Phylogenies and the History of Life

A node (or branch point) on a phylogenetic tree indicates common ancestry.

True

Which statement illustrates the concept of maximum parsimony?

Birds and mammals independently evolved hearts with four chambers

All tetrapods are vertebrates (and so are their fishy ancestors).  Amphibians, reptiles, and mammals are tetrapods (which means they have four limbs, or at least their ancestors did).  Mammals are the only tetrapod clade with hair.  Birds are the only tetrapod clade with feathers.  Anurans (frogs and toads) are the only amphibian clade without tails.

Lack of a tail in frogs and toads would be considered a

Shared derived character

All tetrapods are vertebrates (and so are their fishy ancestors).  Amphibians, reptiles, and mammals are tetrapods (which means they have four limbs, or at least their ancestors did).  Mammals are the only tetrapod clade with hair.  Birds are the only tetrapod clade with feathers.  Anurans (frogs and toads) are the only amphibian clade without tails.

Hair on mammals would be considered a

Shared derived character

All tetrapods are vertebrates (and so are their fishy ancestors).  Amphibians, reptiles, and mammals are tetrapods (which means they have four limbs, or at least their ancestors did).  Mammals are the only tetrapod clade with hair.  Birds are the only tetrapod clade with feathers.  Anurans (frogs and toads) are the only amphibian clade without tails.

For birds, the vertebral column is a

shared ancestral character

All tetrapods are vertebrates (and so are their fishy ancestors).  Amphibians, reptiles, and mammals are tetrapods (which means they have four limbs, or at least their ancestors did).  Mammals are the only tetrapod clade with hair.  Birds are the only tetrapod clade with feathers.  Anurans (frogs and toads) are the only amphibian clade without tails.

For frogs and toads, four limbs are a

shared ancestral character

Define the following

synapomorphy

homoplasy

parsimony

phylogenetics

systematics

synapomorphy - a shared derived trait among a group of organisms

homoplasy - independent evolutions of similar traits in two or more organisms

parsimony - choosing a phylogenetic tree that implies the fewest number of evolutionary changes

phylogenetics - a scientific field of study that investigates the evolutionary history and relationships among living things

systematics - a scientific field of study that classifies and organizes living things based on their evolutionary relationships