Bio Exam 2# Ekdale
Blastopore
(first opening) that becomes the mouth
Synapomorphies of Bilateria
-Bilateral Symmetry - Cephalization -Triploblastic tissues
Clades of Hexapoda
-Diptera- flies -Lepidoptera- butterflies -hymonoptera- bees -coleoptera- beetles (most diverse)
Identify four major clades of Arthropoda
1) Chelicerata (spiders, scorpions, mites, sea spiders, horseshoe crab) 2) Myriapoda ( millipedes, centipedes) 3) Crustacea (lobsters, crabs) 4) Hexapoda (bees, grasshopper, cricket, dragonfly beetle, fly)
Identify the three major synapomorphies of Arthropoda
1) Chitinous exoskeleton with articulated (jointed) appendages 2) Compound eyes (multiple ommatidia) 3) Segmented bodies (tagmata- functional segments)
Identify types of symbiosis
1) Mutualism- both species benefit 2) Commensalism- one benefits, other unaffected 3) Parasitism- one benefits, other is harmed
What has led to the success of insects? i.e. Why is metamorphosis so advantageous
1) Numerous 2) Ecological diversity 3) Segmentation 4) Some are small 5) Water-tight exoskeleton 6) Flight 7) Specialized mouths 8) Co-evolution with plants 9) Metamorphosis- plants and animals don't compete
List the synapomorphies of hexapoda
1) Three pairs of appendages on thorax (zero on abdomen) 2) Three tagmata -head/Prothorax (sensory, feeding) - thorax/mesothorax (locomotion) -abdomen/metathorax (reproduction, general function)]
life cycle of cnidarians
1. General scheme - "alternation of generations" 2. Sexually produced zygote becomes a free-swimming planula larva 3. Planula settles to become polyp 4. Polyp may or may not develop into a medusa 5. Medusas sexually reproduce to form a zygote
polyps? medusas?
1. Many cnidarians have 2 body forms (dimorphic) 2. Polyp - sedentary or sessile form (e.g., anemone, hydra) 3. Medusa - motile or free-swimming form (e.g., jellyfish); move by contracting "bell"
While making your bed one morning, you encounter the shed cuticle (composed of the polysaccharide chitin) that was left by a small animal that had been crawling through your bed sheets. The body is approximately half an inch long, and it appears to be divided into two functional body segments. One of the segments possesses a number of paired, jointed appendages, and the other segment is legless. It appears that the animal shed the cuticle several days ago, and I'm sure it's no longer in your bed...What kind of animal shed its cuticle in your sheets? Multiple Choice A spider (Chelicerata) A velvet worm (Onycophora) A waterbear (Tardigrada) A leech (Hirudinidae) A polychaete (Annelida)
A spider (Chelicerata)
Do "worms" form a monophyletic group
Animals that often are called "worms" do not form a monophyletic group, which is an ancestor and all of its descendents. Annelids and platyhelminths are more closely related to mollusks than they are to nematodes, and nematodes are more closely related to arthropods than they are to either annelids or platyhelminths. (FYI, the most recent common ancestor of Platyhelminthes, Annelida, and Nematoda is at Protostomia, but not all protostomes would be considered "worms".)
Identify and distinguish between the 2 major clades of Cnidaria
Anthozoa & Medusozoa -Cnidocytes -Free swimming larvae (planula) -Mouth surrounded by solid tentacles -Polymorphism (different body shapes) in some species
What is the largest clade of Animalia
Arthropoda
List the synapomorphies for Arthropoda, Chelicerata, Myriapoda, Crustacea, and Hexapoda.
Arthropoda -chitinous exoskeleton (shed); jointed (articulated) appendages; compound eyes; segmented bodies Chelicerata - two tagmata (cephalothorax and abdomen); chelicerae (first pair of appendages developed as "fangs") Myriapoda -one pair of antennae; loss of compound eyes; two tagmata (head and trunk) Crustacea -compound eyes on stalks; two pairs of antennae; biramous appendages; two tagmata (cephalothorax and abdomen) Hexapoda -three pairs of uniramous legs; abdominal legs lost; three tagmata (head, thorax, and abdomen); two pairs of wings
What feature(s) make arthropods ecdysozoan protostome bilaterian animals?
