Animal Diversity 1









Porifera—sponges
Cnideria—Jellies, corals, anenomes, etc.
Platyhelminthes—flat worms
Nematoda—round worms
Mollusca—molluscs
Annelida—segmented worms
Arthropoda—crustaceans, insects, spiders, etc.
Echinodermata—sea stars
Chordata
Lower Invertebrates
Characteristics to compare/note
Symmetry
 Cephalization
 Digestive tract complexity/organ system
development
 Feeding, movement, support, & reproduction

Porifera (Sponges)
Porifera (Sponges)

Symmetry:



Asymmetrical
No head
Mobility

Adults Non-motile


Larvae are mobile


Filter feeders




Water in through pores by flagellated collar cells
Food is filtered out
Water leaves sponge through osculum
Support by spicules, sometimes of silica or
calcium carbonate


So they can spread to new environement with less
competition
Feeding


Sessile—attached to substrate
Deep-water forms have harder, more durable spicules
No body systems, No true tissues
Simplest/least complex group (phylum)
Cnideria: jellies, anenomes, corals, hydras, etc…
Cnideria

Symmetry



Motile?



Tentacles w/ Nematocysts—
stinging cells capture food
Digestive system with one
opening



Polyp form is sessile
Medusa form is motile/drifts
Feeding:


Radial symmetry
No head
Can only process one meal at a
time
Also used for internal distribution
Basic nervous system
Cnidaria: Jellyfish

Medusa or Polyp?
Cnidaria: Hydra
medusa or polyp?
Cnidaria: Anemones
Cnideria: Corals

“Skeletons”




Made of Calcium carbonate
“rock-like”
Can form reefs over time
Symbiosis




Photosynthetic protists--algae lives within the
cnideria
Algea provide food for cnidarian
Cnidarian provides shelter to algae
Corals must exist in area that allow
photosynthesis
Radial Symmetry

Radial symmetry allows the organism (that
cannot really move on its own) to interact
with environment (potential food/prey items)
from all directions

No matter what direction you food approaches
from; the cnidarian will be able to capture it
Platyhelminthes: flatworms



Symmetry
Cephalization
Digestive
Platyhelminthes

Symmetry


Bilateral
Cephalization


Motility


Motile—self propelled
Digestive System

One opening—inefficient





Sense organs concentrated on
“front”
Only one meal at a time
Also used for internal distribution
Basic nervous system
Some can regenerate
Free living and parasitic forms
Platyhelminthes: Planaria


Free living
Monecious:



Both sexes in same
individual
Eye spots—basic light
detection
Auricles-chemoreceptors
Platyhelminthes: Flukes +
Tapeworms



Monecious
Parasites
Scolex


Proglottid


For reproduction
Source


For attachment
Tapeworms transmitted through
oral-fecal contact and
undercooked meat
Gut
Live in host’s
digestive system
so lacks a digestive system of its
own

Nematoda: Round worms




Symmetry
Cephalization
Digestive System
Pseudocoelom
Nematoda: Round worms


Symmetry

bilateral

Cephalization
Mobility


Digestive System




Allows increased tolerance to dry
environment
Free living forms


‘false’ body cavity, promotes
independent movement of body
parts
Basic nervous system
Protective cuticle


Complete—2 openings
More efficient: allows continuous
feeding
Pseudocoelom:


Motile—self propelled
Are Major decomposers
Some forms are parasites
Parasitic Nematoda
filarial
Hook
worms
filarial worms—
filariasis (Elephantiasis )
Parasitic roundworms

Hookworm
Enters body through skin (often from exposure to
fecally contaminated soil/water)
 Travelles through multiple organs, but chiefly
infects intestines
 Eggs leave through feces


Trichina
Humans can get it from eating undercooked pork
(or other infected meat)
 Travels through body and infects intestines,
muscle, heart ect.

bilateral & cephalization

Cephalization: concentration of sense organ
at one end of organism.


This end is the ‘head end’
Mobile/self-propelled organims are tyically
bilateral and cephalized as the concentration
of sensory organs at the anterior/”head” end
of the organism allows it to better negotiate
the environment.
Complexity overview




Poriferans: Simplest: no tissue, no symmetry, filter feeders,
no organ systems
Cniderians: symmetry present, sessile/drifters w/ radial
symmetry, predators that use tentacles, basic nervous
system, basic digestive system that is also used to distribute
materials throughout organsim, true tissues
Platyhelminthes: increasingly complex; self propelled w/
cephalization and bilateral symmetry, a nervous system,
basic digestive system that is highly branched and use to
distribute materials, true tissues
Nematoda: most complex group in this lab, has a digestive
system with two openings, true tissues, a false body cavity
Terms to know
















Asymmetry
Radial symmetry
Bilateral symmetry
Cephalization
Spicules
Polyp
Filterfeeding
Nematocysts
Medusa
Coral
Complete digestive tract
Host
Scolex
Proglottid
Cuticle
Incomplete digestive tract
Lab manual questions to
review



Asymmetry
Radial symmetry
#1, 6, 7, 8, 10, 11, 12, 15, 16, 17,
20, 21
If needed refer to the following slides
that show the life cycle of several
parasites discussed in this lab.
TAPE WORMS
BLOOD FLUKE
hook WORMS
Trichinosis