33 Flashcards
Invertebrates
are animals that lack a backbone
• They account for 95% of known animal species
Sponges are
basal animals that lack true tissues
they are filter feeders
amoebocytes
cells that use pseudopodia
most sponges are hermaphoridtes meaning:
each individual as both male and female parts
Cnidarians are an ancient phylum of
eumetazoans
eumetazoans
“true animals”
animals with tissues
Cnidarians
- jellies, corals, and hydras
- simple diploblastic, radial body plan
– gastrovascular cavity
– A single opening functions as mouth
and anus
– There are two variations on the body plan: the sessile polyp and motile medusa
nematocysts
cnidae that contain a stinging thread that can penetrate the body wall of prey
Phylum Cnidaria is divided into 4 main classes:
Class Hydrozoa
Class Scyphozoa
Class Cubozoa
Class Anthozoa
Class Hydrozoa
– Polyp and medusa stages
– Most marine and colonial
– Common examples: Portuguese man-of-war and freshwater hydra
Class SCYPHOZOA
- Medusa is prevalent over the polyp stage • All marine
* up to 2 meter in diameter
class ANTHOZOA
• Includes corals, sea fans and anemonies • all marine • medusa stage completely absent • sessile; many colonial
sessile
fixed in one place; immobile.
Class Cubozoa
box jellies, sea wasps
Phylum Ctenophora
• Aka comb jellies
• Used to be grouped with cnidarians but…
– Do not possess cnidocytes
– Use “combs” of cilia for locomotion
lophophore
a crown of cilia that surrounds the mouth
trochophore
larvae that have cilia around their middle
Bilateriates
- Bilaterian animals have bilateral symmetry and triploblastic development
- The clade Bilateria contains Lophotrochozoa, Ecdysozoa, and Deuterostomia
Phylum Platyhelminthes: the flatworms
Triploblasts, bilateral symmetry, dorso-ventrally
flattened
• No blood vessels, no structures for gas exchange, posses a gastrovascular cavity
The Parasitic Platyhelminthes: Cestoda
Parasitic • Most adults infect vertebrates • Possesses a head (scolex) armed with suckers and hooks • Body segments (proglottids) that break off as they ripen with eggs • Lack digestive system • Hermaphrodites but cross mate
Syndermata
Rotifers
are tiny animals that inhabit fresh water, the ocean, and damp soil
– Rotifers are smaller than many protists but are truly multicellular and have specialized organ systems
– Pseudocoelomates
Acanthocephalans
are sexually reproducing parasites of vertebrates
Phylum Mollusca
Molluscs are soft-bodied animals, but most are protected by a hard shell
– Muscular foot – Visceral mass – Mantle
• Many molluscs also have a water-filled mantle cavity, and feed using a rasplike radula
Mollusca:
the 8-plated chitons
Class Polyplacophora
consists of the chitons, oval-shaped marine animals encased in an armor of eight dorsal plates; foot used for locomotion; has radula.
Mollusca: Gastropods (the terrerstrial molluscs)
- Most have a single, spiraled shell
- Slugs lack a shell or have a reduced shell
- The most distinctive characteristic of gastropods is torsion, which causes the animal’s anus and mantle to end up above its head
Mollusca: Bivalves (two shelled molluscs)
- Molluscs of Class Bivalvia include many species of clams, oysters, mussels, and scallops
- They have a flattened shell divided into two halves
- Marine and freshwater
- Reduced head, paired gills, no radula
Mollusca: Cephalopoda (the brainy molluscs)
includes squids and octopuses, carnivores with beak-like jaws surrounded by tentacles of their modified foot
• Mouth with or without radula
• Most octopuses creep along the sea floor in search of prey. Locomotion by jet propulsion
• Closed circulatory system…
Molluscs are the animal group with the largest number of
recent extinctions
Ecdysozoans are the
most species-rich animal group
Ecdysozoans are covered by a tough coat called a
cuticle
The cuticle is shed or molted through a process called
ecdysis
The two largest phyla are
nematodes and arthropods
Nematodes
- Nematodes, or roundworms, are found in most aquatic habitats, in the soil, in moist tissues of plants, and in body fluids and tissues of animals
- Body is covered in a tough cuticle that is periodically shed as the animal grows
Arthropoda
spiders, crabs, insects (a billion billion species)
• Arthropods are the most diverse animal phylum
The head and thorax are sometime fused into a
cephalothorax
Other arthropod characteristics…..
