Vertebrates and invertebrates are the main sub-divisions of animals on earth. This type of classification is based on animals with and without backbones.
Other classification of animals in the Kingdom Animalia are multicellular and heterotrophs organisms. Understanding the characteristics of invertebrates and vertebrates will help to tell their differences.
So, what is the main difference between invertebrates and vertebrates? The former refers to animals that do not have a vertebral column while the latter refers to those animals that contain a vertebral column.
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Comparison Table (Invertebrates and Vertebrates)
|Meaning||Animals without backbone||Animals with backbone|
|Size||Small and slow-moving||Tend to vary in size from small to big|
|Body Symmetry||Bi-radial, Radial or absent||Bilateral|
|Body Structure||Simple with the unorganized nervous system||Complex with highly specialized organs|
|Skin Layers||Have one layer of skin||Have two layers of skin i.e Epidermis and Dermis|
|Types of Eyes||Compounds eyes are present but not the outgrowth of the brain||Compound eyes are absent but the eyes are the outgrowth of the brain|
|Body Temperatures||Cold-Blooded Animals||Warm-Blooded Animals|
|Reproduction||Asexual reproduction is predominant||Sexual reproduction is predominant|
|Regeneration of Power||Good||Poor|
|Segmental Nerve Root||Dorsal and ventral roots not separated||Dorsal and ventral roots are separated|
|Nerve Cord||Double ventral with ganglia||Single dorsal without ganglia|
|Brain||Absent or above the pharynx||Dorsal to pharynx in the head|
|Respiration||Body surface, gills, and trachea||Gills or lungs|
|Dorsal Blood Vessel||Blood flows anteriorly||Blood flows posteriorly|
|Hepatic portal system||Absent||Present|
|Hemoglobin||In plasma or absent||In red blood corpuscles|
|Heart Location||Dorsal, lateral, or absent||Ventrally placed|
|Blood vascular system||Open, closed, or absent||Closed and much developed|
|Anus||Open on the last segment or absent||Differentiated and open on the last segment|
|Pharyngeal gill-slits||Absent||Present at some stages in life|
|Gut position||Dorsal to the nerve cord||Ventral to the nerve cord|
|Limbs Derivation||From the same segment||From several segments|
|Grade of organization||Protoplasmic or organ system||Organ system|
What Are Invertebrates?
These are animals without a backbone. Invertebrates are abundantly found on earth and live in most habitats. The animals are cold-blooded since their internal body temperature is regulated by the surrounding.
Invertebrates do not develop notochord. Examples of invertebrates are starfish, sponges, jellyfish, worms, mollusks, and arthropods.
The absence of a strong exoskeleton makes invertebrates small and slow in movement. The respiration occurs through the skin surfaces and gills.
Characteristics of Invertebrates
- Cold-blooded animals
- Lack notochord
- Breathe through skin surfaces and develop gills
- Have bi-radial body symmetry
- Have a solid nervous system
What Are Vertebrates?
Vertebrates are animals with a backbone. These animals belong to the phylum Chordata of the kingdom Animalia. Vertebrates have organized body systems and structures.
Examples of vertebrates are fish, human beings, reptiles, amphibians, birds, and other mammals. The presence of the spinal cord, notochord, and vertebral column is what distinguishes vertebrates.
Embryos have a notochord that occurs in the middle of the dorsal line body and is later replaced by the spinal column during the adulthood stage.
Characteristics of Vertebrates
- Have a backbone, notochord, and vertebral column
- Animals are warm-blooded
- Breathe through lungs and gills
- Have bilateral body symmetry
- Have the hollow nervous system
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Main Differences between Vertebrates and Invertebrates
- Vertebrates possess notochord while invertebrates lack a notochord
- Vertebrates are large animals whereas invertebrates are small and slow-moving animals
- Invertebrates have a solid nervous system while vertebrates have a hollow nervous system
- Invertebrates have dorsally located heart while vertebrates have ventral heart position
- Vertebrates have a closed circulatory system whereas invertebrates have an open circulatory system
- Vertebrates are warm-blooded animals whereas invertebrates are cold-blooded animals
- Invertebrates lack a hepatic portal system while vertebrates have a hepatic portal system
- Vertebrates have two layers of the skin whereas invertebrates have a single layer of skin
- Vertebrates reproduce sexually while invertebrates through asexual reproduction
- Invertebrates have compound eyes while vertebrates lack compound eyes
Similarities between Invertebrates and Vertebrates
- Both belong to kingdom Animalia
- Both have gills
- Both have a nervous system
- Both have heart
- Both show bilateral symmetry
- Both exhibit movement
- Both can adapt to the environment
- Both live on land and in water
- Both can reproduce and respire
Understanding the comparison between invertebrates and vertebrates is quite important. The information will spearhead a proper understanding of the phylum Chordata in Kingdom Animalia.
Vertebrates are higher animals due to the presence of backbone and invertebrates are lower animals in the kingdom Animalia.
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