More Complex Invertebrate Animals: MollusksAnnelidsArthropodsEchinoderms.

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More ComplexMore Complex Invertebrate Animals:Invertebrate Animals:

MollusksMollusksAnnelidsAnnelids

ArthropodsArthropodsEchinodermsEchinoderms

I. Mollusks:I. Mollusks:

• Snails, slugs, conch,

• Mussels, clams, scallops

• Squid, octopus, chambered nautilus, cuttlefish

I. Characteristics of MollusksCharacteristics of Mollusks:

• 22ndnd largest animal phylum largest animal phylum

– Arthropoda = largest

• from Latin molluscus, which means “soft.– Many have soft bodies – some have a hard shell.

Wide variety Wide variety of organismsof organisms in this phylum:in this phylum:

• FeedingFeeding- Some are sedentary filter feeders while others are fast-moving predators.

• Nervous system:Nervous system: Some are simple some are intelligent

• Circulatory systemCirculatory system:: Gastropoda & Bivalves have open while Cephalopoda has a closed system.

Body Cavity:

• Mollusks are true coelmatescoelmates..

• Have a Have a body cavitybody cavity completely completely lined by mesoderm tissue layer.lined by mesoderm tissue layer.

Mollusk ClassesMollusk Classes1.1. Gastropoda Gastropoda

(snails, slugs, albalone, conch)

2.2. BivalviaBivalvia (clams, oysters, scallops)

3. Cephalopoda3. Cephalopoda (octopuses, squid, cuttlefish, chambered nautiluses)

www.mcaorals.co.uk

www.linsdomain.com

www.iptek.net.id

1. Class Gastropoda1. Class Gastropoda• The largest & most diverse class of mollusks

• Most have a single shellsingle shell. – including snails, abalones, limpets and conchs. – Slugs have no shell.Slugs have no shell.

• Open circulatory systemOpen circulatory system in which a heart pumps hemolymph hemolymph from gills or lungs into the hemocoel (body cavity)hemocoel (body cavity)

Mollusk Gastropod Mollusk Gastropod Body PlanBody Plan• Divided into 2 main parts:Divided into 2 main parts:

– Visceral massVisceral mass• which contains the heart and the organs of digestion, excretion, and

reproduction

– Head-foot,Head-foot, which consists of:

• the head,the head, contains the mouth with Radula- – a tonguetongue like feeding adaptation with tiny teethtiny teeth that point

backwards) and sensory structures

• the foot,the foot, a large, muscular organ for locomotion

• Other parts:Other parts: – Coelom Coelom -limited to space around heart.– MantleMantle -a layer of epidermis that covers the visceral mass.

(secretes the shell)

Gastropod body

Phylum: MolluskPhylum: MolluskClass: GastropodaClass: Gastropoda

Animal: Common garden slugAnimal: Common garden slug

www.ppdl.org/dd/id/slugs.html

Conch shell

http://en.wikipedia.org/wiki/Conch

2. Class Bivalvia2. Class Bivalvia• Aquatic mollusks (clams,

oysters, & scallops)

• Shell is divided into two valves connected by a hinge.

• Most are sessile filter feeders.

• Bivalves lack a distinct head

Clams• The mantle cavity of a clam is sealed except for a

pair of hollow, fleshy tubes called siphons.– Water enters through the incurrent siphon. – Water leaves through the excurrent siphon.

Other Bivalves• Oysters attach to a hard surface

• Scallops can move through the water by repeatedly opening their valves and snapping them shut.

3. Class Cephalopoda3. Class Cephalopoda

• Means “head-foot.” “head-foot.” • Free-swimming

predators • Have tentacles &

beaklike jaws on the head.

• Also- Have a closed closed circulatory system.circulatory system.

Squids• 10 tentacles.• Propels by pumping jets of water with the mantle through an

excurrent siphon.

Octopuses• 8 tentacles • They often crawl along the ocean bottom or lie in wait for prey.

Chambered Nautiluses• The only existing cephalopod with external shell.• Shell is coiled & divided into chambers. • The body is confined to the outermost chamber.

