Animal Symmetry and Body Organization

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Questions and Answers

Which characteristic is unique to the class Cyclostomata compared to other classes of mammals?

Presence of paired fins

Cartilaginous skeleton

Jaws with teeth

Ectoparasitic behavior (correct)

What type of circulatory system do cyclostomes possess?

Systemic circulatory system

Open circulatory system

Closed circulatory system (correct)

Lymphatic system

What enables Chondrichthyes to float without an air bladder?

Lightweight skin

Cartilaginous endoskeleton

Constant swimming motion (correct)

Fatty liver structure

Which feature is NOT associated with the skin of Chondrichthyes?

Presence of operculum Signup and view all the answers

Which reproductive feature is common among many Chondrichthyes?

Viviparous reproduction Signup and view all the answers

Which of the following statements is true regarding Cyclostomata larvae?

They return to the ocean after metamorphosis. Signup and view all the answers

Which of the following is true about the jaw structure in Chondrichthyes?

Jaws are powerful and modified from placoid scales. Signup and view all the answers

What is the main role of the gill slits in Chondrichthyes?

For respiration Signup and view all the answers

What type of symmetry is exhibited by animals which can be divided into identical halves through multiple planes?

Radial symmetry Signup and view all the answers

Which characteristic is associated with diploblastic animals?

Cells organized in two embryonic layers Signup and view all the answers

Which animal groups are classified as triploblastic?

Platyhelminthes to Chordates Signup and view all the answers

What term describes the cavity present between the body wall and gut wall in certain animals?

Coelom Signup and view all the answers

Which of the following correctly describes the presence of mesoglea?

It separates the ectoderm and endoderm in diploblastic animals. Signup and view all the answers

In what situation would an organism be classified as asymmetrical?

When no plane can divide it into equal halves. Signup and view all the answers

What distinguishes bilateral symmetry from radial symmetry in organisms?

Bilateral symmetry results in identical halves in a single plane. Signup and view all the answers

Which embryonic layer is absent in diploblastic animals?

Mesoderm Signup and view all the answers

Which of the following is not a characteristic feature of Mollusca?

Segmented body structure Signup and view all the answers

Which of the following examples is classified as a gregarious pest?

Locusta (Locust) Signup and view all the answers

What is the primary function of the radula in Mollusca?

Feeding Signup and view all the answers

Which one of the following statements related to the phylum Arthropoda is accurate?

All arthropods have a segmented body. Signup and view all the answers

Which type of development is primarily associated with species in the Mollusca phylum?

Indirect development Signup and view all the answers

Which of the following applies to the respiratory structures of Mollusca?

Gills are typically housed in the mantle cavity. Signup and view all the answers

Which of the following is a venomous member of the phylum Arthropoda?

Scorpion Signup and view all the answers

In which specific environment do most molluscs thrive?

Both marine and freshwater environments, as well as terrestrial habitats Signup and view all the answers

What does the term 'incomplete digestive system' refer to?

A system with a single opening functioning as both mouth and anus. Signup and view all the answers

Which type of circulatory system allows blood to bathe directly over the cells and tissues?

Open type circulatory system. Signup and view all the answers

How are animals primarily categorized based on physical characteristics?

According to their symmetry. Signup and view all the answers

What exemplifies a complete digestive system?

Two distinct openings for intake and expulsion. Signup and view all the answers

Which group of animals demonstrates an organ system level of organization?

Echinoderms. Signup and view all the answers

What is a characteristic feature of the closed type circulatory system?

Blood is confined within a set of vessels. Signup and view all the answers

In terms of physiological function, what does the organ system level of organization imply?

Organs are grouped to perform specific functions. Signup and view all the answers

Which of the following correctly illustrates the concept of 'symmetry' in animals?

Different animals can be assessed based on their symmetrical shapes. Signup and view all the answers

What structural feature distinguishes Osteichthyes from other fish classes?

Body covered with cycloid/ctenoid scales Signup and view all the answers

Which feature is NOT typically associated with the Class Amphibia?

Presence of scales Signup and view all the answers

In Osteichthyes, how is buoyancy primarily regulated?

Via the air bladder Signup and view all the answers

Which of the following defines the typical heart structure in Amphibia?

Two auricles and one ventricle Signup and view all the answers

What is the primary mode of fertilization in Osteichthyes?

External without parental care Signup and view all the answers

Which characteristic is shared by both Osteichthyes and Amphibia?

They have cold-blooded physiology Signup and view all the answers

Which term accurately describes the developmental pattern of most Osteichthyes?

