Animals Taxonomy Flashcards
What are the 5 subclasses of Cnidaria?
Hydrozoa
Scyphozoa
Cubozoa
Anthozoa
Staurozoa
What are the two morphological types of Cnidaria?
Polyp: hydroid, sedentary form
Medusa: jellyfish, floating form
What is the mesoglea?
The mesoglea is an extracellular matrix located between the epidermis and the gastrodermis of Cnidarians
What is the name of the particular cell type of Cnidarians and what’s their deal?
Cnidocytes: each of them is able to produce one of over 20 kinds of distinctive organelles called cnidae (e.g. Nematocysts: inject toxin for prey capture and defence)
How does the nematocyst in anthozoans discharge?
When stimulated the high internal osmotic pressure causes water to rush into the capsule, the operculum opens, and the rapidly increasing hydrostatic pressure forces the thread out with great force.
What does the venom of cnidarians contain?
enzymes (lipolytic and proteolytic proteins that catabolize prey tissue),
pore forming toxins and neurotoxins
Hydrozoa
mainly remain in polyp forms and create colonies. When present, medusae are small, and the mouth opens at the end of a manubrium
Scyphozoa
large jellyfish, velum absent, the manubrium usually forms 4 oral arms
Staurozoa
solitary polyps attached to the sea bottom, with the top resembling a medusa with eight
extensions
Cubozoa
the predominant form is medusoid, the bell is almost square with a tentacle or a group of
tentacles at each corner
Anthozoa
there is no medusa stage and may be solitary or colonial. This class contains 3 subclasses:
1. Hexacorallia: are the sea anemones and corals. Sea anemones can glide along a substrate, expand and stretch their tentacles and “swim” by rhythmical bending movements. Scleractinia (true or stony corals) live in calcareous cups in which polyps can retract.
2. Ceriantipatharia: are tube anemones (solitary and found in soft sediments) and thorny corals (are colonial and attached to a firm substratum)
3. Octocorallia: are soft and horny corals, such as sea fans, sea pens, sea pansies, and others
What are organs of equilibrium in invertebrates (e.g. cnidarians)?
statocysts
What are ocelli?
Light sensitive organs in Cnidaria
(not in Staurozoa)
(also in Platyhelminthes, Annelids, Molluscs, Echinodermata, Arthropoda)
In Scyphozoa and Cubozoa, there are different sensory organs called?
- Rhopalia
- Each rhopalium is club-shaped
- Each rhopalium contains a hollow statocyst for equilibrium
- In some species the rhopalia also bear ocelli
- In Cubozoa each rhopalium houses 6 eyes in addition to other sense organs (instead of ocelli)
How does the asexual reproduction in cnidarian occur?
budding
(hydrozoa,anthozoa)
How does the sexual reproduction in cnidarians occur?
By gametes and its present in all medusae and in some polyps
eggs and sperm released in water
In case of sexual reproduction: What is the larvae of cnidarians called?
planula
How do cnidarians feed?
They are all carnivorous and actively preying
What are zooxanthellea?
Mutualistic dinoflagellates of Cnidarians:
- photosynthesis and fixation of carbon dioxide –>provide for hosts
- recycle phosphor and nitrogen
- enhance ability of coral to deposit calcium carbonate
- require light
What are the two types of frameworks in Porifera?
Rigid: calcareous or siliceous structures called spicules
Fibrous: collagen fibrils present in the intercellular matrix. One form is called spongin.
What is the osculum in Porifera?
the point where the water exists the internal canals
What is the name of the typical cell form in Porifera and how are the three systems called according to the position of these cells?
Choanocytes:
1. Asconoid system: the choanocytes lie in a large chamber (Calcarea)
2. Syconoid system, the choanocytes lie in canals (Calcarea, some Hexactinellida)
3. Leuconoid system: the choanocytes lie in distinct chambers. This system has the highest proportion
of flagellated surface area for a given volume of cell tissue.
What do we mean with somatic embryogenesis in sponges?
Entire new sponges can develop from small fragments
How does the asexual reproduction occur in Porifera?
bud formation
External buds, after reaching a certain size, detach from the parent and float away to form new sponges, or they can remain to form colonies. There are also internal buds, called gemmules which remain dormant until the parent animal dies. This is a way of preserving the species during periods of freezing or drought.
how do Sponges produce sexually?
