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INVERTEBRATES
Introduction:
Animalia is the largest of the five kingdom system, with over one million species. It has
an extreme variety of shapes, colors, and sizes. It is made up of eukaryotic, multicellular,
heterotrophic organisms that are either aquatic or terrestrial and reproduce sexually or
asexually.
Invertebrates are a type of animal that have no backbone. They make up for about 97%
of the animal kingdom. Some invertebrates are earthworms, butterflies, jellyfish, and
giant squid. There are two kinds of invertebrates, lower and higher. Lower invertebrates
are further behind in evolution, they are very soft and squishy and more vulnerable to
predators. Higher invertebrates are further along in evolution, they are tougher and can
be considered less vulnerable.
Porifera:
General Characteristics:
oSponges are hollow cylinders that are closed at the bottom and have an opening at the
top called an osculum.
oThe cylinder is lined with special collar cells (choanocytes) which by beating their
flagella pulls water into the sponge through pores and canals and circulates through the
osculum.
oSponges live a sessile lifestyle, so when collar cells pump water into sponge they also
screen bacteria, unicellular algae, protozoans, and bits of organic matter out of it and
engulf it. Known as filter feeding.
oWhile circulating water, wastes are excreted into the water as it exits the osculum.
oFor support some sponges have simple skeletons made of protein fibers called spongin.
Others have skeletons made of tiny, hard particles called spicules.
oSponges reproduce asexually by forming small buds that break off and live seperatley.
And sexually by sending sperm into pores of another sponge.
Evolutionary Development:
Porifera represents the least evolutionarily advanced animals of the animal kingdom.
Classes:
oCalcarea © they have spicules of calcium carbonate.
oHexactinella © They have spicules of silicon dioxide.
oDemospongiae © They have spongin or a combination of spongin and spicules of
silicon dioxide.
oSclerospongiae © They have spongin plus spicules of silicon dioxide and calcium
carbonate.
Didja Know?
.....that sponges come in every color of the rainbow and also come in many varied forms
such as mossy mats, cacti, blobs of fungus, and tall tubes.
10 Questions Review:
1.What is the opening called at the top of a sponge?
An osculum.
2.What is another name for collar cells?
Choanocytes.
3.Sponges are sessile, what does this mean?
It means that they attach themselves firmly to surfaces and do not
move.
4.What is the main diet of a sponge?
Bacteria, unicellular algae, protozoans, and bits of organic matter.
5.What is a sponge's method of eating called?
Filter feeding.
6.What are the two skeletons of porifera known as?
Spongin and spicule.
7.What are a sponge's means of reproduction?
Sexually and asexually by regeneration.
8.What are the four classes of porifera?
Calcarea, hexactinella, demospongiae, and sclerospongiae.
9.What kind of invertebrate is a sponge, lower or higher?
They are lower, because they are further behind in evolution.
10.What do collar cells do to get water pumping?
They rapidly whip their flagella in every which way direction.
Cnidaria:
General Characteristics:
oCnidarians are either polyp (vase shaped) or medusa (bell shaped). Polyp is specialized
for a sessile life and medusa for swimming.
oThey consist of two cell layers © the endoderm and the ectoderm, between them is a
jelly like substance called mesoglea.
oTo feed, their tentacles capture prey and parylize it with coiled stingers called
nematocysts, located in the cnidocytes (stinging cells which characterize cnidarians).
oAfter capturing prey it's drawn into their mouth, called a gastrovascular cavity (hollow
gut), enzymes break up food and specialized cells lining cavity absorb it.
oWastes and undigested foods are expelled through mouth.
oCnidarians have radial symmetry.
Evolutionary Development:
Cnidarians date back 540 © 600 million years ago. They split off from porifera when
they developed layered skin, or layers of cells.
Classes:
oHydrozoa © This includes polyps, medusae, and species that alternate between the two.
oScyphozoa © They're the true jellyfishes, spending most of the life cycle as medusae.
oAnthozoa © They live only as polyps and include anemones and corals.
