edHelper.com
Animal Themes
Invertebrates

Invertebrates

Invertebrates
Reading Level
     edHelper's suggested reading level:   grades 4 to 8
     Flesch-Kincaid grade level:   9.42

Vocabulary
     challenging words:    cuttlefish, cylindrical, headless, mollusk, mollusks, ribbon-like, starfish, tentacle, trigger, unbearable, highly, qualify, opening, miracle, lining, occasionally

Print Invertebrates
edHelper.com subscriber options:
     Print Invertebrates  (font options, pick words for additional puzzles, and more)
     Quickly print reading comprehension
     Print a proofreading activity

Feedback on Invertebrates
     Leave your feedback on Invertebrates  (use this link if you found an error in the story)

Invertebrates   
1     With over 2 million known animal species on Earth, 98% of them are invertebrates. Invertebrates are animals that don't have backbones. They live in a variety of environments, from hot and unbearable deserts to frigid and equally unbearable polar regions. They also come in an assortment of shapes and colors. To better understand invertebrates, scientists group them into eight major categories. Here are the categories and a fact or two about each category:
 
2     Arthropods are invertebrates with hard outer shells (exoskeletons), with jointed legs, and with segmented bodies. Since about 75% of all animal species are arthropods, they represent the largest invertebrate group. Insects (such as butterflies, fleas, and beetles), myriapods (such as centipedes and millipedes), crustaceans (such as crabs, pill woodlice, and lobsters), arachnids (such as spiders, scorpions, and ticks), and horseshoe crabs are all examples of arthropods.
 
3     Sponges are the simplest of all animals. Inhabiting mostly oceans but occasionally freshwater, they are headless and nerveless. As their movement is very difficult to detect, and they always attach to rocks, sponges were once thought to be aquatic plants! Sponges feed through a filter system. Thousands of pores covering the outside of a sponge pump water into the sponge's body. Collar cells lining the inside of the sponge sort out planktons or other microorganisms from the water. Once food particles are trapped and digested by collar cells, sponges expel the water through an opening at the top of the sponge.

Paragraphs 4 to 9:
For the complete story with questions: click here for printable
Copyright © 2008 edHelper