- some are hermaphroditic
- some are gonochoristic
What are the names of Porifera larvae?
solid-bodied, free swimming: parenchymula
not solid-bodied: amphiblastula
How do Porifera feed?
They are suspension feeders
Why do sponges have very few predators?
noxious odor (aka they stink) and elaborate skeletal framework that have antipredator effects
How is the body of Ctenophora composed?
It is composed by 8 rows of combs radially arranged around the body
How do Ctenophores locomote?
They use beating cilia for locomotion
How do Ctenopohores catch prey?
they use colloblasts which are adhesive cells
What cells are present on the epidermis of Ctenophores and what do they do?
Sensory cells which detetct chemicals and other stimuli
What are the free-swimming larva of Ctenophores called?
cydippid
What does the nervous system of Ctenopohores consist of?
A subepidermal plexus concentrated around the mouth and beneath the comb plate rows
What is the only free-living organism class of Platyhelminthes?
Turbellaria
Other classes:
Trematoda (endoparasite)
Cestode (endoparasite)
Monogenean (ectoparasite)
Describe the sensory system of Plathyelminthes
- pair of anterior ganglia
- nerve cords
- nerves
(located in the mesenchyme) - statocysts
- ocelli
Reproduction Platyhelminthes
Asexual: fragmentation
Sexual: cross or internal fertilisation (hermaphroditic, not all!)
What is the intermediate and the final host of Trematoda?
Trematoda: class of platyhelmintes
Molluscs usually represent the intermediate host, while vertebrates present the final host
What is specific about the Tubellaria eggs?
After copulation, the fertilised eggs become enclosed in a small cocoon. The cocoons are attached to stones or plants and embryos emerge as juveniles, which also resemble the mature adults
3 classes of Nemertea
Haplonemertea
Paleonemertea
Pilidiophora
Which Phylum has a Proboscis?
Nemertea
What is a Proboscis?
The proboscis is a long, blind muscular tube that opens at the anterior end at a proboscis pore above the mouth. Its function is in capturing prey: Muscular pressure fluid in the rhynchocoel causes the proboscis to evert rapidly. This exposes a sharp barb called stylet, with which the prey is stabed and inserted with toxins after being coiled around by the proboscis.
in ALL nemertea
What communicates between the outside and the brain in Nemertea?
Sensory ciliated pits on each side of the head
Reproduction Nemertea
Asexual: fragmentation & regeneration
Sexual: gonochoric, fertilisation often external but many exceptions are known
What do Nemerteans eat?
Predators of annelids and other small invertebrates
What are the 2 classes of Nematoda?
Phasmida
Aphasmida
What is the hydrostatic skeleton in Nematoda?
fluid-filled pseudocoelom: internal organs lie here
How is the high hydrostatic pressure (tugor) in Nematoda contained?
- non-cellular cuticle presents several layers of collagen (outer layer)
- cuticle for hydrostatic pressure
- fluid-filled pseudocoel constitutes hydrostatic skeleton
Describe the sensory system of Nematoda
- ring of nerve tissue + ganglia
- small nerves
- 2 nerve cords
- Sensory papillae (taste)
- amphids: anterior, smell
- phasmids: posterior, directional movement away from substrate
What phylum has copulatory spicules, smaller males than females and are gonochoric?
Nematodes
How many juvenile stages do nematodes have?
4 juvenile stages, separated by a molt /shedding of cuticle (some need host for specific stages)
What secretes the shell in Mollusca and encloses the mantle cavity?
The mantle
What is the radula?
A rasping organ in the Mollusca
How do molluscs exchange gas?
Gills, lungs, mantle or body surface
Do Molluscs have a closed circulatory system?
no, its open
How many chambers does a mollusc heart have?
3
Name the 3 layers of the shell (Mollusca)
- Periostracum: outer organic layer, composed of an organic substance called conchiolin. It helps to protect underlying calcareous layers from erosion.
- Middle prismatic layer: composed of densely packed prisms of calcium carbonate.
- Inner nacreous layer: lies next to the mantle and is secreted continuously by the mantle surface, so that it increases in thickness during the life of the animal.
