Macroevolution - Lecture 10

Taxonomy

classification and naming of organisms

What Is The Study Of Systematics

Study of biodiversity and evolutionary relationships between organisms (phylogenies)

Carolus ___________ is the father of taxonomy

Linnaeus

Scientists try to classify organisms by their _____________ history

Evolutionary

Taxon

One taxonomic unit of organisms

List the taxonomy hiearchy

1. Domain

2. Kingdom

3. Phylum

4. Class

5. Order

6. Family

7. Species

Dear
King
Philip
Came
Over
For
Good
Soup

What do nodes represent

An ancestral species at the moment they split into two new species

What do the branches represent?

An evolutionary (changing) lineage through time

The tips can represent 3 things, name them

1. Individuals

2. Species

3. Clades (group of organisms)

What is a sister group?

2 internal branches; descendants of one ancestral species

Parent branch Vs. daughter branch

parent = before the splitting node, daughter = after the node

What is the root & what does it represent?

A node representing the earliest time in the diagram

Ingroup Vs. Outgroup

Ingroup -

Most recent, closely related species

Outgroup - 

Distant relative of the ingroup

Why are outgroups helpful to scientists?

They help determine traits that are closely linked to root ancestors

Most Recent Common Ancestor (MRCA)

most common ancestral node between a group of taxa

What is a clade?

Group of a phylogeny that includes a MRCA and all of it’s descendants

How to determine a clade

Number of clades = number of nodes

(each node can be a separate clade)

What is a Monophyly and how do you determine one?

A clade/group that includes an ancestor and its descendants

Determined by the scissor test

How to differ between clades and monophyly

You can’t, they are the same

Paraphyly

Group made of ancestor and some descendants

Polyphyly

A group that does not contain the MRCA of all members

Paraphyly Vs. Polyphyly Vs. Monophyly/clade

Paraphyly - 

Ancestor + SOME descendants

Polyphyly -

Descendants - MRCA

Monophyly/clade -

Ancestors + ALL descendants

Derived Vs. Ancestral

Derived: if the clade rose within the clade, not present in ancestor

 

Ancestral: if the trait evolved in the clade, present in common ancestor

Synapomorphy

Shared derived trait for a clade

Homology

Structures dervied from a common ancestor

Homoplasy

Similar traits that don’t derive from a common ancestor

EX. human hands, gorilla hands, bear paws

Why Is Paleontology Important?

• Direct record of past evolutionary change

• Inference is strongest for groups in the past (fossilize well) 

Phylogenetics

• Indirect record of past evolutionary change 

• Inference is strongest for groups that have living representatives ( in the present)

Is paleontology and phylogenetics for macroeveolution or microevolution?

Macroevolution