Caribbean reef squidCaribbean reef squid (Venezuela)

Displays an aggressive zebra pattern to ward off other males competing for nearby females. This vivid species can display about three dozen different color patterns. (National Geographic)

In a cloud of greenish ink, a In a cloud of greenish ink, a jumbo squid flees!jumbo squid flees!

If all their dazzling color changes fail to deter a predator, squid use ink as a backup defense that helps them fade from view. Mexican fishermen catch some 100,000 tons (90,000 metric tons) of jumbos a year

National geographic

Huge eye of the world's largest squid• About 11 inches across, researchers believe the colossal squid's eye is the biggest animal eye ever found. • The 10m-long (34ft) specimen has also turned out to be female.• Very little is known about colossal squid; only about 10 have ever

been caught and brought to shore.

www.enricobaccarini.com/.../eyesquid.htm

The giant squid

• remains largely a mystery to scientists despite being the biggest invertebrate on Earth.

• largest of these elusive giants ever found measured 59 feet (18 meters) in length and weighed nearly a ton (900 kg).

Small Squid (Calamari)Kalamarakia (discovergreek food.com)

Caribbean reef octopusCaribbean reef octopus hunting, making a balloon and scaring little fish out from under

rocks to become dinner. Octopus briareus

dive.scubadiving.com

An octopus swimming; an octopus moving between tide pools

http://en.wikipedia.org/wiki/Octopus

• But Octopus are tasty But Octopus are tasty too!!!too!!!

Charred OctopusCharred Octopus With Garlic, Chilli, Lemon And Olive Oil au.lifestyle.yahoo.com

GRILLED BABY OCTOPUS WITH WATERCRESS SALAD &

ORANGESA recipe by Chef Doug D’Avico

www.italian-food-lovers.com

A chambered Nautilus

www.math.tamu.edu

The Chambered Nautilus:The Chambered Nautilus: In which nature flawlessly executes constant

mathematical form (It’s a physics thing) http://en.

wikipedia.org/wiki/Anthropic_principle.

http://www.uh.edu/engines/chamberednautilusform.jpg

(Photo by John Lienhard)

Very Intelligent invertebrates:

• Nervous system is very advanced.Nervous system is very advanced.EXAMPLES:EXAMPLES:• Dexterity, tool use and manipulation. Suction

cups & arms are as efficient as human’s hand.• Can learn through observation (choose colored

balls)• Can “Hide” & act like sea weed, • Assess their prey.• Complete & remember mazes & patterns

http://en.wikipedia.org/wiki/Cephalopod_intelligence , http://www.fortunecity.com/emachines/e11/86/cephpod.html

Many Many Cephalopods Cephalopods use pigments to use pigments to

hide & disguise themselves.hide & disguise themselves.

Blue-ringed octopus (size of a plum) this beak packs a deadly poison that'll kill a human in about 15 minutes.

OctopusesOctopuses have blue “blood”blue “blood”

• Octopuses have three hearts.three hearts.

• Its blood has copper-rich proteincopper-rich protein ((blue) blue) hemocyanin hemocyanin ffor transporting oxygen.– Although less efficient under normal conditions than the iron-

rich hemoglobin of vertebrates, in cold conditions with low oxygen pressure, hemocyanin oxygen transportation is more efficient than hemoglobin oxygen transportation.

• The hemocyanin is dissolved in the plasmaplasma instead of being bound in red blood cells and gives the blood a blue color.

Octopuses:Octopuses: short life expectancyshort life expectancy

• some live for as little as six months. Larger species, such as the North Pacific Giant Octopus, may live for up to five years

• However, reproduction is a cause of death:reproduction is a cause of death: – males can only live for a few months after mating – females die shortly after their eggs hatch.

• They neglect to eat during the (roughly) one month period spent taking care of their unhatched eggs, but they don't die of starvation.

• Endocrine secretions from the two optic glands are the cause of genetically-programmed death

II.II. Phylum AnnelidaPhylum Annelida Segmented worms:Segmented worms:

• Earthworm• Bristle worms

• Leeches

Segmented worms:Segmented worms: AnnelidsAnnelids

• AnnelidsAnnelids means little ringslittle rings (many body segments).