• Evolution of flight
• Open circulatory system in which fluid called hemolymph is circulated into the spaces surrounding the tissues and organs
• A variety of organs specialized for gas exchange have evolved in arthropods
– Aquatic: gills
– Terrestrial:trachealsystem
Arthropoda
A variety of gas exchange mechanisms have developed among arthropods
Arthropoda: Cheliceriforms
horseshoe crabs!
subphylum Cheliceriformes, are named for clawlike feeding appendages called chelicerae
Arthropoda: Cheliceriforms
- Most modern cheliceriforms are arachnids, which include spiders, scorpions, ticks, and mites
- Six pairs of appendages: the chelicerae, the pedipalps, and four pairs of walking legs
- Gas exchange in spiders occurs in respiratory organs called book lungs
Arthropoda: Myriapoda
• Class Chilopoda
– centipedes: 1 pair of walking legs for each body segment
– carnivorous
• Class Diplopoda
– millipedes: 2 pairs of walking legs for each body segment
– Eat decaying leaves and organic matter
torsion
a solution to life in a house with 1 entrance
snails
Gas exchange in spiders occurs in respiratory organs called
book lungs
class chilopoda
Arthropoda: Myriapoda
– centipedes: 1 pair of walking legs for each body segment
– carnivorous
Class Diplopoda
– millipedes: 2 pairs of walking legs for each body segment
– Eat decaying leaves and organic matter
Arthropoda: Clade Pancrustacea
Subphylum Crustacea
– crabs, lobsters, crayfish, shrimp, krill, barnacles – 2 pair of antennae – 3 types of chewing mouthparts – varying number of legs; including swimmerets – distinct larval phase: nauplius larva
Subphylum Crustacea
Isopods
include terrestrial, freshwater, and marine species
– Pill bugs are a well-known group of terrestrial isopods
decapods
are all relatively large crustaceans and include lobsters, crabs, crayfish, and shrimp
Arthropoda: Hexapoda
• Aka the Insects (or tracheates) – very diverse! • powered flight • complex array of specialized mouthparts – 3 tagmata: head-thorax abdomen – three pair of walking legs – 1 pair of antennae – 1 pair of compound eyes – Metamorhposis
_____ open to the atmosphere
spiracles
tracheal system of insects
Ecdysozoa: Nematomorpha
- ‘horsehair worms”
- Similar to nematodes, but in their own phylum
parasites
ecdysozoan….Phylum Tardigrada
major extremophiles
Prevalent in mosses and lichens, where they feed on plant cells, algae, small invertebrates
Echinoderms
Sea stars and most other echinoderms are slow- moving or sessile marine animals
Echinoderms have a unique water vascular system, a network of hydraulic canals branching into tube feet that function in locomotion, feeding, and gas exchange
Echinoderms: Class Asteroidea
Sea stars, class Asteroidea, have multiple arms radiating from a central disk
• The undersurfaces of the arms bear tube feet, each of which can act like a suction disk
• Some sea stars can regrow lost arms
Echinoderms: Class Ophiuroidea
brittle stars
Echinoderms: Sea Urchins and Sand Dollars
• Sea urchins and sand dollars have no arms but have five rows of tube feet
Echinoderms: Sea cucumbers
- Sea cucumbers lack spines, have a very reduced endoskeleton, and do not look much like other echinoderms
- Sea cucumbers have five rows of tube feet; some of these are developed as feeding tentacles
The non-vertebrate Chordates
• Animals in phylum Chordata but NOT in subphylum Vertebrata
• Hagfishes
• Sea lancelet (Amphioxus)
– subphylum Cephalochordata – No vertebrae, but a notochord
• Sea squirts (Tunicates)
– subphylum Urochordata
– larva has notochord
– adult is filter-feeder with degraded nervous system and no-notochord
a land snail, a clam, and an octopus all share
a mantle
which phylum is characterized by animals that have a segmented body?
arthropoda
the water vascular system of echinoderms
functions in locomotion and feeding
which of the following combinations of phylum and description is incorrect?
Porifera- gastrovascular cavity and coelomate
which two main clades branch from the most recent common ancestor of the eumetazoans
cnidaria and bilateria
Digestion in sponges takes place in the _____.
amoebocytes
Sponges lack _____.
all of the above
Sponges feed by _____.
filtering small particles from water
Which one of following features is characteristic of the poriferan (sponge) body plan or life history?
motile larvae
Sponges have an internal skeleton composed of _____.
spicules
Three or four of the following characteristics correctly apply to the sponges. Which characteristic, if any, is NOT true of sponges?
all of the above are true
All the following statements, except one, describe one particular phylum. Which description does NOT belong with the others?
