By *Shannon*, ~Zuhra~, and $Cesco$
Arthropods and Echinoderms are invertebrates.Invertebrates are organisms with no backbone.
Although spiders are not insects, they are part of the arthropod family. This diagram shows that spiders do not have backbones, and are therefore invertebrates.
http://www.infovisual.info/02/052_en.html
Starfish are echinoderms. They have radial symmetry and no backbone.
http://www.infovisual.info/02/011_en.html
Jointed appendages is the source of the name arthropod (Greek for "joint foot"). Exoskeleton is the hard external skeleton that covers the entire body, including the appendages. Chitin is the layers of proteins mixed with polysaccharides that makes
up the exoskeleton. (Chitin is similar to your fingernails.) In order to grow, an arthropod must periodically shed its old exoskeleton and secrete a larger one. This is called molting. Before molting, an arthropod secretes a new exoskeleton beneath the old one. It then forces a liquid between the two layers and the pressure cracks the old layer. Arthropods are fragile for a few days while their fresh skeleton hardens. There are 1 million known species of this organism. All animal species combined number less than one third as many!
Cicada Molting
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Arthropods are classified into 3 main groups: Arachnids, Crustaceans, and Insects. Arachnids have two body sections- a fused head and thorax called a cephalothorax, and an abdomen. They have four sets of legs (8 legs in all), and two pairs of mouthparts. Chelicerae are fang-like mouthparts used to paralyze prey with poison, and pedipalps are mouthparts used to manipulate prey once it has been paralyzed.
This diagram shows the different parts of a spider. You can see that spiders have 2 sections, unlike insects, which have 3 sections.
http://web.pdx.edu/~smasta/Images/SpiderAnatomy.gif
Almost all arachnids live on land. Their bodies are designed to retain water. Malpighian tubules are structures that excrete wastes that have been removed from the fluid in the body cavity. Book lungs are specialized respiratory structures. They look like a book with many flaps of tissue that increase surface area for gas exchange. The most well-known type of arachnid are spiders. Generally, there are two types of spiders. Hunters, like tarantulas and wolf spiders, stalk their prey, but weavers sit and wait for food to get trapped in their carefully weaved webs. They have special organs called spinnerets that spin silk proteins into fibrous webs.
Scorpions are another type of arachnid. They are night time hunters that mainly live in deserts. Their pinchers are modified pedipals. The tip of a scorpion's tail bears a poisonous stinger. Mites and ticks are a third group of arachnid. They are small, often microscopic animals.
A scorpion like this are very common in desert countries.
http://www.flightglobal.com/blogs/flight-international/scorpion.gif
Ticks are parasites that transmit diseases to humans and other animals when they suck their blood.
http://1.bp.blogspot.com/_Gsi21_ZxemI/S-mSvxhyPqI/AAAAAAAAAAU/4zNpGIP0Xgs/s1600/tick1_1%5B1%5D.jpg
Crustaceans include decapods, barnacles, copepods, and isopods. Decapods have 10 legs, one pair of pinchers and 4 walking legs. Like arachnids, they have 2 main body parts. Their exoskeleton are harder and thicker than that of arachnids, as they're reinforced with calcium carbonate (limestone). The carapace the portion of the exoskeleton that covers the back of the cephalothorax, and mandibles are hard mouthparts that bite and grind food. People enjoy eating decapods such as crabs, lobsters, and shrimp. Barnacles secrete calcium carbonate shells in which they live. They grow on wooden piers, ships' hulls, rocks, and even whales' skin. During low tides they open their water tight shells, but during high tides they open their shells and filter feed. Copepods are small krill-like animals that play a major part in the marine food chain living as plankton. Isopods are marine and terrestrial crustaceans such as rollie pollies.
Insects have 3 main body parts: a head, thorax, and abdomen. They have three pairs of walking legs (6 in all) and usually one or two pairs of wings attached to the thorax, and typically have compound eyes and one pair of antannae that detect chemical signals (phereomones). Their ability to fly is one of the reasons for the great success of insects. Diverse feeding habits help insects thrive all over the world. Metamorphosis is the process in which an insect's body changes and becomes mature. One well-known insect that goes through metamorphosis is the butterfly.
http://www.thistledownstudio.com/g-butterflies/images/01MonarchMorph.jpg
Butterflies go through 4 stages: egg, caterpillar (larvae), then they become pupae and form a chrysalis, where they will undergo change to become a butterfly. After 3 weeks, the adult butterfly emerges.
