Evolutionary Anthropology - Macroevolution

Flashcards about Macroevolution, Speciation, and Phylogenetics

What is parapatric speciation?

Speciation between subpopulations of a larger population, where hybrid zones are common.

What is sympatric speciation?

Speciation from a single species in the same geographic area.

What are the three main categories in which phenotypic differences can result in barriers to gene exchange?

Premating, postmating but prezygotic, and postzygotic.

How does natural selection affect populations?

Evolutionary force is non-random and dependent on the environment and results in an increase or decrease of variation within populations, but an increase or decrease in variation between populations.

What is gradualism (in the context of evolution)?

Slow and gradual process with fossil records expected to show smooth species transitions.

What is Punctuated equilibrium?

Long periods of stasis, punctuated by rapid change, rapid speciation at the edges of species range, resulting in gaps in the fossil record.

What does Mass extinction result in?

High rates of evolution, widespread ecological opportunities for surviving lineages.

What is an evolutionary trend?

A persistent temporal change in a characteristic of a lineage or clade.

What is Cope’s Rule?

A bias toward size increases in descendant species compared to their ancestors.

What is systematics?

Biological classification and reconstructing evolution.

What are the steps of Systematics, as defined by Uluutku and Wood, 2023?

Identification and comparison, Species-level classification, Phylogenetic reconstruction, and Classification above the species level.

What is binominal nomenclature?

Assigning an organism two names, a generic name (genus) and a specific name (species).

What is Phylogenetic reconstruction?

Uses phenotypic or genetic information to make inferences about the relationships between taxa, resulting in a hypothesis of relationships represented by a tree diagram.

What is Classification above the species level?

Using the results of phylogenetic reconstruction to allocate species to taxonomic ranks above the species level (genus, family, class, etc.) using a hierarchical system.

What is one of the most fundamental concepts of evolution?

Species share a common origin and have subsequently diverged through time.

What is topology?

The branching order within an evolutionary tree.

What is a polytomy?

Conveys uncertainty/ lack of resolution in a phylogenetic tree.

What does a chronogram show?

Branch lengths are scaled according to time.

What is a monophyletic group (clade)?

A group that contains an ancestor and all of its descendants.

What is a paraphyletic group?

A group that contains an ancestor and only some of its descendants.

What is a polyphyletic group?

A group that contains descendants of more than one common ancestor and does not contain the ultimate ancestor of all of the taxa in the group.

What are characters?

Organism attributes under consideration (features, traits).

What are character states?

Particular values that can be taken by different individuals for specific characters.

What is a model of evolution?

Hypotheses about how characters evolve, taking a mathematical and statistical form.

What is Homology?

A character (trait) shared by two or more taxa due to common ancestry.

What is Homoplasy?

A trait shared by two or more taxa that has evolved independently.

What is a Synapomorphy?

A feature that exhibits states that have been modified relative to the common ancestor and is shared by some but not all taxa.

What is a Symplesiomorphy?

A character that has not been modified relative to the form seen in the common ancestor.

What is a Autapomorphy?

Diagnostic characteristic of one taxon.

What are common methods for inferring a tree from character data?

Distance, Maximum parsimony, Likelihood, and Bayesian.

Why build phylogenetic trees?

Helps us understand evolutionary relationships and to more accurately name and classify organisms as well as understand questions of tempo and mode, diversification, rate of evolution, and evolutionary trends.