Didja Know?
.....that the two different forms of Cnidarians, medusa and polyp, resulted from a different
arrangement of the same body parts.
10 Question Review:
1.What is the difference between polyp and medusa?
Polyp is vase shaped and medusa is bell shaped.
2.What are polyp and medusa specialized for?
Polyp is made for a sessile life, and medusa for swimming.
3.What are the three layers of a cnidarian?
The ectoderm, mesoglea, and the endoderm.
4.What are the coiled stingers on their tentacles called?
Nematocysts
5.What is the hollow gut of the cnidarian known as?
Gastrovascular cavity.
6.What kind of symmetry do they have?
They have radial symmetry.
7.What stinging cells characterize cnidarians?
Cnidocytes.
8.What do anthozoa live their entire life as?
Polyps.
9.Name the three classes of cnidaria!
Hydrozoa, scyphozoa, and anthozoa.
10.How do they rid of wastes and undigested foods?
They send them back into the mouth.
Platyhelminthes:
General Characteristics:
oThey are bilaterally symmetrical.
oThey lack respiratory and circulatory systems.
oThey're flat.
oMostly aquatic.
oTheir soft bodies cause them to be unprotected from predators and dehydration.
oFlatworms are hermaphroditic and they can reproduce sexually and asexually. Sexually
when two planarians simultaneously fertalize eachother and asexually by regeneration.
oThey are capable of fertalizing their own eggs, but they usually dont.
Evolutionary Development:
Flatworms are the first animals to have bilateral symmetry, cephalization, and three tissue
layers.
Classes:
oTurbellaria © They live in marine environments, are hermaphroditic, and are free living.
oTrematoda © Parasitic flukes that are oval shaped, 1cm long, and have two sucker
mouths.
oCestoda © Parasitic tapeworms that have hooks and suckers, they may grow as long as
12m.
Didja Know?
.....that planarians feed by extending a tube, the pharynx, out of their mouth and sucking
up food, kind of like a straw.
10 Question Review:
1.What's the symmetry of a planarian?
They are bilaterally symmetrical.
2.What systems do planarians lack?
A circulatory and respiratory system.
3.What is the body type of a planarian?
Planarians are flat, soft, and very squishy.
4.Are they hermaphroditic?
Yes.
5.Can they fertalize themselves?
Yes, they can, but they usually dont.
6.How do they sexually reproduce?
When two planarians simultaneously fertalize eachother by absorbing eachother's sperm.
7.How do they reproduce asexually?
By regeneration.
8.What are the three classes?
Turbellaria, trematoda, and cestoda.
9.What are the only free living planarians?
Planarians of the class turbellaria.
10.What is the pharynx?
A tube, that in some animals extends out of the mouth, and functions in eating.
Nematoda:
General Characteristics:
oThey have round, slender bodies that taper at each end.
oMost are covered with a protective, flexible cuticle.
oThey range from less than 1mm in length up to 120cm.
oTheir digestive tract has two openings.
oThey have an anterior mouth and posterior anus.
oParasitic in both plants and animals, but most are free living.
oThe male is smaller than the female.
oMost varieties of roundworms aren't hermaphroditic.
oThey're bilaterally symmetrical.
Evolutionary Development:
Roundworms are the first animals to have different sexes. They have developed
adaptations for parasitism.
Classes:
oSecernentea © They're somewhat porous and oval or cleft like.
oAdenophorea © Characterized by reduced or absent caudal papillae and an excretory
system lacking latoral canals. These organisms are usually infective to their final host.
Didja Know?
.....that the most common roundworms are the ascaris, the ancylostoma, the necator, and
the trichinella.
10 Question Review:
1.What type of body do roundworms have?
They are long, slender, and tapered at each end.
2.What is the range in size for roundworms?
They range from 1mm in length up to 120cm.
