Phylogeny and the Tree of Life Quiz

Study Notes

Phylogeny

Refers to the evolutionary history of a species or related species.
Systematists employ fossil, molecular, and genetic data to elucidate evolutionary relationships.

Taxonomy

Involves the ordered division and naming of organisms.
Carolus Linnaeus established a taxonomy system focusing on resemblance, introducing two-part names for species and hierarchical classification.

Binomial Nomenclature

The scientific name for a species consists of two parts: genus and specific epithet.
The genus name is capitalized; both parts are italicized, forming a complete name to identify the species.

Hierarchical Classification

Introduced by Linnaeus, this system categorizes species from broad to specific: domain, kingdom, phylum, class, order, family, genus, species.
A taxon is any group at any hierarchical level; broader taxa cannot be directly compared across lineages.

Linking Classification and Phylogeny

Evolutionary relationships are visually represented using phylogenetic trees.
Linnaean classification may not always align with phylogenetic relationships; PhyloCode emphasizes clades that include an ancestor and its descendants.

Phylogenetic Tree

Represents hypotheses about evolutionary relationships, where branch points signify species divergence.
Sister taxa share an immediate common ancestor; basal taxa diverge early in a group's history.

Learning from Phylogenetic Trees

Trees illustrate descent patterns rather than phenotypic similarity.
They do not provide timelines for species evolution or the extent of change in lineages.

Inferences

Systematists gather morphologies, genes, and biochemistry data to infer phylogenies.

Morphological and Molecular Homologies

Shared ancestry results in phenotypic and genetic similarities termed homologies.
Organisms with similar structures or DNA are likely closely related compared to those with distinct characteristics.

Homology

Defined as similarity arising from shared ancestry.

Analogy

Refers to similarities due to convergent evolution, where different lineages develop similar adaptations under similar environmental pressures.

Sorting Homology from Analogy

Bat wings are homologous as forelimbs and analogous as functional wings.
Structures originating independently are homoplasies, often requiring fossil evidence for distinction between homologies and analogies.

Evaluating Molecular Homologies

Systematists analyze comparable DNA segments using computer programs and mathematical tools.
Molecular systematics aims to evaluate homologies and detect molecular coincidences.

Cladistics

Categorizes organisms according to common descent.
A clade encompasses an ancestral species and all its descendants, allowing for nested groupings within larger clades.

Description

Test your knowledge on phylogeny and the tree of life with this informative quiz. Explore key concepts, including evolutionary history and taxonomy, as you examine the relationships between species. Perfect for students studying biology or anyone interested in the science of classification.