Chapter 33.1 Flashcards
What do invertebrates account for, and where are they found?
over 95% of known animal species
Enhabit every habitat
What is under Phylum Porifera, what kind of group is it, and when did they diverge?
Sponges
Monophyletic- still debating
basal species
Characteristics of sponges (4)
sedentary
lack true tissues
filter feeders
Gas exchange and waste removal can occur via diffusion across membranes
What kind of tissues do sponges have?
different cell types like flagellated collar cells for phagocytosis
Characteristics of complex sponges (3)
Folded body walls
Branched water canals
Several oscula
What is the mesohyl?
gelatinous region separating two layers of cells
What are amoebocytes? (2)
cells that use pseodopodia
Move through mesohyl
Functions of the mesohyl (5)
Take up food from water and from choanocytes
Digests
Carries nutrients to other cells
Manufacture skeletal fibers within the meshoyl
Totipotent
What are examples of skeletal fibers manufactured by the meshol? (2)
Ex- sharp spicules made from calcium carbonate or silica
Ex- flexible fibers made from spongin
What does totipotent mean, and two things it allows?
capable of becoming other types of sponge cells
Provides body with flexibility
Adjust shape in response to environment
How do sponges reproduce? (3)
they are sequential hermaphrodites
Functions as both male and female and produces both sperms and eggs
Functions as one sex and then another
how does cross fertilization occur in sponges?
occurs when water transfers sperm to a female functioning sponge
What results after sponges fertilize?
Results in a zygote > flagellated, swimming larvae dispersing from parent > settles on substrate > develops into a sessile adult
What do sponges produce that help humans, and an example>
Antibiotics that can be used for human diseases
Ex- cribrostatin- used to fight cancer cells and Streptococcis
What are eumatozoans, what do they include, a characteristic, and the oldest lineage?
true animals
All animals except sponges and a few other groups
Clade of animals with true tissues
Cnidaria
What is included in cnidarians, and what did they diverge into?
Include hydrasm corals, jellies
Diverged into Medusozoa and Anthozoa
What kind of body plans do cnidarians have?
simple, diploblastic, radial body plan
What is the basic body plan of cnidarians, and what does it function as?
Sac with a gastrovascular cavity- central digestive compartment
Functions as both mouth and anus
What are two variations of the cnidarian body plan?
Largely sessile polyp
Motile medusa
What is a polyp, what does it do, and an example?
cylindrical forms adhering to substrate by aboral end (opposite from mouth)
Extends tentacles for prey
Ex- hydras and sea anemones
How do polyps move? (3)
Primarily sedentary
Can move slowly using muscles at aboral end
Detaches when threatened and swims by bending and thrashing tentacles
What is a medusa, and how does it move?
flattened, mouth-down version of polyp
Movies freely in water by passive drifting and contractions
What do cnidarians eat, and how? (3)
Predators using tentacles to capture and push food into gastrovascular cavity
Enzymes excreted in this cavity for digestion
Undigested remains expelled from mouth/anus
What are cnidocytes, their function, and what does it contain?
cells unique to cnidarians found in tentacles
Functions in defense and prey capture
Contains cnidae- capsule-like organelles capable of exploding outwards
What are nematocysts?
specialized cnidae containing a stinging thread that penetrates body wall of prey
What kind of tissues do cnidarians have? (2)
Contractile tissues and nerves
Possess contractile fibers (bundles of microfilaments) in epidermis and gastrodermis
What kind of skeleton do cnidarians have?
Gastrovascular cavity acts as a hydrostatic skeleton which contractile cells can work on
WHat kind of nervous system do cnidarians have? (4)
Noncentralized Nerve net coordinates movement
Distributed around body
No brain
Detect stimuli from all directions
What are medusozoans, and what do they include?
All cnidarians that produce a medusa
Includes scyphozoans (jellies),
cubozoans (box jellies), and hydrozoans
What form do hydrozoans exist in?
alternate between polyp and medusa form
What forms do scyphozoans and cubozoans exist in?
spend majority of life cycle in medusa stage
What do anthozoans include, and what form are they found in?
Includes sea anemones and corals
Occurs only as polyps
How do corals live (2), what do they secrete, how do new generations live, and what destroys them (5)?
Live as solitarory or colonies
Forms symbiosis with algae
Secretes a hard exoskeleton of calcium carbonate
Each polyp generation builds on skeletal remains of earlier generation
Destroyed by pollution, overharvesting, ocean acidification, global warming, and rising water temperatures
What is found in Clade Bilateria, four characteristics, and clades it diverges into?
