LECTURE 10: PHYLOGENETICS AND MACROEVOLUTION

Question 1

Darwin’s First Phylogenetic Tree

Answer 1

Wrote I think above his first phylogenetic tree

Question 2

Speciation due to reproductive isolation allows species to diverge and diversify

Answer 2

• What we have is a descendent species that is split up into a multitude of subspecies with differing traits
• Once gene flow between two groups in reduced, natural selection acts upon the population and genetic drift does as well (due to the decrease in size of the groups) which in turn, enables the groups to begin to diverge and diversify

Question 3

Carolus Linneus

Answer 3

• The father of modern taxonomy
• Binomial Nomenclature (How we name species)
• Came up with the Hierarchical System of Classification
  (Kingdom, Phyla, Class, Order, Family, Genera, Species)

Question 4

What is the Purpose of Biological Classification?

Answer 4

• Provides a predictive power because it helps us to identify individuals of certain species
• Enables us to interpret the evolutionary histories of the organisms

Question 5

Taxon - (plural = taxa)

Answer 5

A biological unit at any level

Kindgom, Phyla, Class, Order, Family, Genera, Species

Question 6

Taxonomy

Answer 6

The theory and practice of classification

Question 7

Systematics

Answer 7

The study of the biodiversity and ecological relationships among organisms

Question 8

Phylogenetic Trees

Answer 8

Ingroup: the group we are making inferences about
Outgroup: the group we are using to make a comparison
Node: The speciation events
Internodes: Common ancestors
Line in between species are DERIVED TRAITS

Question 9

Why do we conduct a phylogenetic analysis?

Answer 9

1. To understand the history of life
2. To understand large-scale patterns of evolution
3. To understand how many times a trait has evolved, how fast it has evolved and under what conditions it has evolved under

Question 10

Understanding Phylogenetic Trees

Answer 10

Refer to notes but realize that you can interchange different species as long as you don’t imply they were derived from different ancestors or have changed their evolutionary histories

Question 11

Monophyletic Group

Answer 11

• When a single ancestral form has given rise to all of the members in a given taxon
• Represents all of the members that have been derived by the same single common ancestor

Question 12

Paraphyletic Group

Answer 12

• When two or more ancestral forms give rise to a taxon but not all of the species derived from these ancestors are represented
• Not all of the members derived from the two common ancestors are represented

Question 13

Descent with Modification

Answer 13

Species that have a more recent common ancestor tend to be more similar
- Depicted in phylogenetic trees

Question 14

Clade

Answer 14

Monophyletic group in which all of the species derived from the common ancestor are being represented

Question 15

Ancestral Trait versus Derived Trait

Answer 15

ANCESTRAL TRAIT: a trait that has been inherited due to common ancestry
DERIVED TRAIT: a trait that differs from ancestral traits and has been introduced after speciation events have occurred

Question 16

Homology versus Homoplasy

Answer 16

• HOMOLOGY: similar traits due to common ancestry; human and fish skeletons are homologous structure because they have been derived from our common tetrapod ancestor
• HOMOPLASY: similar traits due to convergent evolution; similar traits with similar functions that are found in organisms that do not share common ancestry

Question 17

Convergent Evolution

Answer 17

The evolution of structure that appear similar and have similar functions due to the shared ecology of unrelated organisms

Question 18

Why is Microbiology Relevant to Phylogeny Contruction and Evolution?

Answer 18

• All life is derived from branching descent
• We have constancy in our genetic code that depicts the evolutionary relationships among all species
• Species that are very similar to each other have very similar DNA sequences
• Individuals in taxa are very good evidence of this because they share their DNA across generations

Question 19

Using Nucelotide Sequences to Construct Phylogenies

Answer 19

• We can sequence the DNA of different organisms
• Using comparison of nucleotide sequences, we can establish the relationships between species and thus construct phylogenetic trees

Question 20

Key Innovations and Phylogenies

Answer 20

• Key innovations are unique traits that arise from adative radiation
• The species with these new traits are now able to exploit a new range of habitats
• This can further their potential for evolution
• Key innovations increase the speed at which species diverge and diversify and account for high diversity clades
  IN ORDER TO ESTABLISH WHY ONE CLADE HAS MORE SPECIES THAN ANOTHER , IT IS NOT SAFE TO ASSUME THAT IT WAS THE RESULT OF A KEY INNVATION WITH ONE TRIAL, must do multiple trials

Question 21

Herbivory and Adaptive Radiations

Answer 21

Plants want to defend themselves against herbivory attacks and they want to do this by changing themselves.

• Herbivores want to adapt so that they can still eat
• Arms race of evolution in which they are both coevolving in order to make sure that the plant is ahead of the herbivore but the herbivore is still on the same plane

Question 22

Factors that contribute to greater diversification

Answer 22

1. More sexual selection
2. More animal pollination
3. Increased dispersal
4. Increased range size