Arthropods are ecdysozoans in that they have an outer, non-cellular cuticle layer that is shed (except in Nematoda). Arthropods are protostomes in that the blastopore (first opening) develops into the mouth, the nerve cord is ventral, and the developing embryo divides with spiral cleavage. Arthropods are bilaterians in that they are bilaterally symmetrical, have triploblastic tissues, and are cephalized (nervous structures concentrate in a head region). Arthropods are animals in that they are multicellular heterotrophs that gain nutrition through ingestion.
Bivalve molluks have lost their radula. How do they eat?
Bivalve mollusks eat through suspension feeding. They draw water with food particulates into their viscaeral masses through incurrent siphons, which directs the water over the gills. Food is trapped in the gills and moved to the mouth, and water is expelled through excurrent siphons.
Describe the basic mollusk body plan
Body consists of a head-foot portion and a visceral mass (Radula, foot, mantle, mantle cavity, shell, heart, reproductive organs)
What are tagmata and why are they beneficial?
Body segments; It is beneficial because it acts as a "swiss army knife"
Distinguish between branchiopoda, maxillopoda, and Malacostraca (crusteacans)
Branchiopoda - fairy & brine shrimp, clam shrimp, water fleas, tadpole shrimp Maxillopoda - barnacles, ostracods, copepods, fish lice Malacostraca - crabs, lobsters, shrimp, isopods, and krill
Setae
Bristles made of chitin (hard carbohydrate) and are used for stabilization and movement
What is cephalization? Why is cephalization important?
Cephalization is the localization of nervous control within a distinct head region of the body. Cephalization allows motile animals to live freely (not dependant on other organisms), indicates the direction of movement, and allows development of special senses that are controlled by a brain.
Which of the following clades includes animals that shed their outer, non-cellular layer (i.e., cuticle)? Multiple Choice Deuterostomia Chelicerata Cephalopoda Lumbricidae Bivalvia
Chelicerata
How might you tell the difference between a chilopod centipede and a polychaete annelid?
Chilopod arthropods (centipedes) and polychaete annelids look superficially similar because they both have elongate, segmented bodies. However, chilopods have a chitinous exoskeleton (absent in annelids) and jointed appendages (polychaetes have parapodia with setae that look like appendages).
Difference between Chilopoda and Diplopoda
Chilopoda (Centipede): 2) One pair of legs per trunk segment (tergum) 3) Active predators, immobilize prey with venom from fangs Diplopoda (Millipede): 1) Two pairs of legs per trunk segment 2) More susceptible to predation -Cuticle used as heavy armour, exude noxious fluid from sides of body
Distinguish between different myriapod clades.
Chilopods (centipedes) have one pair of legs per trunk segment, whereas diplopods (millipedes) have two legs per trunk segment.
What is a clitellum? What are setae?
Clitellum is a secretory organ and seate are bristles for movement
Non-porifera animals
Cnidaria (= "nettle-like") - includes jellyfish, sea anemones, "men-of-war", hydras, and coralsc. Ctenophora (= "comb-bearing") - includes comb jellies -In the past, zoologists grouped Cnidaria and Ctenophora together, but ctenophores may be more closely related to other animals -radial symmetry
Distinguish between the following clades of hexapoda: Coleoptera, Diptera, Hymenoptera, and Lepidoptera
Coleoptera- beetles Hymenoptera- bees, wasps, and ants Diptera- flies Lepidoptera- butterflies and moths
This semester in BIOL 101, you have learned about the multicellular sponges in the clade Porifera and multicellular sea anemones in the clade Cnidaria. Now consider the Platyhelminthes: Look at the list of characteristics of the clade Platyhelminthes below and pick out the one characteristic that both Platyhelminethes, Porifera, and Cnidaria have in common. Multiple Choice A distinct head region True tissues Collagen Mesoderm True bilateral symmetry
Collagen
Nematoda
Collagenous (non-chitinous) exoskeleton, no legs, unsegmented, longitudinal muscles only, free-living or mutualistic or parasitic; ("round worms")
What is cryptobiosis, and how has it led to the success of tardigrades?
