OVERVIEW : Animals are classified and placed on an appropriate group on the basis of observable characters. Some of the characters to classify the organism are being described below:
🌑Levels of Organisation
🔴All members of Animals are multicellular but all of them do not have same pattern of organisation of cells.
🔴For example, In sponges. the cells are arranged as loose aggregation and every cell perform diffrent function called as cellular level of organisation. The division of labour is present among the cells.
🔴In coelenterates, the arrangement of cells is more complex. The cells are arranged Into tissues to perform the same function.This is called tissue level of organisation.
🔴Another level of organisation called organ level has been first developed by members of Platyhelminthes. In this level of organisation, tissues are arranged in form of organs. Each specialised organ perform a particular function.
🔴ln animals like Annelids. Arthropods. Molluscs.Echinoderms and Chordates. Number of organs have been organised in a functional systems. Each system is associated with the specific physiological function. This pattern ls called organ system level of organisation.
🌑Digestive system
🔴The digestive system in which there is a single opening to the outside of the body that serves as both mouth and anus. This type of digestive system is incomplete.
🔴A complete digestive system has two openings to serve as mouth and anus separately.
🌑Circulatory system
🔴In open type of Circulatory system, the blood Is pumped out of the heart. The cells and tissues are directly bathed in blood.
🔴In closed type of Circulatory system, the blood is circulated through a network of blood vessels like artertes. veins and capillary.
🌑Symmetry
🔴Animals can be categorised on the basis of their symmetry.
🔴When , any plane is passed through the centre of body and it does not divide into equal halves than body is said to be asymmetrical. For Example - Poriferan or Songes.
🔴When any plane is passed through the central axis of the body and it is divided the organism Into two identical halves. This one is said to be radial symmetrical . For Example Coelenterates. Ctenophora
🔴Animals like annelids. arthropods. etc.. where the body can be divided into Identical left and right halves in only one plane. This is a bilateral symmetrical.
🌑Diploblastic and Triploblastic Organisation
🔴During embryonic development, the animals which have the two embryonic layers. an external ectoderm and an internal endoderm. are called diploblastic animals. e.g.coelenterates.
🔴An undifferentiated layer mesoglea is present in between the ectoderm and the endoderm in some Coelenterates.
🔴Those animals In which the developing embryo has a three germinal layer : outer ectoderm, middle mesoderm and inner endoderm. Such are called triploblastic animals For example : Platyhelminthes to chordates.
🌑Coelom
🔴Presence or absence of a cavity between the body wall and the gut wall is very important feature in classification. The body cavity which ls lined by mesoderm is called coelom .
🔴Animals with coelom are called coelomates, e.g.. annelids. molluscs. arthropods. echinoderms. hemichordates and chordates
🔴In some animals. the body cavity is not lined by mesoderm but mesoderm is present as scattered pouches In between the ectoderm and endoderm. Such a body cavity ls called pseudocoelom and the animals with pseudocoelom are called pseudocoelomates. For example: Aschelminthes.
🔴The animals In which the body cavity is absent are called acoelomates. For example platyhelminthes .
🌑Segmentation
🔴In some animals, the body is externally and internally divided Into segments.
🔴But in earthworm, the body is metamerically segmented in which external segments make correspondence to internal segments. This phenomenon is known as metamerism .
🌑Notochord
🔴Notochord is derived from the mesoderm. Notochord is rod- like structure present on dorsal side during embryonic development in some animals.
🔴Animals with notochord are called chordates and those animals which do not have notochord are called non-chordates, For example : Porifera to Echinoderms.
🔴In some choradates, Notochord is replaced by cartilaginous or bony vertebral column. Such choradates are called Vertebrates .
🔴In some choradates, notochord is present as notochord in any stage of lifecycle but not replaced by vertebral column. They are not vertebrates.
🔴Therefore all vertebrates are chordates but all chordates are not vertebrates.
1. In which level of organisation, cells are arranged in loose aggregation and have divison of labour in
A. Porifera (sponges)
B. Platyhelminthes
C. Aschelminthes(roundwom)
D. Coelentreta
Answer : A
2. In coelentrata, the arrangement of cell is more complex & performing some function as
A. Cellular level of Organisation
B. Organ level of Organisation
C . Tissue leve Organisation
D. Organ system level of organisation
Answer: C
3. Organ Level of organisation was first appeared in
A.Annelida
B.Arthropoda
C.Platyhelmenthes
D.Aschelminnthes
Answer : C
4. Match the list -
Level of Phylum
organisation
A.Cellular 1. Porifera
B.Tissue 2.Cnidaria
C.Organ 3.Platyhelminthes
D.Organ 4.Aschelminthes
System
A. B C D
A. 1 2 3 4
B. 2 3 1 4
C. 4 3 2 1
D. 4 2 3 1
Answer : A
5. Which of the following statement is not correct.
A. In complete digestive system, An Alimentary canal has a single openning
Which serve as both mouth and anus.