What sensory organs do Mollusca have?
Touch, smell, taste, equilibrium and vision
Is there asexual reproduction in Mollusca?
No
Larvae types in mollusca
and annelida
free-swimming trochophore larva
(NOT CEPHALOPODS)
Peculiarity of Caudofoveata (class of Mollusca)?
-oral shield
-no shell, but covered in calcareous sclerites
Peculiarity of Solenogaster (class of Mollusca)?
foot is represented by a mid ventral structure called pedal groove
Peculiarity of Polyplacophora (class of Mollusca)?
- chitons
- 7/8 plates or valves
- osphradia for sampling water
Peculiarity of Gastropoda (class of Mollusca)?
-univalve
-respiration by organ called ctenidium
-one nephridium
-well developed circulatory system
What is an osphradium?
A sensory area in Gastropods, located at the base of the incurrent siphon and can be chemosensory in some forms or mechanoreceptive in some others.
What is the offspring of Gastropoda?
veliger larvae
Mantle cavity in Prosobranchs
In Prosobranchs the mantle cavity is anterior as a result of torsion that occurs during the development
How are the two valves in bivalves held together?
hinge ligament, drawn together by adductor muscles (zieht zsm) that work in opposition to the hinge ligament
What is umbo?
The umbo is the oldest part of the bivalve shell, and growth occurs in concentric lines around it.
-one umbo on each valve
Sense organs in bivalves
poorly developed: they include
- a pair of statocysts in the foot
- a pair of osphradia in the mantle cavity
- tactile cells
- simple pigment cells on the mantle
how can bivalves attach to the substrate?
byssus, a secretion made of keratin and other proteins.
Bivalve reproduction
Bivalves are usually gonochoric. Gametes are discharged into the suprabranchial chamber to be carried out with the excurrent flow. In most bivalves fertilization is external and the embryo develops into trochophore.
Nautilus shell
The shell is divided by transverse septa into internal chambers, only the last inhabited by the living animal. The chambers are connected by a cord of living tissue called a siphuncle, which extends from the visceral mass.
How do cephalopods swim?
Force full expulsion of water from the mantle cavity through the ventral funnel (or siphon) creates jet propulsion
Molluscan circulatory system
open circulatory system of
1. heart
2. blood vessels
3. sinuses
4. resparatory pigments in blood
Which animal has giant nerve fibres?
Squids
How to chromatophores work?
Chromatophores are cells in the skin that contain pigment granules: tiny muscle cells surround each elastic chromatophore, whose contractions causes the chromatophore to expand greatly. As the cell expands, the pigment becomes dispersed, changing the color pattern of the animal. When the muscles relax, chromatophores return to their original size, and pigment becomes concentrated again.
What is a protective feature of most cephalopods ?
ink sac containing sepia
What is a hectocotylus?
One arm of adult male cephalopod is modified as an intromittent organ, called a hectocotylus, used to insert spermatozoa into the mantle cavity of a female near the oviduct opening. Eggs are fertilized as they leave the oviduct and are then usually attached to stones.
Do free-swimming larva exist in cephalopods?
no, juveniles hatch from eggs
How do cephalopods feed?
They are active predators, with the help of arms provided with suckers and beak for crushing the prey
3 classes of Annelida
Polychaeta
Oligochaete
Hirudinea
Where do the toxins in molluscs or annelids come from?
Mostly nematocysts of cnidarians the animals have fed on and then stored the undischarged nematocysts in their own tissue (e.g. fireworm)
What is a metameric body?
A body structure composed by segments, like the one of annelids
How does the gas exchange occur in annelids?
Through skin, gills, or parapodia
Circulatory system of annelids
- circulatory system is closed
- muscular blood vessels
- aortic arches (like hearts) for pumping blood
- segmentally arranged.
Do annelids have eyes?
Some species have eyes yes. They can vary from eyespots to well-developed organs with lenses
Annelid reproduction
- asexual: fission (split in 2) and fragmentation
- sexual: gonochoric or hermaphroditic
- trochophore larvae
Palolo worms reproduction
- most of the year as sexually immature animals
- breeding season: portion of the body becomes sexually mature
- that part is then full of gametes
- reproductive period: sexually mature portions (=epitokes) break off and swim to the surface
- release of epitokes is highly synchronous
- freeing eggs and sperm for fertilization
- Anterior portions of the worms remain on the bottom and regenerate new posterior sections.
