The Invertebrates Other Invertebrates - PowerPoint Presentation

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The Invertebrates

Other InvertebratesSlide2

Phylum Molluscaclams, snails, octopuses(second largest phylum of animals)Slide3

General Characteristics*locomotion by muscular footbody covering of ciliated epitheliummost have cephalization (“head” region)

*has a mantlea sheath of tissue enclosing the vital organssecretes a shellforms its respiratory apparatus*shell is multilayered and used for protection or body supportSlide4

Characteristics (cont.)has a complete digestive systemgills or lungs to control respirationc

irculation is by means of heart and colorless bloodhas ganglia and nerve cords for nervous systemspecial sense organs for vision, taste, touch, smell, and balancesexual reproduction with a trochopore larval stageSlide5

Characteristics (cont.)bilateral or asymmetrical*visceral humppart of the body with the heart, digestive, and excretory organsu

sually covered by the mantle*radulasmall organ with many tiny teeth for scraping food particlesSlide6

Classification6 Classes based on shape, shell type, and foot; we will look at 3Class Bivalvia“two-shelled”Class Gastropoda

“stomach-footed”Class Cephalopoda“head-footed”Slide7

Class Bivalviaclams, mussels, oysters, scallops

shell (valve) composed of 3 layershorny layerprismatic layercalcium carbonatepearly layerfootSlide8

Class Bivalviathe shell’s job is toprotect animal from external predators and internal irritationsif mantle gets a grain of sand in it, it will secrete the material of the pearly layer around the sand and form a pearl

the strong muscles holding the two shells together keep predators from being able to eat themSlide9

Class Bivalviaincurrent & excurrent siphonsfilter feeders – no radulagills - oxygen in/CO2 out

open circulatory systemheart helps pump

incurrent siphon

excurrent

siphon

gillsSlide10

Class BivalviaFYIGiant clam of Australia’s Great Barrier Reef can measure more than 1 yard in length weighs hundreds of pounds

Shipwormbivalve who can burrow over 2 feet into wooden ships and wharves once protected all they have to do is extend their siphons to feed causes much damage by weakening the wood to collapseSlide11

Class Gastropodasnails, slugs“stomach-footed”shell (valve)univalvesshell-less

radulamantle cavitySlide12

Class Gastropodamost are aquaticfoot is located below the visceral hump where the stomach is locatedsecretes slime to move over and then the foot contracts over it

enables a snail to glide over an upright razor bladeone shell, univalve nutritionfood is brought into the mouth by the raduladigestive tract is twisted so that the anus comes out above the mouth Slide13

Class Gastropodacirculationopened

heart located below the stomach and some blood vessels carry blood to dorsal area of the animalnervous systemganglia located near the mouthpair of eyes on tope of tentaclesslugs are unique type of gastropod because they are terrestrial and lack a shellSlide14

Class Cephalopodasquid, octopus“head-footed”shell (valve)shell-lessinternal shell

external shellradulaSlide15

Class Cephalopodajet propulsionsiphon or funnel for expelling water from the mantelfastest marine invertebrates

defense mechanismsink to confuse predatorscolor changes for camouflage Slide16

Phylum Echinodermata“spiny skin”starfish, sea urchins, sand dollarsSlide17

General characteristics6 Classeslives in saltwater environmentsradial symmetry in adultsb

ilateral symmetry in larvalocomotion by a water vascular system and tube feetsupport by a series of hard plates beneath the epidermishas spines to give the animal a rough, spiny appearancecomplete digestive system Slide18

General characteristics (cont.)respiration using skin gillsno well organized circulatory or excretory organs

asexual reproduction by regenerationsexual reproduction by separate sexes using external fertilizationSlide19

Echinodermsradial symmetrywater-vascular system

madreporite

radial canals

ring canal

tube

feetSlide20

Echinoderms: Starfishcoelom

body cavityregenerationcoelomSlide21

Class Stelleroidea (starfish)External featuresrays

4-25, but 5 rays are most commoncentral disccentral area of starfish from which rays extendspinesoriginate from the hard plates below the epidermis to give a rough appearance skin gillssmaller tubing around spines for respiration

and excretion by diffusionSlide22

Class Stelleroidea (starfish)External features (continued)anus

opening on dorsal surface of central disc for eliminating wasteSieve plate (madreporite)dorsal surface at edge of central discregulates the water pressure in the tube feet so it can act like suctiontube feetventral surface of rays

used for locomotion and opening shells of bivalvesmouthventral surface of central disc Slide23

Class Stelleroidea (starfish)Internal Featuresstomach

inside central disccan be everted through the mouthreleases enzymes to break down food and then absorb it, then stomach is brought back indigestive glandextends into each raylooks like plant leavesfinishes the digestion begun by mouthr

adial canalruns through the rays as past of its water-vascular system Slide24

Class Stelleroidea (starfish)Internal Features (continued)ring canal

part of the water-vascular system that circles inside the central discgonadsfound in each raysexes are separate so they will either be all ovaries or all testis Slide25

FYIfertilization is external so it is by luck that the sperm and eggs get togetherthe resulting larva is ciliated and bilateralt

hey eventually settle to bottom of ocean and develop into radially symmetrical adultsas long as the ray has a small portion of the central disc it can become a complete adultcrown of thorns starfish are causing much problems on coral reefssea cucumber has the remarkable ability to regenerate new internal organswhen attacked, they can eject some of their internal organs to appease its attacker and then retreat

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FYIThe uniqueness of the echinoderms has caused problems for evolutionists.they claim that starfish are “living fossils”to solve the problem, evolutionists put starfish in a separate non-evolving branch of the phylogenetic tree (

pg 192)“very old” starfish have led evolutionists to assume that they evolved early but have not changed sinceSlide27

Other classes of echinodermataEchinoideasea urchins and sand dollars

Holothuroideasea cucumberOphiuroideabrittle stars and basket starsCrinoideasea lilies and feather stars