Molecular Phylogeny - Cladistics

Question 1

Define phylogeny

Answer 1

evolutionary history of a species

Question 2

Define molecular phylogeny

Answer 2

evolutionary history of a species using DNA sequencing

Question 3

What is a clade?

Answer 3

a section of a phylogenetic tree; group of organisms that consists of a common ancestor and ALL of its lineal descendants

Question 4

How do changes to organisms occur?

Answer 4

Mutations, isolation (geographically, reproductively), changes passed down over generations where divergence becomes more pronounces eventuating in separate species

Question 5

What type of DNA is used to identify molecular phylogeny?

Answer 5

Mitochondrial DNA (mtDNA) because it is solely from mother and maternal line makes easier to track mutation and rate. Also excellent to use for molecular clocks ( determining when one species diverged into two new ones

Question 6

What are cladistics?

Answer 6

classification system according to derived characteristics (anatomical, physiological, behavioural and genetic)

Question 7

Contrast cladograms and phylogenetic trees

Answer 7

cladogram
- length of horizontal/diagonal line does not matter, not based off of a timescale, each node represents a common ancestor
Phylogenetic tree
- length of horizontal line does matter, based off a timescale (evolution of time), each node is last time they shared commonality of being the same species

Question 8

What are common assumptions in cladistics?

Answer 8

shared common ancestor, bifurcating pattern: when a lineage splits it divides into two groups, physical change: organism change over time