Clade Ecdysozoa-Molting Animals Ecdysis- “an escape” -molting of exoskeleton or cuticle Phyla-...
-
Upload
giles-horn -
Category
Documents
-
view
215 -
download
1
Transcript of Clade Ecdysozoa-Molting Animals Ecdysis- “an escape” -molting of exoskeleton or cuticle Phyla-...
Clade Ecdysozoa-Molting AnimalsEcdysis- “an escape”-molting of exoskeleton or cuticle
Phyla- Nematoda andArthropoda
Phylum Nematoda1. Nematodes: roundworms2. Nemata- “ thread”3. Bilateral symmetry4. Tube within a tube
structure-mouth and anus
5. 3 germ layers w/ pseudocoelom
6. Smaller than flatworms, taper at both ends
3
PseudocoelomatePseudocoelomate
EctodermMesodermEndodermFluid filled cavity between the endoderm and ectoderm- pseudocoelom
Differs from a true coelom because…. • It is not entirely lined with mesoderm tissue• Organs are not suspended or attached to membranes
(mesenteries)
Lifestyle
1. Thick outer covering (cuticle) to protect them from harsh environment ex. Stomach acid
2. Move bodies with thrashing motion3. Free living-Decomposers and predators
(tremendously abundant)4. Parasitic- ex. Ascaris, hookworm,
heartworm-host is dog5. Sexually reproduce:
• most are separate sexes• some species are hermaphrodites
5
Nematodes
Found everywhere Soil Oceans Polar ice Hot springs
Parasites of nearly all plant and animal species!
Body Systems No Respiratory or Circulatory Systems- limits
size of worm due to distribution of nutrients via osmosis and diffusion
Complete Digestive Nervous Muscular Excretory Reproductive
Digestive SystemComplete Digestive Tract- Mouth Pharynx Intestine anus
Muscular System Longitudinal muscles
only creates thrashing
movement
9
Nervous System
Nerve ring – “brain”
Dorsal and
ventral nerve cords
Excretory System
Excretory cells Ducts pores
11
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Nematode Reproductive Systems
12
Dioecious- separate sexes
Which is female?
Life cycles of parasitic roundworms
ASCARIS• lives in intestines and feeds off
blood
• ingest eggs from dirty hands or unwashed veggies contaminated with fecal matter
• eggs hatch in intestines and enter bloodstream
• larval worms bore into lungs, must be coughed up and swallowed
• move to intestines where they mature
• Animal planet.com-Baylisascaris, brain eating parasite
TRICHINELLA• bore into muscles causing
painful cysts or live in intestines
• ingest cysts in undercooked/raw meat (usually pork)
• cysts open up in intestines and reproduce there
• Animal planet- “worms borrow through flesh”
HOOKWORMS• lives in intestines • feeds on blood, causes major
damage to intestines• eggs deposited on soil from
contaminated wastes• larvae live in soil• burrow into feet or exposed skin
of host• larvae travel through
bloodstream, to lungs, coughed up, swallowed
• attach to intestinal wall where they mature
• Ap.com- “flesh eating hookworm”“worms crawling under my skin”
PINWORMS
• most commonly infects children
• lives in intestines• ingest eggs from
contaminated soil or sand
• hatch in intestines• female lays eggs near
anus at night causing severe itching
19
Wuchereria bancrofti
Lives in lymphatic system
Vector- mosquito Daytime-worms in
lungs Night-move to skin Obstruct lymph to
cause swelling Mild- Filariasis Severe- Elephantiasis
20
Elephantiasis
Ap.com- “Parasite causes elephantiasis”“40 year parasite”
21
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Source: Redrawn From Centers for Disease Control, Atlanta, GA.
Fig. 11.15
11-13
Life Cycle of Wucheria spp.
22
Loa loa Eye worm River blindness 2nd leading cause of
blindness Vector- deer fly or
black fly Ap.com- “river
blindness”, “worms in my eye”
23
24
Dracunculus medinesis
Fiery serpent Water contaminated
with copepods carrying larva
Females migrate towards legs
Juveniles form blisters and exit via skin
25
26
Dirofilaria immitis
Dog heart worm
27
Nematoda Checkpoint
1. What type of worms belongs to this Phylum? 2. What type of body cavity do Nematodes have?
Explain. 3. Do nematode organs have mesenteries? 4. Are most nematodes parasitic or free living? 5. Nematodes are very small. Why can’t
nematodes grow to become larger animals?
29
The End