1. Explain the fluid mechanics principle known as a “Reynolds Number” and describe its relevance to the life of single cell protists like Paramecium.

2. 3 ways in which a multicellular organism could evolve from a protist.
Symbiotic Hypothesis
3 ways in which a multicellular
organism could evolve from a protist.
Colonial Hypothesis
Cellularization Hypothesis

3. and the Theory of Recapitulation
Ernst Haeckle ( )
and the Theory of Recapitulation
Haeckel promoted the influential (but no longer widely held) recapitulation theory ("ontogeny recapitulates phylogeny") claiming that an individual organism's biological development, or ontogeny, parallels its species' evolutionary history, or phylogeny.
In what way does Haeckle’s colonial theory for the origin of animals reflect his believe in “recapitulation”?

4. Gastrea Blastea Gastrea Strengths: models exist (Volvox, choanoflag.)
(Haeckle’s favorite)
Gastrea
Blastea
Gastrea
Strengths: models exist (Volvox, choanoflag.)
: parallels animal embryology
Weaknesses: ???

5. Blastea Gastrea Strengths: models exist (Volvox, choanoflag.)
(Haeckle’s favorite)
Blastea
Gastrea
Strengths: models exist (Volvox, choanoflag.)
: parallels animal embryology
Weaknesses: ???

6. Similarities of Choanocytes (sponge cells)
and choanoflagellates (protozoan)
Choanocyte
Choanoflagellate

7. Choanoflagellates live as solitary and colonial forms

8. a. Phylogeny based on protein domain comparisons
b-d. choanoflagellate cells bear a single
Flagellum and an apical collar of actin-filled microvilli (bracket, c). D. an overlay of b-tubulin (reen), polymerized actin (red) and DNA (blue) localization reveals the position of the flagellum within the collar of microvilli.

9. Why present in a species that is unicellular?
Monosiga genome:
Encodes a diverse array of cell adhesion and extracellular protein domains previously thought to be restricted to metazoans. (cadherin required for cell sorting and adhesion
during embryology (why in protist????)
Lectins….cell recognition, adhesion
Integrin and immunoglobulin…adhesive and immune functions
Collagen domains: Key component of basement membrane in
metazoan tissues
Why present in a species that is unicellular?

10. Conclusions on Metazoan Origin
Evidence best supports the colonial theory
Choanoflagellate group is most likely ancestor;
Evidence includes cell structure and genetic similarities
Idea that metazoans are monophyletic is supported

11. Systematics, Classification and Phylogeny
Accompanying textbook
pages 19-31

12. II. Some Important Terms and Concepts
Character
Homologous
Convergent
states
Polarity
attributes or features of organisms
similarity due to descent from a common ancestor
similar-appearing structure evolved in entirely unrelated groups
various conditions of homologous character ex. fins of fish, arms of humans, forelegs horses
Direction of change...Ancestral and derived...is relative

13. Convergent vs. Homologous Ancestral vs. Derived
Distinguishing characters by these criteria is key to learning about evolution and phylogeny.
Why?

14. Key rules of cladistics taxonomy
Only shared derived homologous characters determine phylogeny : synapomorphies
All species in a grouping must share a recent common ancestor
All species derived from a common ancestor as well as
that ancestor must be included in the taxon
All species must be in monophyletic taxa
( true reflection of evolutionary history)

15. Monophyletic Taxon? Polyphyletic Taxon: Paraphyletic Taxon:
A taxonomic grouping of species that evolved from a single ancestor and includes all descendants of that ancestor
Polyphyletic Taxon:
An incorrect taxonomic grouping of species that arose from two or more recent ancestors
Paraphyletic Taxon:
An incorrect grouping of species sharing an immediate ancestor but not including all descendants of that ancestor.

17. Key rules of cladistics taxonomy
All species in a grouping must share a common ancestor
All species derived from a common ancestor as well as
that ancestor must be included in the taxon
Thus all species must be in monophyletic taxa
all species in this taxon share a common ancestor and all species derived from that common ancestor are included
Reptiliomorpha

18. Key rules of cladistics taxonomy
All species in a grouping must share a common ancestor
All species derived from a common ancestor as well as
that ancestor must be included in the taxon
Thus all species must be in monophyletic taxa
This is polyphyletic as the
Two lineages do not share
A recent common ancestor

19. Key rules of cladistics taxonomy
All species in a grouping must share a common ancestor
All species derived from a common ancestor as well as
that ancestor must be included in the taxon
Thus all species must be in monophyletic taxa
Grouping contains the immediate common ancestor but not all descendants of that ancestor are included

20. Ex. Vertebrate lineage Class Pisces? Class Reptilia?
Orthodox classification of Vertebrate Animals.

21. Use the Linnean categories: PCOFGS
Three important cladistics conventions in converting cladograms to taxonomic categories:
Use the Linnean categories: PCOFGS
Minimum taxonomic decisions will be made
Minimize use of empty or redundant categorial ranks
Division Ginglymodi
Family Lepisosteidae
Genus Atractosteus
Genus Lepisosteus
Ranks of well known clades will be retained
3. Asymmetric trees containing terminal taxa may be placed at the same hierarchal rank and listed in order of their branching sequence (Sequencing convention)

22. Ex. Vertebrate lineage Phylogenetics nested hierarchy
Phylogenetics Sequencing convention
Ph Chordata
SubPh Vertebrata
Class Pisces
Class Amphibia
Class Mammalia
Class Anapsida
Class Lepidosaura
Class Crocodilia
Class Aves
Orthodox classification
of Vertebrate Animals.