• True coelom animals: have a body cavity that is divided into separate compartments by partitions.

Other terms:

• Most have external bristles called setae setae • Some have fleshy protrusions called parapodiaparapodia

Class OligochaetaClass Oligochaeta• Live in the soil or in fresh water

• Most familiar is the earthworm.

Structure and Movement• An earthworm’s body has over 100 nearly-identical

segments.

• Circular and longitudinal musclesCircular and longitudinal muscles line the interior body wall.

• Locomotion is made possible by segmentation.

EarthwormsEarthworms

www.separationsnow.com

Earthworms Feeding /DigestionIngest soil as they burrow through it.

• Soil is moved through these structures:– mouthmouth

– pharynxpharynx

– esophagus esophagus

– cropcrop

– gizzard gizzard

– intestineintestine

– anusanus • Earthworms play an important role in the condition of soil.

Closed circulatory system.• Contractions of the aortic arches and the dorsal blood

vessel force blood through the vessels of the body

Respiration and Excretion• Oxygen and carbon dioxide diffuse through moist skin, • Cellular wastes and excess water are excreted through

nephridia.

Neural Control• Consists of a chain of ganglia connected by a ventral nerve

cord. • Sensory structures are found in all segments but are

concentrated at the anterior end.

ReproductionReproduction

• Earthworms are hermaphroditeshermaphrodites, but an individual worm cannot fertilize its own eggs.cannot fertilize its own eggs.

• During mating, earthworms press their ventral surfaces together.

• Held together by their setae and by a film of mucus

secreted by each worm’s clitellum.clitellum. • Fertilization occurs inside the tube, which forms a

protective case for the young worms.

Earthworms reproducing

http://upload.wikimedia.org/wikipedia/commons/thumb/9/97/Earthworm_klitellum_copulation_beentree.jpg/800px-Earthworm_klitellum_copulation_beentree.jpg

Earthworm diagrams

Class PolychaetaClass Polychaeta • “many bristles” “feather duster worms”• Polychaetes differ from other annelids in that they have

antennae & specialized mouthparts.

Class HirudineaClass Hirudinea• Hirudinea is the smallest class, consisting of about 500

species of leeches.

• Leeches -Leeches -have no setae or parapodia. • Many leeches are carnivores but some are parasites that

suck blood from other animals.

Haemophagic Leeches • Attach to their hosts & remain until they

become full & they fall off to digest. • Bodies are 34 segments. • Have an anterior (oral) sucker formed

from the first six segments of their body, used to connect to a host for feeding and releases an anaesthetic to remain unnoticed by the host.

• Use a combination of mucus and suction to stay attached and secrete an anti-clotting enzyme into the host's blood stream.

• http://en.wikipedia.org/wiki/Leech

Famous Film Moment for leeches: Humphrey Bogart in The African Queen

http://img.metro.co.uk/i/pix/2008/07/Bogart180708_450x302.jpg

How to Remove and Treat Leech Bites Find the skinny end [the head end] and use your finger or fingernail to push it sideways off the bite point." - Authority Mark Siddall in the NOVA Science Internet site.

You should avoid "remedies" such as simply pulling the leech from its moorings; plying it with salt, insect repellent, shampoo or vinegar; or heating it with a smoldering match, grass stem or cigarette. These techniques might cause the leech to discharge the contents of its gut, including bacteria, into the bite.  This might cause complications such as localized infection or even blood poisoning.

www.desertusa.com/mag08/sept08/leeches.html

Leeches and a History of Medicinewww.leeches.biz/medicine-leech.htm

• For over 4000 years, the leech has been a familiar remedy, with Greek and Roman physicians praising the application of this clever invertebrate. 

In the 19th century leeches

• were enjoying a golden age. • Millions were raised for medical use as their fame

as a cure-all ensued. • The mid 1800s saw their constant use for local

bloodletting. Druggists administered thousands of leeches to patients with anything from gumboils to facial discoloration.

• They were also put inside the mouth.

Leeches Today

• are bred in captivity in many institutions.• Leeches have found new fame in microsurgery,

where doctors require the precision of the leech to drain congested blood from wounded sites.