- they are hermaphroditic
What are the sexually mature portions in palolo worms called?
epitokes
What feeders are errant worms like the fireworm?
Predators and scavengers
What part of the fireworm contains a poisonous secretion?
The setae (hair-like structure)
What are the two main subphyla we looked at in the Arthropoda?
Chelicerata & Crustacea
What is a characteristic of arthropoda?
jointed appendages, which are often modified for specialised functions
What are the functional groups (tagmata) of arthropoda?
- Head and trunk
- Head, thorax and abdomen
- Cephalothorax and abdomen
To what nervous system is the one of Arthopods similar to?
Annelids
- dorsal brain connected to
- a double nerve chain of
- ventral ganglia
In which taxa do we observe parthenogenesis (egg development without fertilisation)?
Arthropoda
class: Malacostraca
What are the two main species inside the subphylum of chelicerate?
sea spiders & horseshoe crabs
What are the tagma of Horshoe crabs (Xiphosaurids)?
Cephalothorax & Abdomen
What are the gills of horseshoe crabs called?
Book gills
What are the tagmata of Malacostraca (shrimps)?
Cephalothorax , rostrum & telson (both unsegmented)
What are tactile hairs?
in Malacostraca widely distributed over the body, are delicate projections of cuticle that are especially
abundant on the chelae, mouthparts, and telson
- also known as setae
- serve as mechanoreceptors, detecting touch and vibration in the surrounding environment
What is the name of the walking legs in crustacea?
- Chelipeds
(also for food capturing) - first one usually larger then others, also for capturing prey or defense
- first ones are often asymmetrical
How do barnacles feed?
they use their legs, which bear a thick fringe of setae, to create water currents that sweep food
Branchiopoda fun fact
they have flattened and leaflike legs that serve as respiratory organs (hence the name branchiopods). Most branchiopods also use their legs for suspension feeding, and for locomotion as well.
- Phylum: Arthropoda
- Subphylum: Crustacea
- Class: Branchiopoda
How is the locomotion in echinodermata achieved?
tube feet, movement of spines, or by movement of arms, which project from central disc of body
How is the nervous system of echinodermata?
any receptors maybe?
- circumoral ring
- radial nerves
- No brain
- specialized sensory organs as:
- tactile receptors
- chemoreceptors
- terminal tentacles
- photoreceptors
- statocysts
What are Asteroidea (Seastars) composed of?
central disc, 5 arms (or more) emerging, mouth is centred under oral side
What are podia?
tube feet that border the ambulacral groove in Asteroidea
What can we find around the bases of spines of Asteroidea?
- groups of pincerlike pedicellariae
- bearing tiny jaws manipulated by muscles
- jaws keep the body surface free of debris
- protect papulae
Papulae
- soft projections of the coelomic cavity
- covered only with epidermis
- involved with respiration
- (also called skin gills)
How do sea stars catch prey?
Stomach can be everted through the mouth
Do Ophiuroidea (brittle star) have pedicellariae or papulae?
- No, but seastars
- picture: papulae on abural surface (nach oben gerichtet)
- pedicellariae are specialized structures involved in defense and protection
- papulae are specialized for respiratory function and gas exchange
How does gas exchange happen in Ophiuroidea (Brittle stars)?
- Structures called bursae open toward the oral surface
- water circulates in and out of these sacs for exchange of gases
- On the coelomic wall of each bursa there are small gonads
- they discharge sex cells into the bursa
- Gametes then pass into the water for fertilization.
What is the Aristotle’s lantern?
Complex chewing mechanism in sea urchins to which teeth are attached
What is the side applied to the substratum in sea cucumbers called?
sole(?)
ventral side oder?
What is a tegmen?
The skin that covers the body disc in sea lilies (Crinoidea, Echinodermata)
What do all organisms in the super phylum chordata have in common?
bilateral symmetry
3 germ layers
coelom
notochord (at least in some life stages)
nerve cord (single, dorsal, tubular)
complete digestive system
What are the names of the two siphons found in Ascidian (Tunicata)?