Cryptobiosis is a state of suspended animation observed in tardigrades, and it is characterized by a nearly complete drying of the body and a stop of metabolism. Cryptobiosis allows tardigrades to survive if the film of water in which they live dries, and it also allows them to survive extremely low temperatures, and even the vacuum of space!
What feature(s) make an earthworm a protostome bilaterian animal?
Earthworms (annelids) are protostomes in that they exhibit a blastopore (first opening) that develops into the mouth and the nerve cord is positioned ventrally (along the belly side of the animal). Earthworms are bilaterian in that they are bilaterally symmetrical (divided into right and left halves), are cephalized (have a distinct head with a centralized nervous system), and have triploblastic tissues (three tissue layers). Earthworms are animals in that they are multicellular eukaryotic organisms, heterotrophic, obtain nutrients through ingestion, and have collagen.
Identify the synapomorphy of Ecdysozoa
Ecdysis- molting of cuticle (non cellular layer)
What are the three layers of triploblastic tissue?
Ectoderm- outermost tissue layer (lining body) Mesoderm- (middle tissue layer (not mesoglea) Endoderm- innermost tissue layer (lining gut)
Polyplacophora
Flat shells with eight valves, foot adheres body securely to rocks, graze on algae; ("chitons")
Which major clade of mollusk is the most diverse in terms of the greatest number of species?
Gastropoda.
Dioecious
Having male and female reproductive organs in separate plants or animals
What is the difference between radial symmetry and bilateral symmetry?
In radial symmetry, body parts are arranged concentrically around an oral-aboral axis (mouth-opposite of mouth axis). In bilateral symmetry, body parts are symmetric along one axis only, which divides the body into right and left halves.
Distinguish between complete and incomplete metamorphosis in hexapods.
Incomplete metamorphosis is a gradual transition from larvae to adults with an intermediate nymph stage. During complete metamorphosis, the larva develops dramatically within a chrysalis (pupa) before emerging as an adult. (No nymph stage during complete metamorphosis.)
Incomplete gut
Lacks an anus
Identify the significance of the mantle, valve (shell), radula, and foot of different mollusks
Mantle- Secretes shell in most species shell- secreted by mantle; composed of calcium carbonate (sometimes called valves); pearls are formed when a foreign object comes between shell and mantle Radula- rasping, tongue-like organ (not in bivalves like clams) Foot- adapted for locomotion, attached to head
Identify major synapomorphies of Mollusca
Mantle- secretes shell in most species • Calcareous valve • Muscular "foot" • Chambered heart -atria and ventricle • Radula -mouth part for feeding • Posterior gill
Identify two of the major synapomorphies of Annelida
Metameric segmentation Setae (bristles for movement)
Annelids have metameric segmentation. What does that mean?
Metameric segmentation is division of the body into serial parts divided by septa. The segments are easily observed in lumbricid annelids (earthworms).
What makes mollusks protostome bilaterian animals?
Mollusks were born with mouth first and posses bilateral symmetry.
List the synapomorphies of Myriapoda and Crustacea
Myriapoda: 1) 2 tagmata(head and trunk with multiple appendages) 2) One pair of antennae 3) Compound Eyes lost (multiple simple eyes) Crustacea: 1) Compound eyes on stalks 2) Two pair of antennae 3) Biramous (two branches) jointed appendages
How do myriapods differ from other arthropod clades?
Myriapods have two tagmata (head and trunk) and they lack compound eyes (secondarily lost).
