Test 4/Final Flashcards
the round worms
Phylum Nematoda
They are typically considered the most abundant and widespread animals on the planet. They are found from the bottom of the deepest ocean to near the tops of the highest mountains, from the tropics to polar regions, and from every conceivable habitat.
Nematodes
These are also found in or on most other types of organisms as parasites or commensals: everything from earthworms, insects, molluscs, fish, reptiles, birds, and mammals, including humans.
Nematodes
How can Nematodes be harmful to the economy?
loss of agricultural production, pasture and turf damage, invasion of forest trees, adverse effects on the health of wild and domestic animals and humans
How are Nematodes beneficial to the economy?
controlling soil nutrient cycling, controlling harmful species, serving as animal models (C. elegans) for studying aging and development
How are the Nematodes so successful?
Simplicity (a simple design that works great in very common environments)
The nematodes are a very __________ group in terms of their structure (both external & internal).
homogeneous
The following characteristics belong to which phylum usually small (most species 1-2 mm long), cylindrical body, tapered at both ends, no segmentation or appendages, complete digestive tract, eutely
Nematode
What does the term eutely mean?
constant cell number, growth by increasing cell size, not number
Their lack of any indication of true segmentation separates and distinguishes them, as well, from the annelid worms, such as “bristle” and earth worms.
Phylum Nematoda
This is a complex and multilayered structure that is secreted by an underlying epidermis.
The Nematode’s cuticle
What does the cuticle’s major layers consist of?
How many layers of this are there? How are they arranged and why?
protein collagen, at least 3, like plywood (layers alternate in direction). This gives strength and resiliency to the body wall.
Nematodes: The place where these creatures mature and reproduce in the human body.
the small intestine
Nematodes (Hookworms: Nectator americanus): The place where these creatures enter the human body.
The feet
Nematodes: These tough fibers are laid down in layers and make up the cuticle.
Collagen
Nematodes: Since they molt their cuticles, this phylum is grouped with others that can do the same – the __________.
Ecdysozoa
Nematodes: This phylum’s key to success seems to be their _________.
Simplicity
Echinoderms: Shared derived characters: radial, indeterminate cleavage, blastopore becomes anus, mouth forms from second opening
Deuterostome
Echinoderms: central disc with five or more arms, use tube feet for locomotion
subclass Asteroidea
Echinoderms: Pincer-like structures on sea stars. Some keep debris off body, others used for defense or capturing prey.
Pedicellaria
Echinoderms: If you irritate or attack me, I’ll aim my backside at you and shoot sticky red tubules out of my anus. That will teach you a lesson!
Sea Cucumber (Class Holothuroidea)
Hemichordates: part shaped like an acorn, muscular & covered with mucus, used for burrowing & moving within burrows
proboscis
Hemichordates: The class name literally means “gut breather.”
class Enteropneusta
Hemichordates: Class _____________ - form colonies, proboscis is shield shaped, most live in deep water, trunk is short & sac-like, digestive tract is U-shaped
class pterobranchia
Hemichordates: Recent DNA evidence suggests that this phylum is more closely Related to (Echinodermata or Chordata).
Echinodermata
Chordates: 90% of the invertebrate species within this phylum are members of the __________ subphylum.
Urochordata
Chordates: flexible, supporting notochord; dorsal, tubular nerve cord; pharyngeal slits; muscular postanal tail; endostyle or thyroid gland
the defining characteristics of Chordates
Chordates: Members of the Urochordata produce a protective covering of protein and a polysaccharide similar to cellulose.
tunic
Chordates: Say hello to our closest non-vertebrate kin!
the Cephalochordata, lancelet, or amphioxus
Chordates: Class ________ - found in most areas of the oceans, retain their larval form as adults, make big gelatinous “houses” which act as giant filters for feeding, frequently abandon their dirty house & make a new one; abandoned houses, sinkers, are food for many ocean animals
Class Larvacea
The Nematode’s cuticle is permeable to water and gases. Therefore, gas exchange occurs how?
across body surface
Nematodes do not have ____ muscles, only _____ muscles. Therefore, how do they move?
circular, longitudinal, by alternating the muscles on their dorsal then ventral surfaces; this creates a whip-like up & down movement
What is important for a Nematode’s locomotion?
their hydrostatic skeleton & cuticle
Why do Nematodes have high internal pressure (more than human blood pressure)?
