Evolution (Part 3)

Phylogeny & Classification

Modern Taxonomy Diagrams Reflect Evolutionary

History

Classification is Based on Evolutionary Relationships

• Phylogeny is the evolutionary history for a group of species

• Phylogenic tree – diagram reflecting evolutionary relationships between species in a branching pattern.

• Each branch point represents a common ancestor of the species above it.

A

B

C D

What is the common ancestor of the wolf, dog, skunk, and otter?

Cladistics & the Cladogram• Cladistics - an approach to classification in which organisms are

grouped together based on whether or not they share derived characteristics.

• A cladogram is an evolutionary tree diagram made using cladistics.

• Cladograms use derived characters to organize & arrange species (def.)Traits shared in different degrees represented by hash

marks.

• More closely related species share the most derived characteristics

Sample Cladogram

Constructing a Cladogram - YouTube

Cladogram Video & Worksheet

• MACKEN, MICHAEL / Evolution 4.6 Cladograms

The current tree of life has three domains.

The three domains in the tree of life are Bacteria, Archaea, and

Eukarya.• Domains are the HIGHEST level of

classification.

• There are 3 Domains:1. Eukarya2. Bacteria3. Archaea

►Domain Bacteria includes prokaryotes in the kingdom Bacteria.

largest groups on Earth

classified by shape, need for oxygen, and diseases caused

known for living in extreme environments

“extremophiles”

►Domain Archaea includes prokaryotes in the kingdom Archaea.

cell walls chemically different from bacteria

►Domain Eukarya includes all eukaryotes. kingdom Protista

►Domain Eukarya includes all eukaryotes. kingdom Protista kingdom Plantae

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►Domain Eukarya includes all eukaryotes. kingdom Protista kingdom Plantae kingdom Fungi

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►Domain Eukarya includes all eukaryotes. kingdom Protista kingdom Plantae kingdom Fungi kingdom Animalia

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