Briefly discuss the lifestyle(s) of nematodes. Are they free-living, symbiotic, or parasitic?
Nematodes can be free-living (such as the model organism C. elegans), mutualistic (such as species that live in the intestines of iguanas to help digest plant material), OR parasitic (such as round worms, hook worms, and pin worms).
What feature does members of Onycophora share with members of Tardigrada, but not with Nematoda?
Onycophora (velvet worms) and Tardigrada (water bears) - unjointed appendages and exoskeleton of chiton Nematoda- no appendages and has exoskeleton composed of collagen.
Which of the following clades of Mollusca has members with more than two valves? Multiple Choice Polyplacophora Hirudinidae Cestoda Gastropoda Bivalvia
Polyplacophora (chitin)
Identify the following clades: Polyplacophora, Bivalvia, Gastropoda, and Cephalopoda
Polyplacophora- chitons, multivalved Bivalvia- clams (two valves) Gastropoda- snails (single valve), slugs (no shell), Carnivorous and herbivorours Cephalopoda- squids and octopuses, single valve
What is meant by radial symmetry?
Possess radial symmetry - body parts arranged around an oral-aboral axis (no discernable head)
What are the parts of the hexapod thorax, what does each possess?
Prothorax -1st pair of legs, no wings Mesothorax- 2nd pair of legs and forewings Metathorax- 3rd pair of legs and back wings
Differentiate between Protostomia and Deuterostomia
Protostomia is a monophyletic clade of Bilateria that is characterized by the blastopore (first opening in the embryo) developing as the mouth and position of the nerve cord along the ventral (belly) side of the body. Deuterostomia is a monophyletic clade of Bilateria that is characterized by radial cleavage during early development, the blastopore (first opening in the embryo) developed as the anus, and position of the nerve cord along the dorsal (back) side of the body.
Clitellum
Secretory organ (saddle shaped structure on the animal's body like that straw extender part of the worm)
Differentiate among types of appendages in Chelicerates
Six pairs of appendages: 4 pairs of walking legs, one pair of pedipalps, one pair of chelicerae
What feature(s) make a snail a protostome bilaterian animal?
Snails (gastropod mollusks) are protostomes in that they exhibit a blastopore (first opening) that develops into the mouth and the nerve cord is positioned ventrally (along the belly side of the animal). Snails are bilaterians in that they are bilaterally symmetrical (divided into right and left halves), are cephalized (have a distinct head with a centralized nervous system), and have triploblastic tissues (three tissue layers). Snails are animals in that they are multicellular eukaryotic organisms, heterotrophic, obtain nutrients through ingestion, and have collagen.
Identify the members and synapomorphies of Chelicerata
Synapomorphy- first pair of appendages developed as chelicerae (fang-like jaws) -6 pairs of appendages -chephalization -tagmata Clades- 1)Pycongonida (sea spiders) 2) Merostomata (horseshoe crabs) 3) Arachnida (spiders, scorpions, harvestman, ticks, mites)
How do the tagmata differ among different arthropod groups?
Tagmata are the segmented, functional body parts of arthropods. Myriapods, chelicerates, and crustaceans have two tagmata (head and trunk in myriapods; cephalothorax and abdomen in crustaceans and chelicerates). Hexapods have three tagmata (head, thorax, and abdomen).
Which one of the following does NOT represent an arthropod lineage? Multiple Choice Crustacea Tardigrada Hexapoda Chilopoda Chelicerata
Tardigrada
How does the cuticle differ between crustaceans and all other arthropods?
The cuticle of all arthropods is composed of chitin. However, the cuticle in crustaceans is calcified to form a carapace.
What is the most diverse clade of Hexapoda called in terms of number of species?
The most diverse clade of hexapods (insects) is Coleoptera (beetles).
What synapomorphy is shared by myriapoda, crustacea, and hexapoda?
