BIOSCI101 Evolution - Lecture 7

❌ is the discipline of naming and classifying (grouping) organisms.

TAXONOMY AND SYSTEMATICS

These words have a similar history: over time these have been used as synonyms, as overlapping or as complementary terms.

In today's usage, ❌ deals with discovering, describing and naming organisms. ❌ deals with the phylogenetic relationships between taxa, especially at the higher levels.

Todays systematics is greatly influenced by DNA data from nuclear, mitochondrial and chloroplast genes – ❌ systematics.

CHARACTERS AND CHARACTER STATES

Phylogenetic ❌ is based on the analysis of characters and changes in character states (presence / absence or ❌). ❌ can be m❌, b❌ or molecular and need to have a shared ancestry -
❌. A potential source of confusion when constructing a phylogenetic tree is similarity between organisms that is due to convergence – ❌. Shared ancestral (❌) characteristics are inherited with little / no change from an ancestors. Shared derived characters are those that have undergone ❌ change and may be found only in closely related species.

INFERRING PHYLOGENIES

❌ the characteristics of an organism arose at some particular point in time Therefore it should be possible to determine the ❌ in which each shared derived character first appeared. ❌ are unique to a particular clade. This information can then be used to infer evolutionary ❌. However to do this we need an ❌ to serve as a point of ❌. An outgroup is a species or group of species that i known to have diverged ❌ the lineage that includes the species we are studying.