flatworms and roundworms

roundworm adaptations

Roundworms have a round body because they have a partial fluid-filled body cavity (pseudocoelom). This is one way that roundworms differ from flatworms. Another way is their complete digestive system. It allows them to eat, digest food, and eliminate wastes all at the same time. Roundworms have a tough covering of cuticle on the surface of their body. It prevents their body from expanding. This allows the buildup of fluid pressure in their partial body cavity. The fluid pressure adds stiffness to the body. This provides a counterforce for the contraction of muscles, allowing roundworms to move easily over surfaces.

roundworm reproduction

Roundworms reproduce sexually. Sperm and eggs are produced by separate male and female adults. Fertilization takes place inside the female organism. Females lay huge numbers of eggs, sometimes as many as 100,000 per day! The eggs hatch into larvae, which develop into adults. Then the life cycle repeats.

flatworms

Flatworms are invertebrates that belong to Phylum Platyhelminthes. There are more than 25,000 species in the flatworm phylum. Not all flatworms are as long as tapeworms. Some are only about a millimeter in length.

flatworm adaptations

Flatworms have a flat body because they lack a fluid-filled body cavity. They also have an incomplete digestive system with a single opening. However, flatworms represent several evolutionary advances in invertebrates. They have the following adaptations: Flatworms have three embryonic cell layers. They have a mesoderm layer in addition to ectoderm and endoderm layers. The mesoderm layer allows flatworms to develop muscle tissues so they can move easily over solid surfaces. Flatworms have a concentration of nerve tissue in the head end. This was a major step in the evolution of a brain. It was also needed for bilateral symmetry. Flatworms have bilateral symmetry. This gives them a better sense of direction than radial symmetry would. Watch this amazing flatworm video to learn about some of the other firsts these simple animals achieved, including being the first hunters: http://shapeoflife.org/video/flatworms-first-hunter MEDIA Click image to the left or use the URL below. URL:

how flatworms reproduce

Flatworms reproduce sexually. In most species, the same individuals produce both eggs and sperm. After fertilization occurs, the fertilized eggs pass out of the adults body and hatch into larvae. There may be several different larval stages. The final larval stage develops into the adult form. Then the life cycle repeats.

ecology of flatworms

Some flatworms live in water or moist soil. They eat invertebrates and decaying animals. Other flatworms, such as tapeworms, are parasites that live inside vertebrate hosts. Usually, more than one type of host is needed to complete the parasites life cycle, as shown in Figure 12.12.

roundworms

Roundworms are invertebrates in Phylum Nematoda. This is a very diverse phylum. It has more than 80,000 known species. Roundworms range in length from less than 1 millimeter to over 7 meters in length. You can see an example of a roundworm in Figure 12.13.

textbook_image

textbook_image

how roundworms make a living

Roundworms may be free-living or parasitic organisms. Free-living worms are found mainly in freshwater habitats. Some live in moist soil. They generally feed on bacteria, fungi, protozoa, or decaying organic matter. By breaking down organic matter, they play an important role in the carbon cycle. Parasitic roundworms may have plant, invertebrate, or vertebrate hosts. Several roundworm species infect humans. Besides ascaris, they include hookworms. Hookworms are named for the hooks they use to grab onto the hosts intestines. You can see the hooks in Figure 12.14. Hookworm larvae enter the host through the skin. They migrate to the intestine, where they mature into adults. Female adults lay large quantities of eggs. Eggs pass out of the host in feces. Eggs hatch into larvae in the feces or soil. Then the cycle repeats. You can learn more about parasitic roundworms in humans by watching this short video: . MEDIA Click image to the left or use the URL below. URL:

textbook_image

instructional diagrams

description_image

This diagram shows the earthworm anatomy. The segmented body parts provide important structural functions. Segmentation can help the earthworm move. Each segment or section has muscles and bristles called setae. The bristles or setae help anchor and control the worm when moving through soil. The bristles hold a section of the worm firmly into the ground while the other part of the body protrudes forward. The earthworm uses segments to either contract or relax independently to cause the body to lengthen in one area or contract in other areas. Segmentation helps the worm to be flexible and strong in its movement. If each segment moved together without being independent, the earthworm would be stationary.

description_image

Flatworms are invertebrates. They belong to Phylum Platyhelminthes. There are over 25,000 species of flatworms in the world. Not all flatworms are as long as tapeworms. Some are actually only around a millimeter in length. Flatworms reproduce sexually, in most species the individual able to provide both egg and sperm for reproduction. Flatworms go from egg, to larva to adulthood. Flatworm adaptations include mesoderm, muscle tissues, a head region, and bilateral symmetry. Flatworms are free-living heterotrophs or parasites. Roundworms are invertebrates in Phylum Nematoda. Roundworms have a pseudocoelom and complete digestive system. They are free-living heterotrophs or parasites.

