Download II. Invertebrates A

I. Animals
A. Overview
1. 5th Kingdom
(old system)
2. 10th Kingdom
(new system)
3. > Million Species
4. Why so much on animals?
a. Diverse Forms
b. Diverse Functions
c. Much known
d. similarities to us
B. Animal Characteristics
1. Multicellular
a. multicellular strategy occurs many times
- colonial protists - algae
- plants
- fungi
- animals
b. differ from many unicellular protists
B. Animal Characteristics
2. Eukaryotic
a. different from bacteria
2. Eukaryotic
b. Lack Cell Walls
- membrane is phospholipid bilayer
- Differ from plants, fungi
B. Animal Characteristics
3. Heterotrophic
a. require ingestion of preformed organic molecules
- depend on autotrophs for food
- directly or indirectly
b. NO photosynthetic bodies
B. Animal Characteristics
4. Locomotion
a. Most capable of some form of locomotion
- actively moving around
b. Occurs at some stage in the life cycle
II. Invertebrates
A. SPONGES (Parazoa)
1. loose federation of cells
2. Eumetazoa
- all other animals
(including vertebrates)
- true tissues
II. Invertebrates
A. Sponges (Phylum Porifera)
1. Only member of Parazoa
2. No distinct tissues
a. Cellular level of organization
b. Division of labor among cells
B. Eumetazoa
1. all other animals
2. true tissues
3. Radiata
a. Radial symmetry
Radiata
Parazoa
(sponges)
Eumetazoa
3. Radiata
a. Radial Symmetry
- symmetrical around central axis
i. Like wheel or pie
- have a top and bottom
i. Oral (mouth)
ii. Aboral (opposite side of mouth)
- good for animals that are less active
i. Sessile (stay in one place)
ii. Drifting or weak swimming
3. Radiata
b. Cnidarians
- Hydra
- Jellyfish
Polyp Stage
- Sea Anemones/corals
Medusa Stage
4. Bilateria
a. Bilateral Symmetry
- central plane
- some radial adults
i. bilateral stage
(e.g sea urchins)
b. Triploblastic
- have three germ layers in developing embryos
i. endoderm, ectoderm, mesoderm
- germ layers become specialized tissues
- Radiata - diploblastic (2)
i. No mesoderm
Ectoderm
body covering
Endoderm
digestive tract
Mesoderm
muscles
most organs
C. Body Cavities
1. In Triploblastic animals
(3 developmental layers)
2. 3 groups
3. Based on presence of
fluid filled space in tissues
4. Acoelomates
a. no body cavity
b. flatworms
5. Pseudocoelomates
a. Coelomic space
-between mesoderm and endoderm
- 7 Phyla
6. Coelomates
a. True Coelom
within mesoderm
b. 2 major groups
D. Coelomate Invertebrates
1. Mollusks
a. Foot
b. visceral mass
c. mantle (often produces shell)
d. radula (scraping structure for eating)
e. Common Mollusk Groups
Bivalves (clams, oysters,
Gastropods
Muscles, scallops)
Snails, slugs
Chitons
Cephalopods (squid, octopus)
2. Annelids (Segmented worms)
Earthworms
Polychaete Worms
Leeches
3. Arthropods
a. Exoskeleton
- molting growth
b. Segmented body
- fused segments
(tagmata)
c. jointed appendages
d. Arachnids (Class Arachnida)
Spiders
Scorpions
Ticks
Mites
- four pairs of walking legs
- Chelicerae
i. capture1st pair of appendages
ii. biting mouth parts - feeding
iii. claw-like
- Pedipalps
i. 2nd pair of appendages
ii. used in prey
- 2 tagmata (body sections)
i. cephalothorax
(fusion of head and thorax)
ii. abdomen
Lobster
Barnacles
e. Crusteceans
(Subphylum Crustecea)
- antennae - 2 pair
- Biramous appendages
Fairy shrimp
Shrimp
Crab
f. Centipedes and Millipedes
(Subphylum Myriopoda)
Centipedes
- antennae
- 1 pair walking legs/segment
- terrestrial carnivores
i. modified 1st legs - fangs
Millipedes
- two pairs walking legs/segment
- pairs of segments fused
- generally eat plant matter
g. Insects
(Subphylum Hexapoda Class Insecta)
- outnumber all other forms of life combined
- 26 orders
- explosion of diversity with evolution of flight
- Three segments
i. Head
- 1 pair antennae
ii. Thorax
- 3 pairs of segmented walking appendages
- Uniramous
iii.. Abdomen
Direct Development
i. juvenile has adult form
ii. egg, nymph, adult
Indirect Development
i. egg, larva, pupa, adult
ii. larval stage different from adult
iii. requires metamorphosis
4. Echinoderms (Phylum Echinodermata)
a. Marine
b. Secondary radial symmetry (larvae bilaterally semetric)
c. Endoskeleton
Brittle Stars
Sea Urchins, Sand Dollars
Sea Stars
Sea Lilies
Sea Cucumbers