Chapter 23Chapter 23

Animals: The InvertebratesAnimals: The Invertebrates

Characteristics of AnimalsCharacteristics of Animals

1.1. MulticellularMulticellular. Cells are usually . Cells are usually arranged in organs or organ arranged in organs or organ systemssystems

2.2. HeterotrophsHeterotrophs

3.3. Require oxygenRequire oxygen to perform to perform aerobic respirationaerobic respiration

4.4. Most are motile at some point Most are motile at some point in the life cyclein the life cycle

5.5. Life cycle includes someLife cycle includes some sort of sort of embryonic developmentembryonic development

6.6. Mostly reproduce sexuallyMostly reproduce sexually (some asexually)(some asexually)

Radial SymmetryRadial Symmetry

No clear front No clear front or rear or rear

Body parts Body parts are arranged are arranged around a around a central axiscentral axis

Bilateral SymmetryBilateral Symmetry

Organism is Organism is the same on the same on either side of either side of one plane of one plane of symmetrysymmetry

Has a true Has a true front and rearfront and rear

Phylum Porifera - Phylum Porifera - SpongesSponges

Animals with no symmetry, no Animals with no symmetry, no tissues or organstissues or organs..

Range in size from tiny (like a Range in size from tiny (like a fingernail) to large enough to sit infingernail) to large enough to sit in

Engulf particles to feedEngulf particles to feed (phagocytosis)(phagocytosis)

Can reproduce sexually with a larva Can reproduce sexually with a larva or asexually by fragmentationor asexually by fragmentation

SpongesSponges

Phylum CnidariaPhylum Cnidaria

Jellyfish, sea anemones, coralJellyfish, sea anemones, coral All are aquaticAll are aquatic – most are ocean – most are ocean

dwellingdwelling Have tissuesHave tissues Have nematocysts – Have nematocysts – ““stinging dartsstinging darts”” Reproduce sexuallyReproduce sexually Have a nerve net for stimulationHave a nerve net for stimulation

Jellyfish, Corals, HydraJellyfish, Corals, Hydra

Phylum Platyhelminthes - Phylum Platyhelminthes - FlatwormsFlatworms

Turbellarians, Flukes, and Turbellarians, Flukes, and TapewormsTapeworms

Have a simple digestive system – Have a simple digestive system – absorb food from a hostabsorb food from a host

Body is flattenedBody is flattened Most are hermaphroditesMost are hermaphrodites, but will , but will

reproduce sexually with another reproduce sexually with another flatwormflatworm

FlatwormsFlatworms

Sea slugsSea slugs

Phylum Nematoda - Phylum Nematoda - RoundwormsRoundworms

Thrive nearly everywhereThrive nearly everywhere Have a complete digestive Have a complete digestive

systemsystem Have a partial body cavity where Have a partial body cavity where

reproductive organs are foundreproductive organs are found Most are free-living, with few Most are free-living, with few

parasitic speciesparasitic species

RoundwormsRoundworms

Ancyclostoma Ancyclostoma duodenaleduodenale ((hookwormhookworm))

Phylum Annelida – Phylum Annelida – Segmented WormsSegmented Worms

Segmented wormsSegmented worms – segments – segments are repeating body sectionsare repeating body sections

Many have setae (small hair like Many have setae (small hair like bristles) to help them move bristles) to help them move through soilthrough soil

Have a complete gut, Have a complete gut, rudimentary brain (with nerve rudimentary brain (with nerve cord), and circulatory systemcord), and circulatory system

Earthworms and LeechesEarthworms and Leeches

Phylum MolluscaPhylum MolluscaOctopus, squid, clams, Octopus, squid, clams,

scallops, snails, slugs, oystersscallops, snails, slugs, oystersMost have a hard shell with a Most have a hard shell with a

soft bodysoft bodyHave well developed organ Have well developed organ

systemssystemsHave a brainHave a brain

Octopus, Squid, Snail, Octopus, Squid, Snail, OysterOyster

Phylum ArthropodaPhylum Arthropoda(I accidently left this off – add (I accidently left this off – add

it!)it!) Insects, crustaceans, arachnidsInsects, crustaceans, arachnidsHardened exoskeletonsHardened exoskeletons Jointed appendagesJointed appendagesRespiratory StructuresRespiratory StructuresSensory StructuresSensory StructuresDivision of laborDivision of labor

Class ArachnidaClass Arachnida

Class InsectaClass Insecta

Class CrustaceaClass Crustacea

Phylum EchinodermataPhylum Echinodermata

Sea urchins, star fishSea urchins, star fish Have spines or platesHave spines or plates of calcium of calcium

carbonatecarbonate Well developed skeletonWell developed skeleton No brain, but nervous system is No brain, but nervous system is

presentpresent Water vascular system to deliver Water vascular system to deliver

water to tube feet for movementwater to tube feet for movement

Sea Stars, Sea UrchinsSea Stars, Sea Urchins

Class Class AsteroideaAsteroidea

Phylum ChordataPhylum Chordata

Includes Includes some invertebrates some invertebrates and ALL vertebratesand ALL vertebrates

Subphylum Vertebrata – Subphylum Vertebrata – all all vertebrates are in this vertebrates are in this subphylumsubphylum

Works CitedWorks Cited http://www.okc.cc.ok.us/biologylabs/Documents/Animals/Symmetry.htm http://trc.ucdavis.edu/biosci10v/bis10v/week9/sponge.gif http://www.okc.cc.ok.us/biologylabs/Images/Animal_Images/Sponge_copy.JPG http://www.aloha.com/~lifeguards/jellie75.jpg http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio%20102/Bio%20102%20lectures/a

nimal%20diversity/lower%20invertebrates/hydra_l.s._X_40.jpg http://www.seaslugforum.net/images/flatworm.jpg http://waynesword.palomar.edu/images/taworm4b.jpg http://images.google.com/imgres?imgurl=http://biology.nebrwesleyan.edu/Courses/Labs/Biology_of_

Animals/ZooLab10/Ancylostoma_male_10X.jpg&imgrefurl http://www.biology.iastate.edu/Courses/201L/Annelida/42%20whole%20worm.JPG http://upload.wikimedia.org/wikipedia/commons/thumb/0/00/Leech_blutegel.jpg/300px-Leech_bluteg

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