Unit 7: Topic 9 - Phylogeny Flashcards
What are the differences and similarities between a cladogram and a phylogenetic tree?
Both show relationships of lineages. Unlike cladograms, phylogenetic trees take into account change over time. The approximate change time intervals can be calculated by a molecular clock or fossils. In a phylogenetic tree, time heads in the direction from the roots to the branches of the tree.
Note: The terms lineages and branches are interchangeable
What types of data and features are phylogenetic trees and cladograms constructed around?
Traits that have been gained or lost by a species. Shared morphological or molecular traits are in multiple branches and can be categorized into a clade. They show common ancestry among the species because of the shared trait. The data is found from current and past (fossilized) species and DNA and protein sequences.
What does the out-group or lone lineage represent?
The least closely related species/organism to the rest of the tree/cladogram.
Which is more accurate, morphological or molecular data, in a phylogenetic tree or cladogram, and why?
Molecular data. This is because morphological data can include analogous traits which do not show common ancestry. Morphological data can be misleading and argued against, while molecular data, such as amino acid or DNA sequences, are scientifically accurate and more reliable.
What components are phylogenetic trees and cladograms consisted of, and what do they represent?
There is a root lineage, which represents a common ancestor, split by a node, representing speciation (when new species form), followed by the next set of lineages, and so on. A taxon is a species or group of organisms seen in a tree or cladogram, usually at the tip of the lineages. A clade is a group of lineages/taxons that all share a specific trait. Click here
Phylogenetic trees are permanent and unchangeable: True/False
False. They are constantly being revised because of the new evidence and findings scientists make.