Contains majority of animal species
Bilateral symmetry
Triploblastic development
Digestive tract with two openings
Coelom
Diverges into Lophotrochozoa, Ecdysozoa, and Deuterostomia
What is the most diverse clade of bilaterians in terms of body plan?
Lophotrochozoans
What is in phylum Platyhelminthes and where do they live?
flatworms, flukes, and tapeworms
Lives in marine, fresnwater, and damp terrestrial habitats
What kind of body do flatworms have? (6)
Thin body
Flattened dorsoventrally
Triploblastic development
Acoelomates
Gastrovascular cavity with one opening
contains protonephridia
What is protonephridia, and what does it do?
networks of tubules with ciliated structures called flame bulbs
Pull fluid through branched ducts opening to the outside
Why is being flat important for flatworms? (4)
Increases surface area
Places cells close to water to allow gas and waste exchange by diffusion
Maintains osmotic balance
No organs for gas exchange
What kind of circulatory system do flatworms have?
Lack a circulatory system
Fine branches of gastrovascular cavity distributes food
What lineages do flatworms diverge into?
Catenulida
Rhabditophora
WHat is found in catenulida, and how do they reproduce (4)?
Freshwater flatworms
Reproduce asexually by budding posterior end
Offspring produces their own bud before detaching
Forms a chain of 2-4 identical individuals
Aka chain worms
What is included in phylum Rhabditophora, and where are they found?
Freshwater and marine
Free-living and parasitic
How do free-living rhabditophora get food?
Predators and scavengers
Where are planarians found, what do they prey on, and how do they move (3)?
found in unpolluted ponds and streams
Preys on smaller animals or feeds on dead animals
Move using cilia in ventral surface
Slides along mucus they secrete
Some uses muscles to swim
What is found in the head of free-living rhabditophora? (2)
Light-sensitive eye-spots and lateral flaps to detect chemicals
Complex and centralized nervous system
How do free-living rhabditophora reproduce? (3)
Reproduce asexually through fission
Parents constricts in the middle, separating head and tail
Sexual reproduction as hermaphrodites
What do parasitic rhabditophora possess?
Most possess suckers attaching to internal organs
Possess tough covering to protect from the immune system
How do parasitic rhabditophora immune system work? (3)
Mimics surface proteins of hosts
Creates partial immunologcial camouflage
Releases molecules tha manipulates host immune system into tolerating the parasite
What kind of lifecycle do trematodes have, and what do they require?
Complex life cycle of both sexual and asexual
Require an intermediate host which larvae develop before infecting the final host, where adults live
Ex- human parasites first infect snail hosts
Example of a trematode
Blood flukes- trematodes that cause schistosomiasis- disease causing pain, anemia, and diarrhea
What are tape worms, and what two things do they possess?
Parasitic rhabditophoran
scolex- anterior end
proglottids- long ribbons of units in the posterior
What does the scolex do? (2)
Armed with suckers or hooks to attach to the intestines
Absorbs nutrients released by digestion in the host- Body surface absorbs
What do proglottids do (2)?
Used for sexual reproduction
Filled with fertilized eggs that leave the host in feces
What is found in phylum Rotifera, where do they inhabit, and what do they possess (3)?
Rotifers
Inhabits freshwater, marine, and damp soil cavity
Possess alimentary canal instead of a gastrovascular cavity
Digestive tube with two openings, mouth and anus
Possess crown of cilia that draws a water cortex into the mouth
Possess trophi- jaws that grind food
What is lined in the pseudocoelom, what is unique about it, and what does the fluid do?
Organs line in the pseudocoelom
Cavity not completely lined by mesoderm
Fluid in this cavity serves as a hydrostatic skeleton
How do rotifers reproduce (4)?
Some under go parthenogenesis
Only females producing more females from unfertilized eggs
Produce sexually in certain conditions, like crowding
Embryos remain dormant, and develop into females
What phylums are lophophorates found, what do they have (2), and how do they move?
Bilaterians in the phyla Ectoprocta and Brachipoda
lophophore
true coelom lined by mesoderm
sessile
What kind of body do lophophorates have? (2)
U-shaped alimentary canal
No distinct head
What are extoprocts, and what are they encased in?
colonial animals resembling moss
Encased in a hard exosheleton with pores which lophophores extend
What do brachiopods resemble, their shell orientation, and how are they found?
resemble clams
Shells are dorsal and ventral instead of lateral
Aka lamp shell
Attach to the seafloor by stalk
What phlyum are mollusks, what do they include, and how diverse are they?
