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251 Cards in this Set

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  • Back
Around how many phyla of animals are known?
Which animals are most closely related to choanoflagellates?
How tall are sponges?
1 cm to 2 m
How many species of sponges are there, and how many are freshwater?
9k and 100
What structure does a sponge have?
a sac with holes in it
How does a sponge exchange water?
It draws water through the pores into the spongocoel, from which it flows out the main opening, the osculum.
How do sponges feed?
They are suspension feeders (filter feeders), collecting food from the water by trapping it.
How much water must a sponge filter to grow?
10k times the amount they grow
What structure does the lining of a sponge have?
Choanocytes (collar cells) have flagella that generate the water inflow, and the collars collect food to be phagocytized.
What structure does the body of a sponge have?
Two layers of cells are separated by the mesohyl, with pseudopodia-using amoebocytes.
What do amoebocytes do in sponges?
They digest food, distribute the nutrients, form skeletal fibers in the mesohyl, and sometimes make CaCO3/SiO2 spicules or flexible collagen-based spongin, used in sponges.
How do sponges reproduce?
Most are hermaphrodites, keeping their eggs in the mesohyl and distributing their sperm in the water current. They can also produce asexually by fragmentation.
What are the two main characteristics of Radiata?
radial symmetry and diploblastic embryos
What are the two phyla in Radiata?
Cnidaria and Ctenophora
What animals are cnidarians?
hydras, jellies, sea anemones, and coral animals
What body plan does a cnidarian have?
a sac with the digestive gastrovascular cavity on the inside and a dual mouth/anus opening.
What are the two variations on the radiata body plan?
the sessile polyp and plankton medusa
Describe a polyp.
a cylinder attached to a substratum on the bottom and extend tentacles upward
What are examples of polyps?
hydras and sea anemones
Describe a medusa.
a bell-shaped body used for moving, with tentacles and mouth/anus pointing downwards
How do cnidarians feed?
They use tentacles to grab prey and push it into their gastrovascular cavity, using cnidocytes.
What do cnidocytes do?
defend the cnidarian and capture prey, using the organelles cnidae that can evert, such as nematocysts which sting
How do cnidarians change shape and detect changes in their surroundings?
They don't have muscles, but can contract and expand certain cells, especially when the mouth is closed and the volume of the cavity is fixed. They have a nerve net and sensory receptors but no brain.
What are the three major classes in phylum Cnidaria?
Hydrozoa, Scyphozoa, and Anthozoa
What are examples of hydrozoans?
the Portuguese man-of-war, hydras, Obelia, and some corals
What are the main characteristics of hydrozoans?
alternation of polyp and medusa forms, with the polyp form bigger, except hydras, which are only polyps and reproduce asexually by budding or sexually, making resistant dormant zygotes
What are examples of scyphozoans?
jellies, sea wasps, and sea nettles
What are the main characteristics of scyphozoans?
mainly medusa, although coastal variants have a polyp stage
What are examples of anthozoans?
sea anemones, most corals, sea fans
What are the main characteristics of anthozoans?
exclusively polyps, marine, sessile, and mostly colonial
How do corals grow?
They excrete hard CaCO3 exoskeletons, which build up over generations as coral, providing a habitat for invertebrates and fishes.
What is the common name for a ctenophore?
a comb jelly
How many species of comb jellies are there?
What shape do ctenophores have?
most spherical or ovoid, but some are long, like ribbons
How do comb jellies move?
They have 8 rows of fused comb-like cilia, which they use for locomotion.
How do ctenophores feed?
They have long, retractable tentacles with colloblasts (lasso cells) which stick to prey.
According to the molecular data, what kind of bilaterian was the common ancestor of acoelomates, pseudocoelomates, and coelomates?
a relatively advanced Precambrian coelomate
Are lophotrochozoans protostomes or deuterostomes?
Where do flatworms live?
the ocean, freshwater, and damp areas of land
Where do flatworms get their name?
Their bodies are thin and flat between their dorsal and ventral surfaces.
What phylum are flatworms in?
What are the four classes in phylum Platyhelminthes?
Turbellaria, Monogenea, Trematoda, and Cestoidea
What do tubellarians have in common?
Most are free-living and marine and have a ciliated body surface.
What are the most common examples of tubellarians?
planarians, in class Dugesia, which are carnivores
How to flatworms exchange gases without organs for that?
All cells are close to the water surface so they can exchange gas directly.
How do flatworms excrete waste?
Individual cells release ammonia, and ciliated flame cells waft fluid out through branched ducts for osmoregulation.
How do planarians move?
They glide on mucus they create using cilia on the ventral epidermis.