3.How many openings do their digestive tract have?
It has two.
4.What is the placement of their mouth and anus?
Their mouth is anterior and their anus is posterior.
5.What kind of lifestyle do most nematodes live?
Most are freeliving, but some are parstitic in both plants and animals.
6.Is the male larger than the female?
No, the female is larger than the male.
7.What is the roundworms symmetry?
They are bilaterally symmetrical.
8.Is it true that most roundworms aren't hermaphroditic?
Yes, it sure is true.
9.What animals are the first to have different sexes?
Nematodes.
10.What are the two classes of nematodes?
Secernentea and adenophorea.
Rotifera:
General Characteristics:
oRotifera are transparent, free-swimming, microscopic animals.
oThey live in marine or fresh-water environments.
oThey are between 100 and 500 nanometers long, the female is much larger than the
males.
oRotifers have a crown of cilia around their mouth, while feeding they use their cilia to
sweep food into their mouth. This food moves through the pharynx and into the mastax,
a muscular organ that chops up food.
oThey feed on unicellular algae, bacteria, and protozoa.
oThey have no skeleton, they maintain their shape bye the hydrostatic pressure within the
pseudocoelum.
Evolutionary Development:
The crown of cilia that surrounds the rotifer's mouth is an adaptation for free living.
Classes:
oDigononta © They have paired ovaries. There's two orders, bdelloidea and selsonidea.
oMonogononta © There are free-swimming and sessile forms. Females posses one
ovary. Males are only present for several days out of the year. It has three orders:
collothecacea, flosculariacea, and ploimidia.
Didja Know:
.....that under a microscope while a rotifer beats it's cilia it apears as if the cilia are
rotating wheels.
10 Question Review:
1.What type of environment do rotifera live in?
Marine and freshwater.
2.What size do rotifera range in?
Anywhere from 100-500 nanometers.
3.Who's larger, the male or the female:
Females are much larger than the males.
4.What structure on rotifera is an adaptation for free-living?
The crown of cilia around their mouth.
5.Explain the rotifer's feeding process!
They sweep food into their mouth with the cilia, it then passes through the pharynx, and
on into the mastax.
6.What do rotifera eat?
They eat unicellular algae, bacteria, and protozoa.
7.How do rotifera maintain their shape?
Since they have no skeleton, they maintain their shape with hydrostatic pressure within
the pseudocoelum.
8.What are the two classes of rotifera?
Digononta and monogononta.
9.What are the two orders of digononta?
Bdelloidea and seisonidea.
10.What are the three orders of monogononta?
Collothecacea, flosculariacea, and plamida.
Annelida:
General Characteristics:
oThey all have true coelums.
oTheir body is divided into many segments. This is known as metamerism.
oMost annelids have external bristles called setae, which function in movement.
oSome have fleshy appendages called parapodia.
oTerrestrial and aquatic environments.
Evolutionary Development:
The anterior segment of earthworms reflect the cephalization thats an adaptation for
burrowing. They also have gizzards, which is adapted for burrowing as it grinds up the
soil.
Classes:
oOligochaeta © They have over 100 segments (metameric units). To move, the
earthworm anchors it's posterior setae and elongates forward then anchoring its anterior
setae and pulling it's posterior forward. They burrow and feed on soild and organic
matter at the same time. Food passes from pharynx to the esophogus, to the crop, then to
the gizzard. They have a closed circulatory system. Oxygen and carbon dioxide are
diffused directly across the skin, this requires moist skin. They are hermaphroditic,
though they are not capable of fertalizing their own egg.
oPolychaeta © They live in all marine habitats. Some are free swimming predators,
somw burrow and eat sediment, and other pump water through their body and scour floor
with tentacles.
oNirudinea © Theyre leeches and have no setae. They have suckers on each end of their
body. Most live in calm bodies of freshwater.
Didja Know?
.....that leeches are often used by doctors in the reattachment of a body part so that proper
blood flow will take place which will allow the operation to be successful.
