10--Mollusks, Arthropods, Echinoderms

Intro Movie Phylum Echinodermata

Section Four: Echinoderms

I.Echinoderms—phylum Echinodermata

a.Invertebrates with an internal (endo)skeleton and water vascular system

b.Skin is stretched over endoskeleton—bumpy texture—radial symmetry

c.Water vascular system (p. 71) allows tubes to contract or squeeze together to give water to tube feet---what stick out of bottom (sticky)

d.Reproduction: eggs fertilized in water—female releases eggs, male releases sperm—larvae metamorphosis to adult

e.Four major groups:

i.Sea Stars—predators—use tube feet to move and capture prey (digestive chemicals bread down tissues)

ii.Brittle Stars—flexible joints—slither—tube feet catch prey

iii.Sea Urchins—no arms-spines

iv.Sea Cucumbers—leather like skin, soft, flexible, muscular, crawl along floor—mouth has tentacles

Section Three: Insects

most bizarre insects

Nautilus--mollusk

I.Insects-Phylum Arthropoda

a.Three body sections, six legs, one pair of antennae and usually one or two pairs of wings

i.Head—sense organs—compound eyes (many lenses which focus light to form images)

ii.Thorax—midsection—where wings and legs are attached—only invertebrates to fly

iii.Abdomen—internal organs—small tubes on the outside allow oxygen to enter

b.Obtain food—insects can eat pretty much anything—their mouths are highly adapted for their specific type of food

i.Butterfly mouthparts shaped like coil tube which uncoils to suck up nectar from flowers

c.Reproduction: Complete metamorphosis or Gradual Metamorphosis

i.Complete: four different stages: egg, larva, pupa, adult (fruit fly) (p. 58 figure 19)

ii.Gradual: no distinct larval stage: egg, nymph—molts to eventually become adult (p.59 figure 20)

1.Grasshoppers, termites, cockroaches, dragonflies

Insect Worlds--Episode 1 (Jan. 21)

End Movie Insects of Madagascar

Intro Movie Phylum Arthropoda

Section Two: Arthropods

Intro Movie Phylum Molluska

Section One: Mollusks

II.Major groups: Crustaceans, Arachnids, Centipedes, Millipedes and Insects

a.Crustaceans—shrimp, crabs, crayfish, lobsters (p.50 Figure 11)

i.Two or three body sections, five or more pairs of legs, two pairs of antenna

ii.Antenna—smelling, tasting, touching, keeping balance

iii.Gills to obtain oxygen (under body)

iv.Metamorphosis—dramatic change in life cycle from larva to adults

b.Arachnids—spiders, mites, ticks, scorpions

i.Two body sections, four pairs of legs, no antennae

ii.Spiders

1.Predators, eat insects, hollow fangs with venom—fangs then suck up food

iii.Mites—parasites

iv.Scorpions—spinelike stinger—inject venom—live in hot climates

v.Ticks—parasites (lyme disease-deer ticks)

c.Centipedes and Millipedes

i.Two body sections and many legs

1.Centipedes--One pair of legs attached to each segment (inject venom into prey)

2.Millipedes—two pairs of legs attached to each segment (scavengers, curl up in ball)

I.Arthropods—Phylum Arthropoda

a.Invertebrate—have external skeleton (exoskeleton)—segmented body—appendages

b.“Jointed foot”---open circulatory system, digestive system two openings, reproduce sexually

c.Exoskeleton—waterproof covering, sometimes shed and get new larger one—molting

d.3 sections: head, midsection, hind section

e.Appendages—jointed give flexibility to move

f.More species of arthropods then all other species of animals combined!

I.Mollusks--—phylum molluska –clams, oysters, scallops , squids, and snails

a.Invertebrates with soft bodies with hard outer shell

i.Also has a thin layer of tissue—mantle-- that covers its internal organs

ii.Organ called a foot—crawling, digging, catching prey

b.Bilateral symmetry, digestive system two openings

c.Open circulatory system—blood is not always inside the blood vessels

d.Have gills if live in water –contain cilia

II.Three Main groups of Mollusks

a.Gastropods, bivalves, cephalopods

i.Gastropods—snails and slugs

1.Single external shell or no shell

2.Radula—flexible ribbon of tiny teeth, to obtain food

3.Move by creeping along on a broad foot—may ooze mucus to move on

ii.Bivalves—oysters, clams, scallops and mussels

1.Two shells held together by hinges and strong muscles

2.Capture food as water flows over their gills—cilia on gills move food to mouth

3.Move slowly or don’t move

iii.Cephalopods—octopuses, squids, nautiluses, cuttlefishes

1.Tentacles formed around its mouth

2. Closed circulatory system

3.Carnivores—captures prey with tentacles, scrapes and cuts flesh with radula

4.Large eyes and excellent vision, most complex nervous system of an invertebrate

5.Move by jet propulsion

Insect Worlds--Episode 3 (Jan. 21)

http://www.miragehabitat.com/pages/student_lessons_ocean.asp

Chapter Two:

Mollusks, Arthropods, and Echinoderms