Hey Defenders - ever wonder why a human body looks totally different than the body of a wasp? Well that's because we have different body plans! In the animal world, a body plan is just the set of features that make the blueprint of the type of body an animal has. Us humans cannot fly, so our body plan doesn't include wings! A goldfish doesn't walk on land, so their body plan doesn't include legs! Across the planet there are tons of animals with similar and very diverse body plans, making up the animal kingdom. I know what you're thinking now - "I clicked the segmentation tile, why are we talking about body plans???" Well worry not, because body plans are very important to know to talk about segmentation! Segmentation occurs in many animals and plants, and is a part of an organism's body plan, where there are a bunch of repetitive segments connected. A common example would be the backbone or spine in us vertebrates - it's made of a series of repetitive bone segments connected as one. While some animals have certain parts that are segmented, many animals have their entire body plans created through segmentation, especially invertebrates & arthropods.

  • Take the earthworm for example - if you look closely at an earthworm, you'll see all these rings going down their body...those are all the segments that the animal is made of!
  • Often times spiders can be confused for insects, but one sure way to tell the difference is look at the body segments! Insects are composed of 3 body segments - head, thorax, and abdomen. Arachnids on the other hand, are composed of only 2 body segments - head, and a cephalothorax.
  • In certain types of animals like earthworms, segmentation actually helps the body regenerate if a group of segments are removed!
  • Each segment will repeat the same structures - if you look at an animal like a millipede, each body segment comes with a set of legs.

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