120 terms



Terms in this set (...)

Isopods are...
How many species of isopods do we know of?
How do isopods breathe?
With gills
Where do isopods live?
Marine, freshwater, and terrestrial environments
When threatened, pillbugs ___________ and sow bugs __________
Curl into a ball, try to flee
Habitat of pillbugs
Moist, dim/dark, under rocks, logs, boards, leaves, etc.
What do pillbugs eat?
Decaying wood, leaves, and other vegetation
How long are pillbugs?
5-15 mm
What are the 3 body parts of pillbugs?
Head, thorax, and abdomen
Describe a pillbug's body
Exoskeleton with shield-like plates, body flattened laterally, 7 identical jointed appendages, 1 pair antennae, 1 pair compound eyes
How are pillbugs born?
They hatch from eggs which are carried in a pouch under the female's thorax. They are self-sufficient upon hatching.
How do pillbugs grow?
They molt their exoskeletons
What is taxis?
The turning of an animal's body relative to a stimulus
What is kinesis?
The random movement of an animal in relation to a stimulus
Type of Symmetry
3 Regions of Decapods
Cephalon + Thorax = Cephalothorax & Abdomen
How many segments do decapods have?
15-20 segments
Shell made of chitin, strengthened by calcium carbonate
Feeding appendages (by mouth), located in cephalothorax
walking legs
Walking appendages (on sides), located in cephalothorax
Swimming appendages (at back), located in abdomen
Male Crab Distinction
Pointed flap v flap
Female Crab Distinction
Roundded (U-shape) flap
when they grow a new shell.
Where do females hold eggs?
Egg sponge in abdominal flap
Reproductory Behavior
Male guards female until she molts --> Insemination ---> Guards female until she forms exoskeleton
How many eggs do crabs release?
1.5 - 2 Million through mouth
What direction do crabs walk-in and why?
Sideways, legs act as hinges and only able to bend one way
What kind of circulatory system does a crab have?
Open circulatory
How do crabs breathe?
Counter-current gas exchange, water comes in through cheliped, moves across gills in opposite way of blood
1st Jaw Function
Manipulating food
2 and 3rd Jaw Function
Tearing food, pulling it into the mouth
Crop and Gizzard
Composed of hard plates in the anterior part of the stomach
used to eat
for chewing
for cutting into smaller pieces
hold and crush food assist manipulation of food items by passing food forward to the mandibles for chewing
- developed from common biramous appendages
- where females cary the eggs
- secreted cuticle is made of chitin, protein, and calcareous material
- specialized segments
- major body tagmata are usually head, thorax, and abdomen (not homologous across taxa)
- in most crustaceans, one or more thoracic segments are fused with the head as a cephalothorax
- anterior, beaklike projection like snout
posterior, last segment
two flaps on the side of telson
- dorsal cuticle of the head
- may cover most of body including thoracic and abdominal segments or just the cephalothorax in some species
tergum - sternum - pleurite
tergum = dorsal cuticular plates
sternum = ventral cuticular plates
pleurite = lateral cuticular plates
- major space in arthropods which is filled with blood
green gland (antennae/maxillary gland)
- end sac of antennal gland has a small vesicle and a spongy labyrinth which connects by an excretory tubule to dorsal bladder that opens to exterior pore
coelomic compartments remain as end sacs of excretory organs and space around the gonads
statocyst - statolith
statocyst opens at base of first antenna in crayfish and contains a ridge that bears sensory setae formed from the chitinous lining and grains of sand that serve as statoliths
- many photo receptor units to make a compound eye
- 3 sets of pigment cells
a common larval form with uniramous first antennules, biramous second antennae, and mandibles that all aid in swimming at this early stage
small crustacean (oppossum shrimp) found in freshwater lakes of Northern America
- asexual
- clones of mother
- jointed hairlike setae things
- parasite in crab
- kentrogon stage that injects parasitic cells into the hemocoel of host
survey ostracoda
- enclosed in bivalve carapase
- "mussel shrimp"
- moves/feeds using head appendages
- benthic or climb or burrowing
- most are dioecious, some parthenogenetic, and a few have males that emit light that synchronize to attract females
