Kevin+Washington


 * Mollusks**

 "Snail." //Snail Facts and Pictures//. Web. 10 May 2011.  .

Molluscs have more forms than any other animal phylum. They include snails, slugs and other gastropods; clams; squids and other cephalopods; and other uncommonly but similarly distinctive sub-groups. The majority of species still live in the oceans, from the seashores to the abyssal zone, but some form a significant part of the freshwater fauna and the terrestrial ecosystems. Molluscs are extremely diverse in tropical and temperate regions but can be found at all latitudes. About 80% of all known mollusc species are gastropods.

Freshwater and terrestrial molluscs appear pretty vulnerable to extinction. Estimates of the numbers of non-marine molluscs vary widely, partly because many regions have not been thoroughly watched over. There is also a shortage of specialists who can identify all the animals in any one area to species. However, in 2004 the IUCN Red List of Threatened Species included nearly 2,000 endangered non-marine molluscs. For comparison, the great majority of molluscs species are marine but only 41 of these appeared on the 2004 Red List. 42% of recorded extinctions since the year 1500 are of molluscs, almost entirely non-marine species. = = = Arthropods =

 "Arthropods." //Ecology Explorers//. Web. 12 May 2011.   ecosystem/arthropods/>.

Arthropods are invertebrate animals with exoskeletons, segmented bodies, and jointed limbs. Arthropods are characterized by their jointed limbs and cuticles, which are mainly made of α-chitin; the cuticles of crustaceans are also biomineralized with calcium carbonate. The respiratory and excretory systems of arthropods are different, depending as much on their environment as on the subphylum to which they belong. Arthropods' methods of reproduction and development are also different; all terrestrial species use internal fertilization, but this is often by indirect transfer of the sperm through an appendage or the ground, rather than by direct injection. The versatility of the arthropod modular body plan has made it difficult for zoologists and paleontologists to classify them and work out their evolutionary ancestry, which dates back to the Cambrian period.

=**Echinoderms** =

 "Echinoderms: Starfish, Sea Urchin and Family.  "//Echinoderms: //Starfish, Sea Urchin and Family//. // // Web. 12 May 2011. // /science/animals/Echinoderms.htm>. //

A phylum of marine animals. Echinoderms are found at every ocean depth, from the intertidal zone to the deepest abyssal zone. Aside from the problematic //Arkarua//, the first definitive members of the phylum appeared near the start of the Cambrian period. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are also the largest phylum that has no freshwater or terrestrial representatives.

= Aves =

 "The Birds." //Introduction to the Aves//. Web. 12 May  <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px;"><span style="-webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px; color: #333333; font-family: 'times new roman',times,serif; font-size: 12px; letter-spacing: 2px; line-height: normal;"> 2011. <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px;"><span style="-webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px; color: #333333; font-family: 'times new roman',times,serif; font-size: 12px; letter-spacing: 2px; line-height: normal;"> <http://www.ucmp.berkeley.edu/diapsids/birds/snow <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px;"><span style="-webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px; color: #333333; font-family: 'times new roman',times,serif; font-size: 12px; letter-spacing: 2px; line-height: normal;"> yowl.gif>.

<span style="font-family: 'times new roman',times,serif;"> These are feathered, winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. Around 10,000 living species makes them the most speciose class of tetrapod vertebrates. They live in habitats across the globe, from the Arctic to the Antarctic. <span style="font-family: sans-serif,helvetica,sans-serif; line-height: 19px;">Modern birds are characterized by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. Many species undertake long distance annual migrations, and many more perform lesser irregular movements.

<span style="font-family: 'times new roman',times,serif;"><span style="color: #000000; font-family: sans-serif,helvetica,sans-serif; font-size: 13px; line-height: 19px;">**Cited Sources:** <span style="-webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px; color: #333333; font-family: 'times new roman',times,serif; font-size: 12px; letter-spacing: 2px; line-height: normal;">Washington, Kevin "Bird." //Wikipedia//. N.p., 12 May 2011. Web. 12 May 2011. <http://en.wikipedia.org/wiki/Aves>. <span style="-webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px; color: #333333; font-family: 'times new roman',times,serif; font-size: 12px; letter-spacing: 2px; line-height: normal;">Washington, Kevin "Echinoderms." //Wikipedia//. N.p., 12 May 2011. Web. 12 May 2011. <http://en.wikipedia.org/wiki/Echinoderms>. <span style="-webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px; color: #333333; font-family: 'times new roman',times,serif; font-size: 12px; letter-spacing: 2px; line-height: normal;">Washington, Kevin "Arthropods." //Wikipedia//. N.p., 12 May 2011. Web. 12 May 2011. <http://en.wikipedia.org/wiki/Echinoderms>. <span style="-webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px; color: #333333; font-family: 'times new roman',times,serif; font-size: 12px; letter-spacing: 2px; line-height: normal;">Washington, Kevin. "Mollusk." //Wikipedia//. N.p., 12 May 2011. Web. 12 May 2011. <http://en.wikipedia.org/wiki/Mollusk>.