This document provides information about the phylum Echinodermata. It describes their key characteristics such as radial symmetry, tube feet powered by a water vascular system, and calcareous plates or spines covering their skin. Examples of classes within this phylum are mentioned, including sea stars, brittle stars, sea urchins, sea cucumbers, and sea lilies. Their ecology, behavior, reproduction, and classification are summarized.

1. Kingdom Animalia 3
BFT 1023
Chapter 9
By
Dr. Md. Shafiqur Rahman
Faculty of Agro Industry and Natural resources
UMK

2. Characteristics of Echinodermata
1)Possess 5-rayed symmetry, mostly
radial, sometimes bilateral.
2)Body has more than two cell layers, tissues
and organs.
3)Body cavity a true coelom.
4)Most possesses a through gut with an anus.
5)Body shape highly variable, but with no head.
6)Nervous system includes a circum-
oesophageal ring.
7)Has a poorly defined open circulatory system.

3. Echinodermata
Echinoderms are characterized by radial
symmetry, several arms (5 or more,
mostly grouped 2 left - 1 middle - 2
right) radiating from a central body (=
pentamerous). The body actually
consists of five equal segments, each
containing a duplicate set of various
internal organs.

4. Echinodermata
They have no heart, brain, nor eyes, but
some brittle stars seem to have light
sensitive parts on their arms. Their
mouth is situated on the underside and
their anus on top (except feather stars,
sea cucumbers and some urchins).

5. Echinodermata
Echinoderms have tentacle-like structures
called tube feet with suction pads
situated at their extremities. These tube
feet are hydraulically controlled by a
remarkable vascular system.

6. Echinodermata
This system supplies water through canals
of small muscular tubes to the tube
feet. As the tube feet press against a
moving object, water is withdrawn from
them, resulting in a suction effect.
When water returns to the
canals, suction is released. The resulting
locomotion is generally very slow.

7. Ecology and range of Echinoderms
Echinoderms are exclusively marine. They
occur in various habitats from the
intertidal zone down to the bottom of
the deep sea trenches and from sand to
rubble to coral reefs and in cold and
tropical seas.

8. Behavior of Echinoderms
Some echinoderms are carnivorous (for
example starfish) others are detritus
foragers (for example some sea
cucumbers) or planktonic feeders (for
example basket stars).

9. Echinodermata
8)Possesses a water vascular system, which
hydraulically operates the tube feet or feeding
tentacles.
9)Without excretory organs.
10)Normally possesses a sub epidermal system
of calcareous plates
11)Reproduction normally sexual and
gonochoristic.
12)Feeds on fine particles in the water, detritus
or other animals.
13)All live marine environments.

10. Echinodermata
The Echinodermata are Spiny-skinned
animals such as Feather
Stars, Starfish, Sea Urchins, Brittle
Stars, Sea Cucumbers, Sand Dollars and
Sea Lilies.

11. Echinodermata
They are one of the best known and most
loved groups of invertebrates. They are
popular as symbols because of their
unique shapes and beautiful colours.
They are also one of the most
evolutionarily advanced phyla, yet they
are totally unique in many ways.

12. Class Asteroidea
Starfish, or Sea Stars are often a pest of
commercial clam and oyster beds, a single
Starfish my eat over a dozen oysters or young
clams every day. The now infamous Crown-
of-Thorns Starfish (Acanthaster planci) has
caused serious damage to many coral reefs
around the world, e.g. Asterias, Pisaster,
Astropecten.

13. Adult Sea Star

14. Sea Star

15. Common Sea Star

16. Sea Star

17. Class Ophiuroidea
Brittle stars, star shaped echinoderms with
arms distinct from the central disc; tube feet
absent or reduced to censory organs. There
are about 2000 species. e.g. Ophioderma
(brittle star), Gorgonocephalus (Pacific basket
star)

18. Giant Green Brittle Star

19. Giant Brittle Star
Ophiocomina nigra

20. Basket Star
Basket Star (Gorgonocephalus
Caputomedusae)

21. Class Echinoidea
Sea urchins, heart urchins, and sand dollars.
Echinoderms with a rigid test of focused
skeletal plates. Body covered with movable
spines. Five rows of the tube feet (bearing
sucker) around the test. About 950 species.

22. Sea Urchin

23. Sea Urchins

24. Heart Urchin
The common heart urchin

25. Sand Dollar

26. Sand dollar
A sand dollar digging into the sand on the Playa Novillero
beach at low tide on the pacific coast of Mexico

27. Class Crinoidea
Sea Lilies, basket stars. Flower like echinoderms
with a central calyx and five (or multiples of
five) branching arms. Some species attach to
the sea bottom by a stalk. About 625 species.
e.g. Cerocrinus (crinoid).

