time

Question 22

polytomy

Answer 22

-an area of a phylogeny where a node branches into more than 2 branches

Question 23

monophyletic

Answer 23

all descendants of a single common ancestor

Question 24

paraphyletic

Answer 24

-one common ancestor, but not all descendants are included

Question 25

polyphyletic

Answer 25

group of organisms without a common ancestor

Question 26

molecular clock hypothesis

Answer 26

Emile Zuckerkandl and Linus Pauling hypothesized that rates of molecular change were constant enough to predict divergence times

Question 27

Phylogenies –> Classification

Answer 27

• both are hierarchical, so its easy to go between the two
• DKPCOFGS
• names are binomial, italicized, need to be published

Question 28

Molecular Systematics

Answer 28

• using genes instead of morphology for classification
• entire genomes are regularly sequenced
• rRNA is common sequencing site
• compare sequences of similar species to each other on public sites, like Genbank