Lecture 2 - Tree of life and biodiversity

Question 1

What is phylogeny?

Answer 1

Relationship between organisms

Visual representation of the evolutionary history of populations, genes or species

Question 2

What are the 3 types of evidence to construct phylogeny?

Answer 2

Morphology

Molecular evidence

Fossils

Question 3

What are homoplastic traits?

Answer 3

Traits that are similar for reasons other than inheritance from a common ancestor

Question 4

What are synapomorphies?

Answer 4

Derived form of a trait shared by a group of related species

Shared derived characteristics

Question 5

How is molecular evidence used to construct a phylogeny tree?

Answer 5

Take DNA of modern animals and compare to others to see how similar it is to another animal

Question 6

Who classified the diversity of life and when did they do it?

Answer 6

Linnaeus

1700s

Question 7

What are the tips in a phylogenetic tree?

Answer 7

The terminal ends of an evolutionary tree

Question 8

What are nodes?

Answer 8

Points in a phylogeny where a lineage splits

Branching point

Represents where populations became genetically isolated

Question 9

What are clades?

Answer 9

Single branches - an organism and all its decedents

All organisms that share a common ancestor

Set of hierarchically nested groups

Question 10

What is morphology and how is it shown in a phylogenetic tree?

Answer 10

Study of size, shape and structure of organisms

Each own characteristic shows a separate trait

Question 11

What are characters in the study of evolution?

Answer 11

Heritable aspects that can be compared

Question 12

What are taxa in the study of evolution?

Answer 12

Group of organisms that form a cohesive taxonomic unit

Question 13

What is homology?

Answer 13

Similarity of traits in different species resulting from their inheritance from a common ancestor

Question 14

What is the first principle of phylogenetic inference?

Assumes similar features are…

Answer 14

homologous until shown otherwise

Question 15

What is the second principle of phylogenetic inference?

Doesn’t use shared ancestral features but..

Answer 15

uses shared derived features

Question 16

What are autapomorphies?

Answer 16

Unique morphological features

Do not provide useful grouping information

Question 17

Why might microorganisms share genes?

Answer 17

Due to horizontal gene transfer

Where genetic material other than other than from parents to offspring is transferred to another organism

Question 18

When was Darwin’s theory of evolution?

Answer 18

1859

Question 19

What can phylogeny be used for?

Answer 19

Used to identify source of viruses

Date of disease onset

Track viral evolution

Identify modes of potential transmission

Organize knowledge of diversity

Question 20

How do you know if organisms are more closely related in a phylogenetic tree?

Answer 20

Taxa that diverged from each other more recently

Have more character states in common

Question 21

How can timing be estimated within phylogeny?

Answer 21

Combing phylogenetic morphological evidence with fossils

Question 22

What are branches?

Answer 22

Lineages evolving connecting other branching events

Question 23

What are internal nodes?

Answer 23

Occur within phylogeny, represent ancestral populations or species

Question 24

What is a cladogram?

Answer 24

When phylogenetic tree shows only relationship among species

Question 25

What does monophyletic mean in phylogeny?

Answer 25

Group of organisms that form a clade

Question 26

What does polyphyletic mean in phylogeny?

Answer 26

Taxon that doesn’t include common ancestor of all members of the taxon

Question 27

What does paraphyletic mean in phylogeny?

Answer 27

Group of organisms that share a common ancestor although the group doesn’t include all the decedent of that common ancestor

Question 28

What is an outgroup?

Answer 28

Group of organisms outside of monophyletic group

Question 29

What is homoplasy?

Answer 29

Character state similar not due to shared descent

Question 30

What is convergent evolution?

Answer 30

Independent origin of similar traits in separate evolutionary lineages

Question 31

What is evolutionary reversal?

Answer 31

Describes reversion of a derived character state to form resembling its ancestral state

Question 32

What is polytomy?

Answer 32

Internal node of phylogeny with more than 2 branches

Question 33

What is exaptation?

Answer 33

Trait that initially carries out one function and its later co-opted for a new function, original function may be lost