10 Question Review:
1.What kind of coelum do they have?
All annelids have true coelums.
2.Annelid's bodies are divided into many segments, what is this known as?
This is known as metamerism.
3.What are their external bristles known as?
Setae.
4.What do the setae function in?
They function in movement.
5.What is parapodia?
They are the fleshy appendages of an annelid.
6.What kind of environments do they live in?
Terrestrial and aquatic.
7.What are the three classes?
Oligochaeta, polychaeta, and nirudinea.
8.What class do earthworm's fall in?
Oligochaeta.
9.What animals make up the class nirudinea?
Leeches.
10.What is a gizzard?
A structure adapted for burrowing as it grinds up soil.
Mollusca:
General Characteristics:
oThey have very soft bodies, but most mollusks have a shell that protects and conceals
their soft bodies.
oSome are sedentary filter feeders and other s are predatory.
oSquids and octopuses move by jet propulsion.
oAll mollusks have a true coelum.
oThey have three main body parts: the muscular foot, the head, and the visceral mass.
oThey have organ systems for circulations, respiration, digestions, excretion, nerve
impulse conduction, and reproduction.
oThey are bilaterally symmetrical.
oUsually have one or more shells.
Evolutionary Development:
Mollusks adapted the shell because it protected their soft body from predators. But the
shell posed a problem because it reduced the area available for gas exchange, this
problem was fixed when a new adaption evolved, the gills.
Classes:
oPolyplacophora © Also called chitons. Animals of the seashore, they live mostly on
rocks. Their shells are divided into four seperate, overlapping plates.
oGastropoda © They have single shells. They have torsion, the visceral mass twists 180
degrees in relation to the head. This twisting brings the mantle cavity to the animal's
front, this allows the animal to draw it' head into the mantle cavity when endangered.
oBivalvia © They are sessile and filter food from the water. They have a shell with two
valves and a muscular foot. This foot acts as an anchor and holds it down in the sand.
oCephalopoda © They have a "head-foot", meaning a large well developed head with
many tentacles. They are free swimming and live a predatory existence. Their tentacles
have strong suckers, they kill and eat their prey with the help of the radula and a sharp
beak. They have a closed circulatory system.
Didja Know?
.....that as a result from torsion during larval development, the sail developed an anus
above it's head.
10 Question Review:
1.What type of body do mollusks have?
Soft bodies, though most have protective shells.
2.How do mollusks feed?
Some are filter feeders and others are predatory feeders.
3.What kind of coelum do they have?
A true coelum.
4.What are their three main body parts?
Muscular foot, head, and the visceral mass.
5.What are squids and octopuses means of movement?
They move by jet propulsion.
6.What is a mollusks symmetry?
They have bilateral symmetry.
7.What kind of organ systems do they have?
Circulatory, respiratory, digestive, excretory, nerve impulse conduction, and
reproduction.
8.What are the four main classes?
Polyplacophora, gastropoda, bivalvia, and cephalopoda.
9.What kind of circulatory system do cephalopoda have?
Closed circulatory system, which means that they have veins, arteries, and capillaries.
10.How does bivalvia use it's muscular foot?
It uses it as an anchor to be held into the sand, because they're sessile creatures.
Arthropoda:
General Characteristics:
oAll have jointed appendages (extensions of the body, includes legs and antennae).
oSegmented body. A pair of appendages on each segment, though evolution has changed
this in some species.
oThey have exoskeletons.
oThey have ventral nervous system, and open circulatory system, a digestive system, and
specialized sensory receptors.
oIn order for arthropods to grow they must periodically shed and form a new
exoskeleton, this process is known as molting.
Evolutionary Development:
Evolved more than 600 million years ago. Arthropods all evolved from a common
ancestor. The evolution of arthropods shows them having less and less segments as time
goes on.