- development is by gradual metamorphosis
- considerable fusion of trunk segments that obscure division between trunk and abdomen
- most are ectoparasites with modified mouthparts for sucking
- have suction cups to attach to host fish
- direct development ... no nauplius
- babies are mini adults
- has 3 orders
Order Anostraca, includes fairy shrimp and brine shrimp that lack a carapace
Order Notostraca, includes tadpole shrimp with carapace forming a large dorsal shield
Order Diplostraca, includes water fleas with carapace that encloses the body but not the head or clam shrimps where the carapace encloses the whole body
- branchiopods have flattened, leaf-like legs called phyllopodia that serve as respiratory
- most branchiopods use legs for suspension feeding and locomotion
- generally freshwater and form a large and important component of freshwater zooplankton
- may reproduce by parthenogenesis to rapidly boost summer populations and then by sexual reproduction with the onset of unfavorable conditions
- fertilized eggs are highly resistant to cold and dessication, called ephipia, which are critical for winter survival of population
- usually have gradual metamorphosis
- generally small with elongate and tapering bodies that lack a carapace and retain simple, median, nauplius eye in the adult
- have single pair of uniramous maxillipeds and four pairs of flattened, biramous, thoracic swimming appendages
- a major articulation separates the posterior from the anterior, appendage-bearing portion of the body
- some free living some parasitic
- carapace surrounds body and secretes a set of calcareous plates
- head is reduced, abdomen is absent, and thoracic legs are long, many jointed cirri with hairlike setae that extend from the plates to feed on small particles
- most barnacles are marine while those in intertidal zones have plates that close to protect against dessication and temperature changes
- adults are sessile
- barnacles are monoecious but generally cross fertilize
- barnacles undergo metamorphosis
- rhizocephalan parasitic forms infect crabs and are generally dioecious ... kentrogon
- largest and most diverse class
- one of the few truly terrestrial crustaceans
- common land forms include sow bugs and pill bugs that live under stones and in damp spaces
- even though terrestrial, the isopod cuticle lacks effective protection of insect cuticle to conserve water such that generally have to live in moist habitats
- some isopods are highly modified as parasites of fishes or crustaceans while some grow mucho big
- development typically direct but may be metamorphic in parasitic forms
- resemble isopods that lack a carapace, have sessile compound eyes, and one pair of maxillipeds
- laterally compressed
- direct development ... no true metamorphosis
- small crustaceans that lack maxillipeds and all limbs have exopods
- most are bioluminescent with a light-producing organ called a photophore
- eggs hatch as nauplii and development is indirect and metamorphic
- have 5 pairs of walking legs and 3 pairs of maxillipeds
Synapomorphies "Radiata" + remaining Animalia
• Loss of Collar Cells
• "True" Tissues - diploblastic
• Gastrovascular Cavity - "incomplete gut"
• Nervous System (rudimentary)
Bilateral symmetry
Radial symmetry
Gastrovascular cavity
Primary organ of digestion and circulation in two major animal phyla: the Cnidaria (including jellyfish and corals) and Platyhelminthes (flatworms). Food enters and waste exits through the same orifice.
Incomplete gut (= blind gut)
Same thing as gastrovascular cavity
Complete gut
Has a clear beginning (the mouth) and a separate end (the anus).
True tissue
Diploblastic Germ Layers
Having a body derived from only two embryonic cell layers (ectoderm and endoderm, but no mesoderm), as in sponges and coelenterates.
the outer layer of cells covering an organism
the inner layer of cells that serves as a lining membrane of the gastrovascular cavity of Cnidarians.
Triploblastic germ layers
Has 3 germ layers: ectoderm, endoderm, and mesoderm.
Found in animals with bilateral symmetry
the middle layer of an embryo in early development, between the endoderm and ectoderm.
the innermost layer of cells or tissue of an embryo in early development, or the parts derived from this, which include the lining of the gut and associated structures.
