Terms in this set (42)
Why are sponges not considered true animals? In what two fundamental ways are sponge bodies different from the bodies of eumetazoans?
Lack true tissues.
Digestion, gas exchange, waste removal is all at cellular level.
Cell types change rolls.
How does the organization of the sponge body and its different types of cells relate to the way it feeds, digests, exchange gas, and gets rid of waste?
-create a current that draws water in through the pores and out through the osculum
--movement of choanocytes flagellum also draws water through its collar of finger like projections. Food particles are trapped in mucus that coats the projections.
-transport nutrients to other cells of sponge body
-produce materials for skeletal fibers (spicules)
*or become any type of sponge cell as need
-water enters the sponge through pores
-protein fibers, supports sponge
-outer layer of tightly packed epidermal cells
-wall of this sponge consists of two layers of cells separated by a gelatinous matrix, (middle matter)
-water passing through pores enters cavity called spongocoel
-water flows out of this opening
In what type of habitat would you never find a sponge and why?
Aquatic mostly marine
How are sponge bodies supported?
Spicules made out of of protein fibers
How do sponges feed?
feed by passing water through sticky structures and catch tiny food bits
How do sponges reproduce?
-one ind. makes both egg and sperm
-flagellated larvae dispersed then settle
In what habitats could you find examples of cnidarians and ctenophores?
In what two fundamental ways are the bodies of cnidarians and ctenophores different from the bilaterians?
They're radial symmetrical.
They have a topside and downside, but no front and back like bilaterians.
How does the symmetry of cnidarian and ctenophores relate to their mode of feeding?
Sit and wait carnivores.
Cnidarians use tentacles to capture prey and are able to have an all around approach.
Compare and contrast the body plan of a cnidarian in its poly and medusa form?
Polyp has a body stalk
How do cnidarians obtain, ingest, and digest their food How do they get rid of undigested food?
Cnidarians are carnivores that often use tentacles arranged in a ring around their mouth to capture prey and push the food into their gastrovascular cavity, where digestion begins. Enzymes are secreted into the cavity, thus breaking down the prey into a nutrient-rich broth. Cells lining the cavity then ab- sorb these nutrients and complete the digestive process; any undigested remains are expelled through the mouth/anus.
How do cnidarians distribute nutrients throughout the body? How do their cells get the oxygen they need and get rid of the CO2?
Direct O2 and CO2 exchange between cells and water.
Gastrovascular Cavity- one opening digestive sac
extracellular and intracellular digestion
*Gastrovascular cavity distributes nutrients to body
Using the colonial Hydrozoan Obelia example, describe the typical cnidarian life cycle.
What are the classes of cnidarians and examples? Which class is almost exclusively medusa in form?
ex- Hydra; Obelia
**Mostly medusa form
ex- Sea Wasp
medusa with eyes
*polyp form only
How are ctenophores different from and similar to cnidarian medusae in anatomy? In lifestyle?
Have tentacles- usually only two
Cells eject a sticky thread to capture prey whereas cnidarians use stinging tentacles to do so.
They move with 8 comb like plates with fused cilia while cnidarians move with contractile cells and simple net of nerve cells.
How does ctenophore locomotion differ from that of cnidarian medusa?
Cnidarian move with contractile cells and simple net of nerve cells.
Ctenophores move with 8 comb like plates fused with cilia.
How does the anatomy of a typical flatworm compare to a cnidarian's body? How are their digestive systems similar?
radial symmetrical and diploblastic
bilateral symmetrical and triploblastic
Gastrovascular cavity with one opening that distributes nutrients throughout body.
How are nutrients distributed and gas exchange and metabolic waste removed handled in a flatworm?
Gas exchange direct at cell level
Gastrovascular cavity with one opening is highly branched to distribute nutrients.
What are the major classes of flatworms? How do they differ in lifestyle?
free living carnivores or scavengers
flukes parasitic on animals
ex- Liver flukes
mostly in vertebrate intestines
*no mouth, scolex for attachment
*repeated reproductive segments (proglottids full with eggs)
Describe the Schistosoma blood fluke life cycle and why this is important to humans
Snail host -> motile larva -> motile larva burrows into skin
Sexual reproduction inside humans
Eggs released in bloodstream
What features of cestodes are uniquely adaptive for a parasitic existence?
No mouth or digestive system. *Absorptive
anterior scolex for attachment on vertebrate intestine
Describe the rotifers and how they feed. Why might they be mistaken for a protist?
Rotating wheel of cilia, feeding on plankton.
How is their digestive system different from flatworms?
Flatworms a coelomate with gastrovascular cavity or no digestive tract
Rotifers pseudocoelom with alimentary canal (digestive tube with mouth and anus); jaws (trophi) in pharynx; head with ciliated crown
How are nutrients distributed in a rotifer's body?
What unusual form of reproduction is seen in some rotifers?
Reproduce by parthenogenesis.
Based on producing eggs that do not need to be fertilized by males.
What are the shared feature of lophophorate phyla?
Aquatic sessile, suspension feeders, lophophores, U shaped alimentary tract
Why do you think ectoprocta were called bryozoans or moss animals?
colonial, making mineralized exoskeleton
looked like a moss
A colony of bryozoans might be easily confused with what other sort of colonial marine invertebrate?
Brachiopoda could be easily confused with what? How could you tell them apart?
Tell them apart by their lophophore and lack of foot
What are the three basic parts of a mollusks body plan and their function?
Visceral mass- internal organs; well developed organ systems; most with circulatory system
Mantle- covers visceral mass; makes shell and pearls, forms mantle cavity with gills or lungs
Foot (Radula)- many feed with this by scraping food
How do most mollusks deal with gas exchange, digestion and distribution of nutrients?
Mantle cavity formed with gills or lungs. Gas exchange occurs here. Gills have access to outside but is protected by the mantle cavity.
They have a digestion tract
How can we distinguish among the four major classes of mollusks on basis of external anatomy?
8 dorsal plates from shell
no distinct head
torison, mantle cavity over head end
two part shell joined by hinge
no distinct head
food modified into grasping arms and tentacles
How do different anatomical adaptations of the different mollusk classes relate to their life styles?
torison moves mantle cavity over head end
graze on plants and some are predators, land adapted, freshwater snails
burrowing or sessile
filter with gills- no radula
arms for grasping prey- big predators
Which class of mollusks has been able to adapt to land life?
(land adapted snails and slugs)
How are mollusks of economic importance to humans?
What combo of features distinguishes annelids from all other phyla?
segmentation- external and internal features are repeated
What is segmentation and why is it an advantage for these worms to be segmented? What other invertebrate phyla are segmented?
External and internal features are repeated
if one segment was hurt, the others would be fine and would have all the needed abilities
Ecydysozoans are also segmented
Describe the organization of the annelid body. How does it deal with issues of ingestion, digestion, circulation and gas exchange, and disposal of metabolic waste?
How does a segmented coelom contribute to annelid locomotion?
coelom acts as hydrostatic skeleton.
longitudinal muscle relax while circular contract to move annelids.
What are the classes of Annelids and how can you distinguish them?
fleshy parapodia and many bristles
ex: bristle worms with jaws
ex: fan worms, sessile-suspension feeders
few bristles, no parapodia
terrestrial or fw
ex: earthworms- eat dirt, aerate soil
fw predators, or bloodsucking parasites
suckers at both heads
some on land
In what ways are annelids of economic or health importance to humans?
Oligochaeta aerate soil
What features distinguish nematodes from other wormlike phyla? What anatomical feature do they share with other ecydysozoans?