1) non-stretchable cuticle 2) muscles are always partially contracted, squeezing the internal fluids, and 3) osmosis causes water to move into their bodies from the outside {which is why they are so round}
Nematodes: Contraction of a ____ on one side is transmitted through the ____ and stretches the ___ on the opposite side of the body. When the muscle relaxes, the cuticle contracts and the body returns to its ______.
longitudinal muscle, hydrostatic skeleton, cuticle, resting position
Nematodes reproduce ____ and most are (mon/di)oecious. Fertilization is ____, sperm are _____, and there is _____ larval stage.
sexually, dioecious.
internal, amoeboid, no distinct
Male/Female Nematodes: have a cloaca, a common opening for the anus and genital pore. This opening is located slightly in front of the worm’s posterior end. It generally has a pair of copulatory spicules which protrude from the cloaca.
Male
What are male nematode’s copulatory spicules for?
To assist in holding the mate’s genital aperture open during copulation.
The (male/female) genital aperture is located about midway along the animal, on its ventral surface.
Female
These characteristics describe what? most are carnivores. However, some feed on algae and fungi and some are detritivores. Others feed on plants, especially the roots. many root feeding ones are major agricultural pests estimated to destroy 12% of the world’s cash crops annually
Free-living nematodes
The following are all _____. Ascariasis: Ascaris lumbrioides, Pinworms: Enterobius vermicularis, Whipworms: Trichuris trichiura, Hookworms: Necator/Ancylostoma, Trichinosis: Trichinella spiralis, River blindness: Onchocerca volvulus, Guinea worm: Dracunculus medinensis, Canine Heartworm: Dirofilaria immitis, Filarial worms: Wucheria/Loa/Brugia
human-parasitic nematodes
These worms ingest blood. <100 worms don’t cause much trouble & may not be noticed. >500 worms make the host anemic & weak from blood loss. These host will suffer severe abdominal pain, fever and dizziness.
Hookworm (Necator americanus
For a long time nematodes were grouped with animals that have a ____. However, it turns out that a lot of nematodes are ____. Therefore, the various groups were all split out and each made into their own phylum when it was decided that they were not a ____ group.
pseudocoelom. acoelomates. monophyletic
What kind of symmetry do the echinoderms have?
radial
Since the echinoderms are radially symmetric, why are they placed in the Bilateria, instead of the Radiata?
because their radial symmetry was secondarily evolved from bilateral ancestors (the bilateral body plan is still seen in the echinoderm larvae)
Their radial symmetry is imposed on a relatively advanced coelomate body plan which includes a endoskeleton formed from mesoderm. This partly explains their success as a group. Who are they?
Echinoderms
This phylum is unique in that they have combined mobility with radial symmetry & show lots of different lifestyles and feeding methods. They are similar to other radial animal in that they have a non-centralized nervous system (no brain). This lets them deal with their environment equally from all sides.
Echinoderms
Echinoderms are _____. They have shared derived characters including radial, have indeterminate cleavage, the blastopore becomes the anus, and the mouth forms from the second opening.
deuterostomes
Marine animals with
spiny “skin”: endoskeleton of calcium carbonate, well-developed coelom, water vascular system, tube feet, mutable connective tissue, and Larvae exhibit bilateral symmetry but, most adults exhibit pentaradial symmetry
Phylum Echinodermata
Many echinoderms have certain connective tissues that contribute to their body “tone” through rapid changes in their properties. In a matter of seconds or minutes the fibers of these tissues can become relatively rigid, thereby reducing body flexibility. What are these tissues called?
mutable connective tissue
Mutable connective tissue is not ______. It is involved in __, ___, and the intentional shedding of arms or ____ when the animals are attacked
muscles; locomotion, feeding; viscera
Sea lilies and feather stars are part of which class of Echinoderms?
Class Crinoidea
Bristle stars are part of which class and subclass of Echinoderms?
Class Stelleroidea, Subclass Ophiuroidea
Subclass Asteroidea of Phylum Echinodermata consist of what?
sea stars
Class Echinoidea of Phylum Echinodermata consist of what?
sea urchins, heart urchins, & sand dollars
Class Holothuridea of Phylum Echinodermata consist of what?
sea cucumbers
Except for a few brackish-water species, echinoderms are strictly ____.
marine
Why have Echinoderms been unable to invade land or freshwater?
