Bio 108 - Lecture 19 Flashcards
Ecdysozoa
New group of protostomes
- Moult entire cuticle to grow
Ecdysis
Entire cuticle shed at once
Cuticle
- Non living outer layer of skin
- Frequently sclerotized in arthropods
3 Layers of Cuticle
1) Endocuticle
2) Exocuticle
3) epicutucle (epi = upon)
Moulting Process
1) Epidermis separates form the endocuticle
2) Inactive moulting fluid is secreted by epidermis
3) Thin protective layer is deposited between moulting fluid and epidermis
4) Endocuticle is digested
5) New undifferentiated layer of cuticle forms with greater surface area and wrinkled
7) New cuticle expanded
8) Outside of new cuticle is scloertized by secretions
Apolysis
apo =
lys =
When the epidermis separates from the endocuticle
= away
= loosening
Phylum Onychophora
Onych =
Phor =
- Velvet worms
- Soft body, segmented, and unjointed legs with tipped claws called Lobopods
Lobopods
Many pairs of unjointed legs tipped with claws
Onychophora Morphology
- Originally a mollusc, now Ecdysozoa
- Head is poorly developed, little cephalization
- Open circulatory system
- Haemolmyph directly bathes the organs
- Coelom becomes reduced to pockets around gonads during embryonic development
- Exchange gases using a tracheal system
Haemocoel
Open circulatory system
Tracheal system
- Openings in side of the body ( stigmata or spiracles)
- Lead to large-bore tubes (trachea)
- Terminate in many fine tubes (tracheoles)
Ecology of Onychophora
- All predators
- Capture prey from shooting glue from glands next to mouth
- Separate sexes (Dioecious)
- Several sperm transfer methods including hypodermic insemination
- Oviparous
- Ovoviviparous
- Viviparous
Hypodermic Insemination
- spermatophore places on females skin, digests trough into gaemocoel, sperm released and crawl to eggs
Oviparous
Ovi =
Pareo =
Lay eggs that undergo embryonic development outside females body
= egg
= to give birth
Ovoviviparous
Viv =
- Eggs retained in the mothers body where the young develop, nourished by yolk, and hatch inside the mother
= alive