Describe the planarian nervous system.
A planarian has a head with eyespots and smelling lateral flaps with a nerve cord running down each side of the body.
How do planarians reproduce?
asexually, with the parent splitting in the middle, or sexually as hermaphrodites
What do the monogeneans and trematodes have in common?
They are all animal parasites.
What is another name for trematodes?
What structural features do monogeneans and trematodes share?
All have suckers to attach to hosts, a tough covering, and lots of reproductive organs.
What do trematodes have in common?
complex life cycles with both sexual and asexual stages, and intermediate hosts for larvae
What is an example of a pathogenic trematode?
the blood fluke, Schistosoma, causing body pains, anemia and dysentery
What do monogeneans have in common?
Most are external fish parasites, have simple life cycles, and are closely related to tapeworms.
What class are tapeworms in?
What do tapeworms do?
parasitize vertebrates including humans, in their digestive tracts
What is at either end of a tapeworm?
The scolex or head has suckers and hooks for locking into the digestive tract, and the other end has ribbons of proglottids, sacs of sex cells
How can tapeworms be stopped?
with the drug nilosamide
Where do rotifers live?
mainly freshwater
How big are rotifers?
.05 to 2 mm, even smaller than many protists
What do rotifers have that flatworms and cnidarians lack?
a complete digestive tract with distinct mouth and anus
What does a rotifer's pseudocoelom do?
It serves as a hydrostatic skeleton, and a circulatory system for nutrients and wastes.
How do rotifers feed?
Cilia draw water into the mouth, where the pharynx has trophi (jaws) that grind the food.
How do rotifers reproduce?
when conditions are favorable, parthenogenesis, and when not, degenerate males also form that make sperm to fertilize the females to make resistant zygotes
What is parthenogenesis?
females make unfertilized eggs that develop into females
What are the lophophorate phyla?
Bryozoa, Phoronida, and Brachiopoda
Why are the lophophorates named as such?
They all have a lophophore, a horseshoe or circle of cilia surrounding the mouth.
What do lophophorates have that rotifers lack?
true coelems, completely lined with mesoderm
What do bryozoans have in common?
They look like mosses, form colonies, often with a hard exoskeleton, and are often marine
Why are bryozoans important?
They are widespread sessile marine animals, and some build reefs.
What do phoronids have in common?
They live in sand within chitin tubes, extending their lophophore out of the tube to get food.
What is another name for brachiopods?
lamp shells
What do brachiopods resemble, and how are they different?
They resemble clams, but the two shells are different in brachiopods and the same in clams.
What do brachiopods have in common?
They live attached to a substatum in the ocean, and were more common in the past.
How many species of lophophorate animals are there?
around 5k bryozoans, 15 phoronids, and 330 (30k extinct) brachiopods
What is the common name for members of the phylum Nemertea?
proboscis worms or ribbon worms
How long are proboscis worms?
less than a millimeter to 30 meters
Where do proboscis worms live?
almost all are marine, some nekton and others benthos
How are proboscis worms similar to flatworms?
They are acoelomate but have fluid in a sac that may be reduced true coelom.
How are proboscis worms different from flatworms?
They have a complete digestive tract and a closed circulatory system powered by muscles.
How many mollusk species are known?
What do mollusks have in common?
Most are marine; all have soft bodies with a similar body plan; most also have a hard carbonate shell.
What are six examples of mollusks?
snails, slugs, oysters, clams, octopuses, squids
What are the three main parts of the mollusk body plan?
the foot for movement, the visceral mass for storing internal organs, and the mantle to make a shell
What is a mollusk's mantle cavity?
the space between the mantle and the visceral mass, where the anus, gills, and excretory pores are found
How do mollusks feed?
They scrape food into their mouths with a radula.
How do mollusks reproduce?
sexually, with different sexes except for snails, including a trochophore or a ciliated larva.
What are the major classes in phylum Mollusca?
Polyplacophora, Gastropoda, Bivalvia, and Cephalopoda, and four others
What animals are in class Polyplacophora?
What do chitons have in common?
Chitons have oval shapes and 8-plated shells.
Where do chitons live?
the intertidal zone
How do chitons move?
Their foot acts as a suction cup, clinging to rocks and allowing them to creep slowly along.
How do chitons feed?
They graze, using their radulas to cut and ingest algae.
Which class in Mollusca is the largest?
What animals are in class Gastropoda?
snails and slugs
What process distinguishes gastropods?
What is torsion?
the embryonic development that twists the digestive system of a gastropod so the anus is above the mouth
How do gastropods use their shell for protection?
They hide in it when threatened.