Probably because of their method of exchanging gases across their skin and because they don’t have any excretory or osmoregulatory structures.
Almost all _____ are benthic and in some parts of the deep sea they may compose 95% of the biomass.
Echinoderms
What phylum? spiny skin, lack cephalization, no anterior or posterior end so, refer to aboral and oral surfaces
Echinoderm
One of the unique characteristics of the echinoderms is the _____. It consists of calcium carbonate in the form of plates and spines and it is derived from mesodermal cells.
endoskeleton
The most unique derived character of phylum Echinodermata is what?
The water vascular system
What do Echinoderms use for respiration?
dermal gills (or papulae) connected to the main coelomic cavity
This functions in feeding and gas exchange and serves as a hydrostatic skeleton in locomotion
water vascular system
Sea water flows in and out of the water vascular system through an opening in the body wall called what?
Madreporite
What connects the madreporite to the ring canal?
The stone canal
These run down the length of the arms & connect to the ampullae.
radial canals
___ lining the canals of the water vascular system move the water along. Branches of the water vascular system lead to many ______ that extend when filled with fluid.
Cilia, tiny tube feet
Each tube foot receives fluid from the main system of canals in a rounded muscular sac called an ___. It is located at the base of the foot, stores fluid, and is used to operate the tube foot
ampulla
What supports the tube feet and ampullae? They are part of the of calcium carbonate skeleton.
ossicles
What can tube feet be used for?
a suction-type structure that presses against and sticks to surfaces, gas exchange & can be the main site for excretion (by simple diffusion), also can be used for chemoreception
pincer-like structures that respond to external stimuli independently of the main nervous system
pedicellaria
Most echinoderms can ____ lost parts. Some echinoderms can reproduce ____ (most that do are ___).
regenerate, asexually, delicious
the oldest class of living echinoderms, it is a group “past its prime”
Class Crinoidea
Feather starts are ___, although they ____. Sea lilies are ____ and _____.
(motile or sessile, fill in blank)
motile, although they often stay put for long periods of time. sessile and stay attached to the ocean floor by a stalk.
Unlike other echinoderms, the crinoid’s oral surface is on the ___ side of the disc & have a number of branched feathery arms reaching upwards.
upper
Because Class Crinoidea are often sessile, they are what kind of feeders?
Filter/Suspension feeders
A crinoid’s tube feet are not involved in locomotion like others but, what are they involved in?
feeding, gas exchange, and probably excretion
Class Crinoidea’s tube feet are coated with mucus. How does this help in feeding?
The mucus coated tube feet trap microscopic organisms & then food is carried to the mouth by cilia in the ambulacral grooves.
How do sea lilies change the direction of their feeding structures if they have no muscles?
They use their “smart” connective tissue. (Movement happens by varying the stiffness of the connective tissue)
Name my class, subclass, and common name. I have a central disc with five or more arms. I use tube feet for locomotion. Most of us are carnivorous predators and scavengers but we aren’t fast so our prey is usually sedentary or slow.
Class Stelleroidea, subclass Asteroidea, sea stars
In an Asteroidea, what is the main organ digesting food?
cardiac stomach
Some species protrude a pyloric stomach out through their mouth and push it up against prey can push it into small spaces such as into a bivalve’s shell. Enzymes externally digest the prey and then nutrients are transported upward into the pyloric stomach. This feeding method is unique to who?
subclass Asteroidea (sea stars)
Who are we? We’re ~diameter of a pencil, live 1 kilometre below the surface of the sea, and it is assumed we get our food by absorbing nutrients from decomposing logs. We have no mouth, guts or anus. Our upper surface is made of numerous perforated scales and is fringed with spines. Specimens hauled up contained fully developed embryos within their reproductive organs, indicating we give birth to live young.
Subclass Asteroidea:The concentricycloids (sea daisies)
Our arms are longer, more slender than sea stars and more distinct from central disc. We use them for locomotion because our tube feet lack suckers.
