Echinoderms

The starfish is one of the members of the phylum Echinodermata , a group of marine

invertebrates that has a spiny skin. The animals belonging to this group are called

echinoderms .

The spines projecting from a bone plates that are just below the layer of soft leather .

These plates form an endoskeleton . An endoskeleton is a skeleton which is within the

body of an animal .

• The Myriapoda

are terrestrial invertebrates group arthropods characterized because they have the

elongated body and divided into two parts ( head and trunk) . The head is provided

with a pair of antennas and the body is formed by a very large number of rings or

segments provided with one or two pairs of legs each. Boca masticatory and

development without metamorphosis. His body is covered with chitin.

• The Fish

The characteristics of the fish

Fish are vertebrates that live in water and breathe through gills. They are ectothermic ;

ie , cold-blooded animals . A ectotermo is an animal that gets the heat of his body ,

mainly the environment. The fish have the backbone of cartilage or bone . Most of the

fish are adapted to living in fresh or salt water. Most have fins.

Most fish have scales that cover and protect the body. Circulatory, digestive and

nervous systems of fish are very well developed . There are three kinds of fish : The

Agnatha , Chondrichthyes and Osteichthyes the . The earliest of the three classes is the

jawless fish (the Agnatha ) . Sharks and mantas ( stripes ) are the class Chondrichthyes .

The largest class is the Osterichthyes . The fish of this class have a skeleton made

almost entirely of bone.

• roundworms

It is a pest that causes considerable damage to garden crops .

The types of roundworms are various: some attack inside the roots ( Heterodera

rostochiensis , Pratylenchus and Melogyne ) , others live in the outer part of roots (

Tylenchides and Dorilaimides ) and others attack the aerial part of the stem.

Roundworms are divided into roundworms Ascardiasis , Pinworms , Trichurdiasis ,

Uncinariasis .

• The flatworms

They are worms with dorsoventrally flattened body and digestive tract devoid of year.

Nor have circulatory system and most are hermaphrodites. Almost always parasites.

There are locomotor appendages and some have cilia.

Mostly lack digestive, circulatory, respiratory , and sensory organs. They usually have

suction pads .

• Birds

Birds belong to the phylum Chordata , subphylum Vertebrata and the class Aves. They

are endothermic vertebrates with feathers. Most birds have similar body structures .

Order to distinguish one from another , taxonomists have for variations in bone

structure , in losmúsculos and internal organs .

• Invertebrates

Invertebrates are the most primitive multicellular animals group, which means less

development of nutrition systems ( digestive, circulatory ... ) and relational ( nervous

system, sense organs .

Unlike vertebrate , this group is characterized by the absence of backbone . However ,

may , however , have other skeletal structures serve qque protection and support. The

shells of some mollusks exoskeleton exemplify or extern skeleton surrounding or

encircling the body of the animal.

Other invertebrates , such as sponges , presenting skeletal parts inside , internal

skeleton endoskeleton one speaks of or .

• No Vertebrates Mammals , Fish

Fish are vertebrates to aquatic life . Logically their way of swimming motions so that

the fusiform shape ( bone ) was provided presented . Furthermore developed

appendages , the fins adapted to displacement in the water. Generally have two pairs

of alestas p ( ventral pectoral ) and three major fins (dorsal, anal and caudal) .

Fish live in both the sea and in fresh water ( rivers and lakes) , from shallow waters to

depths let them know where the darkness is total. Are known to exist in these regions

producing organs of fish with light ( luminescent ) .

Another easy features observed is the absence of eye lids , which therefore remain

always open , and the presence of several rows of teeth in the mouth . They lack

external ears , but are able to perceive sounds , YA having inner ears .

• The Arachnids

Spiders , scorpions . Ticks and mites are arthropods of the class Arachnida . They are a

very large class in the subphylum Chelicerata , each spider has four pairs of walking

legs , chelicerae , pedipalps , simple eyes and no antennae . The simple eyes called

ocelli . The body of an arachnid has two parts ; cephalothorax and abdomen.

• Amphibians

The characteristics and classification

Amphibians are vertebrates that have gills as larvae and are usually lungs as adults.

Amphibians , class Amphibia were the first vertebrates to adapt to life on land. After

the eggs hatch , the majority of young amphibians are aquatic and breathe through

gills . As adults , amphibians live on land, at least part time and breathe through lungs.

Of the three groups of amphibians, the best known and abundant is the frogs and

toads . The order Anura include frogs and toads, no tail and have two pairs of legs. The

hind legs are much larger than the front .