description_image

The diagram shows the earthworm's internal anatomy with its key parts and definitions. An earthworm is a tube-shaped, segmented worm found in the phylum Annelida. The body of the earthworm is segmented which looks like many little rings joined or fused together. Segmentation helps the worm to be flexible and strong in its movement. An earthworm's digestive system runs through the length of its body. The digestive system consists of the mouth, the crop, the gut and the gizzard. Earthworms are hermaphrodites where each earthworm contains both male and female sex organs. Some other key features of the earthworm include its brain, which consists of a large cluster of nerve cells connected to a ventral nerve cord which runs the length of the body, and its heart, which is a set of typically five muscular swellings that pump blood through their bodies.

questions

Which statement is true about both flatworms and roundworms?

a. They lack body symmetry

-->  b. They may be parasites

c. They have a complete digestive system

d. all of the above

How many species belong to Phylum Platyhelminthes?

-->  a. more than 25,000

b. fewer than 15,000

c. about 10,000

d. about 8,000

Flatworms are flat because they

a. have an incomplete digestive system

-->  b. lack a pseudocoelom or coelom

c. have just two embryonic cell layers

d. lack a mesoderm cell layer

All flatworms

a. are less than a meter long

b. live in water or moist soil

c. reproduce asexually by budding

-->  d. have a concentration of nerve tissue in the head end

Which of the following organisms is a flatworm?

a. hookworm

b. ascaris

-->  c. tapeworm

d. all of the above

Flatworms reproduce by producing

a. buds

b. spores

-->  c. gametes

d. none of the above

Both flatworms and roundworms may be found living in

a. water

b. moist soil

c. vertebrate hosts

-->  d. any of the above

The body of a roundworm is covered with

a. slime

b. hooks

c. suckers

-->  d. cuticle

Which statement about roundworm reproduction is true?

a. Sperm and eggs are produced by the same adult

b. Fertilization occurs in the water outside the adults body

-->  c. Eggs hatch into larvae, which develop into adults

d. Reproduction may occur sexually or asexually

A roundworms body is stiff because of

a. the endoskeleton

b. the exoskeleton

-->  c. fluid pressure

d. a notochord

Free-living roundworms may feed on

a. bacteria

b. fungi

c. protists

-->  d. all of the above

How many eggs can a single roundworm lay in a day?

a. about 10

b. up to 100

c. around 1,000

-->  d. as many as 100,000

Most flatworm species have separate sexes.

a. true

-->  b. false

When flatworms reproduce, eggs are fertilized outside the body.

a. true

-->  b. false

Flatworms can eat, digest food, and eliminate wastes all at the same time.

a. true

-->  b. false

Free-living roundworms may feed on bacteria, fungi, or protozoa.

-->  a. true

b. false

Roundworms play an important role in the carbon cycle.

-->  a. true

b. false

_All flatworms are several meters long.

a. true

-->  b. false

_Flatworms have a concentration of nerve tissue in the head end.

-->  a. true

b. false

_Flatworms may have several different larval stages.

-->  a. true

b. false

_A parasitic flatworm usually needs more than one type of host to complete its life cycle.

-->  a. true

b. false

_Phylum Nematoda has less than 800 known species.

a. true

-->  b. false

_The body of a roundworm has a tough covering of cuticle.

-->  a. true

b. false

_All parasitic roundworms have vertebrate hosts.

a. true

-->  b. false

___name of the phylum to which roundworms belong

a. hookworm

b. flatworm

-->  c. Nematoda

d. roundworm

e. ascaris

f. Platyhelminthes

g. tapeworm

___common name for the type of worm that has a pseudocoelom

a. hookworm

b. flatworm

c. Nematoda

-->  d. roundworm

e. ascaris

f. Platyhelminthes

g. tapeworm

___parasitic roundworm with special structures for attaching to the hosts intestines

-->  a. hookworm

b. flatworm

c. Nematoda

d. roundworm

e. ascaris

f. Platyhelminthes

g. tapeworm

___common name for the type of worm that lacks a pseudocoelom

a. hookworm

-->  b. flatworm

c. Nematoda

d. roundworm

e. ascaris

f. Platyhelminthes

g. tapeworm

___example of a flatworm that is a human parasite

a. hookworm

b. flatworm

c. Nematoda

d. roundworm

e. ascaris

f. Platyhelminthes

-->  g. tapeworm

___name of the phylum to which flatworms belong

a. hookworm

b. flatworm

c. Nematoda

d. roundworm

e. ascaris

-->  f. Platyhelminthes

g. tapeworm

___largest and most common parasitic worm in humans

a. hookworm

b. flatworm

c. Nematoda

d. roundworm

-->  e. ascaris

f. Platyhelminthes

g. tapeworm

diagram questions

question_image

Identify the cuticle in this picture

a. M

b. J

-->  c. C

d. L

question_image

Which organ is directly behind the crop?

