The upcoming discussion will update you about the difference between Protozoa and Metazoa.
Difference # Protozoa:
1. Protozoans are unicellular animals.
2. Protozoans are generally microscopic.
3. Acellular or body is not differentiated into cells.
4. Single cell can perform all sorts of functions like a complete multicellular organism.
5. Single cell is capable of independent existence.
6. Body of protozoa is bounded by cell membrane or plasmalemma.
7. Pellicle, the outer thin firm protective layer, present in some species.
8. Cytoplasm contains nuclei, chromosomes, Golgi bodies, mitochondria, endoplasmic reticulum, lysosomes and centrioles.
9. Chloroplasts present in some species of protozoa.
10. Contractile vacuole, an osmoregulatory structure found in freshwater ciliates, flagellates and sarcodines.
11. Many individuals possess one, two or many flagella or numerous cilia.
12. Many protozoans possess complex arrays of microtubules and microfilaments in flagella and cilia.
13. Digestion is intracellular in protozoa.
14. Food vacuole is present in protozoa.
15. Most protozoans lack respiratory, circulatory and excretory structures.
16. Haemoglobin present in a few species of protozoa but its role has not yet been worked out.
17. Gonads are absent in protozoa.
18. No larval stage occurs in their life cycle.
19. They do not develop from the embryonic blastula stage. From the zygote develops a new individual.
20. Colony formation takes place in some species of protozoa by the division of asexual reproduction.
Difference # Metazoa:
1. Metazoans are multicellular animals.
2. Metazoans are generally seen in naked eyes.
3. Body of Metazoa is differentiated into cells which may transform into tissues, organs and systems in most cases.
4. Single animal can perform different types of functions by different systems in most groups.
5. Metazoan cells are interdependent and cannot survive in isolated condition.
6. Individual cell of Metazoa is covered by also cell membrane or plasma- lemma.
7. Pellicle is absent in Metazoa.
8. Cytoplasm is present in Metazoa.
9. Chloroplast is present in some species (sponges).
10. Contractile vacuoles found only in freshwater sponges.
11. Many cells are mono or multi-ciliated.
12. Cilia and flagella have same ultra-structures.
13. Digestion intracellular or extracellular or both in some.
14. Food vacuole is absent in Metazoa.
15. Lower groups of metazoans do not possess circulatory, respiratory and excretory structures.
16. Haemoglobin, haemocyanin, haemoerythrin, and chlorocruorin—all respiratory pigments present in many groups of Metazoa.
17. Gonads present except a few lower metazoan groups.
18. Motile larvae in their life cycle.
19. The developmental stages possess the embryonic blastula and gastrula stages.
20. Colonial organization is prevalent in some sponges, cnidarians, lophophorates and in some lower chordates.