THEME 5A AND 5B

Question 1

4 Macroevolutionary Patterns

Answer 1

Adaptive Radiations

Cladogenesis

Anagenesis

Phyletic Gradualism and Punctuated Equilibrium

Question 2

Cladogenesis

Answer 2

Evolution that results in the splitting of the lineage

Question 3

Anagenesis

Answer 3

Evolution within a lineage

Question 4

Adaptive Radiation

Answer 4

Rapid evolution of species occupying NEW NICHES

Question 5

Phyletic Gradualism vs Punctuated Equilibrium

Answer 5

Phyletic Gradualism: gradual changes over time

Punctuated Equilibrium: changes coming in burst

No clear result, as to which model dominates

Question 6

Phylogenetic Trees

Answer 6

Shows relationships between species according to the recency of their common ancestor

Question 7

Homologous characters

Answer 7

characters similar due to its conservation in its lineage.

I.e. Both species have inherited the trait from a common ancestor and kept it in their lineage

Question 8

Analogous characters

Answer 8

characters that are similar due to adaptations to the same environment.

analogous due to CONVERGENT EVOLUTION

E.g. bat and bird

Question 9

Analogous vs Homologous for constructing the tree

Answer 9

Homologous, as traits are derived from common ancestry. As such, it can tell us about the common ancestors of species

Question 10

Character States

Answer 10

Several observed conditions

I.e. the presence or absence of a character. Lungs are present in tetrapods, but not in other vertebrates

Question 11

Derived Character State

Answer 11

A modified condition of the primitive character state present in a sub-clade of the clade of interest

Question 12

Synapomorphies

Answer 12

A character which is derived, and because it is shared by the taxa or clared under consideration, is used to infer common ancestry (shared derived state

Question 13

Parsimony

Answer 13

Choosing the simplest tree, with fewest assumptions –> fewest changes –> simplest

Question 14

Comparative morphology

Answer 14

like morphospecies concept. Comparing whether organisms have similar features

Question 15

How to use molecular data to construct phylogenetic tree?

Answer 15

Those with the most recent common ancestor have little differences between their genomes

Descendants of an ancient ancestry have vast difference between their genomes

Question 16

Molecular clock

Answer 16

Based on studying mutations and the rate at which they are incorporated into the genome. i.e. base changes can occur at a rate of 1 change per 0.56 billion years

Question 17

Example of how it can be used

Answer 17

a length of DNA from a species differs from the DNA of another species by 4 nucleotide bases.

Assuming the DNA changes at a rate of 1 base per 24 million years, then this implies that the 2 DNA are 100 mya different and their common ancestor lived 50 mya

Question 18

Why 50 mya?

Answer 18

Because 4 bases imply that 2 base pairs are different from the other 2 base pairs and 2 base pairs ago equates to 2x25 mya = 50 mya

50 mya, they had the same genome, which is their common ancestor

Question 19

3 types of characters that can be used

Answer 19

morphological

chromosomal

molecular

Question 20

Homoplasy

Answer 20

Analogous traits

as a result of convergent evolution –> i.e. via adaptations

Question 21

How to recognize homologous traits? (3 requirements)

Answer 21

Structural similarity
- e.g. bones that support limbs of mice are the same

Same connections to other parts
- e.g. pelvis and femur connected via ball and socket

Same development
- e.g. embryonic development limbs came from same buds

Question 22

Advantage of using molecular data

Answer 22

The amount of molecular data is sufficient in building a phylogenetic tree

Question 23

Disadvantage of using molecular data

Answer 23

Most molecular data comes from extant species. Unfortunately, extant species only make up 10% of the taxa

Question 24

Why is parsimony favoured?

Answer 24

This is due to the principle of fewest assumptions.

Parsimonious –> simplest tree, less evolutionary changes

We like this because most mutations are deleterious, therefore mutations that lead to evolution of new traits are unlikely –> RARE

Question 25

T/F If ancestor and modern species have the same character states, WE CANNOT assume that the intermediates (those in the middle) have the same character states.

Answer 25

False

Question 26

Three ways to root a tree

Answer 26

1) Have a character with two states. Determine which organism evolved from which organism
2) Use an outgroup for comparison
3) Using fossils, oldest are likely to be the ancestral state

Question 27

Types of groups on a Taxa

Answer 27

Monophyletic

Paraphyletic

Polyphyletic

Question 28

Taxonomy ranking

Answer 28

Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 29

Taxonomy

Answer 29

Based on “rough” phylogenetics

Question 30

Monophyletic group

Answer 30

Common ancestor + Members of a group that share a common ancestor
Important for phylogenetics –> tying phylogenetics with taxonomy

Question 31

Paraphyletic group

Answer 31

Common Ancestor + SOME members only

Question 32

Polyphyletic group

Answer 32

groupings that DO NOT include common ancestor

E.g. Birds and Bats

Question 33

Advantage of using living organisms to build a phylogenetic tree

Answer 33

Many features are available to generate phylogenetic hypotheses (e.g. morphology, DNA sequences)

Question 34

Disadvantage of using living organisms to build a phylogenetic tree

Answer 34

We don’t enough about the evolutionary histories, evolutionary time and evolutionary context

Question 35

When did chimp and human lineage diverge?

Answer 35

~6mya

Question 36

Hominin

Answer 36

Any species more closely related to humans than chimps

Question 37

When did Homo Sapiens evolve?

Answer 37

~200 000 years ago

Question 38

Limitations of fossil record

Answer 38

When did hominin lose their body hair?

When did they start wearing clothes?

Question 39

Resolution for limitation of fossil record

Answer 39

Find tools that make clothes

Question 40

How old is the oldest needle?

Answer 40

40 000 year old

Question 41

How old is the Earth?

Answer 41

4.5 billion years

Question 42

When did the first unicellular eukaryote first appear?

Answer 42

3.5 billion years ago