Classes:
oTrilobita © extinct organisms called trilobites.
oCrustacea © Shrimp, lobsters, crabs, barnacles, ciadocerans, ostracods, crayfish, water
fleas, and copepods.
oChelicerata © spiders, scorpions, ticks, mites, sea spiders, and horseshoe crabs.
oUniramia © The only group that has evolved on land, it includes centipedes, millipedes,
and insects.
Didja Know?
.....that the exoskeleton is made mostly of protein and the tough carbohydrate chitin. The
waxy outer layer repels water and prevents desiccation, the hard middle layer provides
important protection, and the flexible inner layer allows animals to move freely.
10 Question Review:
1.What are appendages?
Extensions of the body, like legs and antennae.
2.What kind of protection do arthropods have?
They have an exoskeleton.
3.What different systems do they have?
A ventral nervous system, an open circulatory system, a digestive system, and specialized
sensory receptors.
4.What must arthropods do in order to grow?
They must molt.
5.What is molting?
The process by which arthropods shed and form a new exoskeleton.
6.About how long ago did they evolve?
More than 6 million years ago.
7.What are the four classes of arthropoda?
Trilobita, crustacea, chelicerata, and uniramia.
8.Which class is extinct?
Trilobita.
9.Which is the only group to have evolved on land?
Uniramia
10.Which animals are in the class of uniramia?
Centipedes, millipedes, and insects.
Insecta:
General Characteristics:
oBody has three main parts: the head, thorax, and the abdomen.
oThe head has one pair of antennae.
oThe thorax has three pairs of jointed legs, and in many species, one or two pairs of
wings.
oThe abdomen is divided into eleven segments. It has no legs or wings attached to it.
oThey also have exoskeletons, jointed appendages, and a segmented body.
oThere are three main categories that set different insects apart: structural variations,
physiological variations, and behavioral variations.
oThey have an open circulatory system.
oThey do not breath with lungs or gills, but with tiny openings on their abdomen and
thorax, called spiracles.
Evolutionary Development:
Adaptations such as those of other arthropods have allowed insects to be successful. But
they have also adapted other characteristics of their own.
Didja Know?
.....that the reproductive organs of both male and female grasshoppers are located in their
abdomen.
10 Question Review:
1.What are the three main parts of an insect?
The head, thorax, and the abdomen.
2.How many antennae do they have?
One pair.
3.How many pairs of legs do they have?
Three pairs.
4.How many segments is their abdomen divided into?
Eleven segments.
5.What three main categories set different insects apart?
Structural variations, physiological variations, and behavioral variations.
6.What kind of circulatory system do insects have?
They have an open circulatory system.
7.What do they breath with?
Spiracles.
8.What are spiracles?
They're tiny openings on the abdomen and thorax that insects breath through.
9.What do insects have as well as all arthropods do?
Exoskeleton, jointed appendages, and a segmented body.
10.If an insect has wings, what are they attached to?
They are attached to the thorax.
Echinodermata:
General Characteristics:
oThey inhabit all kinds of marine environments.
oThey range from 1cm to 1m in diameter.
oThey often have brilliant coloring.
oMost undergo metamorphosis from a free-swimming, bilaterally symmetrical larva to a
bottom dwelling adult with radial symmetry.
oMost have five radii, known as pentaradial symmetry.
oThey have an endoskeleton.
oThey have a water-vascular system, which is a network of water filled canals.
oThey have tube feet that aid in movement, feeding, respiration, and excretion.
oNo circulatory, respiratory, or excretory systems.
oHave a nervous system, but no head or brain.
oThere are two sexes and they reproduce sexually or asexually.
Evolutionary Development:
Echinoderms have existed over 500 million years. They evolved from bilaterally
symmetrical ancestors. Scientists believe echinoderms used to be sessile.
Classes:
oCrinoidea © They are sessile and have a long stalk attached to a rock or the sea bottom.
