BI 101: Invertebrate Animals

Home , Coelom, Glaucus atlanticus, Pteraeolidia ianthina

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Hornwort- a bryophyte

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Announcements • Lab tomorrow: Invertebrates ( lab worksheet provided) – No prelab

• Extra credit: Mycorestoration at Sequoia creek – Friday June 6th, 2014 3-4pm – the street Coffee culture, Corvallis • Extra credit: World Oceans Day- beach cleanup – Sunday June 8th – Nye Beach, Newport

Classification

The three-domains Bacteria Archaea Eukarya

The six-kingdom system Bacteria Archaea Protista Plantae Fungi Animalia

The traditional five-kingdom system Monera Protista Plantae Fungi Animalia

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(Forams and Radiolarians) Rhizarians Alveolates Rhodophyta Stramenopile

CHLOROPHYTA Euglenozoa AMOEBOZOANS

What are some characteristics animals share? List as many as you can think of. Discuss this in your groups

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Animal Cell

Fungus Cell

Evidence indicates that animals evolved from choanoflagellates (protists) ~ 570 mya

• Single cells • Often clonal • Heterotroph • No specialization or coodination between cells

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Animal Classification

1. DNA sequencing

2. Body Symmetry

3. Presence or absence of body cavity

4. Embyonic Development

Symmetry

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Body Cavity

Most bilateral animals have body cavities – Body cavities are fluid-filled cavities between the digestive tube and the outer body wall – Functions: • skeleton, providing support for the body and a framework against which muscles can act • protective buffer between the internal organs and the outside world • They can allow organs to move independently of the body wall

Body Cavity?

epidermis gut cavity

organs packed between A No coelom gut and body wall (acoelomate animal)

Fig. 25-4a, p. 405

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Body Cavity?

epidermis gut cavity

B Pseudocoel (pseudocoelomate animal) unlined body cavity around gut

Fig. 25-4b, p. 405

Body Cavity?

gut epidermis cavity

C Coelom body cavity with a lining (dark (coelomate animal) blue) derived from mesoderm

Fig. 25-4c, p. 405

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Embryonic Development Blastopore forms Protostomes mouth first

Deuterostomes

Blastopore forms anus first

What is the difference between vertebrates and invertebrates?

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Porifora - sponges

• Sessile (Larva motile) • No true tissues or organs • Exhibit asymmetry or radial symmetry • Filter feeders

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(water flow out Sponge Anatomy of the sponge)

epithelial cell pore

spicules (water flow into the sponge)

amoeboid cell

pore cell

collar cell

(water flow) Fig. 23-5

Sponge filtration/feeding

Collar Cell

Collar Cell http://www.youtube.com/ watch?v=T7E1rq7zHLc&feat ure=player_embedded http://www.youtube.com/watch?v =29W77870BgE&list=PLVN5247pO BYcE1Mn_pWHIL9l0sMIx19TI

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Sponges for Breast Cancer Research! • The artificial component called eribulin mesylate imitates an element found in sponges.

• It can check cell division, which is a reason of cells to self-damage.

• http://www.topnews.com.sg/content/22106-marine- sponge-probable-treatment-breast-cancer

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Cnidaria – Sea Anemone

• Radial symmetry • Two tissue layers • Filled with water– supports body • Nerve net • Nematocysts -stinging organelles that release toxins

Cnidarian Weaponry: The Cnidocyte

trigger filament

trigger

nuclei

(b) Cnidocytes Fig. 23-8

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Cnidaria: Symbiosis

Coral is a mutualism between photosynthetic dinoflagellates (protist) and a cniderian (animal) • Algae in coral called zooxanthelle

In many coral species polyps form colonies

Cnideria video

Colonial polyps secrete a hard external skeleton of calcium carbonate The skeleton remains after the polyp dies New polyps build on the skeletal remnants of earlier generations

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Platyhelminthes - flatworms

• Bilateral symmetry • 3 tissue layers • Cephalization (nerve mass) • True organs and organ systems • Aceolomate (no body cavity) • Parasitic forms but some free living

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Evolved ~500 mya

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Fig. 32-8 Nematoda - Round worms Coelom Body covering • Exoskeleton (molts)– 25,000 (fromspecies ectoderm) body coved in a thick Tissue layer cuticle lining coelom Digestive tract and suspending • Psuedocoelom (false (from endoderm) internal organs (from mesoderm) body cavity) • Bilateral worms (a) Coelomate

• 3 tissue layers Body covering • Unsegmented (from ectoderm) Pseudocoelom Muscle layer • Parasitic (50%) (from and free-living (50%) mesoderm) Digestive tract (from endoderm) (b) Pseudocoelomate

Body covering (from ectoderm) Tissue- filled region (from 16 mesoderm)

Wall of digestive cavity (from endoderm)

A Freshwater Nematode

posterior end intestine

anterior end

ovary vagina eggs mouth cuticle Fig. 23-25

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Arthropoda– Earth’s most diverse phylum Billions of species!

