12/4/2013

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BI 101: Invertebrate Animals

Announcements

• Lab tomorrow: Invertebrates ( lab worksheet provided)

– 8 am start

– No prelab

• Holiday: No class Friday!

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Classification

Bacteria Archaea Eukarya

Bacteria Archaea Protista Plantae Fungi Animalia

Monera Protista Plantae Fungi Animalia

The three-domains

The six-kingdom system

The traditional five-kingdom system

Alveolates

Euglenozoa

(Forams and Radiolarians) Rhizarians

CHLOROPHYTA

Stramenopile Rhodophyta

AMOEBOZOANS

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What are some characteristics animals share? List as many as you

can think of.

Discuss this in your groups

Animal Cell

Fungus Cell

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

• Single cells • Often clonal • Heterotroph • No

specialization or coodination between cells

Animal Classification

1. DNA sequencing

2. Body Symmetry

3. Presence or absence of body cavity

4. Embyonic Development

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Symmetry

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

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Fig. 25-4a, p. 405

epidermis gut

cavity

A No coelom

(acoelomate animal)

organs packed between

gut and body wall

Body Cavity?

Fig. 25-4b, p. 405

epidermis gut

cavity

B Pseudocoel

(pseudocoelomate animal) unlined body cavity around gut

Body Cavity?

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Fig. 25-4c, p. 405

gut

cavity epidermis

C Coelom

(coelomate animal) body cavity with a lining (dark

blue) derived from mesoderm

Body Cavity?

Embryonic Development Blastopore forms

mouth first

Blastopore forms anus first

Protostomes

Deuterostomes

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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

epithelial

cell

amoeboid

cell

pore

spicules

pore cell

collar cell

(water flow)

(water flow out

of the sponge)

(water flow into

the sponge)

Sponge Anatomy

Fig. 23-5

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Sponge filtration/feeding

http://www.youtube.com/watch?v=T7E1rq7zHLc&feature=player_embedded

Collar Cell

Collar Cell

http://www.youtube.com/watch?v=29W77870BgE&list=PLVN5247pOBYcE1Mn_pWHIL9l0sMIx19TI

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

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trigger

filament

trigger

nuclei

(b) Cnidocytes

Cnidarian Weaponry: The Cnidocyte

Fig. 23-8

Coral is a mutualism between photosynthetic dinoflagellates (protist) and a cniderian (animal)

• Algae in coral called zooxanthelle

Cnidaria: Symbiosis

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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

In many coral species polyps form colonies

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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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Announcements

• Quiz 7 today

• Final exam next Monday

• 8-10am (longer if needed)

• Study both Midterm & Final study guide

• Study groups encouraged!

Evolved ~500 mya

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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 80% of mollusk species • Snails • Slugs • Nudibranchs

Bivalves Aquatic • Clams • Mussels

Cephalopods Most neurologically advanced Marine predators • Octopus • Squid • Cuttlefish

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Nudibranchs • 3,000 described species

• Snails without a shell

• Unique lifestyle and defense mechanisms

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

Elysia– the photosynthetic animal (video)

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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Fig. 32-8Coelom

Body covering

(from ectoderm)

Digestive tract

(from endoderm)

Tissue layerlining coelomand suspendinginternal organs(from mesoderm)

(a) Coelomate

Body covering

(from ectoderm)

Pseudocoelom

Digestive tract(from endoderm)

Muscle layer(frommesoderm)

(b) Pseudocoelomate

Body covering(from ectoderm) Tissue-

filled region(frommesoderm)

Wall of digestive cavity(from endoderm)

(c) Acoelomate

Annelida - segmented worms

• Segmented body

• Bilateral symmetry

• 3 tissue layers

• Coelom (fully enclosed body cavity)

• Organ systems are more fully developed

• Decomposers and Parasites

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Annelida - segmented 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

Discussion questions

1. How do earthworms differ from tapeworms and planarians?

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Nematoda - Round worms Fig. 32-8

CoelomBody covering

(from ectoderm)

Digestive tract

(from endoderm)

Tissue layerlining coelomand suspendinginternal organs(from mesoderm)

(a) Coelomate

Body covering

(from ectoderm)

Pseudocoelom

Digestive tract(from endoderm)

Muscle layer(frommesoderm)

(b) Pseudocoelomate

Body covering(from ectoderm) Tissue-

filled region(frommesoderm)

Wall of digestive cavity(from endoderm)

(c) Acoelomate

• Exoskeleton (molts)– body coved in a thick cuticle

• Psuedocoelom (false body cavity)

• Bilateral worms

• 3 tissue layers

• Unsegmented

• Parasitic (50%)

and free-living (50%)

25,000 species

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A Freshwater Nematode

Fig. 23-25

ovary vagina mouth cuticle eggs

anterior

end

posterior

end

intestine

Discussion questions

1. How do earthworms differ from tapeworms and planarians?

2. How do earthworms differ from nematodes?

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Arthropoda– Earth’s most diverse phylum

Billions of species!

Major groups: • Crustaceans

• Myriopods

• Arachnids

• Hexapods

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Arthropoda Characteristics

1. Exoskeleton= External skeleton

2. Specialized body segments

3. Jointed appendages

4. Bilateral symmetry

5. True coelom (body cavity)

Trachea

Arthropoda respiratory

system:

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Example: Grasshopper

• Spiracles: pores in exoskeleton

• Trachea: connect to spiracles, carry oxygen to the body cells

Arthropoda respiratory

system:

Arthropoda respiratory system

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Arthropod Phylogeny

Chelicerata

8 legs

• Arachnids – spiders,

–Mites

– Ticks

– scorpions

• Horseshoe crabs

• Pseudoscorpians

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Arthropod Phylogeny

Crustaceans

Rolly pollies– Isopods

Lobsters

Crayfish

Crabs

Shrimp

Krill

Baracles

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Arthropod Phylogeny

Myripoda

• Class: Symphyta

• Class: Chilopoda (centipedes)

• Class: Diplopoda (millipeds)

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Arthropod Phylogeny

Hexapoda:

Reduction in body segments to 3

Reduction in legs to 6

Co

llem

bo

la

Insecta Pro

tura

Dip

lura

Arthropod Phylogeny

Hexapoda:

Reduction in body segments to 3

Reduction in legs to 6

Co

llem

bo

la

Pro

tura

Dip

lura

Insecta: mouthparts

outside head capsule

Arc

hae

gnat

ha

Slve

rfis

h:

Thys

anau

ra

Wings!

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Figure 23-19 Segments are fused and specialized in insects

abdomen

thorax

head

antennae

compound eye

mouth parts

wing

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.

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Insect Development

Discussion

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

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6,000 species

Includes sand dollars, sea urchins, sea stars, sea cucumbers, and sea lilies

Phylum Echinodermata

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?

VS

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Animal Diversity Ancestral Derived

Radial

0, 2

1

Acoelomate, Pseudocoelomate

Protostome

Symmetry

# of tissue layers

# gut openings

Type of coelom

Type of development

Bilateral

3

2

Eucoelomate

Deuterostome