Lecture 9 - Phylogenetics

Question 1

Classification

Answer 1

Coming up with convenient ways of grouping together similar things

Question 2

Scala Naturae

Answer 2

Humans at the pinnacle of life

Does not represent evolution

Question 3

What is the taxonomic order?

Answer 3

Life, domain, Kingdom, Subphylum, Class, Order, Family, Genus, Species

Question 4

Systematics

Answer 4

Study of patterns of evolutionary relationships

Question 5

Cladistics

Answer 5

Hypothesizing relationships among organisms based upon uniquely shared charecters or traits

Question 6

Phylogenetics

Answer 6

The study of the tree of life (slightly less broad than systematics)

Question 7

What are the rules for cladistics?

Answer 7

Characters change or are acquired over time,
Any group of organisms are related by common descent,
Character similarities and differences reflect evolutionary history

Question 8

Phylogeny

Answer 8

Inferred evolutionary history of clades/hypothesis of evolutionary relationships

Question 9

What things to consider when building a phylogeny?

Answer 9

Molecular characters, morphological characters

Question 10

How many trees of life are there?

Answer 10

There is only one true tree of life with each phylogenetic tree an estimation to try and get closer to the true tree of life

Question 11

What are the uses of phylogenies?

Answer 11

Fundamental for understanding evolution: processes and history,
Can inform effective conservation: biodiversity, priorities and risks
Important for understanding and treatment of infectious disease

Question 12

What molecular characters are measured when considering evolution?

Answer 12

DNA sequences, RNA sequences, Amino acid sequences

Question 13

What is the best molecular character to measure?

Answer 13

Amino acid sequences however it is difficult and expensive so DNA is often used

Question 14

How are homologous molecular sites established?

Answer 14

Sequence alignment using algorithms

Question 15

How are morphological charecters compared?

Answer 15

Presence or absence

Condition (e.g. pubis direction)

Multistate (i.e. how many there are)

Question 16

Homology

Answer 16

Similarity due to shared ancestry between different taxa

Question 17

Homoplasy

Answer 17

A similarity that does not arise from shared ancestry

Question 18

Convergence

Answer 18

Distantly related organisms independently evolve similar traits to adapt to similar necessitites

Question 19

Examples of Convergence

Answer 19

Camara eyes in humans and cephalopods,
Body shape in marine vertebrates,
Echolocation in bats and whales

Question 20

Morphological vs molecular studies: data size

Answer 20

Morphology- hundreds of characters but maybe over saturated

Molecules - Very abundant but also could be over saturated

Question 21

Morphological vs molecular studies: Character identification

Answer 21

Morphology - subjective, up to human interpretation

Molecules - objective, computer algorithms

Question 22

Morphological vs molecular studies: Accesibility

Answer 22

Morphology - labour intensive, but museum specimens available

Molecules - Expensive, but becoming cheaper and cheaper

Question 23

Morphological vs molecular studies: Time scales

Answer 23

Morphological - Fossil record

Molecules - Molecular clocks

Question 24

What is total evidence in evolution?

Answer 24

Combined molecular and morphological analyses of molecular data act as a scaffold for fossils that can break up gaps and provide timescales. The inclusion of morphology can increase congruence

Question 25

What is happening to the relative importance of morphology?

Answer 25

It is declining