Major groups: • Crustaceans • Myriopods • Arachnids • Hexapods

Arthropoda Characteristics

1. Exoskeleton= External skeleton 2. Specialized body segments 3. Jointed appendages 4. Bilateral symmetry 5. True coelom (body cavity)

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Arthropoda respiratory system: Trachea

Arthropoda respiratory system: Example: Grasshopper • Spiracles: pores in exoskeleton • Trachea: connect to spiracles, carry oxygen to the body cells

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Arthropoda respiratory system

Arthropod Phylogeny

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Chelicerata

8 legs • Arachnids – spiders, – Mites – Ticks – scorpions • Horseshoe crabs • Pseudoscorpians

Arthropod Phylogeny

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Crustaceans

Rolly pollies– Isopods Lobsters Crayfish Crabs Shrimp Krill Baracles

Arthropod Phylogeny

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Myripoda

• Class: Symphyta

• Class: Chilopoda (centipedes)

• Class: Diplopoda (millipeds)

Arthropod Phylogeny

Diplura Insecta

Protura Collembola

Hexapoda: Reduction in body segments to 3 Reduction in legs to 6

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Arthropod Phylogeny

Thysanaura

: :

Slverfish

Archaegnatha

Diplura

Protura Collembola

Wings!

Insecta: mouthparts outside head capsule Hexapoda: Reduction in body segments to 3 Reduction in legs to 6

Figure 23-19 Segments are fused and specialized in insects

antennae head thorax abdomen compound eye mouth parts

wing

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Specializations for Feeding

Grasshoppers (a) – mouth has numerous manipulating and shearing parts for eating vegetation. Flies (b) – has a labium mouth part that has a sponge like end for absorbing nutrients from moist foods. Butterflies & Moths (c) – mouth part is a tube like maxilla for sucking up nectar from flowers. Mosquitoes (d) – have a stylus for piercing their prey to draw blood like a hypodermic needle.

Insect Development

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Discussion

Why might it be advantageous for insects to have complete metamorphosis?

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Annelida - segmented worms

Fig. 32-8 Coelom Body covering • Segmented body (from ectoderm)

• Bilateral symmetry Tissue layer lining coelom • 3 tissue layers Digestive tract and suspending (from endoderm) internal organs • Coelom (fully enclosed (from mesoderm) body cavity) (a) Coelomate Body covering • Organ systems are more (from ectoderm)

fully developed Pseudocoelom Muscle layer (from mesoderm) • Decomposers and Digestive tract (from endoderm) Parasites (b) Pseudocoelomate

Body covering (from ectoderm) Tissue- filled region (from mesoderm)

Wall of digestive cavity (from endoderm) Annelida - segmented(c) Acoelomate worms • Class: Polychaetes – Each segment with many hairlike chetae – 12,000 species – Mostly marine

• Class: Clitellata – Earthworms - Oligochaete 10,000 species Terrestrial Decomposers

– Leeches – Hirudinea 700 species Predators or parasites Most freshwater

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Discussion questions

1. How do earthworms differ from tapeworms and planarians?

Discussion questions

1. How do earthworms differ from tapeworms and planarians?

2. How do earthworms differ from nematodes?

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Mollusca Characteristics:

• bilateral symmetry • Coelomates- true body cavity • Unsegmented • aquatic & terrestrial • possess all organ systems

Mollusca Diversity 2nd most diverse animal group: 93,000 species

Gastropods Cephalopods Bivalves 80% of mollusk Most neurologically Aquatic species advanced • Clams • Snails Marine predators • Mussels • Slugs • Octopus • Nudibranchs • Squid • Cuttlefish

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Nudibranchs • 3,000 described species • Snails without a shell • Unique lifestyle and defense mechanisms Elysia– the photosynthetic animal (video)

Glaucus atlanticus consumes ‘man of war’ jellyfish and puts the nematocytes on its own back!

Nudibranchs

The Blue Dragon, Pteraeolidia ianthina, has a symbiosis with dinoflagellates. It also steals the armed tentacles of a sea anemone, a Cniderian, for defense and combat!

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Phylum Echinodermata 6,000 species Includes sand dollars, sea urchins, sea stars, sea cucumbers, and sea lilies

Three tissue layers True coelom

Echinodermata characteristics 1. Deuterostomes

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Echinodermata characteristics 2. Larvae exhibit bilateral symmetry; adults show radial symmetry

Echinodermata characteristics 3. Endoskeleton (internal skeleton) that sends projections through the skin Composed of calcareous plates or ossicles

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Echinodermata characteristics

4. Water vascular system:  Food and waste transport  Respiration  Locomotion

Discussion question

• How do sea urchins and sea stars differ from sea anemones and coral?

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Phylum Chordata Contains both vertebrates AND invertebrates!

All Chordates share four characteristics: 1. Dorsal nerve cord 2. Notochord (Primitive skeleton) 3. Pharyngeal gill slits 4. Post-anal tail

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Animal Diversity Ancestral Derived

Radial Symmetry Bilateral

0, 2 # of tissue layers 3

1 # gut openings 2