lecture 2 systematics, Phylogeny & the tree of life

Question 1

what is taxonomy

Answer 1

the sciecne of naming and classifying organisms within groups (taxa)

Question 2

phylogeny

Answer 2

the evolutionary history of a species or group of species ‘tree of life’

Question 3

systematics

Answer 3

the relationship of determining relationships among organisms

Question 4

what are the schools of thought in systematics

Answer 4

phenetic system
classic evolutionary system
cladistic system

Question 5

what is the phenetic system

Answer 5

groups organisms based on phenotype similarity only (how it looks/acts)

most similar traits = most closely related

Question 6

how reliable is phenetic

Answer 6

unreliable- doesn’t disstinguish between homologous and analogous characters

uncommon but somtimes best option/ first stage

Question 7

what is the classic evolutionary system

Answer 7

group organisms based on evolutionary relationships.

all shared characterss primitive and derived (accepts mono and paraphyletic groups)

Question 8

what is the meaning of monophylectic

Answer 8

Monophyletic, or monophylogeny, is a term used to describe a group of organisms that are classified in the same taxon and share a most common recent ancestor. A monophyletic group includes all descendants of that most common recent ancestor.

Question 9

what is the meaning of paraphylectic

Answer 9

(of a group of organisms) descended from a common evolutionary ancestor or ancestral group, but not including all the descendant groups.

Question 10

what is the cladistic system

Answer 10

based on similarity of characters that reflect evolutionary relationships

derived characters most important, only accepts monophylectic groups

Question 11

what is a phylogenetic tree

Answer 11

a graphical representation of evolutionary relationships among a set of organisms or groups

Question 12

how to interpret a cladogram

Answer 12

node position indicates relative time but branch lengths are arbitrary

Question 13

how to interpret a phylorgram

Answer 13

branch lengths represent amount of change

Question 14

how to interpret a dendrogram (ultrametric)

Answer 14

nodes associated with a specific geological time

Question 15

what are the types of group in phylogenetic trees

Answer 15

ancestor and decendants

ancestor and not all dcendants

missing ancestors (less common)

Question 16

example of a monophyletic taxon

Answer 16

class mammalia

Question 17

example of a paraphyletic taxon

Answer 17

class reptillia
(becuase birds are not included)

Question 18

what is a polyphyletic taxon

Answer 18

(of a group of organisms) derived from more than one common evolutionary ancestor or ancestral group and therefore not suitable for placing in the same taxon.

Question 19

example of a polyphyletic taxon

Answer 19

algae

Question 20

what is parsimony

Answer 20

Parsimony is the idea that, given a set of possible explanations, the simplest explanation is the most likely to be correct

Question 21

how do taxonomists use parsimony

Answer 21

to determin which phylogenetic tree (hypothesis) is most likely to be correct; whichever has the fewest evolutionary steps

Question 22

why are there differences between morphological and genetic similarity

Answer 22

body form changes at a different rate to DNA/RNA

much molecular evolution not expressed in body form

Question 23

how can time be added to the phylogenetic tree

Answer 23

radiometric dating (isotopes in fossils)

stratigraphy: layering of deposited rocks allows geolgical timescale to be estimated

molecular clocks: amount of genetic divergence used to estimate timing

Question 24

what are the 6 kingdoms

Answer 24

plantae
animalia
fungi
protista
eubacteria
archaebacteria

Question 25

cell type :plantae

Answer 25

multicellular, eukaryotic

Question 26

cell type: animalia

Answer 26

multicellular, eukaryotic

Question 27

cell type:fungi

Answer 27

multicellular, eukaryotic

Question 28

cell type: protista

Answer 28

multicellular, and unicellular, eukaryotic

Question 29

cell type: eubacteria

Answer 29

unicellular, prokaryotic

peptidoglycan cell wall

Question 30

cell type: archae bacteria

Answer 30

unicellular, prokaryotic

no peptidoglycan wall

Question 31

what are the three domains

Answer 31

bacteria
eucaria
archaea

Question 32

eubacteria example

Answer 32

cyanobacteria
soil bacteria
pathogenic bacteria

Question 33

archaea example

Answer 33

halophile bacteria (saline conds.)
thermophile bacteria (heat)
methanogen bacteria (produce methane as a metabolic byproduct in hypoxic conditions)

Question 34

protista example

Answer 34

heterotrophic/photosynthetic

Question 35

fungi example

Answer 35

heterotrophic, not mobile

eg mushrooms and yeast

Question 36

plantae example

Answer 36

photosynthetic, non mobile

fern mosses trees

Question 37

animalia example

Answer 37

heterotrophic, mobile

corals, insects, mammals