Class 11 Animal Kingdom - Classification of Animals

Q: Consider following features(a) Organ system level of organisation(b) Bilateral symmetry(c) True coelomates with segmentation of bodySelect the correct option of animal groups which possess all the above characteristic's.

True segmentation is present in Annelida, Arthropoda and Chordata. They also have an organ-system level of organisation, bilateral symmetry and are true coelomates. On the other hand, molluscs have an unsegmented body.So, the correct answer is 'Annelida, Arthropoda and Chordata'

Q: Which of the following are correct?(i) Sponges : Cellular level of organisation(ii) Cnidaria : Tissue level of organisation(iii) Platyhelminthes : Organ level of organisation(iv) Annelids, Arthropods, Molluscs, Echinoderms and Chordates : Organ system level of organisation.

Animals show four different grades of organization:(i) Protoplasmic grade found in protozoans.(ii) Cellular grade is the characteristic of sponges and mesozoans because in a sponge, cells exhibit division of labour for performing specialized functions.(iii) Tissue grade is of two types : Cell-tissue grade is seen in coelenterates as there are cells not only specialised for different functions but also certain similar cells gather together to form tissue as well. Tissue - organ grade appears in flatworms (Platyhelminthes) with arrangement of tissues to form organs.(iv) In organ system level of organisation, organs are joined in a system to perform basic functions. It is found in higher invertebrates and all vertebrates.Hence the correct option is D.

Q: Define coelom. Explain the 3 types of organisms based on coelom.

Coelom is a fluid-filled cavity between the body wall and gut wall. It is lined by mesoderm. On the basis of the presence or absence of coelom, animals are classified into three groups, namely coelomates and pseudocoelomates and acoelomates. Coelomate animals possess coelom between the body wall and digestive tract. For example, annelids, molluscs, arthropods. Pseudocoelomate animals have the body cavity that is not lined by mesoderm. In these animals, mesoderm is scattered between ectoderm and endoderm. For example, Aschelminthes. In acoelomate animals, the body cavity is absent. For example, Platyhelminthes.

Q: Schizocoelomates and enterocoelomates are

The true coelom is categorized into two types- schizocoelom and enterocoelom. They are categorized based on ways in which true body cavity or coelom arises in different animals. Schizocoelom arises from the mesodermal split. This body cavity is formed from blocks of mesoderm around the gut that enlarge and hollow out. Example- animals belonging to the Phyla Annelida, Mollusca, and Arthropoda.Enterocoelom arises from outpocketing of the embryonic gut(endoderm). This type of body cavity is formed by outpocketings of the primitive gut that break off and form the coelom. Example- animals belonging to the Phyla Echinodermata and Chordata.Hence Schlzocoelomates and enterocoelomates are true coelomates.So, the correct answer is 'True coelom'.

Q: Tissue level of organization is found in:

Comb jelly belongs to the phylum Ctenophora and shows tissue level of organization. It does not show the presence of organs and organ systems. They are marine, radially symmetrical, and diploblastic organisms.Thus, the correct answer is option D.

Q: Which of the following animal's body shows bilateral symmetry?

Earthworm belongs to Phylum Annelida. The organisms belonging to Annelida show organ system grade of organisation and are coelomates and bilaterally symmetrical.Starfish belongs to Phylum Echinodermata and is radially symmetrical.Jelly fish belongs to Phylum Cnidaria and is also radially symmetrical.Sponges belong to Phylum Porifera and are asymmetrical or radially symmetrical.So, the correct answer is 'Earthworm'

Q: Match the following list of animals with their level of organisation.Level of organisation AnimalA. Organ leveli. \$Pheritima\$B. Cellular levelii. \$Fasciola\$C. Tissue leveliii. \$Spongilla\$D. Organ system level iv. \$Obelia\$Choose the correct match showing the level of organisation with an animal example.

\$\textbf{Correct option: (C)}\$\$\textbf{Explanation for correct option:}\$\$\text{A)}\$ Organ level \$\text{ii)}\$ \$Fasciola\$\$\bullet\$ \$Fasciola\$ is a parasite belonging to phylum platyhelminthes and has organ level of organisation.\$\text{B)}\$ Cellular level \$\text{iii)}\$ \$Spongilla\$\$\bullet\$ The cellular level organisation can be seen in \$Spongilla\$ which belongs to phylum porifera.\$\text{C)}\$ Tissue level \$\text{iv)}\$ \$Obelia\$\$\bullet\$ Tissue level of organisation can be seen in the animals of the phylum cnidaria (\$Obelia\$).\$\text{D)}\$ Organ system level \$\text{i)}\$ \$Pheretima\$\$\bullet\$ Organ system level of organisation can be seen in animals of phylum annelida (\$Pheretima\$)

Q: Body cavity is the cavity present between body wall and gut wall. In some animals the body cavity is not lined by mesoderm. Such animals are called ________________.

