18.1-18.4 Objectives: 1) Be able to describe the characteristics of animals2) Be able to describe and recognize the different patterns of

symmetry3) Be able to describe the process of development (fertilization,

blastulation, gastrulation4) Be able to identify the 3 germ layers that are a result of

development5) Be able to describe and identify the 3 types of body plans that

an organism diplays

Chapter 18The Evolution of Invertebrate Diversity

18.1 What is an animalI. Characteristics

A. Multicellular, eukaryotic

B. No Cell Wall

C. Chemoheterotrophs1. Ingest food

a. Internal digestion

D. Movement1. Most but not all2. Nervous tissue& muscle tissue

Fertilization

ZygoteCleavage

Embryo

II. Life CycleA. Sexual reproduction and development

1. Sperm fertilizes egga. Zygote

BLASTULA

2. Blastulationa. The process of several successive cleavages (cell division) creating

a small, hollow raspberry-shape mass of cells1. Blastula

3. Gastrulationa. The process of transforming a blastula into a multilayered organismb. Blastula folds inward at one point of blastula

1. 1 fold = 2 layers2. 2 fold = 3 layers

c. Forms what are called germ layersd. Germ layers

1. Tissue layers in a developing organism that gives rise to a specific structure

2. Ectoderma. Outer germ layer

1. Skin, hair, nails, nervous system

3. Endoderma. inner germ layer

1. Digestive system throat & gut2. Respiratory system

4. Mesoderma. Middle germ layer

1. Everything else Skeleton, muscles, circulatory system

I. SymmetryA. A consistent, overall body pattern

B. Asymmetrical body pattern

1. No consistent pattern

Sponge

18.3 Animals can be characterized by basic features of their “body plan”

C. Radial Symmetry1. Repeating body parts radiating out from the center of the organism

4. Bilateral symmetrya. 2 identical halves

b. Have a dorsal (back/top) and a ventral (front/bottom) sidec. Have an anterior (head) and a posterior (tail)d. Have a right and lefte. Exhibit cephalization

1. Concentration of sensory or brain structures in the anterior end2. A head

No Body Cavity

Body cavity between Endoderm & Mesoderm

II. Types of body plansA. Acoelomate

1. Body cavity missing2. All 3 germ layers are in direct contact with each other

B. Pseudocoelomate1. Have a body cavity between the endoderm and mesoderm

Body cavity inside of the Mesoderm

C. Coelomate1. Have a cavity within the mesoderm

18.5 Phylum Porifera

I. ClassificationA. Kingdom Anamalia

1. Phylum Porifera-”pore bearer”

2. Supporta. Sponginb. Spicules

1. Calcium Carbonate (CaCO3)2. Silicon Dioxide (SiO2)

II. CharacteristicsA. General

1. Aquatic animals2. Exhibit minimal specialization3. Adults are sessile

B. Body plan1. General

a. 2 cell layers1. Choanocytes2. Epithelial Cells

b. Osculum opening at the top

C. Feeding & digestion1. Suspension feeders

a. Screen food out of water that moves through it’s body 2. Flagellated choanocytes

I. ClassificationA. Phylum Cnidaria

1. Class Hydrozoa2. Class Scyphozoa3. Class Anthozoa

II. General characteristicsA. Body structure/symmetry

1. 2 formsa. Polypb. Medusa

18.6-Phylum Cnidaria

III. Body PlanA. 2 tissue layer

1. Ectoderm2. Endoderm3. Mesoglea

B. Cnidae1. Nematocysts

a. Stinging structuresb. Occur in all classesc. Must be stimulated to work

C. Feeding1. Carnivores

D. Nervous system1. A simple nerve net

E. Reproduction1. Asexual & sexual

18.7-Phylum Platyhelminthes

I. ClassificationA. 3 groups

1. planariansa. Free-Living

2. Flukesa. Parasites

3. Tapewormsa. Parasites

II. General characteristicsA. What are they?

1. Flat wormsB. Body structure/symmetry

1. bilateralC. Body plan

1. 3 germ layers2. Acoelomates

III. GroupsA. Planarian

1. Spade-shaped anterior end & tapered posterior end

2. Digestion a. Food ingested through a muscular tube

1. Pharynx

b. Have a highly branched gastrovascular cavity (only one opening)

3. Neural controla. Cerebral ganglia

1. 2 clusters of nerve cells at the anterior endb. Have a latter like nervous systemc. Contain a variety of sensory cells

