Kingdom Animalia 3BFT 1023

Chapter 9

By

Dr. Md. Shafiqur RahmanFaculty of Agro Industry and Natural resources

UMK

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.

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.

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).

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.

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 As the tube feet press against a moving object, water is withdrawn from them, resulting in a suction effect.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.

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.

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).

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.

Echinodermata

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

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.

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.

Adult Sea Star

Sea Star

Common Sea Star

Sea Star

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)

Giant Green Brittle Star

Giant Brittle Star

Ophiocomina nigra

Basket Star

Basket Star (Gorgonocephalus Caputomedusae)

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.

Sea Urchin

Sea Urchins

Heart Urchin

The common heart urchin

Sand Dollar

Sand dollar

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

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).

Class Crinoidea

Sea Lilies

Class Crinoidea

Basket star

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.

Class Holothuroidea

Sea Cucumber

Class Holothuroidea

Sea cucumber

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'

Echinodermata

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

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.

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.

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.

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.

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.

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.

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.

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.

The common starfish

The common Starfish

(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.

(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.

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.

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

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

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.

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.

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

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.

• Classification:• Kingdom: Animalia• Phylum: Chordata

The Phylum Chordata contains the following subgroups: – Subphylum: Tunicata (tunicates)– Subphylum: Cephalochordata (lancelets)– Subphylum: Vertebrata (vertebrates)

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)

Sea Squirt (Polycarpa), Tunicates

Sea Squirts (Tunicates)

Sub phylum Cephalochordata (Lancelets)Elongate, fishlike chordates with a

persistent notochord and dorsal nerve cord.

e.g. Branchio-stoma (Amphioxus).

Cephalochordata (lancelts)

Subphylum Vertebrata (Vertebrates)

Chordates witha backbone skullbrainand kidneys.

Chordates

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.

Classification of vertebrates

VertebratesVertebrates

Fish Amphibians Reptiles Birds Mammals

Next

Fin

Slimy scales

Gill

Fish(Live in water) • Lay eggs in water

• Cold - blooded

Streamlinedbody

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Characteristic of fishFish 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:

Amphibians(Live both on land and in water)

Wet, slimy skinsand no scales

Breathewithlung

Four limbs

• Lay eggs in water • Cold - blooded

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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).

Reptiles

Breathe with lung

Hard dry scales

• Lay eggs on land• Cold - blooded

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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.

BirdsBreathe with lung

Beak

WingsFeathers

• Lay eggs on land• Warm - blooded

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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

Hummingbird

MammalsHair

Breathe with lung

Mammary glands

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• Embryo is developed inside mother’s body( viviparous)

• Warm - blooded

More...Back

BAT DUCK TOAD

TURTLE SHARK

Mammal CharacteristicsAll 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.

Bat, duck, toad, turtle & shark

With wings

Withfeathers

Withoutfeather

Birds Mammals

Without wings

With scale Without scale

Amphibians

With fins Withoutfin

fish reptiles

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