Incurrent/oral siphon: corresponds to the anterior end of the body
Excurrent /atrial siphon: marks the dorsal side
–> In compound ascidians each member has its own incurrent siphon, but the excurrent opening is common to the group
On what does feeding depend in Ascidians?
Feeding depends on formation of a mucous net secreted by a glandular groove, the endostyle, located along the pharynx.
Of what does the circulatory system in Ascidiae (Tunicata) consist and how is the blood flow?
circulatory system:
- ventral heart
- two large vessels
- the heart drives the blood first in one direction for a few beats
- then pauses
- reverses its action
- drives the blood in the opposite direction for a few beats.
What does paedomorphic mean?
sexually mature animals that have retained the larval body form of their evolutionary ancestors
(e.g. Appendicularia / Urochordata)
What Urochordata has a luminous organ?
Thaliacea
Why is the Hagfish (Myxini) a subphylum of the Agnatha?
No jaws
(Hagfish = Schleimaal)
(Agnatha = Kieferlose)
Are Hagfish (Myxini) isosmotic?
Yes
Are Petromyzontida (Lampreys) part of the Agnatha?
- yes
- they also are anadromous
How are the modified pelvic fins in male Chondrichthyes called?
Claspers
Circulatory system of Chondrichthyes
- Several pairs of aortic arches (they have single circulation)
- Heart is composed by
1. sinus venosus
2. atrium
3. ventricle
4. cornus arteriosus
Are four pairs of gills covered by an operculum in chimaeras?
Yes
Do Chondrichthyes have a swim bladder or a lung?
No, but they have ophisthonephric kidneys
and gills
How do Chondrichthyes reception vibration?
By their lateral-line system
What are the reproductive modes of Chondrichthyes?
oviparous, ovoviviparous or viviparous
What animal is this?
Chimaeriformes, subclass of Chondrichthyes
What is the tube pattern on the surface of the skin in the head region of Chimaeriformes (= Seekatzen <3)?
distinctive mechanosensory lateral line canal system
The also have many electro receptive ampullae
What do males as sexual dimorphism represent in Chimaeriformes?
sexual dimorphism:
- claspers,
- frontal tenaculum (sharp denticles to grasp pectoral fins of female during copulation)
- paired pre-pelvic tenacula
What are the three main body shapes of subclasses in Elasmobranchs?
Sharks, skates and rays
What is the spiracle, present in Elasmobranchs?
- provides oxygenated blood directly to the eye and brain through a separate blood vessel
- Rays present larger spiracles to actively pump water over the gills to allow the ray to breathe while buried in the sand.
What are the different types of scales in Actinopterygii?
- Ganoid in ancestral forms, scales cycloid
- Ctenoid or absent in derived forms
Fins of Acinopterygii
They have paired and median fins supported by long dermal rays called lepidotrichia. The muscles controlling fin movement are within body and fins can present modifications.
- median fins: dorsal, anal and caudal
- paired: pectoral and pelvic
What is different in Actinopterygii to Chondrichthyes concerning the olfactory lobes?
- both located in forebrain
- in Actinopterygii: don’t open into the mouth cavity
- Olfactory lobes are regions of the brain that are involved in processing olfactory (smell) information
What acts as mechanoreceptors in Squamata (sea snakes)?
scale sensilla
What are Testudines (marine turtles) characterised by?
- large adult body size
- hypertrophied forelimbs called flippers
- streamlined shells
Why can’t the ribs not be responsible for respiration in marine turtles?
Because they are incorporated in the shell, instead the two abdominal muscles are involved
What is a Rhamphotheci?
- keratinized covering on the beak or bill
- aiding in feeding and protection
How do Cetaceans produce sounds?
Sound production is associated with the nasal passages. The clicks are produced by pressurization within intranasal spaces and then, as air is forced between the phonic lips, there is vibration. Periodic opening and closing of the phonic lips break the airflow and determines the click repetition rate.
What is jaw hearing?
Good hearing abilities in cetaceans, related to a unique sound reception pathway in odontocetes, commonly referred to as “jaw hearing.” Fat body that directly connects with the lateral wall of auditory bulla of the middle ear.
lower jaw acts as a pathway for sound vibrations to reach the inner ear