Humans and other organisms depend on insects. For example, bees and beetles pollinate flowering plants. Termites and ants break down organic matter, helping to produce new soil and recycle nutrients. Unfortunately, certain insects are carriers of diseases that affect humans, such as mosquitos.
http://news.nationalgeographic.com/news/2009/01/photogalleries/locust-swarm-theory-serotonin/images/primary/090130-04-swarm-theory-desert-locusts-461.jpg
http://insected.arizona.edu/arthroinfo.htm
Most echinoderms have a rough and spiny skin. In fact, the word echinoderm means "prickly skin". Echinoderms lack body segments, and in most adult forms the external parts of the animal radiate from the center like spokes of a wheel. A system of water-filled canals, called the water-vascular system, extend into structures called tube feet that function in locomotion, feeding and respiration (gas exchange with the environment). Echinoderms have the power of regeneration, which is the ability to replace lost or damaged body parts. There are over 7000 known species of echinoderms. The six classes are sea urchins, sea stars, brittle stars, sea lilies, sea cucumbers, and sea daises.
The Six Classes of Echinoderms
| Sea Urchins |
Sea Stars |
Brittle Stars |
Sea Lilies |
Sea Cucumbers |
Sea Daises |
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http://www.shogunofdelmar.com/images/blog/2009.04.17.1.sea.urchin.jpg
Sea urchins are small, spiny, globular animals that have five-fold symmetry.
They have spines that are sometimes poisonous to protect them from predators.
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http://www.starfish.ch/Fotos/echinoderms-Stachelhauter/starfish-Seesterne/Fromia-indica.jpg
More commonly known as starfish, sea stars use their suction tube feet to move around and feed. They typically have 5 arms, which can regenerate themselves, but some species can have up to fifty.
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 http://sharonapbio-taxonomy.wikispaces.com/file/view/brittle_star.jpg/48063727/brittle_star.jpg
Brittle stars are closely related to sea stars. They crawl across the seafloor using their flexible arms for movement. They generally have five long slender, whip-like arms.
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 http://www.sciencenewsforkids.org/articles/20051026/a919_1857.jpg
Sea lilies are some of the most attractive but least known animals of the sea. The main body of a sea lily is composed of an extended, slender stalk that is usually anchored by a simple rootlike arrangement of arms.
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 http://www.starfish.ch/Fotos/echinoderms-Stachelhauter/seacucumbers-Seewalzen/Bohadschia-argus1.jpg
Sea cucumbers are marine animals with leathery skin and an elongated body. They are found on the sea floor worldwide. Sea cucumbers communicate with each other by sending hormone signals through the water.
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 http://www.treasuresofthesea.org.nz/uploads/images/151_image_main.jpg
Sea daisies live near New Zealand and the Bahamas in deep water sunken wood. They eat bacteria, dissolved nutrients on sunken wood, waste, and possibly microscopic mollusks.
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click below for a cool video
http://video.google.com/videoplay?docid=-1067581086327048501#
arthropod song!
&<span class="mceItemHiddenSpellWord">nbsp</span>;http://www.youtube.com/watch?v=s2HHEeRPRVM&feature=related&<span class="mceItemHiddenSpellWord">nbsp</span>;
informational arthropod video...
http://www.youtube.com/watch?v=-jNNvjJkLoc&feature=related&<span class="mceItemHiddenSpellWord">nbsp</span>;
Questions:
1. How much body segments do arthropods have?
2. Are arthropods and echinoderms vertebrates or invertebrates?
3. Do arthropods have an exoskeleton?
4. How long does a caterpillar stay in the cocoon?
5. What does invertebrate mean?
6. Do arthropods have bilateral symmetry?
7. How much species of echinoderms are there?
8. What do crustaceans include?
9. Which animal families are a part of the arachnid family?
10. What are the names of the echinoderm groups?
Bibliography:
Most of the information was found on these two powerpoints...
http://www.rjfisher.lgusd.k12.ca.us/staff/sjoanides/documents/Arthropods7thGrade.pdf
http://www.rjfisher.lgusd.k12.ca.us/staff/sjoanides/documents/Invertebrates7thGrade.pdf
Other sites:
http://animals.jrank.org/pages/1611/Sea-Daisies-Concentricycloidea.html
http://en.wikipedia.org/wiki/Sea_cucumber
http://en.wikipedia.org/wiki/Brittle_star
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