Lab #12 Molluscs and Arthropods - PowerPoint Presentation

Slide1

Lab #12

Molluscs

and ArthropodsSlide2

Class

Scaphopoda

(300 species)tooth shells, tusk shellsall are burrowing marine animalsmost distinctive characteristic – conical shell open at both endsClass Monoplacophoraundivided arched shellflat footClass Caudofoveatawormlike molluscslive in vertical burrows on the deep sea floorlack a shell or a footClass Aplacophora (250 species)“solenogasters”lack a shellmay be closely related to the flatwormsmost have a radulasurface dwellers on coralscarnivores

Phylum MolluscaSlide3

Gastropod

diversity

Subclass Prosobranchia (gill in front of heart): marine snails and abalonelargest group20,000 species, mostly marinefew are freshwater and terrestrialmost are herbivores or deposit feederssome are carnivorous – inject venom into their prey (fishes, other molluscs or annelids) using a modified radula that is shaped like a harpoonClass Gastropoda

abaloneSlide4

Gastropod

diversity

Subclass Opisthobranchia (gill in back of heart): sea hares, sea slugsmostly marinefewer than 2,000 speciesshell, mantle cavity and gills are reduced or may be lost in this groupmany species have nematocysts – acquire these from their cnidarian preyfoot may be modified for swimmingClass GastropodaSlide5

Gastropod

diversity

Subclass Pulmonata17,000 speciesmost are freshwater and terrestrial – snails and slugsmostly herbivoreslong radula for scraping plant materialmantle cavity is highly vascular and serves as a lung – open to the air via a pneumostomeClass GastropodaSlide6

Subclass

PulmonataSlide7

Class Bivalvia

= the ClamSlide8

labial

palps

anterioradductormuscleSlide9

foot

mantle

http://www.youtube.com/watch?v=YKTl5kwtjMcSlide10

http://

iweb.tntech.edu

/mcaprio/clam.htmSlide11
Slide12

Class

Cephalopoda

= the squidhttp://blog.tepapa.govt.nz/2008/04/29/dissection-of-giant-squid/Slide13

Arthropod Phylogeny

Subphylum

Chelicerata

:

first pair of appendages are

pincerlike Class

Merostomata

Class

Arachnida

Class

Pycnogonida

Subphylum

Crustacea

:

head with two pairs of antennae;

biramous

appendages

Class Malacostraca

Class

Branchiopoda

Class

Maxillopoda

Subphylum

Hexapoda

:

body divided into head, thorax and abdomen; uniramous appendages on the thorax

Class

Insecta

Subphylum

Myriapoda

:

body divided into a head and trunk; uniramous appendages

Class

Diplopoda

Class

ChilopodaSlide14

Phylum

Arthropoda

Subphylum Chelicerata:

body divided into a prosoma and an opisthosoma; first pair of appendages are pincer-like and used for feeding

Class Merostomata – horseshoe crabs

Class Arachnida – scorpions, spiders, daddy long legs, mites & ticks

Class Pycnogonida – sea spidersSlide15

Subphylum

Chelicerata

Class ArachnidacheliceraeOrder Scorpionida: scorpionstropical to desert climatesare secretive and nocturnaldistinctive chelicerae that surround the mouth + a pair of chelate pedipalps opisthoma is divided into a pre-abdomen and a post-abdomen (called the tail) – curves dorsally and anteriorly over the

pre-abdomen when arousedtip of the tial

is the telson with a sting – bulbular base that contains venom-producing glands and a hollow, sharp

barbonly a few scorpions are toxic to humans –

Androctonus (northern Africa)- Centuroides

(Mexico, Arizona and New Mexico)

reproduction involves a complicated “dance” that lasts several hours

development of a scorpion requires 1.5 years until maturitySlide16

Order

Opiliones

: daddy long legs or harvestmanbody appears ovoid (unlike a spider)many are omnivorous as opposed to carnivorous spidersOrder Acarina: mites and ticksgreat impact on human health and welfarefree-living forms are herbivores or scavengers – damage to cropsparasitic forms feed on blood and tissue fluidssome can be permanent ectoparasitesticks are ectoparasites during the entire life history