28. Class Crinoidea
Sea Lilies

29. Class Crinoidea
Basket star

30. Class Holothuroidea
Sea Cucumbers. Non sessile soft bodied
animals having a flexible body wall with
many tiny, embeded calcareous ossicles; no
spines or arms. Body elongated in the oral-
aboral axis to a cucumber pickle like form.
About 1200 species. e.g. Thyone, cucumaria.

31. Class Holothuroidea
Sea Cucumber

32. Class Holothuroidea
Sea cucumber

33. Biology
The body wall of echinoderms consists of three
layers. The outer layer, called the
epidermis, is only a single layer of cells which
covers the entire animal including its various
spines. The third layer is also a single layer of
cells the main difference being that these
cells are ciliated. This layer encloses the the
animal's coelom separating the animals guts
from its skin. It is called the 'coelomic lining'

34. Echinodermata
The middle layer is much thicker and is
called the dermis. It is composed of
connective tissue and contains the
exoskeleton

35. Reproduction and life cycle
Echinoderms are fairly advanced invertebrates.
This is evident in their embryology, which is
similar to that of the vertebrates. Most
species of echinoderms are diecious,
meaning there are separate male and female
individuals.

36. Reproduction and life cycle
Although reproduction is usually sexual,
involving fertilization of eggs by
spermatozoa, several species of
echinoderms, such as sea stars and sea
cucumbers, can also reproduce asexually.

37. Reproduction and life cycle
Asexual reproduction in echinoderms
usually involves the division of the body
into two or more parts and the
reproduction of missing body parts.

38. Reproduction and life cycle
Successful fission and regeneration require a
body wall that can be torn and an ability to
seal resultant wounds. Successful
regeneration also requires that certain body
parts be present in the lost pieces. For
example, many sea stars can regenerate a
lost portion only if some part of the central
disk is present.

39. Sexual reproduction
Sexual reproduction involves the external
fertilization of eggs by spermatozoa. The
fertilized eggs develop into planktonic
larvae. The larvae typically go through
two stages, called bipinnaria and
brachiolaria.

40. Sexual reproduction
They are bilaterally symmetrical and have
bands of cilia used in swimming and feeding.
As the larvae gradually metamorphose into
adults, a complex reorganization and
degeneration of internal organs occurs.

41. Sexual reproduction
The left side of the larva becomes the oral
surface of the adult, which faces
down, and the right side becomes the
aboral surface, which faces up. The
larvae settle to the sea floor and adopt
their distinctive adult radial symmetry.

42. Classification
1) Class: Asteroidea--Starfish or Sea Stars (Six-
rayed Starfish--Leptasterias hexactis)--sea
stars have fairly developed senses of
smell, touch, and taste. They also can
respond to the presence of light. They
normally eat small prey whole, but they have
to extrude their stomachs to digest larger
prey outside their bodies.

43. The common starfish

44. The common Starfish

45. (2) Class: Ophiuroidea--Brittle Stars (Daisy
Brittle Star--Ophiopholis aculeata)
Another picture of a Brittle Star -found in all
oceans (but mainly in the tropics). The group
includes about 2000 species, varying in color.
They eat decaying matter and microscopic
organisms that are found on soft muddy
bottoms.

46. (3) Class: Echinoidea- Sea Urchins-they
locomote using short to long, movable
spines. Between their spines are small,
pincerlike organs called pedicellariae which
they use to clean and defend themselves. The
pedicellariae also contain a powerful toxin.

47. Phylum Chordata
All chordates have a dorsal hollow
nerve tube, a notochord, and
pharyngeal gill slits. All vertebrates
(members of a subphylum of chordata)
have a backbone (spinal column) and a
closed circulatory system.

48. All chordates have the following characteristics
at some point in their lives :
1. The notochord is an elongate, rod-like,
skeletal structure dorsal to the gut tube
and ventral to the nerve cord. The
notochord should not be confused with
the backbone or vertebral column of
most adult vertebrates

49. The notochord appears early in
embryogeny and plays an important
role in promoting or organizing the
embryonic development of nearby
structures. In most adult chordates the
notochord disappears or becomes highly
modified

50. The nerve cord of chordates develops dorsally
in the body as a hollow tube above the
notochord. In most species it differentiates in
embryogeny into the brain anteriorly and
spinal cord that runs through the trunk and
tail. Together the brain and spinal cord are
the central nervous system to which
peripheral sensory and motor nerves
connect.