Phylum Mollusca
Snails, slugs, oysters, clams, octopus, and squids
Second most diverse phylum of animals
What kind of body do mollusks have? (4)
Soft-bodied
Most secrete a shell made of
calcium carbonate
Coelomates
Three main parts
What are the three main parts of mollusks, and their roles?
Foot- for movement
Visceral mass- contains organs
Contains ovaries or testes
Mantle- fold of tissue draping over visceral mass and secretes shell
What does the mantle extend over, and two things found in it?
Extends beyound the visceral mass and produces a water-filled chamber
Mantle cavity- houses gills, anus, and excretory pores
Radula- straplike organ to scrape food
How do snails reproduce, and their life cycle?
Snails are hermaphrodites
trochophore stage
What kind of body do chitons have (3), and where are they found?
Oval-body shape
Shell with 8 dorsal plates
Unsegmented body
Marine, clinging to rocks on the shore
How do gastropods move, feed (2), what is found at the head, and role of mantle cavity?
move by foot or cilia
graze as it moves
Some predatory gastropods use radula to bore holes into other molluscs
head has eyes at tips of tentacles
mantle cavity functions as lungs
Shell function of gastropods (2)
protection
prevents dehydration
WHat do bivalves include, type of shell, what they possess (3), and how they move
Includes clams, oysters, mussels, and scallops
Hinged shells, help by adductor muscles
No head and radula
Some possess eyes and sensory tentacles in the mantle
Mantle cavity contains gills used for feeding and gas exchange
sedentary
How do bivalves feed? (3)
Suspension feeders
Food is trapped in mucus of gills
Cilia moves it to the mouth
What do cephalopods include, how do they feed (2), role of foot, and how do they move?
Marine predators
Tentacles grasp prey
Uses jaws to bite and poision with saliva
Foot modified into a muscular excurrent siphon and parts of the tentacles
Moves by drawing water into mantle caivty and firing water htrough the excurrent siphon
What kind of mantle do cephalopods have, and type of circulatory system, nervous system, and sensory system?
Mantle covers visceral mass
Reduced and internal shell
Closed circulatory system- blood remains seperate from fluid in the body cavity
Well-developed sense organs
Complex brains
What did cephalopods descend from?
Descended from predatory shelled molluscW
What are ammonites?
shelled cephalopods that were cephalopods ancestor
What animal group has the most documented extinctions, and what groups are especially threatened?
Molluscs
Freshwater bivalves and terrestrial gastropods are especially threatened
Includes pearl mussels
What are threats to molluscs (4),and what can help (2)?
habitat loss, pollution, competition or predation by introduced species
Reducing water pollution and changing how water is released from dams can help
What kind of body do annelids have (2), and where are they found?
body resemble fused rings
coelomates
segmented worms in the sea, freshwater, and soilW
What where annelids once divided into, and why does it no longer work (2)?
Once Divided into polychaetes, oligochaetes, and leeches
Polychaetes- many bristles made of chitin on body- Paraphyletic
Oligochaetes- subgroup of polychaetes
What are annelids now divided into?
Now divided into Errantia and Sedentaria
WHere are Errantia found, how do they move (2), and what do they feed on?
Marine
Mobile
Swim among plankton or crawl on the seafloor
Predators or algae grazers
What kind of body do Errantia have (4)?
Each body segment has a parapodia- paddle-like structures
Parapodium has numerous chaetae
Richly supplied with blood vessels and can act as gills
Well-developed jaws and sensory organs
How do sedentarians move, where do they live, how do they feed, and what do they include?
Less mobile
Live in tubes or within the marine floor
Elaborate gills for filter feeding
Includes leeches and earthworms
What do leeches feed on, how does it feed, what does it secrete, and what was it once used for?
Predator feeding on invertebrates
Use bladelike jaws to slit skin of host
Possess an anesthetic - Secretes hirudin- keeps blood from coagulating
Now used to dissolve unwanted blood clots
Once Used for bloodletting- draining of blood after surgery
What do earthworms eat, what does it secrete, and what does it do for the environment?
Eats soil, extracting nutrients as it passes through the alimentary canal
Undigested material mix with mucus and is secreted
Tills and aerates earth
How do earthworms reproduce? (2)
Hermaphrodites, but can cross-fertilize
Cross-fertilize
Mating by aligning in opposite direction
Exchange sperm and seperates