Opiliones

Acarina

Class

ArachnidaSlide17

Class

Pycnogonida

sea spidersall are marinemost common in cold waterslive on the ocean floorfeed on cnidarian polyps and ectoproctssome feed through sucking tissues through a proboscisSlide18

Class

Arachnida

Order Araneae: 34,000 species of spiders (carnivorous)prosoma: bears chelicerae with poison glands and fangspedipalps around the mouth are leglike are modified in the males for sperm transferopisthoma/abdomen: swollen and contains openings to the reproductive tract, book lungs and tracheaend of the opisthoma – spinnerets - associated with silk glands – emits a protein as a liquid that hardens with air as it is drawn out = web for prey capture

bite their prey to paralyze them – puncture the body with their chelicerae and inject venom

suck out the blood first, then inject digestive enzymes to “liquefy” internal organsfew are toxic to humans – Black widow (Lactrodectus

) and brown recluse (Loxosceles)

mating involves complex behaviors involving tactile, chemical and visual signalsSlide19

Phylum

Arthropoda

Subphylum Crustacea:

mostly aquatic; head with two pairs of antennae; one pair of mandibles and two pairs of maxillae; biramous appendages

Class MalacostracaClass Branchiopoda

Class MaxillopodaSlide20

Subphylum

Crustacea

Class Malacostraca = the crayfishSlide21
Slide22

Crayfish dissection

External Anatomy

1 – uropods2 – telson3 – abdomen4 – cephalothorax5 – cephalic groove6 – walking legs7 – cheliped8 – eye9 – rostruma - antennaeSlide23

Crayfish dissection

8 paired appendages are present on the cephalothorax

first two pairs = first and second antennaethird through fifth are associated with the mouth – crushing, tearing food

the 3rd pair = mandibles

4th and 5th = maxillae

(#1 and #2)6th through the 8th

are called the maxillipeds – food handlinglast two maxillipeds

bear gills

antennules

(1

)

antennae

(

2)

mandible

(3)

second

maxillae (4

)

first

maxilliped

(5),

second

maxilliped

(

6)

third

maxillipeds

(7)

walking legs or

chelipeds

(8

)

openings

to the green glands (9) Slide24

1 =

uropods

2 = pleopods or swimmerets 3 = walking legs or periopods4 = cheliped (1st walking leg)5 = 1st swimmeret6 = antennae

appendages 9 through 13 are on the thorax – called

walking legs (or

periopods

)

first pair (pair #9) is called the

cheliped

(4)

– chelicera used in defense and capturing food

remaining pairs are for walking/crawling along the sea floorSlide25

1 =

uropods

2 = pleopods or swimmerets 3 = walking legs or periopods4 = cheliped (1st walking leg)5 = 1st swimmeret6 = antennae

appendages 14 through 18 are on the abdomen – called

swimmerets or

pleopods

(2)

1

st

pair of swimmeret is larger in the male – for sperm transfer

abdomen is associated with the

telson

bears the anus which is flanked on either side by flattened

biramous

appendages called the

uropods

(1)

flipperlike

structure used for swimmingSlide26

Male

Female

1 – swimmeret2 – male genital opening3 – 1st

pair of swimmerets - clasper4 – 7 – walking legs8 – base of the first pair of walking legs

1 – swimmeret

2 – seminal receptacle

3 – walking leg #54 – walking leg #45 – female genital opening6 – walking leg #2

in females – eggs attach to the

pleopods

and the embryos brood on these “legs” until hatching

in males – the first two

pleopods

(#10 and #11) are modified into

gonopods

or claspers for sperm transferSlide27

Male crayfish

modified first swimmerets called

gonopods (1)openings to each vas deferens (2) third (3), fourth (4) and fifth (5) walking legsMale crayfishSlide28

