Theme 5AB

Question 1

What is a phylogeny

Answer 1

History of descent with branching
Shown as phylogenetic trees/phylogenies

Question 2

What does a branching diagram tell us

Answer 2

Shows relationships between species often according to time since a common ancestor

Question 3

What do the tips, branches, node and root tell us on a phylogenetic tree

Answer 3

Tips: terminal node
Branches: new species
Node: point where a branch splits, represents a common ancestor from which the descendant species emerge
Root: common ancestor population

Question 4

What are sister groups

Answer 4

Two species that share a common ancestor not shared with any other species or groups

Question 5

What hypothesis do phylogenies provide

Answer 5

Hypothesis of evolutionary relationships

Question 6

What is a phylogram

Answer 6

Tree where the branch lengths represent evolutionary change/time

Question 7

What is a cladogram

Answer 7

Tree where the branch lengths are all the same (no time)

Question 8

How can you use morphological data to infer phylogenies

Answer 8

Use “characters” shared among organisms (vary among, but not within species)and have a genetic basis

Question 9

What is considered to be the “best” phylogenetic tree

Answer 9

The one with the fewest number of changes required

Question 10

How can DNA data be used to infer phylogenies

Answer 10

Each nucleotide in a sequence can act as a trait underlying logic of phylogenetic inference is identical for morphological and molecular characters
DNA sequence differences represent time since common ancestor

Question 11

What is a monophyletic group

Answer 11

Includes a common ancestor and all of its descendants

Question 12

What is a paraphyletic group

Answer 12

Included a common ancestor and some but not all of its descendants

Question 13

What is a polyphyletic group

Answer 13

Does not include common ancestor

Question 14

What is adaptive radiation

Answer 14

The rapid evolution of new species occupying new niches

Question 15

What is anagenesis

Answer 15

Speciation where the ancestor species is wholly replaced by a new species (evolution within lineage)

Question 16

What is cladogenesis

Answer 16

Parent species splits into two species

Question 17

What is graduated evolution

Answer 17

Slow and steady gradual evolution (results in anagenesis)

Question 18

What is punctuated evolution

Answer 18

Rare and rapid events of branching speciation (results in cladogenesis)

Question 19

What is the difference between morphological, chromosomal and molecular characters

Answer 19

Morphological: observable traits (wing patterns)
Chromosomal (number of chromosomes)
Molecular: DNA sequences

Question 20

Homologous verses analogous characters

Answer 20

Homologous: shares a common ancestor
Analogous: similarity in appearance but not origin

Question 21

What is the outgroup

Answer 21

Belonging to similar class of animals

Question 22

What is the principle of parsimony

Answer 22

Not willing to spend resources unnecessarily

Question 23

What does it mean if all the animals on a phylogenetic tree have tips at the same length

Answer 23

All the species still exist (not extinct)

Question 24

How does phylogeny relate to taxonomy

Answer 24

Member of these groups (like genus) are assumed to share a more recent common ancestor with each other then members of other groups

Question 25

What is macro evolution

Answer 25

Evolution above the species level, assess the diversity of an entire Claude and its position on the tree

Question 26

What is a clade

Answer 26

A group of organisms believed to have evolved from a common ancestor

Question 27

What is convergent evolution

Answer 27

Evolution of similar adaptations in distantly related organisms that occupy similar environments

Question 28

What are the drawbacks to using molecular characters for phylogenetic trees

Answer 28

There are only 4 alternate character states that exist at each position in a DNA or RNA sequence Only 20 alternate character states at each position in a protein This makes it difficult to asses the homology of a nucleotide base substitution that appears at the same position in the DNA of 2+ species

Question 29

What are the 2 character states

Answer 29

1) ancestral character states: original state 2) derived character state: newer state

Question 30

What is the difference between apomorphy and synapomorphy

Answer 30

Anapomorphy: derived character state Synapomorphy: derived character state found in 2+ organisms