a. LONGITUDINAL MUSCLE

b. PUMPING VESSELS

c. INTESTINE

-->  d. GIZZARD

question_image

Which label indicates the spermathecal aperture of the worm?

a. N

b. M

c. S

-->  d. V

question_image

Which letter indicates a seminal groove?

a. M

b. C

-->  c. S

d. A

question_image

Which letter represents the head?

a. C

b. S

c. V

-->  d. H

question_image

Identify the crop

a. L

-->  b. N

c. R

d. F

question_image

Which letter is representing the mouth in this diagram?

a. H

b. N

-->  c. R

d. F

question_image

What does R represent?

a. GIZZARD

-->  b. MOUTH

c. CROP

d. ESOPHAGUS

question_image

Which label refers to the mouth?

-->  a. M

b. Y

c. S

d. E

question_image

Which of the labeled elements shows the blood vessels of the worm?

a. W

b. V

c. L

-->  d. T

question_image

Identify the group of the worm:

-->  a. L

b. W

c. H

d. M

question_image

Identify the anus.

a. H

-->  b. F

c. M

d. W

question_image

By what letter is the mouth represented in the diagram?

a. V

-->  b. D

c. S

d. X

question_image

Which label refers to the anus?

a. F

b. X

c. V

-->  d. E

question_image

Where are the dorsal pores located on the worm?

a. S

b. T

c. X

-->  d. F

question_image

Which part of the worm is responsible for eating?

a. E

b. T

c. V

-->  d. D

question_image

Which label refers to the male pore?

a. R

b. F

-->  c. A

d. C

question_image

Identify the female pore in the following image:

a. F

b. A

c. C

-->  d. R

question_image

Which letter indicates the oviduct?

a. T

-->  b. U

c. H

d. V

question_image

Which of the labeled elements shows where the eggs of flatworms are produced?

-->  a. M

b. V

c. U

d. T

question_image

Which label marks the worm's prostomium?

-->  a. Y

b. N

c. D

d. H

question_image

Which label shows the clitellum?

a. D

b. V

-->  c. N

d. Y

question_image

Which part represents the dorsal blood vessel?

a. L

b. W

c. P

-->  d. Y

question_image

Which of the labeled elements shows the muscle layers of the body wall of a worm?

a. X

-->  b. T

c. P

d. V

question_image

Which letter represents intestine?

a. X

b. L

c. M

-->  d. P

question_image

Which label refers to the crop?

a. W

-->  b. C

c. S

d. F

question_image

Which label refers to the gizzard?

a. Y

b. W

-->  c. F

d. C

question_image

Which section of the digestive tract is surrounded by the aortic arches?

-->  a. ESOPHAGUS

b. PHARYNX

c. CROP

d. GIZZARD

question_image

What is the Worm Part labeled Y?

-->  a. INTESTINE

b. OVARY

c. ANUS

d. EGGS

question_image

Which letter represents the Ovary?

-->  a. J

b. U

c. W

d. D

question_image

In the diagram which label refers to the worm's mouth?

a. X

b. K

c. A

-->  d. W

question_image

Which label shows the clitellum

a. L

-->  b. K

c. A

d. F

question_image

What is between the crop and the clitellum?

a. E

-->  b. L

c. A

d. T

question_image

What is the tail end of the worm?

a. K

-->  b. X

c. L

d. A

question_image

Indicate which part corresponds to the mesoderm layer

-->  a. Circular muscle

b. longitudinal muscle

c. epidermis

d. cuticle

question_image

What connects the mouth to the gizzard?

a. cuticle

b. pumping vessel

c. coelom

-->  d. esophagus

question_image

What connects the mouth with the intestine?

-->  a. Esophagus

b. Crop

c. Pumping vessels

d. Pharynx

question_image

How many parts are there in a caterpillar?

a. 28

b. 30

-->  c. 26

d. 27

question_image

This diagram shows the parts of what?

a. snake

b. spider

c. pencil

-->  d. roundworm

question_image

How many types of setae does the earthworm have?

a. 4

-->  b. 2

c. 3

d. 1

question_image

There are how many types of setae?

a. 3

b. 4

c. 1

-->  d. 2

question_image

What does the circulatory system surround in this earthworm?

a. Longitudinal muscle

b. Circular muscle

-->  c. Crop

d. Epidermis

question_image

How many parts are there to the Giant Australian Earthworm?