They have five extending arms which branch out into many more arms. They can have as
much as 200 arms.
oAsteroidea © These are sea stars or starfish. They prey on oysters, clams, and other
organisms that are used as food by humans.
oOphiuridea © These are basket and brittle stars. Have long narrow arms allowing them
to move very quickly. They can regenerate missing body parts that break of very readily.
oEchinoidea © Sea urchins and sand dollars have a rigid endoskeleton called a test. They
have barbs on their long spines, and some have venom.
oHolothuroidea © Armless cucumbers. They have a soft body and modified tube feet
surround their mouth. When threatened many sea cucumbers eject their internal organs
through their anus, a defense mechanism called evisceration. They later regenerate the
lost parts.
Didja Know?
.....that a starfish's mouth is located on it's underside, or oral surface. The top of its body
is called the aboral surface.
10 Question Review:
1.What size do echinoderms range in?
1cm to 1m in diameter.
2.Where do they live?
All kinds of marine habitats.
3.What is their symmetry?
They go from bilateral symmetry to radial symmetry.
4.What is pentaradial symmetry?
A type of radial symmetry when the organism has five radii.
5.What is their support?
They have an endoskeleton.
6.What's a water-vascular system?
A network of water filled canals.
7.What are tube feet?
Small, moveable protrusions that aid in movement, feeding, respiration, and excretion.
8.How do they reproduce?
Sexually or asexually.
9.What are the five classes?
Crinoidea, asteroidea, ophiuridea, echinoidea, and holothuroidea.
10.What systems do echinoderms lack that are very important in most evolved animals?
They have no circulatory, respiratory, or excretory systems.
Keywords:
invertebrates introduction animalia largest five kingdom system with over million species
extreme variety shapes colors sizes made eukaryotic multicellular heterotrophic
organisms that either aquatic terrestrial reproduce sexually asexually invertebrates type
animal that have backbone they make about animal kingdom some invertebrates
earthworms butterflies jellyfish giant squid there kinds lower higher lower further behind
evolution they very soft squishy more vulnerable predators higher further along evolution
they tougher considered less vulnerable porifera general characteristics osponges hollow
cylinders that closed bottom have opening called osculum othe cylinder lined with special
collar cells choanocytes which beating their flagella pulls water into sponge through
pores canals circulates through osculum osponges live sessile lifestyle when collar cells
pump water into sponge also screen bacteria unicellular algae protozoans bits organic
matter engulf known filter feeding owhile circulating water wastes excreted into exits
osculum ofor support some sponges have simple skeletons made protein fibers called
spongin others skeletons made tiny hard particles called spicules osponges reproduce
asexually forming small buds break live seperatley sexually sending sperm pores another
sponge evolutionary development porifera represents least evolutionarily advanced
animals animal kingdom classes ocalcarea spicules calcium carbonate ohexactinella
spicules silicon dioxide odemospongiae spongin combination spongin silicon dioxide
osclerospongiae plus silicon dioxide calcium carbonate didja know sponges come every
color rainbow also come many varied forms such mossy mats cacti blobs fungus tall
tubes questions review what opening what another name collar cells choanocytes sponges
sessile what does this mean means attach themselves firmly surfaces move main diet
bacteria unicellular algae protozoans bits organic matter method eating filter feeding
skeletons porifera known spicule means reproduction sexually asexually regeneration
four classes calcarea hexactinella demospongiae sclerospongiae kind invertebrate lower
higher because further behind evolution pumping rapidly whip their flagella every which
direction cnidaria general characteristics ocnidarians either polyp vase shaped medusa
bell shaped polyp specialized sessile life medusa swimming othey consist cell layers
endoderm ectoderm between them jelly like substance mesoglea feed their tentacles
capture prey parylize with coiled stingers nematocysts located cnidocytes stinging which
characterize cnidarians oafter capturing prey drawn mouth gastrovascular cavity hollow
enzymes break food specialized lining cavity absorb owastes undigested foods expelled
