ii. animal diversity a. lophotrochozoans 1. platyhelminthes a. diversity - planarians (free-living)

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 – parasiticComplex 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