Phylogeny

Speciation is fundamental to what?

Cladogenesis - process and patters of evolution

Speciation involes

– 1 species > 2 (or more) species

– usually involves

• geographical isolation

• subsequent divergence

• e.g., Darwin’s finches on Galapagos

• = “allopatric speciation” - different country, isolated so it evolves

allopatric speciation

inferred from range maps showing largely non-overlapping ranges of species

• e.g., Slender salamanders (Batrachoseps) in California

Parapatric Speciation

evolution of new species in populations that are geographically adjacent, not separated by a physical barrier, but with limited gene flow and strong environmental gradients

Sympatric Speciation

– e.g., apple maggot fly?

– lays eggs on hawthorns and now apples too

– genetic differences among populations on hawthorns and apples

evolutionary process where new species arise from a single ancestral population while living in the same geographic area, meaning no physical barriers separate them

Adaptive Radiation

Many species evolve from a common ancestor, have very divergent lifestyles. – e.g.:
– e.g.:

• Darwin’s finches

• Cichlid fishes of African lakes

the diversification of a group of organisms into forms filling different ecological niches.

Linnean Hierarchy

Carl Linnaeus

Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species

Dear King Phillip Came Over For Good Sex

Ex of linnean hierarchy - Wolves vs Coyotes

Binomial Nomenclature

The two parts are

1) Genus

2) species epithet

• Example: Canis lupus

Genus + species epithet

If names are handwritten what do you do? What about if they’re typed?

Underlined; italicized

Oldest currently used names date back to

to 10 th edition of Systema Naturae (1758)

Who determines what names are recognized?

International Commission on Zoological Nomenclature (ICZN)

What do you do to higher level names?

They are capitalized but not underline/italicized

Typological Species Concepts

“type specimen” needed to name a new species. Use one species and compare all others to it.

Biological Species Concept

Actually or potentially interbreeding populations

Phylogenetic Specis Concept

Smallest unit defined by common ancestry and distinct characters

Evolutionary Tree =

Phylogeny = Cladogram

An evolutionary tree shows patters of

Common ancestry and branching

A cladogram allows us to plot the evolution of _______.

Characters

Monophyletic group (clade) - an ancestor and all its descendants

Paraphyletic Group - an ancestor and some descendants

Monophyletic Groups are recognized by ______

Synapomorphies - shared derived characters.

What do Symplesiomorphies tell us about relationships?

Shared primitive characters tell us nothing. 

What do homoplasies tell us about relationships?

Features evolved independently in two groups. Tell us nothing. 

What data do you use to build phylogenies? What can this data be? What do we typically use?

Data on shared derived characters.

Morphological, behavioral, physiological, molecular characters.

DNA sequence data because there are more possible characters.

What do Tree-building algorithms do?

Sort through character matrix to choose the best possible tree.

Parsimonious

the principle that the simplest explanation, requiring the fewest evolutionary changes is the most likely to be correct