through mouth ocnidarians radial symmetry evolutionary development cnidarians date
back million years split from when developed layered skin layers classes ohydrozoa this
includes polyps medusae species alternate between oscyphozoa true jellyfishes spending
most life cycle medusae oanthozoa live only polyps include anemones corals didja know
different forms cnidarians medusa polyp resulted from different arrangement same body
parts question review difference between vase shaped bell specialized life swimming
three layers cnidarian ectoderm mesoglea endoderm coiled stingers tentacles nematocysts
hollow cnidarian known gastrovascular cavity kind symmetry radial symmetry stinging
characterize cnidocytes anthozoa entire polyps name three cnidaria hydrozoa scyphozoa
anthozoa wastes undigested foods send them back mouth platyhelminthes general
characteristics othey bilaterally symmetrical othey lack respiratory circulatory systems
flat omostly aquatic otheir soft bodies cause them unprotected from predators
dehydration oflatworms hermaphroditic reproduce when planarians simultaneously
fertalize eachother regeneration capable fertalizing eggs usually dont evolutionary
development flatworms first animals bilateral cephalization three tissue oturbellaria
marine environments hermaphroditic free living otrematoda parasitic flukes oval long
sucker mouths ocestoda parasitic tapeworms hooks suckers grow long didja know
planarians feed extending tube pharynx sucking food kind like straw question review
planarian bilaterally symmetrical systems planarians lack circulatory respiratory system
body type planarian flat soft very squishy hermaphroditic fertalize themselves usually
dont simultaneously fertalize eachother absorbing eachother sperm regeneration
turbellaria trematoda cestoda only free living class turbellaria pharynx tube some animals
extends functions eating nematoda round slender bodies taper each omost covered
protective flexible cuticle range less than length otheir digestive tract openings anterior
posterior anus oparasitic both plants most free living othe male smaller than female
omost varieties roundworms aren bilaterally symmetrical roundworms first different
sexes developed adaptations parasitism osecernentea somewhat porous oval cleft like
oadenophorea characterized reduced absent caudal papillae excretory system lacking
latoral canals these organisms usually infective final host most common roundworms
ascaris ancylostoma necator trichinella question type body long slender tapered each
range size range length many openings digestive tract placement anus anterior anus
posterior lifestyle nematodes freeliving parstitic both plants male larger than female
female larger male true aren sure true first sexes nematodes nematodes secernentea
adenophorea rotifera orotifera transparent swimming microscopic marine fresh
environments nanometers much larger males orotifers crown cilia around while feeding
cilia sweep food this moves pharynx mastax muscular organ chops feed unicellular algae
bacteria protozoa skeleton maintain shape hydrostatic pressure within pseudocoelum
crown cilia surrounds rotifer adaptation odigononta paired ovaries there orders bdelloidea
selsonidea omonogononta there forms females posses ovary males only present several
days year orders collothecacea flosculariacea ploimidia under microscope while rotifer
beats apears rotating wheels environment rotifera marine freshwater size rotifera
anywhere nanometers females much males structure adaptation crown around explain
rotifer process sweep then passes mastax protozoa maintain shape since skeleton
maintain shape hydrostatic pressure within pseudocoelum digononta monogononta orders
digononta bdelloidea seisonidea monogononta collothecacea flosculariacea plamida
annelida coelums otheir divided many segments metamerism omost annelids external
bristles setae function movement osome fleshy appendages parapodia oterrestrial aquatic
environments anterior segment earthworms reflect cephalization thats adaptation
burrowing also gizzards adapted burrowing grinds soil ooligochaeta over segments
metameric units move earthworm anchors posterior setae elongates forward then
anchoring setae pulling forward burrow soild organic matter same time passes esophogus
crop then gizzard closed circulatory oxygen carbon diffused directly across skin requires
moist skin though capable fertalizing opolychaeta habitats predators somw burrow
