(BIOL) Phylogeny, Fossils, and the History of Life

What is a phylogenetic tree?

A reasoned hypothesis of the evolutionary relationships among organisms.

What basis is used to construct a phylogenetic tree?

Shared derived characters.

What does the fossil record provide evidence for?

Direct evidence of evolutionary history.

How do phylogeny and fossils support the theory of evolution?

They provide independent and corroborating evidence of evolution.

What is a polytomy in phylogenetics?

A node with more than two immediate descending branches, indicating uncertainty in relationships.

What are sister groups in a phylogenetic tree?

Taxa that share a most recent common ancestor that is not shared with any other taxon.

What are monophyletic groups?

Groups that include all descendants of a common ancestor and only those descendants.

What is binomial nomenclature?

A system for naming species using a genus and a specific epithet, both italicized.

How is the genus name abbreviated in binomial nomenclature?

By shortening it to the single capitalized first letter followed by the specific epithet.

What is a synapomorphy?

A shared derived character used to define a group in phylogenetics.

What distinguishes homologous characters from analogous characters?

Homologous characters are derived from a common ancestor, while analogous characters arise due to similar selective environments.

What is the significance of branch lengths in a phylogenetic tree?

They can represent time or the degree of divergence between species.

What is the role of mass extinctions in evolution?

They alter the course of evolution by eliminating important groups of species and opening new possibilities.

What is the geologic timescale used for?

To represent the timing of evolutionary events and the appearance of new groups.

What does the term 'extant sister group' refer to?

The closest living relative of a group of organisms.

What is the importance of Tiktaalik in evolutionary biology?

It represents a transitional form between fish and tetrapods, showcasing mixed traits.

What is the difference between paraphyletic and polyphyletic groups?

Paraphyletic groups include a common ancestor and some descendants, while polyphyletic groups do not include the common ancestor.

What is the significance of molecular sequences in phylogenetics?

They help reveal evolutionary relationships and the classification of organisms into domains.

What are the three domains of life revealed by molecular sequences?

Bacteria, Archaea, and Eukarya.

What is a trace fossil?

Fossils that provide evidence of the activity of organisms, such as footprints or burrows.

What is the role of isotopes in radiometric dating?

Isotopes like Carbon-14 are used to determine the age of fossils based on their decay rates.

What does the term 'amniotic egg' refer to?

An egg that contains a protective amniotic membrane, characteristic of sauropsids and mammals.

What is the significance of shared ancestral characteristics in phylogenetics?

They help define relationships among taxa but are not modified in all taxa.

What is the importance of the fossil Eusthenopteron?

It is a key transitional fossil that provides insight into the evolution of tetrapods from fish.

What is the main goal of constructing a phylogenetic tree?

To break down evolutionary relationships into dichotomous, monophyletic sister groups.

What does 'species' refer to in biological classification?

An invariable word that has no form specific to singular or plural.

What is the correct format for writing a species name?

Italicized, with the genus capitalized and the specific epithet in lowercase.