-->  a. 26

b. 12

c. 25

d. 13

question_image

What is the outermost layer of the earthworm called?

a. nephrostome

b. septum

-->  c. cuticle

d. coelom

question_image

What is a thickened glandular and non-segmented section of the body wall near the head in earthworms?

a. grizzard

-->  b. clitellum

c. crop

d. intestine

question_image

What is between the heart and the gizzard?

-->  a. crop

b. mouth

c. clitellum

d. intestine

question_image

How many intestines are present?

a. 2

b. 3

-->  c. 1

d. 5

question_image

What is found =be=tween the intestine and the segmental ganglion

-->  a. segmental nerves

b. mouth

c. pharynx

d. gizzard

question_image

What is made up of reproductive segments?

-->  a. clitellum

b. intestine

c. crop

d. segmental ganglion

question_image

What is shown in the picture?

a. Body Parts of Humans

b. Body Parts of Birds

-->  c. Body Parts of Flatworms and Roundworms

d. Body Parts of Whales

question_image

Which part of the worm is located between the esophagus and the gizzard

a. Mouth

-->  b. Crop

c. Clitellum

d. Setae

question_image

What is a thickened glandular and non-segmented section of the body wall near the head in earthworms and leeches?

-->  a. Clitellum

b. Gizzard

c. Mouth

d. Setae

question_image

What can be found at the tip of the earthworm's head?

a. Intestines

-->  b. Mouth

c. Esophagus

d. Gizzard

question_image

What is shown in the picture?

a. Body Parts of a Common Mammal

-->  b. Body Parts of a Common Earthworm

c. Body Parts of a Common Fish

d. Body Parts of a Common Caterpillar

question_image

Which body part of the worm transports blood?

a. Crop

b. Mouth

c. Gizzard

-->  d. Vessels

question_image

What is located just below the gorp in the worm?

-->  a. Gizzard

b. Intestine

c. Pharynx

d. Esophagus

question_image

Food such as decaying animals first passes through this part of the flat worm...

a. crop

-->  b. mouth

c. hearts

d. brain

question_image

What among the following doesn't lie between the mouth and the crop?

-->  a. Gizzard

b. Brain

c. Hearts

d. Pharynx

question_image

How many mouths on a worm?

a. 2

-->  b. 1

c. 3

d. 4

question_image

How many parts are labeled inside the worm?

a. 8

-->  b. 10

c. 11

d. 9

question_image

What is shown in the picture?

a. Body Parts of a Human

b. Body Parts of a Fish

-->  c. Body Parts of a Worm

d. Body Parts of a Snake

question_image

What is the head end of the worm called?

-->  a. Anterior end

b. Posterior end

c. setae

d. Dorsal

question_image

How many openings beside the mouth and anus can you find in the worm?

-->  a. 3

b. 1

c. 2

d. 4

question_image

The earthworm's mouth is at which end?

-->  a. anterior end

b. posterior end

c. male openings

d. setae

question_image

What is a raised band encircling the body of oligopolistic worms and some leeches, made up of reproductive segments?

a. Anus

-->  b. Clitellum

c. Anterior End

d. Dorsal Pores

question_image

Where does a worm excrete its waste?

a. Mouth opening

-->  b. Anus

c. Setae

d. Transverse grooves

question_image

How many anuses does an earthworm have?

a. 3

b. 2

c. 4

-->  d. 1

question_image

How is the anus connected to the prostomium?

a. through the ring of setae

-->  b. through the clitellum

c. through the setae

d. through the mouth opening

question_image

What is the second body segment in an annelid worm's body in the anterior end?

a. Prostomium

b. Anus

-->  c. Peristomium

d. Setae

question_image

How many pores can be found in the image?

a. none

b. 1

c. 3

-->  d. 2

question_image

In the diagram, how many suckers does the worm have?

a. 1

b. 3

-->  c. 2

d. 4

question_image

The leech in the diagram belongs to which phylum?

a. Chordata

b. Nematoda

c. Platyhelminthes.

-->  d. Annelid.

question_image

What kind of animal is shown in the picture?

-->  a. Leech

b. Fish

c. Crocodile

d. Bird

question_image

Which part of the flatworm's reproductive system is associated with sperm storage?