Acoelomates are characterised by absence of coelom or body cavity while coelomates are those organisms where mesoderm lines the coelom. Pseudocoelomates are those, which have a body cavity (derived from blastocoel of embryo) but is not lined with mesoderm, e.g., roundworms.Hence the correct option is B.

Q: Radial symmetry is not found in:

Radial symmetry refers to the arrangement of parts of organisms around a single axis that can be divided into equal halves across any plane. This type of symmetry is seen in some sessile aquatic animals. Animals of the phyla Cnidaria (Hydra) and Echinodermata (starfish) show radial type of symmetry. Spider belongs to phylum Arthropoda which shows bilateral symmetry. Thus, the correct answer is option C.

Q: Which among these is not a homeotherm?

Homeothermic animals are those organisms that maintain its body temperature at a constant level by its metabolic activity.Poikilothermic animals are those which do not use metabolic heat to maintain their body temperature but take in the temperature of the environment.A. Aptenodytes is a genus which contains species of penguins collectively known as the great penguins.All the birds including penguins are warm-blooded or homeothermic animals.B. Testudo is a genus which contains species of tortoises.Most fishes, invertebrates, reptiles and amphibians are poikilotherms or cold-blooded animals.C. Delphinus is the genus which contains species of dolphins.Whales, dolphins, seals and marine mammals can maintain a stable body temperature.D. Neophron is a genus which contains species of scavenger vultures.They are homeothermic animals as they are birds.So, the correct answer is Testudo.

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Classification of Animals

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Classification of Kingdom Animalia

ExampleDefinitionsFormulaes

Important Questions

Consider following features
(a) Organ system level of organisation
(b) Bilateral symmetry
(c) True coelomates with segmentation of body
Select the correct option of animal groups which possess all the above characteristic's.

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Which of the following are correct?
(i) Sponges : Cellular level of organisation
(ii) Cnidaria : Tissue level of organisation
(iii) Platyhelminthes : Organ level of organisation
(iv) Annelids, Arthropods, Molluscs, Echinoderms and Chordates : Organ system level of organisation.

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Match the following list of animals with their level of organisation.
Level of organisation Animal
A. Organ level i. $P h e r i t i m a$
B. Cellular level ii. $F a s c i o l a$
C. Tissue level iii. $S p o n g i l l a$
D. Organ system level iv. $O b e l i a$
Choose the correct match showing the level of organisation with an animal example.

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Body cavity is the cavity present between body wall and gut wall. In some animals the body cavity is not lined by mesoderm. Such animals are called ________________.

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Radial symmetry is not found in:

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Which among these is not a homeotherm?

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Level of organisation	Animal
A. Organ level	i. $P h e r i t i m a$
B. Cellular level	ii. $F a s c i o l a$
C. Tissue level	iii. $S p o n g i l l a$
D. Organ system level	iv. $O b e l i a$

Revise with Concepts

Classification of Kingdom Animalia

Consider following features (a) Organ system level of organisation (b) Bilateral symmetry (c) True coelomates with segmentation of body Select the correct option of animal groups which possess all the above characteristic's.

Which of the following are correct? (i) Sponges : Cellular level of organisation (ii) Cnidaria : Tissue level of organisation (iii) Platyhelminthes : Organ level of organisation (iv) Annelids, Arthropods, Molluscs, Echinoderms and Chordates : Organ system level of organisation.

Define coelom. Explain the 3 types of organisms based on coelom.

Schizocoelomates and enterocoelomates are

Tissue level of organization is found in:

Which of the following animal's body shows bilateral symmetry?

Match the following list of animals with their level of organisation.Level of organisation AnimalA. Organ leveli. PheritimaB. Cellular levelii. FasciolaC. Tissue leveliii. SpongillaD. Organ system level iv. ObeliaChoose the correct match showing the level of organisation with an animal example.

Body cavity is the cavity present between body wall and gut wall. In some animals the body cavity is not lined by mesoderm. Such animals are called ________________.

Radial symmetry is not found in:

Which among these is not a homeotherm?

Consider following features
(a) Organ system level of organisation
(b) Bilateral symmetry
(c) True coelomates with segmentation of body
Select the correct option of animal groups which possess all the above characteristic's.

Which of the following are correct?
(i) Sponges : Cellular level of organisation
(ii) Cnidaria : Tissue level of organisation
(iii) Platyhelminthes : Organ level of organisation
(iv) Annelids, Arthropods, Molluscs, Echinoderms and Chordates : Organ system level of organisation.