This phylum has more species than any other phylum.
__________ are members of the phylum __________ and feed by __________.
Corals … Cnidaria … using stinging cells to capture small animals that venture too close to them
Jellies and corals are members of the same __________, all members of which __________.
phylum … have special stinging cells on their tentacles
Which of the following are found in members of the phylum Cnidaria?
stinging cells, radial symmetry
Many cnidarians go through both a motile and a sessile (attached) stage during their life cycle. The attached stage is called a(n) _____.
polyp
Through what means do coral animals obtain their food?
tentacles that trap food particles
The choanocyte of a sponge and the nematocyst of a cnidarian both function in _____.
obtaining food
A distinctive feature of the Cnidaria is _____.
nematocysts
An advance of the cnidarians over the sponges is _____.
animalwide coordination and the presence of a gut
You are given an unknown animal to study in the laboratory. You find it is triploblastic, it is acoelomate, it has a resistant cuticle, and it has male and female gonads in the same individual. This animal probably belongs in the phylum _____.
Platyhelminthes
Tapeworms are highly specialized worms that make their living as endoparasites. To which of the following phyla and classes do the tapeworms belong?
phylum Platyhelminthes, class Cestoidea
Which of the following classes is(are) totally parasitic?
Cestoidea and Trematoda
The proglottids of a tapeworm contain an elaborate __________ system.
reproductive
Cephalopods are the only mollusks _____.
with a closed circulatory system
Consider the following list of animals: giant squid, earthworm, largemouth bass, snail, tapeworm, coral, and starfish. The two that belong to the same phylum are the __________ , and their phylum is __________.
giant squid and snail … Mollusca
An active marine predator is found possessing these characteristics: a series of tentacles (modified from the foot), a highly developed nervous system, and elaborate eyes. To which of the following animal classes does this organism most likely belong?
Cephalopoda
You go to the supermarket and ask a clerk where you can find the gastropods. He takes you to the “weird food” section and points out a container of _____.
snails
The structure of primitive mollusks suggests that this group shared a close common ancestry with _____.
segmented worms
Which of the following most clearly demonstrates the evolutionary relationship between annelids and arthropods?
body segmentation
Leeches are members of the phylum _____.
Annelida
Earthworms are most closely related to _____.
leeches
During reproduction by the oligochaete earthworm Lumbricus _____.
hermaphroditic individuals exchange sperm
Which one of the following is NOT a feature of polychaete worms (phylum Annelida, class Polychaeta)?
water vascular system
The excretory organs of earthworms are called _____.
metanephridia
Annelids __________.
all of the above are true
Animals such as ______ are the simplest animals to have _________.
roundworms … a complete digestive tract
Biology deals with many kinds of worms. Which choice includes three different phyla of “worms”?
Platyhelminthes, Annelida, Nematoda
The _____ include the largest number of species.
arthropods
The key to the diversity and success of the arthropods is _____.
jointed appendages
Sowbugs are really crustaceans, not insects. Therefore, a sowbug does NOT have _____.
three pairs of legs
In insects, gas exchange is accomplished by _____.
a tracheal system
The majority of animal species are _____.
insects
The arthropods superficially resemble earthworms in that both groups __________, yet the two are distinctly different because arthropods, but not earthworms, __________.
have prominently segmented bodies … have jointed appendages
Which one of the following shows the animals listed in such a way that their phyla are in alphabetical order?
spiders, jellies, squids, tapeworms, sponges, rotifers
Complete metamorphosis __________.
features a larval stage that looks different from the adult
In arthropods, molting is necessary because ________.
the chitinous exoskeleton cannot grow
An unidentified species of animal displays the following characteristics: bilateral symmetry, determinate embryonic cleavage, a complete digestive system, an open circulatory system, and distinct body segmentation. To which one of the following animal phyla does this species most likely belong?
Arthropoda
Which one of the following animals is most closely related to spiders?
scorpions
A major characteristic of arthropods is _____.
a chitinous exoskeleton
The water vascular system of a sea star functions in _____.
movement of the tube feet
A starfish and a squid belong to the phyla __________ and __________, respectively.
Echinodermata … Mollusca
Which one of the following statements about the phylum Echinodermata is FALSE?