What shape do most gastropods' shells take on?
spiral, conical
How do gastropods move?
The bottom of their foot ripples to provide very slow motion
How do gastropods feed?
They graze on algae or plants using their radula, prey on other mollusks or animals with a hole-boring radula, or form poison darts out of the radula's teeth to attack fish (cone snails).
Which mollusks have populated the land?
What animals are in class Bivalvia?
bivalves: clams, oysters, mussels, scallops
What do bivalves have in common?
They have a shell with two parts that closes tightly to protect their innards or opens to allow the foot to dig or anchor.
How do bivalves feed?
They are suspension feeders, trapping food particles in mucus in their gills while siphoning water through.
How do bivalves move?
They don't really need to, but secrete threads that attach them to things, dig with their foot, or flap their shells to skitter across the ocean floor.
What animals are in class Cephalopoda?
squids, octopuses, and chambered nautiluses
What happened to cephalopods' shell?
Squids internalize it, many octopuses have lost it altogether, but chambered nautiluses still have an external shell.
How do cephalopods feed?
They have beaklike jaws to bite, surrounded by long tentacles, and also poison their prey.
How do squids move?
Squids draw water into their mantle cavity and squirt it out through their excurrent siphon.
What happened to cephalopods' foot?
It became the excurrent siphon that propels them.
Where do cephalopods live?
Squid live in the open ocean, but octopuses live on the seafloor.
What is special about cephalopods?
They have a closed circulatory system, a well-developed nervous system, a complex brain, and well-developed sense organs.
From what did cephalopods likely evolve?
shelled predatory ammonites, cephalopods that went extinct at the end of the Cretaceous
What is the common name for members of phylum Annelida?
segmented worms
Around how many annelid species are there?
How long are annelids?
between less than a millimeter to the 3-meter-long giant Australian earthworm
Where do annelids live?
the sea, freshwater, and damp soil
What are the most well-known examples of annelids?
What is segmented and what is not in segmented worms?
The coelom is segmented by septa, but the digestive tract, nervous system, and circulatory system run the length of the worm
What specialized regions exist in the annelid digestive tract?
the pharynx, esophagus, crop, gizzard, and intestine
Describe the respiratory and circulatory systems of an earthworm.
The skin carries tiny blood vessels and acts as its respiratory system, while the circulatory system is mainly two vessels, a dorsal and a ventral.
Describe the excretory system of an earthworm.
Metanephridia in each segment remove wastes from blood and coelom via nephrostomes and discharge that waste through exterior pores.
Describe the nervous system of an earthworm.
Brainlike ganglia lie above the pharynx and are connected to a pair of ventral nerve cords with associated ganglia in each segment.
How do earthworms reproduce?
Two hermaphroditic earthworms exchange sperm and then each build a mucous cocoon and put eggs and sperm in that. Some can also fragment to reproduce asexually.
How do annelids feed?
Some swim, but most burrow in sand as benthos.
What are the major classes in phylum Annelida?
Oligochaeta, Polychaeta, and Hirudinea
What animals are in class Oligochaeta?
earthworms and aquatic segmented worms
How do earthworms feed?
They extract nutrients from soil, and secrete the remainder as castings.
Why are earthworms useful?
They till soil, and castings improve the texture.
What animals are in class Polychaeta?
polychaetes, mostly marine segmented worms
What's special about polychaetes?
They have parapodia, ridges on each segment that function in locomotion and as gills in most.
Where do polychaetes live?
most on the seafloor, some, like fanworms, within tubes they make out of mucus and sand/shells
What animals are in class Hirudinea?
Where do leeches live?
freshwater, but there are some land leeches in moist vegetation
How do leeches feed?
Most eat other invertebrates, but some suck blood from animals including humans.
How do parasitic leeches attack their hosts?
They either slit the skin or secrete digestive enzymes to break through the skin, secrete an anesthetic so the host doesn't notice, secrete hirudin, which keeps the blood from coagulating, and then sucks a lot of blood.
How have humans used leeches?
in bloodletting, nowadays to treat bruised tissues and to stimulate circulation of blood to fingers and toes that have been sewn back onto hands and feet.
Why is a coelom important?
It provides a hydrostatic skeleton, new forms of locomotion, space for storage and development of complex organs, a cushion, and separation between internal and external muscles.
What is the common name of members of phylum Nematoda?
roundworms (or nematodes)
Where are nematodes found?
water, wet soil, and in the bodies of plants and animals
How many species of nematodes are there?
