II. Animal Diversity
a. Lophotrochozoans
1. Platyhelminthes
a. Diversity
- Planarians
(free-living)
II. Animal Diversity
a. Lophotrochozoans
1. Platyhelminthes
a. Diversity
- Planarians
- Tapeworms - parasitic
II. Animal Diversity
a. Lophotrochozoans
1. Platyhelminthes
a. Diversity
- Planarians
- Tapeworms - parasitic
- Flukes – parasitic
Complex life cycles
II. Animal Diversity
a. Lophotrochozoans
1. Platyhelminthes
b. body plan
- bilateral
- nerve net cephalized – nerve ring
II. Animal Diversity
a. Lophotrochozoans
1. Platyhelminthes
b. body plan
- bilateral
- nerve net cephalized – nerve ring
- ‘acoelomate’ – deep tissues…
II. Animal Diversity
a. Lophotrochozoans
1. Platyhelminthes
b. body plan
- bilateral
- nerve net cephalized – nerve ring
- ‘acoelomate’ – deep tissues…
- pharynx and convoluted gut: convoluted
gut serves to distribute nutrients to “deep” tissues…acts
as a ‘vascular’ (distributive) system… so the gut is called
a “gastrovascular” cavity.
II. Animal Diversity
a. Lophotrochozoans
2. Lophophores
- a diverse group of
worm-like animals that
have the same feeding
structure – a “lophophore”
- complete gut
II. Animal Diversity
a. Lophotrochozoans
3. Spiralians – wormy or segmented
a. Annelida – segmented worms
II. Animal Diversity
a. Lophotrochozoans
3. Spiralians – wormy or segmented
a. Annelida – segmented worms
1. Diversity
- polychaetes
- oligochaetes
- leeches
II. Animal Diversity
a. Lophotrochozoans
3. Spiralians – wormy or segmented
a. Annelida – segmented worms
2. Body Plan
- coelomate
- segmentation – allows for
specialization of body parts and
refined locomotion
II. Animal Diversity
a. Lophotrochozoans
3. Spiralians – wormy or segmented
a. Annelida – segmented worms
2. Body Plan
- coelomate
- segmentation – allows for
specialization of body parts and
refined locomotion
- neural ganglia, closed
circulation, excretory system
II. Animal Diversity
a. Lophotrochozoans
3. Spiralians – wormy or segmented
b. Mollusca – reduced segmentation; shells
1. Diversity
- chitons
II. Animal Diversity
a. Lophotrochozoans
3. Spiralians – wormy or segmented
b. Mollusca – reduced segmentation; shells
1. Diversity
- chitons
- snails
II. Animal Diversity
a. Lophotrochozoans
3. Spiralians – wormy or segmented
b. Mollusca – reduced segmentation; shells
1. Diversity
- chitons
- snails
- bivalves
II. Animal Diversity
a. Lophotrochozoans
3. Spiralians – wormy or segmented
b. Mollusca – reduced segmentation; shells
1. Diversity
- chitons
- snails
- bivalves
- cephalopods
II. Animal Diversity
a. Lophotrochozoans
3. Spiralians – wormy or segmented
b. Mollusca – reduced segmentation; shells
2. Body Plan
II. Animal Diversity
a. Lophotrochozoans
3. Spiralians – wormy or segmented
b. Mollusca – reduced segmentation; shells
2. Body Plan
- reduction of segmentation (fusion)
- decephalization in sessile orgs
II. Animal Diversity
Aside… Patterns
1. Digestion:
- blind gut
- complete gut,
- sementation and specialized organs,
- reduced segmentation
II. Animal Diversity
Aside… Patterns
2. Cephalization:
- nerve net – radial symmetry (no head)
- bilateral symmetry - head
- increased cephalization – senses forward
- complex brain (cephalopods)
II. Animal Diversity
b. Ecdysozoans
- exoskeleton that must be shed for growth;
either a thin flexible CUTICLE, or a more
rigid exoskeleton with chitin.
II. Animal Diversity
b. Ecdysozoans
- Phylogeny
II. Animal Diversity
b. Ecdysozoans
- exoskeleton that must be shed for growth;
either a thin flexible CUTICLE, or a more
rigid exoskeleton with chitin.
- This is also a very diverse assemblage of Phyla;
we are only going to consider a few.
II. Animal Diversity
b. Ecdysozoans
1. Nematoda
- molt four times, resecreting their cuticle each time
II. Animal Diversity
b. Ecdysozoans
1. Nematoda
- molt four times, resecreting their cuticle each time
- complete digestive tract
II. Animal Diversity
b. Ecdysozoans
1. Nematoda
- molt four times, resecreting their cuticle each time
- complete digestive tract
- some cephalization with anterior neural ganglion
II. Animal Diversity
b. Ecdysozoans
1. Nematoda
- molt four times, resecreting their cuticle each time
- complete digestive tract
- some cephalization with anterior neural ganglion
- free living and parasitic
II. Animal Diversity
b. Ecdysozoans
1. Nematoda
- molt four times, resecreting their cuticle each time
- complete digestive tract
- some cephalization with anterior neural ganglion
- free living and parasitic
- human parasites: trichinosis, filariasis, elephantiasis,
Ascariasis (two foot intestinal worms)
II. Animal Diversity
b. Ecdysozoans
2. Onchyphora and Tardigrada:
thin chitinous exoskeleton; flexible; unjointed legs
II. Animal Diversity
b. Ecdysozoans
2. Onchyphora and Tardigrada:
thin chitinous exoskeleton; flexible; unjointed legs