• Plastic surgeons are particularly grateful for the contribution made by the leech, due to their use in the treatment of difficult grafts and reconstructive surgery.

III. Arthropods & III. Arthropods & InsectsInsects

“The real rulers of the Earth”Sources used include textbook, (Holt Modern Biology) http://www.ucmp.berkeley.edu/arthropoda/arthropoda.htmlhttp://evolution.berkeley.edu/evolibrary/article/_0_0/arthropods_intro_01

More than More than 83%83% of all animal of all animal species are species are arthropodsarthropods..

• That's about 160 million insects for each person on Earth.

• Have evolved to fill a variety of ecological niches — from tiny internal parasite to giant bird-eating predator.

• Arthropods are a lot more than just delicious feasts and disgusting pests

                                                                                                                                                                 

5 Characteristics of all Arthropods

Segmented BodySegmented Body• Each segment repeats repeats the same set of structures

(ie, a pair of legs, a set of breathing organs, & a set of nerves),

• sets of segments are grouped into a larger unit, such as the abdomen & cephalothorax.abdomen & cephalothorax.

Hard ExoskeletonHard Exoskeleton• Made of protein & Chitin (a polysaccharide)• Must molt many times as grows

• Enzymes digest the layer of exoskeleton inside soften & then shed. It takes a few days for the newly excreted exoskeleton to harden.

Jointed LegsJointed Legs• All arthropods ((arthroarthro = joint, = joint, podpod = =

foot)foot) have jointed limbs. • How can an animal with a rigid body

covering move its legs?• The exoskeleton is hardexoskeleton is hard, but at the the

jointsjoints it is softer & bendablesofter & bendable, (allowing movement in same way a suit of armor does).

Many pairs of limbsMany pairs of limbs

• TagmaTagma- are specialized segments

The five major subphyla of the phylum Arthropoda.

Arthropods usually divided into 5 subphyla based on:– differences in

development – in the structure

of appendages, such as mouthparts.

1. Trilobites1. Trilobites

• Extinct• Many body appendages with one

pair of appendages per segment• Trilobites, living in shallow seas, flourished as

swimmers, crawlers and burrowers for some 350 million years.

• Fossils found on all continents, entrapped in the hardened sediments of Ancient Seas.

http://www.trilobite.com/

2. Subphylum 2. Subphylum MyriapodaMyriapoda

• Means”many feet”• One pair of branched antennae

• Many body segments• Includes classes:

– Diplopoda (millipedes)• Up to 100 body segments

• 2 pairs of legs on each segment

– Chilopoda (centipedes)• In tropical regions can reach 12 inches long

• From 15 to 175 pairs of legs

3. Subphylum Crustacea3. Subphylum Crustacea• about 38,000 known species.

• Terrestrial & Marine

• so diverse their single defining characteristic is having two pairs of antennae.

• Most also have:– a pair of mandibles– a pair of appendages on each body segment– some branched appendages– 16 to 20 segments & – several tagmata

http://copepodes.obs-banyuls.fr/images/NAUPLIUS.jpg

b. Aquatic Crustaceans (many species)

• Copepods -important part of the ocean’s plankton.

• In freshwater, much of the plankton are water fleas such as Daphnia species.

• Barnacles are sessile as adults.

– Free-swimming barnacle larvae attach to surfaces and develop a shell that encloses the body.

– Barnacles use their cirri (singular, cirrus) to sweep food.

www.divediscover.whoi.edu

www.microscopyu.com

www.ryanphotographic.com

Types of barnacleshttp://www.marinebio.net/marinescience/03ecology/tphi.htm

Gooseneck Barnacles

Balanus Barnacle with legs out, filter feeding on plankton

More aquatic crustaceans

• Order Decapoda -means“10 feet”

• Decapods have five pairs of legs

• Crayfish, lobsters, crabs, and shrimp are decapods

• Respiration through gills• (see more about crayfish in handout & know parts

for dissection lab)

4. Subphylum Chelicerata• Defined by presence of chelicerae

– The first pair of appendages– Modified into pincer or fangs

• Class Arachnid- spiders, scorpions, mites, ticks

• Some important Parts : – Chelicerae ( in spiders = fangs to inject poison)

– Pedipalps (hold food)

– 8 simple eyes at anterior of cephalothorax (NOT compound eyes!)