90k are known, perhaps 900k exist
What structure do roundworms have?
nonsegmented bodies: a cylinder is tapered at both ends, but is blunter at the head
What systems do nematodes have?
longitudinal muscles, a complete digestive tract but no circulatory system; the pseudocoelom serves this purpose
How are nematodes protected?
They have a tough exoskeleton called the cuticle, which they shed periodically.
What a nematode shedding its cuticle called?
molting or ecdysis
How do roundworms reproduce?
sexually, with separate sexes, and the zygotes that develop are resistant
How are nematodes helpful?
They decompose and recycle nutrients, and Caenorhabitis elegans is used as a model research organism in developmental biology.
How are nematodes harmful?
Many attack plant roots, and parasitize animals, including the human parasite Trichinella spiralis that causes trichinosis and is acquired as cysts from infected animal muscle tissue.
How many arthropods are estimated to exist today?
a billion billion, 10^18
How many species of arthropods are known?
a million, which is 2/3 of all species known
What three characteristics of arthropods contribute to their success?
segmentation, a hard exoskeleton, and appendages
How do arthropods defend themselves?
They all have a hard cuticle or exoskeleton made of protein and chitin.
How do arthropods use their exoskeleton?
for defense, to attach muscles on, to protect against desiccation, but they have to shed it (molting or ecdysis) to grow
Describe the nervous system of an arthropod.
They have developed senses, eyes, olfactory receptors, and antennae, and lots of cephalization.
Describe the circulatory system of an arthropod.
Arthropods have open circulatory systems with hemolymph pumped by the heart into sinuses called hemocoel.
Describe the respiratory system of an arthropod.
In aquatic organisms, gills exchange gases, while in land arthropods, internal air ducts allow for gas diffusion.
What are the main clades within phylum Arthropoda?
trilobites, chelicerates (arachnids and others), uniramians (centipedes, millipedes, and insects), and crustaceans
What defines chelicerates?
their clawlike chelicerae for feeding
What defines uniramians?
their uniramous or unbranched appendages
What defines crustaceans?
their biramous or branched appendages
Describe arthropod eyes.
Chelicerates have simple eyes, while uniramians have compound eyes with multiple lenses.
Describe arthropod antennae.
Chelicerates lack them; uniramians have one pair, and crustaceans have two pairs.
How did the exoskeleton help arthropods on land?
It prevents water loss and helps with structural support without water's buoyancy.
When did arthropods invade the land?
in the late Silurian and early Devonian, with the oldest eurypterid tracks 450 million years ago
What phylogenetic issues does Arthropoda face?
First, it has been proposed to be split into four phyla, Trilobita, Chelicerata, Uniramia, and Crustacea. The Uniramia class has also been proposed to be split into Diplopoda, Chilopoda and Insecta because Insecta seems to be more closely related to Crustacea than the other two.
When did trilobites live?
the Paleozoic era, dying off in the Permian extinctions 250 million years ago
Describe trilobite appendages.
lots of appendages but with little variation from one to the next
What chelicerates were contemporaneous with trilobites?
eurypterids or water scorpions
Describe the appendages of a chelicerate.
more specialized than trilobites, anterior appendages made into chelicerae
What happened to marine chelicerates?
They went extinct like the trilobites, except for the horseshoe crab.
What are arachnids?
chelicerates, arthropods
What are examples of arachnids?
scorpions, spiders, ticks and mites
Besides chelicerae, what makes do chelicerates have in common?
They have an anterior cephalothorax and a posterior abdomen.
Describe the specific appendages of an arachnid.
six pairs: chelicerae, pedipalps, and four pairs of legs
How do spiders feed?
They have poison glands in their chelicerae and dump digestive juices on the food to suck it up more easily.
How do spiders breathe?
They have book lungs, with a large surface area in stacked sheets for gas exchange.
What's special about spiders?
They build webs of silk that they can trap food and inherit this complicated behavior.
Describe millipedes.
long, four legs per segment, feed on decaying leaves and plant matter
What class are spiders in?
What class are millipedes in?
What class are centipedes in?
Describe centipedes.
carnivorous, have antennae, mandibles, poison claws, and two legs per segment
What class are insects in?
What's special about insects?
More than half of all species are insects.
What is the study of insects called?
Where do insects live?
all terrestrial habitats and freshwater, some in the ocean but not as dominant there
When did insects become so common?
when flight evolved during the Carboniferous and Permian
What could have caused the insect boom?
evolution of flight, diversification of mouthparts, and/or the evolutionary radiation of flowering plants
What advantages does flight offer to insects?
the increased abilities to escape predators, move to new habitats, and find mates
What are insects' wings made of?
extensions of the cuticle, not appendages
Which insects can fly?
dragonflies, bees, wasps, butterflies, and beetles
How many pairs of wings does each type of insect have?
