Biodiversity and Classification

These flashcards cover the vocabulary and key concepts of biodiversity, taxonomy, and cladistics from Dr. Amy-Marie Gilpin's lecture.

Biodiversity

The variety of living organisms and the variety of ecosystems that they form.

Genetic Diversity

One of the three levels of biodiversity, referring to the variety of genes within populations and species.

Biodiversity Hotspot

A region with an exceptional level of species richness, especially endemic species, that is under serious threat from human activities; it must contain at least $1,500$ endemic vascular plant species and have lost at least $70\%$ of its original habitat.

Endemic species

Species that are found nowhere else except in a specific region.

Biological Species Concept

A concept stating that two organisms belong to the same species if they can interbreed and produce fertile offspring.

Systematics

A method of classification that emphasises evolutionary interrelationships through phylogenies.

Taxonomy

The science of describing, naming, and classifying organisms.

Taxon

A group within a classification system; the plural form is taxa.

Binomial system

A system conceived by Carolus Linnaeus where each species is assigned two names: the genus and the species identifier.

Taxonomic Hierarchy

A series of ranks for grouping organisms, ordered from most to least inclusive: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Bacteria

A domain of life consisting of microscopic, unicellular prokaryotes that lack a membrane-bound nucleus.

Archaea

A domain of life consisting of microscopic, unicellular prokaryotes.

Protists

A group of mainly unicellular or simple multicellular eukaryotes, including protozoa and algae.

Ancestral trait

A trait inherited from a common ancestor, such as the four limbs inherited by all mammals.

Derived trait

A trait that differs from the ancestral trait in a lineage, such as the single digit found in hooved animals.

Cladogram

A diagram used to show evolutionary relationships between organisms based on shared derived traits, where branch lengths are arbitrary.

Synapomorphies

New traits that evolved in a common ancestor and were passed on to its descendants, used to distinguish clades.

Cladistics

The method by which evolutionary (phylogenetic) trees are constructed based on the identification of common ancestors and shared traits.

Analogous traits

Traits shared between species but not present in their ancestor, often resulting from convergent evolution (same function, different origin).

Homologous traits

Traits shared between species and their common ancestor that follow the same basic plan, indicating common ancestry.

Outgroup

A taxon that separated from the group being reconstructed before evolutionary radiation; it lacks homologous structures and is used to ground the taxa of interest.

Monophyletic

A taxonomic grouping that includes the most recent common ancestor and all of its descendants; also known as a clade.

Paraphyletic

A grouping that includes the most recent common ancestor of the group but does not include all descendants.

Polyphyletic

A grouping of taxa from different evolutionary arms that does not include the most recent common ancestor of all members.

Phylogenetic Tree

An illustration of evolutionary relationships where branch points (nodes) represent divergence and branch length represents the extent of genetic change or time.