They all have mandibles (mouthparts)
Identify 3 clades of symbiotic Platyhelminthes and discuss their life cycles
Trematoda (endoparsitic flukes; live in animals) -use an intermediate host (typically snails), then move to final definitive host which is a vertebrate --------------------------------------- Monogenea (ectoparasitic flukes; live on animals) -Most attach to the gills of fish with hook-like opisthaptor/Much simpler life cycle; they have lost the intermediate host --------------------------------------- Cestoda- endoparasitic tapeworms (live in animals) - Attach to hose by scolex, proglottids are fertilized by their neighbors, and eventully are shed from tape-like strobila
Of the four major groups of Platyhelminthes, which are free-living and which are symbiotic parasites?
Tremotoda, monogenea, and cestoda are symbiotic parasites while turbellaria are free living flatwroms
Identify the major synapomorphies of non-Porifera Animalia (sister taxon to Porifera)
True tissue -Diploblastic-two tissue layers -Incomplete gut - simple Nervous system
Distinguish between uniramous and biramous appendages
Uniramous: (one branch per leg; also in chelicerates and hexapods) Biramous: (two branches) jointed appendages
In examining an unknown animal species during its embryonic development, how can you be sure what you are looking at is a protostome and not a deuterostome? (Think carefully...) Multiple Choice You see a mouth, but not an anus. The animal is triploblastic. There is evidence of cephalization. The animal is multicellular. The animal is clearly bilaterally symmetrical.
You see a mouth, but not an anus.
You are a deuterostome! (I.e., a member of Deuterostomia.) What feature(s) do you share with all other deuterostomes?
You share development of the blastopore into the anus (first opening to develop) and a dorsally positioned nerve cord.
What is the difference between endoparasites, ectoparasites, and free-living?
[endoparsitic (inside) and ectoparasitic (outside)]
Contrast segmentation in arthropods and annelids (segmented worms)
annelida have metameric segmentation and tagmatic segmentation
Compound eyes, a chitinous exoskeleton, and jointed appendages are synapomorphies for: Multiple Choice Protostomia Arthropoda Ecdysozoa Nematoda Crustacea
arthropoda
Unlike nematodes, arthropods (spiders, crabs, centipedes, and insects) have an exoskeleton that is composed of: Multiple Choice keratin calcium carbonate collagen cellulose chitin
chitin
Tardigrada
chitinous exoskeleton, four pairs of unjointed legs with claws, completely lack circulatory and respiratory systems, feed using stylets, undergo cryptobiosis; ("water bears")
Onycophora
chitinous exoskeleton, numerous pairs of unjointed appendages with claws, papillae that secrete slime from slime glands; ("velevet worms")
When two earthworms (Lumbricidae) love each other very much, they come together to make baby earthworms. During the process of baby making, mucus is secreted by a collar or saddle-shaped structure known as the to surround the fertilized eggs. Multiple Choice mantle clitellum septum setae proglottid
clitellum
Ommatidia are small and hexagonal units that are clustered together to form the of arthropods. Multiple Choice compound eyes jointed appendages cuticle made of chitin chelicerae blastopore
compound eyes
Bivalve mollusks have a hatchet-shaped that is used for locomotion and burrowing. Multiple Choice mantle radula cnidocytes (e.g., nematocysts) foot gastrovascular cavity
foot
Cephalopoda
foot is fused to head and forms a funnel to expel water from mantle cavity, tentacles for food capture surround beak-like radula, complex eye and sophisticated brain, may have external shell or internal guards (pens); ("squid")
Monoecious
having both the male and female reproductive organs in the same individual; hermaphrodite.
