BIOLOGY 1M03 Lecture Notes - Lecture 14: Neanderthal, Phenetics, Paranthropus
7 Jun 2019
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Some viruses evolve so fast that morphological characteristics can be more stable than gentile characteristics. Inferring the common ancestor: we want to know what the common ancestor was like, so we can tell which characters are derived (as opposed to basal, this can be done sometimes by common sense. Inferring the common ancestor statistically is difficult, for technical reasons: we can make use of an outgroup to study a group. An outgroup is an organism closely related to, but outside, the group being studied: we assume that the the root, or beginning, of the tree is where the outgroup branches from the group. Confusing the phylogeny: two species may have the same trait because the trait evolved twice independently convergent evolution, flight, trees, dolphins and ichthyosaurs, an organism may lack a character that its ancestors had secondary loss. This can be even more confusing: similarities that are not homologies (ie. , not due to common ancestry) are called homoplasies fig.