Female crayfish

swimmerets (1)

opening to the seminal receptacle (2)openings to the oviducts (3)third pair of walking legs (4). Note: These openings have been expanded to make them more visible. Slide29

Crayfish meat

abdominal flexor muscles (1

) & abdominal extensor muscles (2) = MEATintestine (3), one of the fifth walking legs (4), carapace (7), uropods (5) and telson (7). Slide30

Crayfish internal anatomy

digestive glandSlide31
Slide32

1 – walking legs

2 – gills

3 – cephalic groove4 – 3rd pair maxilloped5 –cheliped6 – right eye7 – rostrum8 – right long antennaSlide33

Internal anatomy

green glands (1)

, compound eyes (2), the digestive gland (3), mandibular muscles (4), gills (5), abdominal extensor muscle (6), a portion of the fifth walking leg (7), and one of the third maxillipeds (8). Slide34

Class Branchiopoda

primarily live in freshwater

all possess flattened, leaflike appendages used in respiration, filter feeding and locomotionorder Cladocera: water flease.g. Daphnialarge carapace covers their bodysexual reproduction produces “wintering eggs” that hatch in springorder Anostraca: fairy shrimp and brine shrimpfairy shrimp live in temporary ponds that are formed through thaws and rainseggs are brooded by the femaleafter the female dies and the pond dries – eggs encyst and enter a dormant stagewith water – hatch into larval stagesdormant embryos can be carried by wind and rain

sea monkey

daphnia

water flea

fairy shrimpSlide35

Phylum

Arthropoda

Subphylum Hexapoda:

body divided into head, thorax and abdomen; five pairs of head appendages; three pairs of uniramous appendages on the thoraxClass

InsectaSubphylum

Myriapoda: body divided into a head and trunk; four pairs of head appendages; uniramous appendages

Class DiplopodaClass ChilopodaSlide36

Subphylum

Myriapoda

terrestrial4 classes –

characterized by a body consisting of head and trunk plus uniramous appendagesClass Symphyla

Class Pauropoda

Class Diplopoda: millipedes

Class Chilopoda: centipedes

Class

Diplopoda

Class

ChilopodaSlide37

Subphylum

Myriapoda

Class Diplopoda: millipedeshead

with mandibles for chewing + two antennaecircular body with

11 to 100 trunk segments – each segment is actually two segments fused togethertwo pairs of legs per segment – push against the substrate for locomotion

two ganglia, two pairs of ostia and two tracheal trunks per segmentfeed on decaying plant material using mandibles Slide38

Subphylum

Myriapoda

Class Chilopoda: centipedesnocturnal

head with maxillae and mandibles + 2 antennae

+ compound eyes or ocelliflattened body - 15 or more trunk segments

each with one pair of legs per segmentfirst pair of legs modified into forcipules or venom claws

not seen in other arthropodsrest of the legs = maxillopeds

fast-moving predators – small arthropods, earthworms and snails

bite can be annoying to humansSlide39

Subphylum Hexapoda

= InsectsSlide40
Slide41

Grasshopper External AnatomySlide42
Slide43

Grasshopper Internal Anatomy

Dorsal viewSlide44

gastric

caecae

below the cropovarieshindgut/intestineMalphigian

tubules

ovipositor

Tracheae

Ventral viewSlide45
Slide46

Subphylum

Trilobitomorpha

the fifth, extinct subphylum trilobitesdominant form of life in the oceans 600 MYAcrawled along the substrate feeding on annelids, molluscs and decaying organic matteroval body – flattened and divided into three longitudinal regionsall body segments are articular – roll into a ballappendages – two lobes or rami – called biramousinner lobe - walking legouter lobe bears spikes or teeth – digging or swimming or as gills in gas exchange