Phylogeny and Evolutionary Relationships: Tree Analysis and Applications(Week 4 Slides)

Speciation

Results in a nested branching pattern of evolutionary relationships among different lineages.

Phylogenetic trees

Represent evolution and show patterns of descent.

Branch point/Node

Represents the divergence of two evolutionary lineages from a common ancestor.

Sister taxa

Groups that share an immediate common ancestor not shared by any other group.

Basal taxon

A lineage that diverges from all members of its group early in the group's history.

Root

The common ancestor from which all members of a phylogenetic tree descend.

Evolutionary relationships

Described by the patterns shown in phylogenetic trees.

Common ancestor

The ancestor from which two or more species have diverged.

Monophyletic groups

Only these groups reflect evolutionary relationships.

Taxa

The groups of organisms that are represented at the branch tips of a phylogenetic tree.

Divergence of populations

The process by which new species arise from a common ancestor.

Evolutionary tree

A diagram that shows the evolutionary relationships among various biological species.

Phylogenetic tree limitations

Do not generally show how old lineages are or how much they have changed.

Inference of evolution

It should not be assumed that a taxon evolved from the taxon next to it.

Sister groups

Two groups that are more closely related to each other than either is to anything else on the tree.

Trace most recent common ancestors

A method to address evolutionary relationships by tracing branches.

Branch movement

Branches can freely move around nodes without influencing the evolutionary relationships.

Evolutionary relationships inference

We can only infer that taxa evolved from a recent common ancestor.

Order of taxa appearance

Does not represent the sequence of evolution in a phylogenetic tree.

Patterns of descent

Shown by phylogenetic trees.

Evolutionary tree question

Which group shares a more recent common ancestor with turtles?

Evolutionary relationships question

Which statement best reflects the evolutionary relationships among the organisms?

Monophyletic group

Also called a clade, it shows the evolutionary path a group has taken since its origin.

Paraphyletic group

A group that includes an ancestor and some, but not all, of its descendants.

Polyphyletic group

A group that does not include the most recent common ancestor of its members.

Homologous traits

Traits that are similar because of inheritance from a common ancestor.

Analogous traits

Traits that are similar due to convergent evolution, not inheritance.

Shared derived characteristics

Characteristics that are shared by all the lineages of a particular monophyletic group, but are absent in the sister taxa of the group.

Synapomorphies

Shared derived characteristics that help build phylogenetic trees.

Bipedalism

A shared derived trait in humans indicating the ability to walk on two legs.

Cranial capacity

A shared derived trait in humans referring to the size of the braincase.

Phylogenetic tree

A diagram that shows the evolutionary relationships among various biological species.

Evidence of HIV transmission

Phylogenetic analysis showed that a dentist gave HIV to his patients in the 1980s.

mtDNA

Mitochondrial DNA used to identify species and track biological material.

Illegal harvesting

The act of capturing species, such as whales, that are not legal to harvest.

COVID-19 strain tracking

Using phylogenetic trees to track the spread of COVID-19 strains across the globe.

Convergent evolution

The process where organisms not closely related independently evolve similar traits.

Ancestral lineage

The lineage from which traits are inherited or evolved.

Selection pressures

Environmental factors that influence the evolution of traits.

Phylogenetic analyses

Methods used to study the evolutionary relationships and origins of species.

Morphological features

Physical characteristics used to identify shared derived traits.

Genetic characteristics

DNA traits that can be used to determine evolutionary relationships.