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The Six Kingdoms of Life

Scientists have too many crazy classifications, but you might as well learn them instead of failing a quiz in school.

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Yes, science is filled with a bajillion fancy words that literally mean the same thing, but instead of failing your upcoming science test, just learn some of the vocabulary! You see, scientists classify all living things into these categories: domain, kingdom, phylum, class, order, family, genus and species. The scientific name of a living thing is always the genus and the the species. For example: humans have the scientific name of Homo (genus) sapiens (species), but that’s not what we’re talking about today.

Today we're talking about the six kingdoms of life: animals, plants, fungi, protists, eubacteria, and archaebacteria. We'll go through the characteristics of these different kingdoms later. But right now, we’re going to address the domains, or the largest groups that organisms can be separated into. There are three domains: Archaea, Bacteria, and Eukarya. Animals, plants, fungi, and protists all are in Eukarya, whereas archaebacteria is in Archaea (obviously) and eubacteria is in Bacteria.

But how do scientists differentiate between the kingdoms? How can they tell which kingdom an organism fits in? Well, there are defining characteristics of each category, which you probably could’ve seen coming. There are many things you can tell by, like if they’re unicellular (one-celled) or multicellular (made up of many cells). Their cells can also be key in identifying them, like if they have a cell wall or are prokaryotic (the cells don't have a nucleus) or eukaryotic (the cells do have a nucleus). What is a nucleus? Well, in the cells that do have one, it's the organelle that contains the genetic material. Anyway, how living things get food is also a key thing in identifying what type of organism it is. Organisms can be either autotrophic (can make its own food, such as a plant) or heterotrophic (it has to find food, like us animals). Those are practically all of the ways that scientists and just regular people can organize it, but now I'm tired of this long paragraph, so let's move on.

In this paragraph, we're going to be talking about the characteristics of each kingdom, starting with the animals! Animals are multicellular heterotrophs that all move at least a little in their lifetime. Their cells are eukaryotic and do not include a cell wall. Moving on to plants, they are autotrophs (photosynthesis) with many cells, all of which are eukaryotic and have a nice rigid cell wall made of cellulose. They have leaves, stems, and roots, so yeah. Fungi often get labeled as plants even though they are quite different. The main difference between the two is that fungi are heterotrophs, feeding off dead/decaying material, but there are also small things that set them apart, such as the fact that fungi can be unicellular or multicellular and that fungi cell walls are made of chitin (a protein). Okay, now we’re at eubacteria, the unicellular or multicellular organisms that can be found just about anywhere, equipped with prokaryotic cells.

Here's where habitat really comes in. Archaebacteria could be confused with eubacteria, if not for the fact that they’re only unicellular and live in very extreme environments, such as some without oxygen. As a prefix, ’archae’ means ’ancient’, so ‘archaebacteria’ means ‘ancient bacteria.’ Why name it this? Because scientists suspect that archaebacteria were the first organisms on Earth, which would explain why they live in such brutal environments. And last but not least, the protists! This is kind of a miscellaneous category, I don’t know how else to explain it. Some can photosynthesize, some have to catch food, it’s crazy! And with that, this article must come to a close.

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