NEMATODA

ANATONY AND PHYSIOLOGY In spite of their widely differing sizes and

lifestyles, all nematodes are similar in their anatomy and physiology. All are simple animals with relatively few cells, and this phylum is one of only a very few that include species with fixed cell numbers and an invariant pattern of cell divisions during development. The basic nematode body plan can be simply described as a tube within a tube. The outer tube is an epidermal layer of cells (hypodermis), which secretes a tough, flexible collagenous cuticle covering the animal’s exterior. Associated with the inside of this tube are.

ANATONY AND PHYSIOLOGY neurons and body-wall muscles. The inner

tube is the digestive tract, including a muscular pharynx as well as the intestine, which runs from the posterior end of the pharynx to the anus. Between the two tubes is a space called the pseudocoelom, which is occupied by the gonad in adults. In free-living species, the pharynx is used to ingest and crush bacteria; in plant parasites it is specialized for boring into root tissue. Nematodes lack skeletal components and maintain their body shape by hydrostatic pressure

ANATONY AND PHYSIOLOGY

STRUCTURES

The nematode assemblages along a deep-sea transect in the Mediterranean are composed of individuals that are as small as those found in other areas at much greater depth. This may be related to the low surface primary production since chloroplastic pigment equivalent (CPE) values in the sediments are low as well. A significant decrease of both nematode size and sedimentary CPE values with increasing water depth was found. At all water depths average nematode length increases with depth in the sediment (0–2 cm) due to the decreasing abundance of smaller nematodes.

STRUCTURES

DISTRIBUTION

DorylaimiaEnopliaSpirurinaTylenchinaRhabditina

DISTRIBUTION

CHARACTERISTICS

1)Bilaterally symmetrical, and vermiform. 2)Body has more than two cell layers, tissues and organs. 3)Body cavity is a pseudocoel, body fluid under high pressure. 4)Body possesses a through gut with a subterminal anus. 5)Body covered in a complex cuticle. 6)Has a nervous system with pharyngeal nerve ring. 7)Has no circulatory system (no blood system) 8)Reproduction normally sexual and gonochoristic. 9)Feed on just about everything. 10)Live just about everywhere, many species are endoparasites

CHARACTERISTICS

DIVERSITY

There are some species of the neatodes, the parasits, and the free live.

Nematodes have a lot of diversity some of they are the ascarids,filarias,hookwoorms, pinworms, and whipworms.

Some of this ones are dangerous for the human for example the heartworm go around your hart, always atac to the lungs of dogs and cats.)

And the haemonchus is one of the most abundant infectious agents sheep around the world.

DIVERSITY

CLASSIFICATIONClassification of the Nematoda

Phylum Class Order

NematodaAdenophorea

Enoplida

Isolaimida

Mononchida

Dorylaimida

Trichocephalida

Mermithida

Muspiceida

Araeolaimida

Chromadorida

Desmoscolecida

Desmodorida

Monhysterida

Secernentea

Rhabdita

Strongylida

Ascaridida

Spirurida

Camallanida

Diplogasterida

Tylenchida

Aphelenchida

CLASSIFICATION

PROS AND CONS

PROS Green lacewing larvae consume large numbers of a variety of pests. Unlike lady beetles, green lacewings will not wander far after you release them. The larval form-the beneficial predatory stage-is wingless.

CONS Suppliers typically mix the eggs with rice hulls or some other carrier that you then sprinkle over plants. This may be an aesthetic problem on ornamentals.

PROS AND CONS

Lesson

Answer

Luis BalsecaSebastián Campaña