Class Stelleroidea–subclass Ophiuroidea (Brittle stars & basket stars)
What is the largest group of echinoderms both in number of species and number of individuals
subclass Ophiuroidea (Brittle stars & basket stars)
Though most tube feet are used for locomotion, this subclass only uses them collect/handle food and they may have a sensory function.
subclass Ophiuroidea (Brittle stars & basket stars)
What kind of feeders are brittle stars and basket stars? Are they diurnal or nocturnal?
Many are deposit feeders, sucking up sediments. Some suspension feeders and some are carnivores or scavengers. Usually nocturnal.
This class lack arms, have a solid shell called a test, and are covered with spines.
Class Echinoidea (Sea & heart urchins, sand dollars)
The flattened body of the _____ is adapted for burrowing in the sand, where it feeds on tiny organic particles and they have really small spines.
sand dollar
Spines of ____ can penetrate human skin and can be hard to remove. They use their tube feet for locomotion & also push themselves along with their movable spines. Many graze on algae, and some love to eat kelp. If populations are not kept in check they can destroy kelp forests creating what are sometimes called what?
sea urchins, urchin barrens
This class has elongated flexible bodies and a circle of modified tube feet that surrounds their mouth.
Class Holothuroidea (Sea cucumbers)
The endoskeleton of Class Holothuroidea is made up of what?
microscopic plates embedded in the body wall
Their circulatory system is more advanced than the other echinoderm groups and transports oxygen and maybe nutrients.
Class Holothuroidea (Sea cucumbers)
We are sluggish and usually live on the bottom of the sea. Sometimes we burrow into the mud. Some graze with their tentacles; others stretch their branched tentacles out in the water and wait for dinner to float by. Algae and other small stuff are trapped in mucus along the tentacles.
Class Holothuroidea (Sea cucumbers)
What is this process of the sea cucumbers called? The digestive tract, respiratory structures, and gonads are ejected from the body when environmental conditions are unfavorable or when they are being harassed by a predator. Afterwards, they will regenerate the lost parts.
evisceration
This is a small phylum of ~100 species. They are important for the study of vertebrate evolution.
Phylum Hemichordata
This structure found in Phylum Hemichordata is an evagination of the anterior gut & it is not considered homologous with a notochord.
stomochord
The hemichordates are (deuterostomes/protostomes) that are placed between the ___ and ___.
Recent DNA evidence suggests that this group is more closely related to the ___ but there is other analyses that point to a closer relationship with the ___.
deuterostomes, Echinoderms and Chordates, Echinoderms, Chordates
A dorsal extension of the pharynx forms an anterior buccal tube called the stomochord. This is a defining characteristic of what?
Hemichordates
There are two major classes of Hemichordates. What are they?
Class Enteropneusta (the acorn worms) and Class Pterobranchia
All adult hemichordates are _____ animals.
benthic marine,
Most Hemichordates use part of their gut for gas exchange so they are considered gut breathing. These make up which class? The others are known has the feather gill. These are Class ___.
Enteropneusta, Pterobranchia
Class ____ are sedentary worms which usually live buried in soft sediments, among algae holdfasts, or under rocks. Most live in intertidal areas.
Class Enteropneusta
What are the 3 basic parts of Class Enteropneusta? Each of these have a ___.
the proboscis, collar, and trunk, coelom
The ___ is shaped like an acorn, thus the common name. It is muscular and used for burrowing & moving within their burrow. The ___ is where the mouth is. The ___ contains the digestive system & gonads. The pharynx opens to the ___ of the body as a series of paired gill slits.
proboscis, collar, trunk, outside
What is the stomochord used for?
probably to support the surrounding tissue
Most of the digestion and absorption of class Enteropneusta happens where?
in the intestine
Class Enteropneusta may be _____ or ____ feeders.
suspension or deposit
Class _____ has no brain, but have some nerve cords, have a well-developed open circulatory system with blood vessels, sinuses, and a heart vesicle (not a true heart).
Class Enteropneusta (the acorn worms)
Note: Class Enteropneusta (the acorn worms)
The beating of the heart vesicle squeezes a sinus that forces blood through the vessels. The blood vessels pulsate to move blood along. Blood moves into a structure called the glomerulus where metabolic wastes are removed.