Dragonflies have two of the same; bees and wasps have two that are connected; butterflies have two that overlap, and beetles have just one flying pair, the other as protection on the ground.
Describe the excretory system of an insect.
Wastes come from the hemolymph and are removed by the Malpighian tubules.
How do insects breathe?
They have a tracheal system of tubes that take oxygen directly to the cells.
Describe the nervous system of an insect.
two ventral nerve cords with segmented ganglia and cephalization
What is incomplete metamorphosis?
when the young resemble the old but are just smaller or of different proportions
What is complete metamorphosis?
when larval stages look very different from the adult stages
How do insects reproduce?
sexually, with separate males and females, and each reproduces only once in a lifetime
What help can insects be to humans?
They pollinate our orchards and crops.
What harm can insects cause humans?
They can spread disease and eat our crops.
What order are sucking lice in?
What order are beetles in?
What order are earwigs in?
What order are flies and mosquitoes in?
What orders are bugs like bedbugs in?
What order are ants, bees and wasps in?
What order are termites in?
What order are butterflies and moths in?
What order are damselflies and dragonflies in?
What order are crickets, roaches, grasshoppers, and mantids in?
What order are fleas in?
What order are caddisflies in?
Where do crustaceans live?
marine and freshwater environments
How many species of arthropods are known?
Describe crustacean appendages.
very diverse: two pairs of antennae, 3+ pairs of mouthparts (including mandibles), walking legs attached to the thorax and others attached to the abdomen
How do crustaceans breathe?
small ones exchange gas across thin parts of the cuticle, and big ones have gills
What are isopods?
small marine crustaceans, some of which live at the bottom of the ocean, and include terrestrial pill bugs/wood lice
What are copepods?
some of the most numerous species on earth, small crustaceans that play vital roles in marine and freshwater ecology
What are decapods?
big crustaceans, mainly marine, with a CaCO3 exoskeleton/cuticle
What are euphausiids?
krill; small whale food, planktonic crustaceans
What are barnacles?
sessile crustaceans with CaCO3 cuticles, filter feeders
What genes are thought to play a major role in the evolution of segmentation?
Hox genes
What are the two phyla of deuterostomes?
Echinodermata and Chordata
What shape do most echinoderms have?
a five-spoked
What do echinoderms have in common?
sessile/slow, marine, radial symmetry, often five spokes, calcareous plates, and the water vascular system
What is unique about echinoderms?
their water vascular system: hydraulic canals and tube feet that help the echinoderm move, feed, and exchange gases
How do echinoderms reproduce?
Males and females release their sperm and eggs into the water.
Why are echinoderms radial if they are members of Bilateria?
Their larvae are bilateral, and even the adults aren't completely radial; some openings are directed.
What are the six classes of echinoderms?
Asteroidea, Ophiuroidea, Echinoidea, Crinoidea, Holothuroidea, and Concentricycloidea
What echinoderms are members of class Concentricyclodea?
sea daisies
Where do sea daisies live?
waterlogged wood in the deep sea
What echinoderms are members of class Asteroidea?
sea stars
How do echinoderms generate a suction?
They have tube feet that can use the hydraulic system to create or release tension.
What do sea stars use their suction to do?
hold onto rocks, move and grab prey
How do sea stars feed?
Their tube feet hold onto the prey bivalve, then they eject their stomach between the shells of the bivalve to start digesting it.
What echinoderms are members of class Ophiuroidea?
brittle stars
Describe brittle stars.
They are distinguished by their central disk, along with five flexible arms.
How do brittle stars move?
They don't have tube feet, so they lash their arms back and forth.
What echinoderms are members of class Echinoidea?
sea urchins and sand dollars
Describe sea urchins.
roughly spherical, spines, no arms, tube feet on bottom
Describe sand dollars.
flattened disk shape, no arms, tube feet on bottom
How do sea urchins move?
using their tube feet and spines
What echinoderms are members of class Crinoidea?
sea lilies and feather stars, combined they're crinoids
How do sea lilies move?
They are sessile and stay attached to the substratum with stalks.
How do feather stars move?
They use their long arms to crawl about.
What echinoderms are members of class Holothuroidea?
sea cucumbers
How do sea cucumbers not resemble other echinoderms?
They don't have spines, or a large exoskeleton, and they aren't radially symmetric.
How do sea cucumbers resemble other echinoderms?
They have five rows of tube feet, like sea urchins, and the water vascular system.
What subphyla are in phylum Chordata?
two invertebrate subphyla and the subphylum Vertebrata