What is the advantage of ecdysis (molting) in arthropods such as crustaceans?
helps in the regeneration of damaged tissue, it can be a disadvantage too because it doesn't allow them to grow
An organism that exhibits cephalization probably also: Multiple Choice is a deuterostome has metameric segmentation is diploblastic is bilaterally symmetrical has radial symmetry
is bilaterally symmetrical
Which of the following structures is responsible for secreting the shell in mollusks? Multiple Choice cnidocytes (e.g., nematocysts) mantle radula foot gastrovascular cavity
mantle
In triploblastic animals, what tissue layer is located between the ectoderm and the endoderm? Multiple Choice mesoderm lubriderm macroderm epidermis protoderm
mesoderm
Annelids have segmentation, which allows for a greater control of movement. Multiple Choice biramous tagmatic metameric bilateral
metameric
Radula
mouth part for feeding. Rasping, tongue-like organ (not in the bicalves like clams)
There is only one clade of mollusk that includes fully terrestrial (land dwelling) species. Which clade is it?
only some members of Gastropoda are fully terrestrial.
Chelicerae
pair of head appendages on members of Chelicerata (including arachnids)
Which of the following features is shared by all polychaete annelids, but not lumbicids or hirudinids? Multiple Choice chelicerae clitellum chitinous exoskeleton mantle parapodia
parapodia
What is an evolutionary adaptation shared by Trematoda, Monogenea, and Cestoda? Multiple Choice formation of a calcareous skeleton for colonial living radial symmetry suspension feeding parasitism a mantle
parasitism
Spiracles
respiratory openings along the sides of abdominal segments
Which animal group is most closely related to the horseshoe crabs (Merostomata)? Multiple Choice scorpion (Chelicerata) centipede (Chilopoda) snow crab (Malacostraca) fairy shrimp (Branchiopoda) barnacle (Maxillopoda)
scorpion (Chelicerata)
Pedipalps
second pair of appendages in arachnids
Mantle
secretes the shell, allows the clam to sense the world around it, allows the water to flow around and through the filter-feeding organs, the gills. (the fleshy part)
Lumbricidae
segmented bodies without appendages, seatae but no parapodia, obvious clitellum; ("earthworms")
Hirudinidae
segmented bodies without appendages, setae are absent, clitellum is hidden (internal), anterior and posterior ends have "suckers" for attachment, a strong pharynx for sucking fluids; ("leeches")
"polychaetes"
segmented bodies without appendages, setae grow from parapodia, well differentiated heads, include suspension feeders (that live in tubes) and voracious predators; ("marine annelids")
Carapace
shell-like plate (calcified chitin) covering the cepahlothorax of some crustaceans
Gastropoda
single valve that often is coiled, muscular foot used for crawling (motile), well-developed heads and radulae, predatory and herbivorous; ("snails")
Chitin
skeletons w/ toughness and flexibility
Platyhelminthes, Annelida, Nematoda, and Onycophora are all commonly referred to as "worms". However, they do not form a monophyletic group. Why not? Multiple Choice don't be silly - they do form a monophyletic group! some of the "worms" listed above possess a ventral nerve cord whereas others possess a dorsal nerve cord some of the "worms" listed above are more closely related to non-"worms" than they are to other "worms" some of the "worms" listed above are carnivorous whereas others are herbivorous some of the "worms" listed above are radially symmetrical
some of the "worms" listed above are more closely related to non-"worms" than they are to other "worms"
What are cnidocytes?
specialized stinging cells (e.g., nematocysts) 1. Key innovation for cnidarian success - contain toxins 2. Nematocysts sit in capsule and are "sprung" 3. Prey items are either impaled or caught by spring action
adductor muscle
the part of the scallop that you eat, next to the groin. The main muscular system in bivalve mollusks
Bivalvia
two valves, valves closed by adductor muscles and opened by hinge ligament, sedentary suspension feeders, no radula, hatchet-shaped foot, breath and feed using siphons; ("clams")
foot (in terms of mollusks)
used for locomotion
In protostomes, the nervous system is located: Multiple Choice laterally on the right side posteriorly ventrally dorsally laterally on the left side
ventrally
What is aposematic coloration?
very bright, often red or orange coloration of poisonous animals is a warning that possible predators should avoid them
