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Home , Dendrogramma, Invertebrate, Tegula (gastropod)

Phylogeny of on Earth Diversity

"The affinities of all the beings of the same Goals: class have sometimes been represented by a To explore in broad terms the phylogeny of Metazoa great ... As buds give rise by growth to fresh buds, and these if vigorous, branch out and the diversity of invertebrate . Eocyte Tree and overtop on all sides many a feebler branch, so by generation I believe it has been - Improve your ability to interpret phylogentic with the great Tree of Life, which fills with its dead and broken branches the crust of - Become familiar with the current understanding of the the earth, and covers the surface with its ever branching and beautiful ramifications.” phylogeny of major groups of organisms

Charles Darwin , 1859 - Review Linnean taxonomic classification - Identify/learn about unique characteristics of invertebrates, especially those living in

www.tolweb.org

Norman R. Pace Phylogeny of Life on Earth (from TREE OF LIFE PROJECT)

Eocyte Tree The major branches of living organisms Why is the name (Domains) Prokaryota no longer • Until 1970’s, 5 Kingdoms were recognized was: practical in defining an Bacteria (Prokaryota Domain) evolutionary grouping of all “ ” Protista, Fungi, Plantae, Animalia (Eukaryota) bacteria ?

How is it possible that • Archeans discovered in 1977 by Carl Woesa and Eukaryota and Archaea are George E. in phylogenetic trees based on the more closely related sequences of ribosomal RNA (rRNA) genetically when Archaea and Eubacteria are so much alike structurally? • First called Archeabacteria, but now 4 phyla of Archeans Archea are VERY different from Eubacteria

Phylogeny of Life on Earth (from TREE OF LIFE PROJECT)

Eocyte Tree The major branches of living organisms Invertebrate Diversity (with an introduction to Eukaryotes biological classification) Opisthokonts Multicellularity

Opisthokont lineage : Loosely based on Ch 1, Pechenik -unicellular motile stage bearing a single posterior flagellum -flattened mitochondrial cristae -a unique ~12 amino acid insertion in the protein EF1alpha.

1 Linnean System of Nomenclature Linnean System of Nomenclature

“Land ” “Black Turban Snail” Class Phylum Mollusca Phylum Mollusca Pulmonata Class Gastropoda Class Gastropoda Helicidia Order Pulmonata Order Prosobranchia Helix Family Helicidia Family Trochidae Species pomatia Genus Helix Genus Tegula Species pomatia Species funebralis Helix pomatia

By convention, species are referred to by their genus and species name. Use of its common name, “land snail” or Helix pomatia “escargot” may be ambiguous in some contexts.

Within the or Metazoa, there are about 32-33 distinct groups or phyla What is a Phylum? Is a Phylum a natural unit? Grouping of organisms that have a common design, (), (50) and share one or a group of fundamental characters that distinguish them from other phyla. (1,050) (7) Or simply , a primary division of a kingdom, as of the animal kingdom, ranking next above a class in size.

(15) Ex. Phylum Arthropoda: jointed (9) Ex. Phylum Chordata (6) Why not phylum Vertebrata????

(50) (15) (12) (20)

Two Newest Phyla What is a Species? Phylum Cycliophora: discovered in 1994 living A group of similar organisms that can potentially attached to the lips of interbreed successfully in nature. (by and Peter Funch who also discovered the in 1986) Is a species a natural unit?

What about Class Order Family Genus ? Phylocode

Key: 1 - adhesive disc attached to bristle surrounding 's mouth More important to understand phylogeny then it 2 - dwarf male 3 - anus is to perfect 4 - ring of cilia around mouth funnel

SEM image kindly supplied by Peter Funch, University of Copenhagen.

2 Two Newest Phyla Rather than new discoveries of higher taxa, most phylogenetic research today is focused on understanding Phylum Micrognathozoa the relationships and of known groups. Discovered in a cold spring in Greenland

2008 Genesis 46:580-586

•1915 described as a •1997 a mollusc based on r-DNA

Xenoturbella •20 new phylum Xenoburbellida •2011 combined with acoel into Xenocoelomorpha by R.M.Kristensen & P. Funch (2000)

Dendrogramma enigmatica incerti sedis

Collected from 400-1000m Off Tamania in 1986

Not Ph Or Ph

Just et al. 2014 PLOS one Vol 9: 1-11

Where do invertebrates live?

• Most species live in terrestrial , (roughly 900 K or about 80% of all species)

•However, only 9 phyla have invaded land and only two are highly successful terrestrial inhabitants

• 16 phyla are exclusively marine; in the oceans we find the greatest higher order diversity

•Three phyla occur only as parasites

3 Exclusively parasitic phyla:

Acanthocephala: spiny-headed ; gut parasites of , especially , mammals Nematomorphs: horsehair worms, juvenile parasites in Mesozoa: also degenerate animals that parasitize invertebrates, particularly and

Parasitism: -- most phyla have parasitic groups -- 3 phyla are exclusively parasitic

Nematomorph

What invertebrates have been most successfull Why Arthropods? in colonizing terrestrial habitats? “” provides support and a barrier to water loss. A waxy component makes the cuticle waterproof Arthropods!!

Chelicerates

Why Arthropods? Based on Pechenik table 1.1 Water Air The tracheal Humidity High Low

Density (support) High Low

Viscosity (resistance) High Low

Oxygen solubility Low High

Oxygen Low High Close up Nutrient Content High Low

What are the implications of each of these differences for What other phyla have invaded land? organisms living in these habitats?

4 Unique Features of Aquatic Animals Unique Features of Aquatic Animals Gas exchange, excretion, absorption 1. Gas exchange through , body wall

2. Absorption of dissolved nutrients Works well for animals of very small size, animals that 3. Fertiliziation by broadcast spawning are flat, and animals that are mostly water: 4. Rigid skeletal support not necessary cnidarians, , flatworms

5. Drifting way of life possible

6. Suspension and filter feeding

7. Sedentary life style possible

Unique Features of Aquatic Animals Unique Features of Aquatic Animals Gas exchange, excretion, absorption Fertiliziation by broadcast spawning Larger animals, animals with thicker integuments require gills, kidneys and other organs Not common in arthropods,

Limitations due to diffusion and dispersal of gametes.

Adaptations?

Unique Features of Aquatic Animals Unique Features of Aquatic Animals

Due to the density of water, a 1. Gas exchange through gills, body wall rigid skeletal support not necessary;

Drifting way of life possible 2. Absorption of dissolved nutrients

3. Fertiliziation by broadcast spawning Hydrostatic Two ways to be a 4. Rigid skeletal support not necessary drifter

5. Drifting way of life possible

6. Suspension and filter feeding

7. Sedentary life style possible

Plankton Video

5 Unique Features of Aquatic Animals Unique Features of Aquatic Animals

Suspension and filter feeding is common and Suspension and filter feeding is common and sedentary life styles are possible sedentary life styles are possible

Problem with suspension feeding: getting sufficient food from a diffuse source

Cnidarians Fan worms (black sea rod)

Sponges

Two solutions to concentrating food: Sedentary life style 1. let currents do the work is possible. and use an effective prey capture device (e.g. cnidarian stinging cells) Modular growth is prevalent among some groups. 2. Use cilia to create a current, and or cilia -Modular vs. unitary life styles to capture food particles:

- Ramets and genets - ciliary reversal mechanism

- opposed band mechanism -What might be the advantages (deuterostomes v. protostomes) of modular body plan? Why aren’t all animals modular? - Growth vs.

Jackson and Coates, 1986

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