Members of the phylum include the insects
Sea stars and sea urchins are members of the phylum __________.
Echinodermata
lining the interior of the spongocoel are flagellated _____ or collar cells that engulf bacteria and food particles by phagocytosis
what animal is this and what clade?
choanocytes
sponges in Poriferia
what class and phylum are fire coral and portuguese man of war in?
Phylum Cnidaria and Class Hydrozoa
polyp and medusa stage
what clade and phylum are true jellies in?
Phylum Cnidaria and Class Scyphozoa
medusa stage
what class and phylum are box jellies sea wasps in?
Phylum Cnidaria and Class Cuboza
What class and phylum are corals and anemones in?
Phylum Cnidaria and Class anthozoa
no medusa stage. colonial and sessile
tentacles of cnidarians are armed with _____
cnidocytes
cnidocytes have _____ that sting prey
nematocysts
the polyp is ____ and the medusa is ____
asexual; sexual
explain the life cycle of hydrozoan Obelia. what class and phylum?
Phylum Cnidaria and class Hydrozoa.
Polyps are asexual and the majority of life cycle is diploid and asexual.
what are Turbellaria and what phylum?
flat worms
Phylum Platyhelminthes
Class Turbellaria
what is cestoda?
tapeworms
Phylum Platyhelminthes
Class Cestoda
what is trematoda?
flukes
Phylum Platyhelminthes
Class Trematoda
flatworms are _____ meaning that they lack a body cavity
acoelomates
what are parasitic species?
trematodes and tapeworms
anatomy of a tapeworm
scolex, hooks and suckers
scallops, clams and oysters are in what class and phylum and clade?
Clade Lophotrochozoa
phylum Mollusca
Class Bivalvia
mollusks have 3 main body parts:
mantle, foot, visceral mass
Ecdysozoa sheds a tough external coat called a
cuticle
in an open circulatory system, what fluid is propelled through body?
hemolymph
what phylum are spiders, crabs, insects in?
arthropod
what are the main parts of the arthropod body plan?
segmented body and jointed appendages
what phylums are deuterostomes that are invertebrates?
Echinoderms and Chordates
what are Shared characteristics define deuterostomes (Chordates and Echinoderms)?
– Radial and interdeterminate cleavage
– Formation of the mouth at the end of the embryo opposite the
blastopore
what phylum and class are sea stars in?
echinoderms
Class Asteroidea
Why are the arthropoda so diverse?
Adaptive radiation; rapid development; more life cycles; lots of offspring and rapid regeneration times; potential for mutations gives them an advantage
Horseshoe crab has special blood with _____
amoebocytes
what is an example of incomplete metamorphosis
Incomplete metamorphasis is a grasshopper
_____ are one of the few extremophiles in the animal kingdom
Phylum tardigrada ( water bears)
Early hominins date back to
7.2 to 6.8 mya
what phylum are sponges in?
Porifera
why phylum are hydras, corals and jellies in?
cnidaria
what class are jellies in?
Class Scyphozoa
what class are hydras in?
Hydrozoa
what class are box jellies in?
cubozoa
what class are sea anemones and coral in?
class anthozoa
what phylum are comb jellies in?
phylum ctenophora
what phylum are flatworms in?
phylum Platyhelminthes
what phylums are in Lophotrochozoans?
- Phylum Platyhelminthes
- Phylum Syndermata
- Phylum Ectoprocta
- Phylum Brachiopoda
- Phylum Mollusca
- Phylum Annelida
what classes are in phylum Platyhelminthes ?
a. Class Turbellaria – free-living flatworms
b. Class Trematoda – flukes
c. Class Cestoda – tapeworms
why phylum are rotifers in?
syndermata
what class are snails and slugs in?
gastropoda
what phylum are segmented worms in?
phylum annelida
what phylums are in Ecdysozoans (invertebrates)?
- Phylum Nematoda
- Phylum Tardigrada
- Phylum Arthropoda
what phylum are round worms in?
phylum nematoda
what phylum are water bears in?
phylum tardigrada
what are the subphylums in arthropoda?
a. Subphylum Chelicerata
b. Subphylum Myriapoda
c. Subphylum Pancrustacea
what phylum and subphylum are horseshoe crabs, spiders, ticks, scorpions in?
Phylum Arthropoda and Subphylum Chelicerata
what phylum and subphylum are millipedes and centipedes in?
Phylum Arthropoda and Subphylum Myriapoda
