Phylogeny and Classification: Key Concepts in Biology

What is binomial nomenclature?

A system developed by Carolus Linnaeus that uses two-part names for species, consisting of the genus and specific epithet.

What are the taxonomic groups in hierarchical classification from most inclusive to least inclusive?

Domain, kingdom, phylum, class, order, family, genus, species.

What does a phylogenetic tree represent?

A hypothesis about the evolutionary relationships among a group of organisms (taxa).

What is the significance of sister taxa in a phylogenetic tree?

Sister taxa are groups that share an immediate common ancestor not shared by any other group.

What is the difference between homology and analogy?

Homology refers to traits inherited from a common ancestor, while analogy refers to traits that arise independently due to similar environmental pressures.

What is the difference between convergent and divergent evolution?

Convergent evolution occurs when unrelated species evolve similar traits, while divergent evolution occurs when related species evolve different traits.

Define clade.

A clade is a group of organisms that includes an ancestor and all its descendants.

What is a monophyletic group?

A monophyletic group consists of an ancestor and all its descendants.

What is a paraphyletic group?

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

What is a polyphyletic group?

A polyphyletic group consists of organisms that do not share a recent common ancestor.

What does it mean when a trait is mapped onto a phylogenetic tree?

It indicates the presence or absence of a trait in the taxa represented in the tree.

What is a basal taxon?

A basal taxon is an early diverging lineage that originates near the common ancestor of a group.

What is the role of systematics in biology?

Systematics classifies organisms and determines their evolutionary relationships.

What is the difference between a rooted and unrooted phylogenetic tree?

A rooted tree includes a branch representing the most recent common ancestor, while an unrooted tree does not.

What do branch tips in a phylogenetic tree represent?

Branch tips represent individual taxa.

What does a branch point (node) in a phylogenetic tree signify?

A branch point represents the divergence of two evolutionary lineages from a common ancestor.

What is the importance of phylogenetic trees in understanding evolution?

They show patterns of descent and relationships among organisms, but do not indicate the ages of taxa or branch points.

How can phylogenetic trees be visually represented?

Phylogenetic trees can be drawn in various forms (e.g., vertical, diagonal) without changing the relationships between groups.

What is the significance of the first letter of the genus in binomial nomenclature?

The first letter of the genus is capitalized.

How is the species name formatted in binomial nomenclature?

The entire species name is italicized.

What should not be assumed about the evolution of taxa?

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

What do connected taxa at a node share?

They share a common ancestor, which is assumed to be extinct and different from either of the derived species.

What is the significance of phylogeny in wildlife forensics?

Phylogeny provides important information about similar characteristics in closely related species, which can help identify illegal harvesting of species.

What types of data do systematists use to construct a phylogeny?

Systematists use morphological, genetic, developmental, and biochemical data.

What are homologies in the context of phylogenetics?

Homologies are character similarities due to shared ancestry, indicating that organisms with homologous characters are likely more closely related.

How can homologous characters be distinguished from analogous characters?

Homologous characters can be distinguished by comparing fossil evidence and molecular data; analogous structures may have similar functions but differ in underlying structure.

What is a clade in phylogenetics?

A clade is a group of species that includes an ancestral species and all its descendants.

What distinguishes a paraphyletic grouping?

A paraphyletic grouping consists of an ancestral species and some, but not all, of its descendants.

What is a polyphyletic grouping?

A polyphyletic grouping includes distantly related species but does not include their most recent common ancestor.

What is a shared ancestral character?

A shared ancestral character is one that originated in an ancestor of the taxon.

What is a shared derived character?

A shared derived character is an evolutionary novelty unique to a particular clade.

How can shared derived characters be used in phylogenetic trees?

They can be mapped onto a phylogenetic tree to infer evolutionary relationships.

What is the role of outgroups in phylogenetic analysis?

Outgroups usually have more ancestral characters, which helps in inferring the evolutionary relationships of the clade being studied.

What is the nature of phylogenies?

A phylogeny is a hypothesis that needs to be supported by data, both morphological and molecular.

What is the importance of molecular studies in understanding cetacean evolution?

Molecular studies have confirmed that hippos are the closest living relatives to cetaceans, indicating they are sister taxa.

What is the significance of identifying homologous characters?

Identifying homologous characters allows for the construction of a phylogeny and understanding evolutionary relationships.

What are some common group names that do not reflect shared ancestry?

Examples include marine mammals, pachyderms, warm-blooded animals, and algae.