Invertebrates Or Vertebrates?

There are two basic groups of higher animals. They are vertebrates and invertebrates. While both have advanced through the processes of evolution, there is one fundamental difference. Invertebrates do not have backbones. Both groups are in the Kingdom Animalia, but their bodies are organized differently. What makes invertebrates different? All invertebrates share common traits. At the bottom of the invertebrate world are the sponges. Sometimes they don't fit in but they are still part of the group. Here's the nice and neat little list.

1. They’re multicellular. Means that the cells are working together for survival, because all of the cells have their own duties and responsibilities
2. No backbone. That’s the whole point of invertebrate, no vertebrae
3. No cell walls. When we talk about plants, we always mentioned cell walls, different with invertebrates. Being an animal means that having cell walls
4. Most of them reproduce sexually (not asexually)
5. That means two gametes combine to form a new organism. Those gametes come from separate organisms (male and female).

6. Invertebrates can't make their own food. Scientists use the word heterotrophic. Heterotrophs feed off other things to get their energy. Plants are autotrophic. They make their own food. Being heterotrophic is one of the main characteristics of being an animal. We eat things, whether it is plants or other animals. That's just the way the world works.

Vertebrates are the most advanced organisms on earth. Just like their name, they have vertebrae or backbone, unlike invertebrates. They have a series of nerves along their back or dorsal side. Vertebrae or the backbone works to support the nerves in the back part of their body, the nerves can’t just sit there, the y need support and protection. Fifty thousand species might seem like a lot. Compared to the invertebrates, there are not that many species of vertebrates. You might be asking why. One reason is that vertebrates are usually larger than invertebrates. They need more space. Another reason is that, even though they are more advanced, there are many limitations on the environments that are available to them. Vertebrates are smart, they have brains, of course. Just like any other living things in this world. But vertebrates are more intelligent than invertebrates because they have advanced nervous system, just like humans, we have advanced nervous system used to think.

General characteristics of the sub-phylum Vertebrata are as follows, although some are already mentioned above, here’s the list:

• Vertebrates have a well developed brain.
• Brain is set inside a bony box, known as cranium.
• Notochord is present in all chordates during sometime of development, it is formed on the dorsal side of the primitive gut in the early embryo stage.
• Most vertebrates possess guts with a non-terminal anus.

• The mouth cavity and the oesophagus is connected by the pharyngeal gill slits to a muscular tube pharynx, which opens to the exterior.
• They possess a dorsal hollow nerve tube at some stage of their life.
• Possess a dorsal cartilaginous nerve rod known as the notochord.
• At some stage of their life possess gill slits in the pharyngeal region.
• Have partially open circulatory system.
• Possess two pairs of appendages.
• The endoskeleton is made of cartilage or bone.
• The first vertebrates were jawless fishes with single caudal fin.
• The advancement of vertebrates with a hinged jaw which opened new food options and jawed fishes became the dominant creatures in the sea.
• All vertebrates have a heart and closed circulatory system.
• Reproduction is normally sexual.
• Feed on variety of organic materials.
• Unisexual animals, have one pair of gonads.

( Post by Aurelia Nadine )