B.When the blood is pumped in network of blood vessel known as open circulatory system.
C. All the cells and tissue are directly bathed in blood in body cavity sinus.
D. A single opening in digestive system form incomplete digestive system.
Answer : A
6. In Diploblastic animals,which of the following embryonic layer is are responsible for formation of all tissue or organs.
A. Mesoderm
B. Ectoderm & Endoderm
C. Mesoderm & Endoderm
D. Mesoderm & Ectoderm
Answer: A
7. Which of the following phylum is / are Diploblastic.
A. Porifera
B. Coelentreta
C. Ctenophora
D. All of the above.
Answer : D
8. Triploblastic condition, In which all tissue and organs are developed from the ectoderm, Endoderm and mesoderm found from
A. Porifera to Platyhelminthes
B. Porifera to ctenophora
C. Platyhelminthes to choradates
D. Fish to mammals.
Answer : C
9. Coelom is a space between
A. Pelvic wall and bodywall
B. Body wall and gut
C. Pelvic wall and gut
D. Pelvic wall and abdomen
Answer : B
10. Coelom or body cavity is lined by
A. Ecto - mesoderm
B. Endoderm
C. Mesoderm
D. Ectoderm
Answer : C
11. In which type of Coelom, body cavity is not lined by the mesoderm but present in form of scattered pouch .
A. A coelom
B. Pseudocoelom
C. Coelom
D. Entero coelom
Answer : B
13. Which of the following pair is not correct.
A.Acoelomate:
Platyhelminthes
B.Pseudocoelomate:
Aschelminthes
C. Coelomate :Porifera
D. Acoelomate : Cnidaria
Answer : A
14. When a body is divided into identical left and right halves when passing a plane vertically than body is said to be
A. Asymmetrical
B. Bilateral symmetrical
C. Radial symmetrical
D. Iso Symmetrical
Answer : B
15. Bilateral symmetrical condition has been started from the
A. Cnidaria
B. Platyhelminthes
C. Annelida
D. Aschelminthes
Answer : B
16. When a plane is passed from central axis of body and divided it into two equal halves called
A. Asymmetrical
B. Bilateral symmetrical
C. Radial symmetrical
D. Iso symmetrical
Answer : C
17. Redial symmetry is not present in
A. Porifera
B. Coelentreta
C. Ctenophora
D. Echinodermata
Answer : A
18. Sponges have
A. Diploblastic
B. Asymmetrical
C. Cellular level of organisation
D. All of the above
Answer : D
19. Consider the following features for the members of Aschelminthes and select the correct code
1. Pseudocoelomate
2. Organ system level of organisation
3. Acoelomate
4. Bilateral symmetrical
5. Triploblastic
A. 1,3,4,and 5
B. 1,2,4 and 5
C. 1,2,3 and 4
D. 2,3,4 and 5
Answers: B
20. First Coelomate animals belong to
A. Annelida
B. Platyhelminthes
C. Aschelminthes
D. Arthropoda
Answer : A
21. Which of the following features are first appeared in members of platyhelminthes.
A. Triploblastic and Bilateral symmetry
B. Organ level of system and Triploblastic
C. Organ level of system and Triploblastic
D. Triploblastic , Bilateral symmetry and organ level of system
Answer : D
22. In which of the following phylum, the larva is bilateral symmetrical and adult is radial symmetrical.
A. Mollusca
B. Echinodermata
C. Hemichordata
D. Ctenophora
Answer : B
23. Metameric segmentation in which external segments make correspondence to internal segments, found in
A. Annelida
B. Platyhelminthes
C. Aschelminthes
D. Arthropoda
Answer : A
24. Which of the following statement is not correct with respect to the Notochord.
A. It is rod like tubular structure present on dorsal side of body of choradates.
B. An animal with the notochord is called as Choradates.
C. It is endodermal in origin.
D. Notochord is absent from Porifera to Echinodermata.
Answer: C
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