Epithilomuscular Cell
cell of coelenterates that is modified to function in contraction and has an elongated fibrillar base that functions in the same manner as a muscle cell.
Nerve Net
(in invertebrates such as coelenterates and flatworms) a diffuse network of neurons that conducts impulses in all directions from a point of stimulus.
• Cnidocytes - contain nematocysts
• Gastrovascular cavity (= Coelenteron)
• Mouth surrounded by tentacles
• Medusoid Body Form
• Planula Larvae
-an explosive cell containing one giant secretory organelle or cnida (plural cnidae) that defines the phylum Cnidaria (corals, sea anemones, hydrae, jellyfish, etc.).
-Key feature to success of Cnidaria.
-Contain nematocytes
a specialized cell in the tentacles of a jellyfish or other coelenterate, containing a barbed or venomous coiled thread that can be projected in self-defense or to capture prey. Found in cnidocytes
a slender flexible limb or appendage in an animal, especially around the mouth of an invertebrate, used for grasping, moving about, or bearing sense organs.
a solitary or colonial sedentary form of a coelenterate such as a sea anemone, typically having a columnar body with the mouth uppermost surrounded by a ring of tentacles. In some species, polyps are a phase in the life cycle that alternates with a medusoid phase.
2nd stage of cnidaria.
form of cnidarian in which the body is shaped like an umbrella. The other main body-form is the polyp.
Sexually reproduces zygotes.
3rd and final stage of cnidaria life cycle
Life Cycle of Cnidaria
1. Sexually produced zygote becomes a free
swimming larvae = planula.
2. Planula settles and becomes a polyp.
3. Polyp may/may not become a medusa.
4. Medusa sexually reproduces zygotes.
Cnidarian Diversity
Phylum Cnidaria - ca. 9,000 species
-Class "Hydrozoa"
-Class Scyphozoa
-Class Cubozoa
-Class Anthozoa
Class "Hydrozoa"
Hydroids, Portuguese
Class Scyphozoa
Larger "true" jellyfishes
Class Cubozoa
Cube jellyfishes
Class Anthozoa
Anemones, coral, sea fans, &
the translucent, non-living, jelly-like substance found between the two epithelial cell layers in the bodies of cnidarians and sponges. the tissue found in jellyfish and it functions as a hydro-static skeleton.
Coral Reef
a ridge of rock in the sea formed by the growth and deposit of coral.
Planula Larval Stage
a free-swimming coelenterate larva with a flattened, ciliated, solid body.
1st stage in life cycle of cnidaria.
the segmented part of the body of a tapeworm that consists of a long chain of proglottids.
a cell type found in ctenophores. They are widespread in the tentacles of these animals and are used to capture prey. consist of a coiled spiral filament that is embedded in the epidermis and an axial filament with a granular dome.
Comb Row
Ctenophores are characterized by eight rows of cilia, which are used for locomotion. The cilia in each row are arranged to form a stack of combs, also called comb plates, or ctenes; thus the name ctenophore comes from the Greek, meaning "comb bearer".
Phylum Ctenophora (Comb Jellies)
• Ca. 150 species
• Marine (open ocean, often deep water)
• 8 plates of ciliated combs ("ctenes")
• Feeding tentacles with colloblasts
- Sticky substance secreted
• Luminescent, fragile
Chestnut cowrie
cypraea spadicea
cone snail
conus californicus
tube snail
serpulorbis squamigerus
purple olive
olivelle biplicata
black abalone
haliotis cracherodil
red abalone
haliotis rufescens
wavy top turban
astraea undosa
kellets whelk
kelletia kelletii
operculum from wavy top
astraea undosa
circle with stripes
keyhole limpets
family fissurellidae
white capped limpet
acmaea mitra
owl limpet
lottia gigantea
slipper shell
crepidula sp.
brown turbans
tegula brunnea
black turbans
tegula funebralis
sea hare
aplysia californica
flabellina iodinea

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