L3 - Cladistics: Charting relationships

Who came up with the Linnaean classification?

Carl Linnaeus

What are the three kingdoms of Linnean classification?

1. Animal

2. Vegetable

3. Mineral

What was the name of the book Carl Linnaeus published?

System a Naturae - Latin?

What are the 4 hierarchical levels a kingdom is divided into?

Class → Order → Genus → Species

• missing family

What are the 6 classes for the animal kingdom?

1. Mammalia

2. Aves (birds)

3. Amphibia (including reptiles and some fish)

4. Pisces (fish, including whales)

5. Insecta - all arthropods, not just insects

6. Vermes - all other invertebrates, including worms, mollusks and echinoderms like sea urchins

What are some similar classification systems we have to Linnaeus classification?

• Still have a hierarchical system

• Still us scientific binomial naming system developed to name life forms

What is the Binomial naming system? Provide an example and the rules

Rules:

• Generic name and a specific name

• The first letter of the genus is capitalized; the first letter of the species is not

• Species is italicized

• Species names can be repeated for many genera but a genus name can be used only once

Example:

• Homo sapiens

How do we determine if animals are closely related?

DNA and Fossils

What was the old way of determining whether two species were closely related?

Taxonomy

What is the hierarchical system used today?

What is the difference between a Phylogenetic tree and a Cladogram?

• Phylogenetic tree = depicts change through TIME

• Cladogram = a diagram based on shared characteristics/morphology

Define a cladogram

a HYPOTHESIS in diagram form showing the possible relationships between organisms

What is Parsimony?

The simplest solution

Define Plesiomorphy

Ancestral character trait, shared by all in cladogram

Define Synapomorphy

Shared derived trait; shared by two or more taxa and their most recent common ancestor

Define Autapomorphy

Uniquely derived character trait

Define convergent evolution

Organisms not closely related independently evolve similar traits as a result of having to adapt to similar environments or ecological niches

How can cladistics indicate that similarities are due to convergance?

Cladistic analysis would find more shared derived characteristics with other groups

What is the main rule in cladistics?

Must be monophyletic (a common ancestor and all of it’s descendants)

Define Paraphyletic

A grouping that does not include all of its descendants

Define Polyphyletic

A grouping that is made of members from unrelated ancestors

Which group is Polyphyletic?

Group 1

What group is Paraphyletic?

Group 3

What group is Monophyletic?

Group 2

Define a Protostome

Protostomia = the clade of animals once thought to be characterized by the creature's blastopore becoming its mouth during embryonic development.

• First opening becomes mouth

Define a Deuterostome

Embryo's first opening (the blastopore) becomes the anus

When did the Deuterostomia and Protostomia trait split in the Kingdom Animalia cladogram?

670 Ma? - Sometime in the pre-cambrian

What does Metazoa mean?

multicellular organism

Define Eumetazoa. When did this trait split in the kingdom animalia cladogram?

a major subkingdom or clade of animals that includes all multicellular forms with true differentiated tissues, leaving out only sponges and a few other simple groups

• multicellular with specialized tissues

• 770 Ma?

Define Bilateria. When did this trait split in the kingdom animalia cladogram?

Bilateria = a group of animals that have bilateral symmetry, meaning their bodies can be divided into matching left and right halves along a central axis

• 680 Ma?

Note the characteristics and relationships between the 6 major animal phyla