Advertisements
Advertisements
प्रश्न
What is the exact difference between grades of organization and symmetry? Explain with examples.
Advertisements
उत्तर
Grades of organization:
- The grades of organization mean the way an organism has a different body formation
- Unicellular organisms, such as amoeba, possess a single cell, resulting in a protoplasmic grade of organization within their body.
- Some organisms have only cells in their body which is called the cellular grade of organization. e.g. Poriferans.
- Some organisms possess tissues, such as Coelenterata. They are supposed to possess tissue-grade organization. Certain things possess organs, they are classified as having an organization-organ grade. For example, Platyhelminthes. All other higher animals possess organ-system grade organization.
Symmetry:
- Symmetry, on the other hand, shows the base of the body formation.
- The symmetry can be understood by taking an imaginary cut through the animal’s body.
- Based on the symmetry, there can be three types.
- In asymmetric animals, there is no symmetry in any plane. e.g. Amoeba.
- Bilateral symmetry is a condition in which an imaginary axis can traverse a single median plane, hence divide the body into two equal halves. The majority of animals have bilateral symmetry, resulting in the symmetrical arrangement of their organs on both sides.
- The imaginary plane passing through the central axis of a body may produce many equal halves. The organs of these animals are organised in a radial configuration around an imaginary circle. For example, Cnidaria and some Echinodermata.
Both grades of organization and symmetry are the bases for classifying animals into different phyla.
APPEARS IN
संबंधित प्रश्न
What is the difference between direct and indirect development?
What are the reasons that you can think of for the arthropods to constitute the largest group of the animal kingdom?
Draw a neat and labelled diagram.
Jellyfish
The largest division of the living world is ______.
Species is the ______ unit of classification.
The symmetry exhibited in cnidarians is ______.
In Pheretima locomotion occurs with the help of ______.
Which of the following have the highest number of species in nature?
Match the following columns and select the correct option.
| Column – I | Column – II | ||
| (p) | Pila | (i) | Devil fish |
| (q) | Dentalium | (ii) | Chiton |
| (r) | Chaetopleura | (iii) | Apple snail |
| (s) | Octopus | (iv) | Tusk shell |
Compare Schizocoelom with enterocoelom.
Choose the term that does not belong in the following group and explain why it does not belong?
Notochord, cephalisation, dorsal nerve cord and radial symmetry.
What are flame cells?
______ was a greek philosopher who classified animals.
In which of the following the notochord is present only in embryonic stages?
Sort out the animals on the basis of their symmetry (radial or bilateral) coelenterates, ctenophores, annelids, arthropods, and echinoderms.
Complete the paragraph using proper words:
(Asymmetrical, Paramecium, Equal, imaginary, central, insects, rats, bird, three, unequal)
If body of any animal is cut through ______ axis of body, it may or may not produce two equal halves. Depending upon this property, there are different types of animal bodies. In the case of ______ body, there is no any such imaginary axis of the body through which we can get two equal halves. For example Amoeba, ______ some sponges. In radial symmetry type of body, if imaginary cut passes through central axis but any plane of body, it gives two ______ halves. For example Starfish. In case of this animal, there are five different planes passing through ______ axis of body through which we can get two equal halves. In Bilateral symmetry type of body, there is only one such imaginary axis of body through which we can get two equal halves. For example: ______ fishes, frog, birds, human, etc.
