phylum onychophora the velvet worms. characteristics of the phylum onychopora
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Phylum Onychophora The Velvet Worms
Characteristics of the Phylum Onychopora
Characteristics of the Phylum Onychopora
• Bilaterally symmetrical with a through gut.
Characteristics of the Phylum Onychopora
• Bilaterally symmetrical with a through gut.• Body with 14-43 pairs of un-jointed fleshy legs.
Characteristics of the Phylum Onychopora
• Bilaterally symmetrical with a through gut.• Body with 14-43 pairs of un-jointed fleshy legs.• Well developed hemocoelic body cavity with a
open circulatory system.
Characteristics of the Phylum Onychopora
• Bilaterally symmetrical with a through gut.• Body with 14-43 pairs of un-jointed fleshy legs.• Well developed hemocoelic body cavity with a
open circulatory system.• Cuticle covered epidermis, with ecdysone
mediated molting (ecdysis).
Characteristics of the Phylum Onychopora
• Bilaterally symmetrical with a through gut.• Body with 14-43 pairs of un-jointed fleshy legs.• Well developed hemocoelic body cavity with a
open circulatory system.• Cuticle covered epidermis, with ecdysone
mediated molting (ecdysis).• Gaseous-exchange organs simple tubular
tracheae issuing in tufts from small spiracles.
Anatomy
Legs with claws
Anatomy
Anatomy
Oral Papilla Lips and Jaws
Well Developed Eyes
Circulation and Gas Exchange
Circulatory system is an open and very similar to the arthropod hemocoel circulatory system.
Gas exchange is by tracheae.
Reproduction
• Accept for one species all dioecious.
• Males deposit spermatophor around or on the female. (ovoviviparous and viviparous)
Viviparous species have a “placenta” like structure.
About 110 species all terrestrial
However their fossils have been found in the Middle Cambrian marine
faunas.
Hallucigenia sparsa an Onychophoran from the Burgess Shale deposits of Canada
Aysheaia, from the Middle Cambirian
Phylum Tardigrada the Water Bears
Characteristics of the Phylum Tardigrada
Characteristics of the Phylum Tardigrada
• Bilaterally symmetrical; minute, squat. 0.3-0.5 mm.
Characteristics of the Phylum Tardigrada
• Bilaterally symmetrical; minute, squat. 0.3-0.5 mm.
• A through straight gut.
Characteristics of the Phylum Tardigrada
• Bilaterally symmetrical; minute, squat. 0.3-0.5 mm.
• A through straight gut.• Body monomeric although with four pairs of
short un-jointed claw-bearing legs.
Characteristics of the Phylum Tardigrada
• Bilaterally symmetrical; minute, squat. 0.3-0.5 mm.
• A through straight gut.• Body monomeric although with four pairs of
short un-jointed claw-bearing legs.• Coelom has been thought to be a pseudocoelom
however, more recently they think it is a reduces hemocoel.
Characteristics of the Phylum Tardigrada
• Bilaterally symmetrical; minute, squat. 0.3-0.5 mm.
• A through straight gut.• Body monomeric although with four pairs of
short un-jointed claw-bearing legs.• Coelom has been thought to be a pseudocoelom
however, more recently they think it is a reduces hemocoel.
• Ecdysone mediated molting like arthropods.
Anatomy
Well Developed Stylet For Feeding
Reproduction
• Sexual and parthenogenesis are the reproductive modes exhibited in the Tardigrada.
Reproduction Most lay Ornamental eggs.
Reproduction
Reproduction
Biology
• Scientists have reported tardigrades in hot springs, on top of the Himalayas, under layers of solid ice, and in ocean sediments.
• Many species can be found in milder environments such as lakes, ponds, and meadows, while others can be found in stone walls and roofs.
• Most tardigrades live in the water/air interface.
Biology• Tardigrades are one of the few groups of species that are capable
of reversibly suspending their metabolism and going into a state of cryptobiosis.
• Several species regularly survive in a dehydrated state for nearly 10 years. Depending on the environment, they may enter this state via anhydrobiosis, cryobiosis, or other ways.
• Their metabolism lowers to less than 0.01% of normal and their water content can drop to 1% of normal. Their ability to remain desiccated for such a long period is largely dependent on the high levels of sugar which protects their membranes.
Tardigrades Produce Tuns
Tardigrade Tun