– Spinnerets- 3 pairs on tip of abdomen, for making silk

– Book lungs- like folds in a book= lots of surface area for gas exchange (some spiders use Tracheae for respiration instead)

– Malpighian Tubes- excretory tubes collect wastes, liquids. The liquid is reabsorbed (to conserve water) & waste is nearly solid.

Spiders-A full facial view of any spider shows its killing ability.

• Two powerful chelicerae, protrude down

• Each chelicera bears a hinged fang.

• Both fangs have ducts that lead up to the venom glands within the head.

• Spiders fall into two groups, each being classified upon how they strike their prey. – The fangs of Tarantulas are so hinged that they articulate in a

front-to-back motion allowing them to strike their prey from above.

– Most other spiders have fangs that are hinged laterally, providing a left-to-right strike.

www.microscopix.co.uk/spiders/fangs/index.htm

Spider Chelicerae

Fangs, Chelicerae of Zebra Jumping SpiderSalticus scenicus

www.microscopix.co.uk/spiders/fangs/index.htm

Fangs and Chelicerae of Tarantula SpiderlingBrachypelma smithi(Mexican Red-Knee Tarantula)

Anatomy of a spider

** Mites and ticks differ from spiders because they

have a fused cephalothorax and abdomen.

Life of a Spider

• Spiders feed on insects and other small animals. Many species are adapted to capture certain prey.

• Spiders rarely harm humans, but two species in the United States are dangerous:– the black widow– the brown recluse

• A male spider is usually smaller than the female. • Females lay eggs in a silken case.

Brown recluse

http://upload.wikimedia.org/wikipedia/commons/9/99/Brown_recluse_spider,_Loxosceles_reclusa.jpg

http://www.lib.uiowa.edu/hardin/md/pictures22/dermatlas/loxosceles_1_020724.jpg

Black widow spider

http://www.spidy.goliathus.com/img/BlackWidowSpider.jpg

“Daddy long legs”Pholcus phalangioides – a real “spider” Harvestmen (Phalangium opili)

• Harvestmen are different from spiders:- in harvestmen the two main body sections (the abdomen with ten segments

and cephalothorax) are nearly joined, so that they appear to be one oval structure;

- they also have no venom or silk glands. - Mouth is different so that ingestion is not restricted to liquid, but chunks

of food can be taken in. - They have a single pair of eyes in the middle of their heads

http://en.wikipedia.org/wiki/Opiliones

Daddy long legs urban legend

• Claims are that the harvestman is the most venomous animal in the world, but its fangs are too small to bite a human and therefore is not dangerous.

• This is untrue on several counts. – None of the known species have venom glands or fangs– The size of its mouth varies by species, but even those

with relatively large jaws hardly ever bite humans or other large creatures, even in self-defense.

– The few known cases of actual bites did not involve envenomation, and had no lasting effect

http://en.wikipedia.org/wiki/Opiliones

Giant sea spider- new finds in Antarctica

• Video link: http://news.nationalgeographic.com/news/2008/02/080219-spider-video-ap.html

http://www.spaceref.com/news/viewpr.html?pid=9218

Camel spider “Urban legend”• Comments: NOT TRUE!!

• This scary-looking creature (actually, it's a pair of scary-looking creatures dangling end-to-end) is indeed commonly called a camel spider, but in fact it is neither a spider, strictly speaking (entomologists call it a solifugid), nor is it found only in the Middle East. Camel spiders reside in arid locales all over the world, including the southwestern United States.

• A typical specimen can grow to about the size of a child's hand, but, though they are known for being vicious predators, camel spiders are neither venomous nor a threat to human beings.

• For the record, they don't eat camels, either.

Common house spiders

• http://www.spiderzrule.com/wind.htm

• http://www.spiderzrule.com/commonspidersusa.htm

Excellent site to look up spiders!!

5. Subphylum Hexapoda5. Subphylum Hexapoda

• Class Insecta• By many standards- the most successful group of

animals on earth.