Acorn worms have separate sexes meaning they are ____. Fertilization is ___. The fertilized egg develops into a “___” larvae and lives as a plankton for several weeks until it ___ and sinks to the ocean floor.
gonochoristic, external, tornaria, metamorphoses into an adult
Class ____ forms colonies by asexual budding & the individuals of a colony are called ___. They are interconnected by stolons.
Pterobranchia, zooids
secretes the collagenous burrow in those species that live in one. It is used for locomotion, like a snail’s foot, for moving inside and outside the burrow.
proboscis
Class Pterobranchia’s ___ is modified into ciliated tentacles; they secrete mucus which is driven, along with trapped food, into the mouth by the beating of the cilia.
collar
Class Pterobranchia’s ___ is short and sac-like, and the digestive tract is U-shaped. The animal’s anus is on the back side about opposite of the mouth. It ends in a contractile stalk and the animals can instantly withdraw into their tubes if a bit nervous.
trunk
We are members of this phylum.
Phylum Chordata
All invertebrate Chordates are ____.
marine
The non-vertebrate Chordates are divided into 2 subphyla. 90% of the invertebrate species are in the _____ subphylum
only about 23 species are in the ____ subphylum.
Urochordata (the tunicates) and Cephalochordata (the lancelets or amphioxus)
These are defining characteristics of what phylum? At some time during life cycle individuals have: flexible, supporting notochord; dorsal, tubular nerve cord; pharyngeal (gill) slits; muscular postanal tail; and endostyle (thyroid gland).
Chordates
Chordates: a dorsal, longitudinal rod of large cells; it is firm but flexible – provides support
Notochord
The chordate ___ differs from those of most other animals because it is dorsal rather than ventral, hollow rather than solid, and single rather than double.
Nerve cord
Chordates: allows for water to enter the mouth and then exit through the gill slits – involved with feeding & respiration
Pharyngeal slits
Chordates: an elongated gland that secretes an iodine-containing mucus and functions as a net that traps food particles in the sea water passing through the pharynx
Endostyle / the thryroid gland
Subphylum Urochordata (=Tunicata) includes what classes?
Class Ascidiacea, Class Larvacea, and Class Thaliacea
Tunicates are what kind of feeders? Larvae are what? Most adults are what?
suspension, free-living, sedentary
Adult tunicates produce a protective covering that is made of protein and a polysaccaride. What is the covering called?
a tunic
Tunicate’s digestion is ___ and nutrients are absorbed in the ___; undigested wastes pass out the ___.
extracellular, intestine, anus
Some species of tunicates form large colonies in which members share tunics and a common excurrent siphon. Colonial species often reproduce by ____, so a colony would all share the same genotype. Sexually reproducing tunicates are usually ___.
asexual budding, hermaphroditic
The tail of a larvacea is much longer than the ____ which contains all the systems (reproductive, digestive, respiratory).
head
members of the class Thaliacea are mostly (free-living/sedentary) as adults.
free living
Subphylum ___ are the lancelets. They are small, segmented, fishlike animals.
Cephalochordata
DNA work indicates that these our closest nonvertebrate relative
Subphylum Cephalochordata
Lancelets use ___ on their pharynx to draw a current of water into their mouth and then strain out microscopic organisms; food particles are trapped in mucus in the pharynx and are then carried back to the intestine. The water passes through the pharyngeal slits into the atrium and then leaves through the ___.
cilia, atriopore
Lancelets have a ___ system for excretion. They have a circulatory system unlike other invertebrates. The blood flows ___ in the ventral vessel and ___ in the dorsal vessel.
nephridial, anteriorly, posteriorly
Lancelets are almost always (gonochoristic/hermaphroditic). Eggs are fertilized ___& develop into ____ larvae and after a couple of weeks metamorphose into the adults.
gonochoristic, externally, free swimming
The muscles of lancelets are arranged in a longitudinal row of about 60 segments called what?
myomeres
Has the most human parasites
Platyhelminthes
Most acute image-forming vision
Cephalopods
Most ecological niches
insects
most intelligent
Cephalopods
largest number of described species
insects
most social
insects
best fliers
insects
most valuable to jewelers
bivalves
first group to have a notochord
invertebrate chordates
first deuterostome group
echinoderms
first group to have tissues
Platyhelminthes
first multicellular group
poriferans
first radially symmetrical group
cnidarians
first segmented group
annelids
