Download Chapter 33 Guided reading

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Chapter 33 - Invertebrates
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As you read, focus on the trends, the increasing complexity of the organisms and the adaptations to their
environment.
Parazoa – no real tissues
o P. Porifera – sponges
Use the information from P. Porifera as a sample for the
type of information you are looking for for each of the
following animals. Go to your book to find
characteristics for each of the following groups.
Complete this BEFORE lecture!

Sessile; no nerves or muscles

Water flows in thru pores and into the spongocoel (central cavity) then out thru the
osculum (large opening)

Filter-feeder → choanocytes (collar cells) trap food particles and ingest by
phagocytosis; they line the spongocoel

Hermaphrodites → can cross fertilize with water currents

Zygote → swimming larva → sessile adult

Regeneration

Symmetry -Use the diagram below to label the anatomy of a sponge.
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Eumetazoa –
TRUE TISSUE
o Radiata → radial symmetry; diploblastic

P. Cnidaria – Ex.


_____opening
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
2 forms:
o
o

Nervous system →

Cnidocytes →

Nematocysts →
1. What is the difference between a polyp and a medusa?
Label the diagram below representing the life cycle of Obelia.

P. Ctenophora – comb jellies


Locomotion →

Tentacles and colloblasts →
o Bilateria → bilateral symmetry; triploblastic


Recall:

Protostomes (characteristics) →

Deuterostomes (characteristics) →
Protostomes

1. Lophotrochozoa – have a lophophore (Definition → ___________________
_______________________________________________________________)
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o P. Platyhelminthes – Ex.
 Symmetry –
 Number of tissue layers—
 Digestive system yes or no Number of openings____
 Gastrulation (protostome or Deuterostome)
 Circulatory system Yes or no – Open or closed

 Gastrovascular cavity with ____ opening
o Cephalization → eyespots vs. lateral flaps
o Nervous system →
o Reproduction →
o P. Rotifera – Ex.
 Pseudocoelomates
 Have organ systems and a complete digestive tract (mouth and anus)
 ___________________________ draws water into mouth
 Parthenogenesis →
 Other types of eggs develop into males, but only long enough to make sperm → zygote →
dormant during unfavorable conditions

o P. Mollusca – Ex.
 Soft-bodied; most protected by a _________________
 Body plan – 3 main parts →
 1.
 2.
 3.
 Fig. 33.16 pg. 656
 Symmetry –
 Number of tissue layers—
 Digestive system yes or no Number of openings____
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 Gastrulation (protostome or Deuterostome)
 Circulatory system Yes or no – Open or closed
 Radula →
 Both sexes; some hermaphrodite
 Trochophore →
 Coelomates; open circulatory system
o Foot acts as a __________________________
 C. Gastropoda – Ex.

o
o
o Grazers and predators –→
o Some are terrestrial with and without shells (snail vs. slugs)
 C. Bivalvia – Ex.
o
o Foot →
o Mantle →
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o No distinct head, no radula
o Path of water →
 C. Cephalopoda – Ex.
o Built for ________________
o Carnivores; inject _____________ = immobilization
o Chambered nautiluses →
o Move using __________________; can point in different directions
o Giant squid →
o Closed circulatory system; will-developed nervous system with complex brain; well
developed eyes
o
o P. Annelida – Ex.
 Symmetry –
 Number of tissue layers—
 Digestive system yes or no Number of openings____
 Gastrulation (protostome or Deuterostome)
 Circulatory system Yes or no – Open or closed

 Nervous system →
 Respiratory organ = _____________ (diffusion)
 Metanephridia →
 Regeneration→
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 3 classes:
 C. Oligochaeta – Ex.
o Undigested food exits thru anus
o Helps till the land
o ________________ head
o No parapodia (almost-feet → locomotion)
 C. Polychaeta
o Has setae (bristles) and parapodia
o Marine; crawl/ burrow on ocean floor
 Two well-adapted developments in annelids:
 1.
 2.
 2. Ecdysozoa – Definition →
o P. Nematoda – Ex.
 Symmetry –
 Number of tissue layers—
 Digestive system yes or no Number of openings____
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 Gastrulation (protostome or Deuterostome)
 Circulatory system Yes or no – Open or closed
o
 Non-segmented; pseudocoelomates
 Exoskeleton →
 Reproduction/ Fertilization →
 Important in _____________________ and ___________________
o Phylum. Arthropoda – Ex.
 MOST SUCCESSFUL OF ALL ANIMAL PHYLA
 Symmetry –
 Number of tissue layers—
 Digestive system yes or no Number of openings____
 Gastrulation (protostome or Deuterostome)
 Circulatory system Yes or no – Open or closed

 Exoskeleton →
 Jointed appendages →
 Cephalization; well-developed sensory organs
 Hemolymph →
 Organs specialized for gas exchange:
 Aquatic = ________________
 Terrestrial = _____________________
 4 main groups:
 1.
Groups can be
classified as phyla,
subphyla, or classes
depending on the
scheme
 2.
 3.
 4.
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 Much segmentation → as arthropods evolved, segments fused and number of segments
decreased
 Chelicerates
 Ex.
 Chelicerae →
 Cephalothorax and abdomen
 Class Arachnida – Ex.
o One or two main parts
o ___ pairs of appendages:
 1 pair –
 1 pair –
 4 pairs –
o Gas exchange →
o Spin silk webs

 Catches flying insects
 Spinning web = inherited trait
 3. Uniramians
o Ex.
o 1 pair ___________________________
o 1 pair ___________________
o ______________________ appendages
o Class Diplopoda – Ex.
 ____ pairs of legs per segment
o Class Chilopoda – Ex.
 ___ pair of legs per segment
o Class Insecta – Ex.
 Now divided into several insect classes
 Most diverse class
 Entomology →
 _______ pairs of wings (on thorax)
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 Wings →
 Early function of wings = ___________________
 Usually mate ___________ per lifetime
 Insects:
 HELPFUL →
 HARMFUL →
 4. Crustaceans
o Ex.
o
o Mainly aquatic
o ___ pair compound eyes
o Only arthropods with 2 pairs of antennae
o
o Gas exchange →
o Circulatory system →
o Separate sexes
o Larval stages →
o Several groups of crustaceans



---------------------------------------------------------------------------------------------------------------------------------How many times did segmentation evolve in animals???
- Still present (ex. vertebrae in backbone)
- 3 theories:
o __ origins of segmentation
Fig. 33.36 pg. 672
o __ origins of segmentation
o __ origin of segmentation
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Up to this point….Protostomes…now….
 Deuterostomia
 P. Echinodermata
o
o Usually center with ___ spokes (sea stars)
o Thin skin covers …
o Water vascular system →
o Reproduction →
o Look radial, but actually have ____________________ symmetry
o All are marine
 C. Asteroidea – Ex.
 5 or more arms with tube feet on the underside (locomotion, suction, grasping prey)
 Digestive System →

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