-->  a. Copulatory Bursa

b. Seminal Vesicle

c. Gonopore

d. Vas Deferens

question_image

What connects the ovary to the vitellaria?

a. muscular organ

b. gonopore

-->  c. oviduct

d. testes

question_image

What is the sperm storage called?

a. Testes

b. Seminal Vesicle

c. Vas Deferens

-->  d. Copulatory Bursa

question_image

How many ovaries are there in the diagram?

a. 3

b. 4

-->  c. 2

d. 1

question_image

What connects the testes to the seminal vesicle?

a. penis

-->  b. vas deferens

c. oviduct

d. ovary

question_image

What must take place for a male to mate with a female?

a. clitellum

b. pore

c. prostomium

-->  d. Sperm transfer

question_image

How many worms are there?

a. 4

b. 3

-->  c. 2

d. 5

question_image

What is the end of the flatworm called?

a. male pore

-->  b. prostomium

c. genital markings

d. clitellum

question_image

What is the first body segment in an annelid worm's body in the anterior end?

a. Male Pore

b. Genital Marking

-->  c. Prostomium

d. Female Pore

question_image

In which part are located the seminal vesicles?

a. Intestine

b. Gizzard

c. Cop

-->  d. Esophagos

question_image

What does the esophagus connect?

-->  a. The pharynx to the stomach

b. The seminal vesicles

c. The crop with the gizzard

d. The intestine with the crop

question_image

What lies between the ovary and the esophagus?

a. Crop

-->  b. Testes

c. Gizzard

d. Intestine

question_image

How many earthworm seminal vesicles are shown in the illustration?

a. 5

-->  b. 2

c. 1

d. 3

question_image

What is in the muscles

a. crop

b. intestine

c. gizzard

-->  d. seminal vesicles

question_image

What is the male gonad in animals?

a. Gizzard

b. Crop

-->  c. Testes

d. Esophagus

question_image

Which part of the earthworm is at the rearmost?

a. mouth

b. setae

c. gizzard

-->  d. anus

question_image

Which of the following parts of an earthworm does NOT repeat in nearly every body segment?

a. Blood vessels

-->  b. Mouth

c. Nephridia

d. Ganglia

question_image

How many clitella are there in a single earthworm?

a. 2

-->  b. 1

c. 5

d. 10

question_image

What are the red tubes surrounding the esophagus?

a. Dorsal blood vessels

b. Crops

-->  c. Aortic arches

d. Gizzards

question_image

What connects the crop to pharynx?

a. aortic arches

-->  b. esophagus

c. gizzard

d. brain

question_image

What connects the gizzard to the esophagus?

a. pharynx

b. blood vessels

c. brain

-->  d. crop

question_image

How many dorsal blood vessels are shown?

a. 3

b. 4

c. 5

-->  d. 2

question_image

What is also referred to as the ventriculus, gastric mill, and gigerium?

a. Esophagus

-->  b. Gizzard

c. Pharynx

d. Crop

question_image

Identify the structure that secretes a cocoon in which the eggs are deposited.

a. Male gonopore

b. Female gonopore

c. Sperm/seminal groove

-->  d. Clitellum

question_image

This structure secretes an albuminous fluid which will form a cocoon for the young annelid.

a. gonopore

b. chaetae

c. nephridiopore

-->  d. clitellum

question_image

What is the outer covering of the worm called?

-->  a. Cuticle

b. Median bulb

c. Nerve ring

d. Stylet

question_image

Which structure in the worm's body is responsible for transporting food from the mouth to the intestine?

a. Ovary

b. Uterus

-->  c. Esophagus

d. Median Bulb

question_image

How many parts of a worm are there?

a. 12

-->  b. 13

c. 10

d. 11

question_image

How many reproductive organs are showed in this image?

-->  a. 4

b. 2

c. 5

d. 3

question_image

What is shown in the picture?

a. Body Parts of a Crocodile

-->  b. Body Parts of a Nematode

c. Body Parts of a Bird

d. Body Parts of a Caterpillar

question_image

Which part of the earthworm is at the rearmost?

a. gizzard

b. mouth

c. brain

-->  d. anus

question_image

The worm has an intestine in what part of the body?

a. gizzard

b. crop

c. head

-->  d. bottom end

question_image

How many hearts does the earthworm have?

a. 1

b. 4

c. 2

-->  d. 5

question_image

How many mouths on an earthworm?

a. 10

b. 5

-->  c. 1

d. 6

question_image

Select the true statement.

-->  a. Roundworms have a complete digestive system.

b. The life cycle can be completed without an host.

c. The cuticle helps digesting small invertebrates.

d. Eggs pass out of the host by the sweat glands.

question_image

What is between the prostomium and the ventral setae

a. Ventral setae

b. male aperture

-->  c. mouth

d. seminal groove

question_image

Identify the crop

a. P

b. X

-->  c. L

d. C