Shimada- Exam 2

Question 1

phylogeny

Answer 1

evolutionary history of organisms

Question 2

systematics phylogenetics

Answer 2

scientific study of the origin, evolution, and interrelationships of organisms

Question 3

Willi Hennig

Answer 3

Cladistics
- methodologists
- one phylogenetic approach -> cladogram
- based on shared derived characters
- the more derived characters the more the two groups of organisms are closely related
- goal: look for monophyletic groups
- relatively objective (strength = repeatable)

Question 4

taxon

Answer 4

named organism (at any taxonomic rank)
ex. sharks

Question 5

rooted vs unrooted

Answer 5

notes

Question 6

clade

Answer 6

means branch, taxon, species, or an entire lineage
- each line represents a taxon

Question 7

node

Answer 7

speciation or divergent evolution took place
- pattern based should be talked about in cladograms

Question 8

sister species/taxa

Answer 8

two species/taxa showing an immediate common ancestor

Question 9

Ingroup vs Outgroup

Answer 9

set of organisms to find interrelationship
- outgroup is the reference organisms

Question 10

character vs character state

Answer 10

attribute (physical/behavioral) have two alternate forms

Question 11

polarity

Answer 11

• based on outgroup
• polarity of outgroup is ancestral state
• ex. blue + brown eyes tow attributes but don’t know which one is ancestral or derived

Question 12

character matrix

Answer 12

finds polarity

Question 13

shared derived characters

Answer 13

character by itself doesn’t show interrelationship between species

Question 14

uniquely derived character

Answer 14

traits = homologous which makes a better tree (parsimonious)

Question 15

Monophyletic

Answer 15

a complete lineage (natural taxon); all organisms in a lineage and their common ancestor
- ex. mammalia
- based on shared derived characters

Question 16

Paraphyletic

Answer 16

an incomplete lineage (artificial taxon)
- ex. “traditional” reptilia

Question 17

Polyphyletic

Answer 17

a misinterpreted lineage (artifical taxon)
- ex. Haematothermia (warm blooded)

Question 18

Taxonomy

Answer 18

hierarchy of organismal classification: scientific study of naming, describing, and classifying organisms
Domain: Eucarya:
kingdom animalia
phylum chordata
class mammalia
order primates
family homonidae
genus homo
species “homo”-sapiens

Question 19

Carlos Linnaeus

Answer 19

• taxonomy
  -god created I organized
  -made binomial nomenclature

Question 20

Statistical types

Answer 20

Descriptive: basic description of data
- measure of central tendency (mean , median, mode)
- measure of dispersion/spread of #s (range & standard deviation)

Inferential: analysis to allow interpretation of the data
- involves hypothesis testing (w/ assumptions) (t-test, x2 test, correlation/regression analysis)
- generate a p-value to asses statistical significance
- p = the probability that the outcome of the
last test may occur by chance
- smaller p-value is better

Question 21

statistical hypothesis

Answer 21

• null hypothesis (H0): no difference/association between groups
• alternative hypothesis (H1): there is a difference/association between groups

Question 22

Common steps

Answer 22

1. Formulate a null hypothesis and set significance level
2. Gather data
3. Conduct descriptive statistics
4. Conduct test (=inferential) statistics
5. Accept or reject the null hypothesis

Question 23

Statistical error

Answer 23

• type II error worse than type I error
• if null rejected and true = type I error
• if null rejected and false = no error
• if null accepted and true = no error
• if null accepted and false = type II error
• alpha level (=significance level): the probability of making the incorrect decision when null is true
  - typical alpha value: 0.05 = 5%

Question 24

Designing a Controlled Experiment

Answer 24

• control group: a group used as a standard comparison
• experimental group: a group exposed to one experimental variable
• replicates: repetition of an experiment
  (NOT all experiments are controlled studies)