51. The visceral (also called pharyngeal or gill)
clefts and arches are located in the
pharyngeal part of the digestive tract
behind the oral cavity and anterior to
the esophagus. The ventral wall of the
pharynx which produces mucus to
gather food particles.

52. Chordates are well represented in marine,
freshwater and terrestrial habitats from
the Equator to the high northern and
southern latitudes. The oldest fossil
chordates are of Cambrian age

53. The smallest chordates (e.g. some of the
tunicates and gobioid fishes) are mature
at a length of about 1 cm, whereas the
largest animals that have ever existed
are chordates: some sauropod dinosaurs
reached more than 20 m and living blue
whales grow to about 30 m.

54. • Classification:
• Kingdom: Animalia
• Phylum: Chordata
The Phylum Chordata contains the following
subgroups:
– Subphylum: Tunicata (tunicates)
– Subphylum: Cephalochordata (lancelets)
– Subphylum: Vertebrata (vertebrates)

55. Classification
Subphylum Tunicata (Tunicates or Sea
squirts)
Animals with a well developed notochord
and dorsal nerve cord in the free-
swimming larva; specializes adults;
sessile or planktonic, and lacking a
notochord and dorsal nerve cord.
e.g. Molgula (sea grape)

56. Sea Squirt (Polycarpa), Tunicates

57. Sea Squirts (Tunicates)

58. Sub phylum Cephalochordata (Lancelets)
Elongate, fishlike chordates with a
persistent notochord and dorsal nerve
cord.
e.g. Branchio-stoma (Amphioxus).

59. Cephalochordata (lancelts)

60. Subphylum Vertebrata (Vertebrates)
Chordates with
a backbone
skull
brain
and kidneys.

61. Chordates

62. Class Agnatha: Members of the class Agnatha
are jawless fish. Examples include lampreys
and hag
Members of the Class Chondrichthyes have
skeletons made of cartilage, placoid scales,
and lack gill covers. Examples include sharks
and rays. fish.

63. Classification of vertebrates
Vertebrates
Fish Amphibians Reptiles Birds Mammals
Next

64. Fish
(Live in water) • Lay eggs in water
• Cold - blooded
Fin
Streamlined
body
Gill
Back
Slimy scales ! More...

65. Characteristic of fish
Fish are aquatic vertebrates that have
vertebral column called spine. A classic fish
is a torpedo shaped. The fish contains head
containing a brain and sensory organs, a
trunk with a muscular wall surrounding a
cavity with the internal organs and a
muscular post-anal tail. The following are
the general characteristic that all the fish
species posses:

66. Amphibians
(Live both on land and in water)
Breathe Wet, slimy skins
with and no scales
lung
• Lay eggs in water
• Cold - blooded
Four limbs
Back

67. Amphibians are cold-blooded animals,
meaning they do not have a constant
body temperature but instead take on
the temperature of their environment.
They have moist, scaleless skin that
absorbs water and oxygen, but that
also makes them vulnerable to
dehydration (loss of bodily fluids).

68. Reptiles
Breathe with lung
• Lay eggs on land
• Cold - blooded
Hard dry scales
Back

69. Reptiles are cold-blooded animals with
scales covering their skin. Most of them
are tetrapods, with four legs or leg-like
appendages. It is believed that reptiles
started evolving around 330 million years
ago and developed many abilities. They
are considered as the first animals on
land with the ability to live and multiply
on land.

70. Birds
Breathe with lung
Beak
• Lay eggs on land
• Warm - blooded
Feathers Wings
Back ! More...

71. Birds are vertebrates, which means
that they are among those animals
that posess a backbone. They range
in size from the minute Cuban Bee
Hummingbird (Calypte helena)
(length 8cm/3.5inch) to the grand
Ostrich (Struthio camelus) length
upto 9 ft.2inch. Birds are
endothermic

72. Hummingbird

73. Mammals
Hair
Breathe with lung
• Embryo is developed
inside mother’s body
( viviparous)
• Warm - blooded
Mammary glands
Back ! More...

74. BAT DUCK TOAD
TURTLE SHARK

75. Mammal Characteristics
All mammals are warm blooded.
Most young are born alive.
They have hair or fur on their bodies.
Every mammal is a vertebrate.
All mammals have lungs to breathe
air.
Mammals feed milk to their babies.

76. Bat, duck, toad, turtle & shark
With wings Without wings
With Without With scale Without scale
feathers feather
Amphibians
Birds Mammals With fins Without
fin
fish reptiles
Back End