sediment other pump scour floor tentacles onirudinea theyre leeches suckers each calm
bodies freshwater leeches often used doctors reattachment part proper blood flow will
take place will allow operation successful coelum annelids coelums annelid divided
segments metamerism external bristles function function movement parapodia fleshy
appendages annelid terrestrial oligochaeta polychaeta nirudinea class earthworm fall
oligochaeta make class nirudinea leeches gizzard structure adapted burrowing grinds soil
mollusca very mollusks shell protects conceals osome sedentary filter feeders other
predatory osquids octopuses move propulsion oall mollusks coelum main parts muscular
foot head visceral mass organ systems circulations respiration digestions excretion nerve
impulse conduction reproduction ousually more shells mollusks adapted shell because
protected shell posed problem because reduced area available exchange problem fixed
adaption evolved gills opolyplacophora chitons seashore mostly rocks shells divided four
seperate overlapping plates ogastropoda single shells torsion visceral mass twists degrees
relation head twisting brings mantle front allows draw head mantle endangered obivalvia
valves muscular foot foot acts anchor holds down sand ocephalopoda meaning large well
developed predatory existence strong suckers kill prey help radula sharp beak closed
result torsion during larval sail above though protective feeders others predatory feeders
coelum main parts visceral mass squids octopuses means movement propulsion bilateral
organ respiratory digestive excretory nerve impulse conduction reproduction four
polyplacophora gastropoda bivalvia cephalopoda cephalopoda veins arteries capillaries
does bivalvia uses anchor held sand creatures arthropoda oall jointed appendages
extensions includes legs antennae osegmented pair segment though changed species
exoskeletons ventral nervous open sensory receptors order arthropods grow must
periodically shed form exoskeleton process molting evolved more million years
arthropods evolved common ancestor arthropods shows having less time goes otrilobita
extinct organisms trilobites ocrustacea shrimp lobsters crabs barnacles ciadocerans
ostracods crayfish fleas copepods ochelicerata spiders scorpions ticks mites spiders
horseshoe crabs ouniramia group land includes centipedes millipedes insects exoskeleton
mostly protein tough carbohydrate chitin waxy outer layer repels prevents desiccation
hard middle layer provides important protection flexible inner layer allows freely
extensions legs antennae protection exoskeleton ventral nervous open sensory receptors
must order grow must molt molting process shed form about evolve years arthropoda
trilobita crustacea chelicerata uniramia extinct trilobita group land uniramia uniramia
centipedes millipedes insects insecta obody thorax abdomen othe pair antennae thorax
pairs jointed legs pairs wings abdomen eleven wings attached exoskeletons jointed
segmented othere categories insects apart structural variations physiological variations
behavioral variations open breath lungs gills tiny openings abdomen thorax spiracles
adaptations such those other allowed successful reproductive organs both grasshoppers
located insect pair pairs eleven categories apart structural physiological behavioral breath
spiracles spiracles tiny breath well segmented insect wings attached attached
echinodermata inhabit kinds diameter often brilliant coloring undergo metamorphosis
larva bottom dwelling adult radial five radii pentaradial endoskeleton vascular network
filled canals tube feet respiration excretion excretory ohave nervous brain othere sexes
echinoderms existed over ancestors scientists believe echinoderms used ocrinoidea stalk
rock bottom five extending arms branch arms much arms oasteroidea these stars starfish
oysters clams used humans oophiuridea these basket brittle stars narrow allowing quickly
regenerate missing break readily oechinoidea urchins sand dollars rigid endoskeleton test
barbs spines venom oholothuroidea armless cucumbers modified feet surround threatened
cucumbers eject internal organs defense mechanism evisceration later regenerate lost
starfish located underside oral surface aboral surface size echinoderms diameter where
kinds habitats bilateral pentaradial organism radii support endoskeleton vascular network
filled feet small moveable protrusions respiration excretion crinoidea asteroidea
ophiuridea echinoidea holothuroidea lack important
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