• Entomology- the study of insects & terrestrial arthropods.

• Body of an insect is divided into 3 tagmata: – Head– Thorax– Abdomen

“bugs”

• Because they dominate all terrestrial environments that support human life, insects are usually our most important competitors for food, fiber, and other natural resources.

Grasshopper

• Example organism

• Please note parts for dissection lab,.

The crayfish- next 4 pages are notes for dissection lab

• an abundant freshwater crustacean that is structurally similar to lobsters, which are marine crustaceans.

• Crayfish, lobsters, crabs, and shrimp are decapods, or members of the order Decapoda. Decapoda means “10 feet.”

• Decapods have five pairs of legs that are used for locomotion.

External Structure• The crayfish’s body is divided into

– the cephalothorax, which is covered by the carapace and is divided into• the head, which has five segments• the thorax, which has eight segments

– the abdomen, which is is divided into six segments

• A pair of appendages is attached to each segment of the crayfish. Several pairs have specialized functions.

• These appendages include:– Antennae– Antennules– Mandibles– Maxillae– Maxillipeds– Chelipeds– Walking legs– Swimmerets

Crayfish -Parts for lab

Excretion• Green glands assist in excretion of excess water that enters the body by

osmosis.

Digestion• Digestive gland near the stomach secretes enzymes for digestion.

Respiration • gills.

Circulation• open.

Nervous & Sensory Organs• Many small sensory hairs. (sense water vibrations & chemicals) Compound eyes are

set on two stalks.

InsectsInsects• Entomologists classify insects into more than 25

orders based on characteristics such as:– structure of mouthparts– number of wings– type of development

Factors responsible for their success include:–ability to fly -exoskeleton

–jointed appendages -small size–large numbers offspring -short life span

Just how dominant are insects?

Comparison of 2 of the 5 groups of Arthropods

Insects as Food • Insects are an important source of nutrition in many parts of the world• In Mexico, dried grasshoppers are sold in village markets.  High in protein and low

in fat, they may be fried or ground into meal and mixed with flour to make tortillas.  • Sago grubs, the larvae of a wood-boring beetle, are considered a delicacy in Papua

New Guinea.  The islanders boil the larvae or roast them over an open fire.  • Ants, bees, termites, caterpillars, water bugs, beetle larvae, flies, crickets, katydids,

cicadas, and dragonfly nymphs are among a long list of edible insects that provide nutrition for the people of Australia, Africa, South America, the Middle East, and China. 

• Americans and western Europeans appear to be unique in having a strong cultural taboo against insects as food.

• Silkworm pupae forhuman food inThailand

•http://www.cals.ncsu.edu/course/ent425/text01/index.html

A Recipe for Maggot Crispies

• 1/4 cup margarine4 cups small marshmallows3 cups crispy cereal3 cups dry roasted maggots or mealwormsIn a saucepan, melt margarine and marshmallows. Remove from heat and stir in cereal and maggots. Spread mixture in a 9x13 greased pan and allow to cool.

Insect bodyInsect body –is divided into three tagmata:three tagmata:

1. Head -has mandibles and one pair of unbranched antennae.

2. Thorax -has three pairs of jointed legs and, in many species, one or two pairs of wings.

3. Abdomen -has 9 to 11 segments but neither wings nor legs in adults.

Humans & insects:• Used for consumer products too:

•Example: cochineal

“Today, the textile industry has largely replaced

cochineal with less expensive aniline dyes, but it is still used as a coloring agent in foods, beverages, cosmetics (especially lipsticks), and art products.”

http://www.cals.ncsu.edu/course/ent425/text01/impact1.html

Got Bugs? http://www.foxnews.com/story/0,2933,479233,00.htmlm

• GOT WAFFLES, LIPSTICK, YOGURT OR STRAWBERRY MILK? HOW ABOUT CANDY, SHAMPOO AND NAIL POLISH?

• THE FDA SAYS SCATTERED ALLERGIC REACTIONS ARE THE BASIS FOR THE RULE CONCERNING DYE DERIVED FROM THE CRUSHED COCHINEAL BUG.