Direct development Signup and view all the answers

What distinguishes the respiratory system of Amphibia from Osteichthyes?

Gills are not present in adults Signup and view all the answers

Study Notes

Animal Symmetry

Sponges are mostly asymmetrical, meaning they cannot be divided into equal halves by any plane passing through their centre.
Radial symmetry occurs when a plane passing through the central axis creates identical halves. Animals like coelenterates, ctenophores, and echinoderms demonstrate this symmetry.
Bilateral symmetry is present in animals like annelids and arthropods, where only one plane can divide the body into identical left and right halves.

Diploblastic and Triploblastic Organisation

Diploblastic animals, such as coelenterates, have cells arranged in two embryonic layers: an external ectoderm and internal endoderm. An undifferentiated layer called mesoglea exists between these layers.
Triploblastic animals, encompassing platyhelminthes to chordates, have a third germinal layer called mesoderm situated between the ectoderm and endoderm.

Coelom

The presence or absence of a cavity between the body wall and the gut wall is important for classification.
This cavity, lined by mesoderm, is called the coelom.
Animals like annelids, arthropods, molluscs, echinoderms, and chordates possess a coelom.

Organ System Level of Organisation

Organ systems in different animal groups exhibit various levels of complexity.
For example, the digestive system of platyhelminthes is incomplete, with only one opening serving as both mouth and anus.
A complete digestive system possesses two openings: a mouth and an anus.
Circulatory systems can be open or closed. In an open system, blood is pumped out of the heart and bathes cells directly. A closed system involves blood circulation through vessels of varying diameters.

Phylum Arthropoda

Arthropods are the largest animal phylum, known for their jointed appendages and chitinous exoskeleton.
This phylum includes diverse species, like insects, crustaceans, arachnids, and myriapods.
Economically important insects include Apis (honey bee), Bombyx (silkworm), and Laccifer (lac insect).
Vectors like Anopheles, Culex, and Aedes mosquitoes belong to this phylum.
Locusta (locust) is a gregarious pest.
Limulus (king crab) is known as a living fossil.

Phylum Mollusca

This is the second largest animal phylum, consisting of terrestrial and aquatic molluscs.
They are bilaterally symmetrical, triploblastic, and coelomate animals.
A calcareous shell covers their unsegmented body, which is divided into distinct head, muscular foot, and visceral hump.
A mantle layer covers the visceral hump, creating a space called the mantle cavity that houses feather-like gills for respiration and excretion.
Sensory tentacles are present in the head region.
The mouth contains a file-like rasping organ called radula for feeding.

Class Cyclostomata

All living members of this class are ectoparasites of fishes.
They have an elongated body with 6-15 pairs of gill slits for respiration.
Cyclostomes possess a circular sucking mouth without jaws.
Their body lacks scales and paired fins.
The cranium and vertebral column are cartilaginous.
Circulation is of the closed type.
Cyclostomes are marine but migrate to freshwater for spawning.

Class Chondrichthyes

These marine animals have streamlined bodies and cartilaginous endoskeletons.
Their mouth is located ventrally.
The notochord persists throughout their lifespan.
Gill slits are separate and lack an operculum (gill cover).
The skin is tough and contains minute placoid scales.
Modified placoid scales form backwardly directed teeth.
They are predaceous and lack an air bladder, requiring constant swimming to avoid sinking.

Class Osteichthyes

This class includes both marine and freshwater fishes with bony endoskeletons.
Their bodies are streamlined with a mostly terminal mouth.
Four pairs of gills are covered by an operculum on each side.
The skin is covered with cycloid or ctenoid scales.
An air bladder regulates buoyancy.
The heart is two-chambered.
These are cold-blooded animals with separate sexes and external fertilization.
Most are oviparous with direct development.

Class Amphibia

Amphibians can live in both aquatic and terrestrial habitats.
Most have two pairs of limbs and a body divisible into a head and trunk.
Some may possess a tail.
Amphibian skin is moist and lacks scales.
They have eyelids and a tympanum (ear).
Alimentary, urinary, and reproductive tracts open into a common chamber called the cloaca.
Respiration occurs through gills, lungs, and the skin.
The heart is three-chambered, and they are cold-blooded.
Sexes are separate and fertilization is external.

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Description

Explore the concepts of animal symmetry and body organization through this engaging quiz. Learn about asymmetrical, radial, and bilateral symmetry, as well as the differences between diploblastic and triploblastic organisms. Test your knowledge on coelom formation and its significance in animal classification.