1. Eyespots

B. Flukes1. Digestion

a. Draws host’s body fluids through an anterior sucker that acts as a mouth

C. Tapeworms1. Intro

2. Digestiona. Have no gastrovascular cavity or mouth

3. Body structurea. Scolex

1. Knob-shaped structure at anterior end2. Contains hooks and suckers that allows worm to

attach to host

b. Proglottids1. Repeated segments making up body2. Reproductive structures

18.9 Phylum Mollusca

I. What is a mollusk?

A. Classification1. Phylum Mollusca

a. Class Gastropoda (gastropods)1. Snails, slugs

B. Defining characteristics1. Visceral mass

a. Internal organs2. Mantle

a. Fleshy fold of tissue lining the inside of the shell3. Muscular foot

c. Class Cephalopoda (cephalopods)1. Squids, octopus

b. Class Bivalvia (bivalves)1. Clams, oysters, scallops

C. Habitat1. Ocean, freshwater, moist terrestial environment

D. Characteristics1. Bilateral symmetry, coelomates, muscular foot for movement, mantle

a. Mantle?1. Thin layer of epidermis covering the body that secretes the

shell

E. Obtaining food1. Squid, octopus, snails, slugs

a. Radula

2. Clams, oysters, scallopsa. Filter feeders

F. Reproduction in mollusks

1. Separate sexes

2. Hermaphroditic

a. How is being hermaphroditic advantageous?

G. Nervous control

1. Simple to complex nervous system

G. Respiration1. Mostly gills2. Diffusion in terrestrial

H. Circulation 1. 3 chambered heart2. Open & closed system

18.10 -Phylum Annelida

I. What is a segmented worm?A. Characteristics

1. Bilateral, coelomate, segmented

2. Setae

B. Habitat

1. Moist environments

C. Segmentation supports diversified function

D. Nervous system

1. Simple system with some variation

E. Circulation and Respiration

1. Closed circulatory system

F. Digestion and Excreation

1. Coelomates

a. Gizzard

2. Nephridia

G. Reproduction

1. Hermaphrodites

2. Separate sexes

I. CharacteristicsA. Jointed Appendages

1. Appendages are extensions of the body & include legs & antennaB. Segmented body

1. 1 pair of appendages/body section

C. Exoskeleton1. Hard/rigid external covering2. Made of chitin

D. Open circulatory systemE. Complete digestive system

1. Coelomates

F. Ventral nervous system1. Specialized sensory receptors

a. Antenna, eyes, olfactory

18.11 Phylum Arthropoda

IV. ClassificationA. 3 Subphylum

1. Crustacea ( KRUSS-TAY-shuh)a. Crabs, lobsters, barnacles, and many others

2. Chelicerata (kuh-LIS-uh-RAHT-uh) a. Spiders, scorpions, ticks, mites, sea spiders, horseshoe crabs

b. Class Arachnida1. Spiders, ticks, mites, scorpions2. Defining characteristics

a. Spinneretsb. Chelicerae

3. Uniramia ( YOO-nuh-RAY-mee-uh)a. The only group thought to evolved on landb. Centipedes, millipedes, and all insects

c. Class Insecta1. Reproduction2. Metamorphosis

a. Change in which an immature organism passes into adulthood

3. The good, the bad, the uglya. Bad

1. Destroy crops2. Transmit disease

a. Malaria, African sleeping sicknessb. Good

1. Pollinators

18.13-Phylum Echinodermata

I. CharacteristicsA. Symmetry

1. Radial symmetry

B. Major characteristics1. Endoskeleton of calcium carbonate plates2. Water-vascular system

a. Network of water-filled canals3. Tube feet

a. Movable extensions of water-vascular systemb. Aid in movement, respiration, feeding, & excretion

II. ClassificationA. Class Echinoidea (EK-uh-NOID-ee-uh)

1. Sea urchins & sand dollarsB. Class Asteroidea

1. Sea stars or starfish2. Asteroidea = “starlike”

III. Class AsteroideaA. External structure

1. General forma. Several arms extend from a central regionb. 2 rows of tube feet run along the underside of each armc. Body often flattened

B. Water-Vascular system1. Network of water filled tubes

a. Connected to the tube feet2. Function

a. Provides movement and suction in tube feet1. Achieved through water pressure

3. Anatomya. Madreporite

1. Pore where water enters system2. White disk structure located on the aboral surface

C. Feeding & Digestion1. Carnivores/herbivores2. Coelomates

D. Circulatory, excretory, respiratory1. Has none

E. Nervous system1. Simple

a. No head or brain2. Contain sensory receptors

E. Reproduction & development1. Separate sexes2. Regeneration

a. Have an extreme capability to regenerate

b. Can regenerate arms from central region of body1. Even if all arms are removed

3. Some species can reproduce asexually by splitting central region in half or by just one arm

PHYLUM CHORDATAI. General characteristics

A. What is a chordate?1. A chordate is any organism that at some stage of its development has

a notochord, a dorsal hollow nerve cord, pharyngeal pouches, and a post-anal tail.a. Notochord A dorsal rod of specialized cellsb. Dorsal, hollow nerve cord A hollow tube just above the notochordc. Pharyngeal pouches Small outpockets of the anterior gut

II. ClassificationA. 3 subphylum

1. Subphylum Urochordataa. Tunicates (Sea squirts)b. That’s nice!!

2. Subphylum Cephalochordataa. Lanceletsb. That’s nice!!

3. Subphylum Vertebrataa. Organisms that have a vertebral columnb. NOW WE’RE TALKING!!!