• UNKNOWN AND UNNOTICED BY MOST CONSUMERS, THE JUICE OF A TINY BEETLE FIRST USED BY 16TH CENTURY SPANISH EXPLORERS IS RESPONSIBLE FOR RED, PINK, ORANGE AND PURPLE COLORING IN HUNDREDS OF U.S. PRODUCTS.

• NOW, THE FOOD AND DRUG ADMINISTRATION HAS DECIDED TO MAKE FOOD AND COSMETIC MANUFACTURERS IDENTIFY THE BUGGY SOURCE OF CARMINE OR COCHINEAL EXTRACT, WHICH MAY BE IDENTIFIED ONLY AS "COLOR ADDED" IN A PRODUCT'S LIST OF INGREDIENTS.

Insects and People• Insects negatively affect humans by:

– competing for food– transmitting diseases– destroying buildings & other manufactured products

• Insects benefit humans by:– serving as food for other animals– pollinating flowers– making valuable products such as honey– recycling nutrients in ecosystems

External Anatomy Grasshopper

Internal Anatomy Grasshopper

Grasshopper body- three tagmata:

– The head • mouthparts -labrum & labium are mouthparts that function

like upper and lower lips, respectively.

• a pair of unbranched antennae• pairs of simple and compound eyes.

– The thorax is composed of:

• Prothorax

• Mesothorax

• Metathorax

– The abdomen has upper and lower plates

Insect mouthparts

Circulation, Respiration, & Excretion

• Insects have an open circulatory system that transports nutrients through the body.

• Gas exchange occurs by means of air-filled tracheae that reach deep into the body.

• Malpighian tubules remove cellular wastes from the hemolymph while conserving water.

Nervous system• The grasshopper’s central nervous system consists of

a brain and a ventral nerve cord with

ganglia located in each body segment.• Nerves extend from the brain to sensory structures.• Insect sensory structures include :

– simple and compound eyes– sensory hairs on antennae and other body parts

– in some species, a sound-sensing tympanum

Reproduction

• Grasshoppers have separate sexes, – as do all insects.

• During mating, the male deposits sperm into the female’s seminal receptacle, where the eggs are fertilized internally.

• The last segment of the female’s abdomen forms the ovipositor, which she uses to lay fertilized eggs.

Most insects go through

metamorphosis.

• In incomplete metamorphosis, a nymph hatches from an egg and resembles the adult but has undeveloped reproductive organs and no wings. The nymph molts several times to become an adult.

• In complete metamorphosis, a wormlike larva called a caterpillar hatches from an egg and molts several times before becoming a pupa. The pupa molts to produce the adult, which resembles neither the larva nor the pupa.

Incomplete vs. Complete metamorphosis

Complete metamorphosis -allows larvae and adults of the same species to avoid competing

for space and food.-allows survival in periods of harsh weather or scant resources.

IV. EchinodermsIV. Echinoderms

(Last phyla of invertebrates)

• Starfish• Sand Dollars • sea urchins

• sea stars• Brittle stars

• Sea cucumbers

EchinodermsEchinoderms• are all benthic (bottom-dwellers) • endoskeleton of interlocking calcium

carbonate plates and spines• All true coelomates• Nervous systems are poorly developed • lack respiratory systems & circulatory

systems (the water-vascular system takes over some of the functions of these systems)

EchinodermsEchinoderms

• water-vascular system of special structures that protrude & help the echinoderm breath, move, and defend itself. – tube feet

– pedicellaria

– gills

• All echinoderms have a, a set of water-filled canals branching from a ring canal that encircles the gut. The canals lead to podia, or tube feet, which are sucker-like appendages that the echinoderm can use to move, grip the substrate, or manipulate objects. These tube feet are extended and retracted by hydraulic pressure in the water-vascular system.

Feeding:

• Some, like many starfish, are predators

• sand dollars often feed on detritus

• crinoids are filter-feeders

• sea urchins scrape algae from rocks

Reproduction

• External fertilization; eggs and sperm are freely discharged into the water.

• A few sea urchins brood their eggs in special pouches, but most provide no parental care.

• Most echinoderms go through several planktonic larval stages before settling down