Chp 33 Intro to Invertebrates Flashcards
What are invertebrates?
Animals that lack a backbone
What percentage of animals are invertebrate?
95%
What is the common ancestor of all animals?
- Protists
What are sponges?
Basal animals that lack true tissues
What are animals in the phylum Porifera informally known as?
- Sponges
What are the characteristics of sponges?
- Sedentary (non-motile/not active)
- Live in marine or fresh waters
What are the 5 phylums in order?
- Porifera
- Cnidaria
- Lophotrochozoa
- Ecdysozoa
- Deuterostomia
What are filter feeders?
Sponges that captures food particles suspended in the water that passes thru their body
What is spongocoel?
A cavity held in which water is drawn thru pores
What is osculum?
The opening of the cavity where water leaves
What are choanocytes?
Flagellated collar cells that generate water current thru the sponge and ingenst suspended foods
What are amoebocytes?
Cells that are found in the mesohyl and play roles in digestion and structure
What are hermaphrodites?
Each individual function as both male and female
- Sponges are hermaphrodites
What is mesohyl?
A gelatinous noncellular layer b/w 2 cell layers of sponges
What do sponges lack?
true tissues and organs
What are the ancient phylum of eumetazoans?
Cnidarians
What is significant about the clade Eumetazoa?
Consists of animals that has true tissues
What are the phylums in clade Eumetazoa?
- Cnidaria
- Lophotrochozoa
- Ecdysozoa
- Deuterostomia
What are some examples of cnidarians?
- Jellies
- Corals
- Hydras
What are the two types of cnidarians?
- Sessile (nonmoving)
- Motile
What do cnidarians exhibit?
- Simple diploblastic, radial body plan
What is the gastrovascular cavity?
Central digestive compartment of the cnidarian
What is the single opening function?
Mouth and anus
What are the two variations of the body plan (cnidarian)?
- sessile polyp
- motile medusa
What is a polyp?
Adheres to the substrate by the aboral end of its body
What is a medusa?
Bell-shaped body with its mouth on the underside
- Don’t attach to the substrate but moves freely
Are cnidarians herbivores or carnivores?
Carnivores in which they use their tentacles to capture prey
What are cnidocytes?
Cells that function in defense and capture prey
Cnidarian’s tentacles have this
What are nematocytes?
Specialized organelles within cnidocytes that eject a stinging thread
What are the 2 major clades of Phylum Cnidaria?
- Meduszoa
- Anthozoa
What are examples of medusozoans?
include all cnidarians that produce a medusa
- (Scyphozoans) Jellies
- (Cubozoans) Sea wasp
- Hydrozoans
What are examples of anthozoans?
- sea anemones
- star corals
What is special about most hydrozoans?
Can alternate b/w polyp and medusa forms
What is significant about hydra?
A freshwater cnidarian that exists only in polyp form and reproduces asexually via budding
What is the predominate life cycle stage of the scyphozoans and cubozoans?
- Medusa
What are 2 significant things of cubozoans?
- Their medusa is box-shaped
- They contain highly toxic cnidocytes
What does anthozoans only occur as?
As polyps
What does corals secrete?
Secrete a hard exoskeleton (external skeleton)
- Forms symbioses with algae
What are bilaterian animals?
Animals that have bilateral symmetry and triploblastic development
What is the triploblastic development?
- Coelom
- DIgestive tract with 2 openings
What does the clade Bilateria contains?
- Lophotrochozoa
- Ecdysozoa
- Deuterostomia
What clade is identified by molecular data and has the widest range of body forms
Lophotrochozoa
What are examples of lophotrochozoa? 6
- Flatworms
- Rotifers
- Molluscs
- Annelids
- Ectoprocts
- Brachiopods
What phylum are flatworms apart of?
Platyhelminthes
Where are flatforms located?
- Marine, freshwater, and damp terrestrial habitats
What are some characteristics of flatworms
- Are acoelomates
- has a gastrovascular cavity with one opening
What does protonephridia do?
Regulates osmotic balance
What are the two lineages of flatworms?
- Catenulida
- Rhabditophora
What are planarians
Free-living rhabditophorans
What are the 2 important groups of parasitic rhabditophorans?
- Trematodes: Parasitize humans and spends parts of their lives in snail hosts
- Tapeworms: Parasites of vertebrates and lack digestive system
What are rotifers?
Tiny animals that inhabit fresh water, the ocean, and damp soil
- Apart of phylum Rotifera
What is an alimentary canal?
digestive tube with a separate mouth and anus that lies within a fluid-filled pseudocoelom found in rotifers
What is parthenogenesis?
Reproductive process of Rotifers in which females produce offspring from unfertilized eggs
What are the two phyla in lophophorates?
Ectoprocta
Brachiopoda
What are some examples of the phylum Mollusca? 6
- snails
-slugs - oysters
- clams
- octopuses
- squids
What are ectoprocts?
Sessile colonial animals that superficially resemble plants; also called bryozoans
What do brachiopods resemble?
Resembles clams and other hinge-shelled molluscs, but the two halves of the shell are dorsal and ventral rather than lateral as in clams
What are the 3 main parts of molluscs?
- muscular foot
- visceral mass
- mantle
most also have
- water filled mantle cavity
- radula
What are the 4 major classes of molluscs?
- Polyplacophora (chitons)
- Gastropoda (snails and slugs)
- Bivalvia (clams, oysters)
- Cephalopoda (squids, octopuses)
