Plants and animals both belong to the domain Eukaryota — organisms with cells that are basically sealed baggies full of fluid suspending little factories called organelles, which have different jobs in the cell, depending on the needs of the organism.
Plants, animals, fungi and protists are all eukaryotes. These organisms are made up of one or more cells with a variety of membrane-bound organelles, including the nucleus — the big boss organelle that contains all the DNA and all the instructions for making that particular bear or ringworm or ficus tree or fruit fly.
Prokaryotes are single-celled organisms that are generally smaller than eukaryotic cells, lack a nucleus to hold their DNA, and contain only a few types of rudimentary organelles. It’s kind of a mess inside a prokaryotic cell, while a eukaryotic cell is highly structured.
Unique Cellular Roles of Plants and Animals
If plants and animals are so similar on a cellular level, why do they seem so different when you take a couple steps back?
Well, it’s because plants and animals have different goals. Each of their eukaryotic cells is customized to make them great at being the thing they are.
For instance, it’s a plant’s job to take carbon dioxide out of the air — which we animals just leave lying around every time we exhale or get in our car. Then they simply add a little sunlight and water and make pretty much everything they need to survive.
Animals, on the other hand, require oxygen (made by plants) to breathe. However, we can’t make our own food like plants do, so we’ve got to go rustle up our own grub. This requires movement, which made it necessary for animals to evolve all kinds of crazy specialized cell types, tissues and organs.
Survival is based on getting basic needs met, and the outsourced requirements of an animal far surpass those of plants.