Introducing the Arthropod
Arthropods are known to be invertebrates with jointed legs. They have been around for quite some time. Through paleontology, the ancestors originated about 518 million years ago. This invertebrate is the most successful group of the animal phylum and are diversely spread out all around the world. They make up 80% of animals found on Earth. Arthropods are a monophyletic group, supported by their compound eyes and exoskeleton (Cheong et al., 2015). They are able to maintain major roles within the ecosystem through their morphological diversity. Take a look at the morphology and evolution illustrated by comparing the body of the arthropod to a swiss army knife. Through evolution, species were able to evolve and adapt with a unique set of specialized tools (Minelli et al., 2013).
The Marine Arthropod: A Successful Design
The beginning of animals whose ancestors would be the first living organisms to breathe air and live on land progressed millions of years ago, and it started with the arthropods which branched off from primitive, bilateral species (In Krames et al., 1974). The diverse morphological features allowed for this specie to become the most dominant and powerful hunters and scavengers. One of the top predators of the sea, the trilobites, first appeared about 570 million years ago during the Cambrian Explosion. This creature was seen as one of the first complex organisms. Trilobites had hard shells which was a different featured when comparing with most of the creatures living around them, which were mostly soft bodied. For over 325 million years, many distinct species were able to evolve and prosper (Rothschild et al., 2004). Over time, the trilobites were able to achieve immense diversity and branched off into thousands of new species.
The body plan has gone through many modifications since it first appeared, and it is seen as a unique evolutionary tool. The build of the body allows for the construction of different parts to be used for particular function that would be advantageous for the creature, which is also known as appendages. The appendages are known to be flexible and can easily be altered. For example, legs can be used for walking, clinging, digging and other different functions. Take a look at the observed evolutionary changes found in marine arthropods for a more visual representation!
What Do Arthropods Do?
Arthropods are very beneficial in a soil and plant-based environment.
Shredding organic material. These creatures are able to shred plant debris. Shredders are important in such an environment because it helps with the rate of decomposition. They are capable of digesting the debris such as bacteria and fungi on the surface of the organic material.
Stimulate Microbial Activity. The digestion of bacteria and fungi allows for the growth of fungi and decomposition of organic matter.
Mix microbes with food. In the point of view of a bacteria, they have limited mobility in blants and fungi. Arthropods are known to be great distributors and they are great at carrying nutrients to these platforms. The bacteria can be found in the stomach of these creatures. When they feed on such matter, they also mix microbes which helps with the decomposition of organic matter. (Halaj et al., 2000)
Evolution and Paleontology
The first arthropod fossil appeared in the Cambrian Period in the Paleozoic Era. Fossils were represented by crustaceans, trilobites and merostomes. Arthropods were known to abundant in the marine environment. When they appeared on land, the earliest fossil found belonged to a terrestrial archanid found in the Devonian Period. As the era progessed, arthropods also began to take all types of shapes and forms. The Carboniferous Period was a time where centipeded, millipedes and insects ruled. (Encyclopædia Britannica, inc., 2019)
Timeline
The diversity
