Bio chap 18: INVERTEBRATES
chelicerates cephalothorax
--- Live in terrestrial, aquatic, and marine environments Include terrestrial spiders, scorpions, ticks, mites, horseshoe crabs, and sea spiders All appendages attached to ---; none on abdomen • First pair (chelicerae) are used for feeding and defense • Second pair (pedipalps) function in feeding or sensory systems
Arthropods (phylum Arthropoda) molt/fused
--- are Rigid, jointed exoskeleton • Must --- as they grow Segmented, but some segments are --- into regions • Head, thorax, abdomen Well-developed nervous system • Brain and ventral nerve cord • Eyes may be simple or compound Variety of respiratory organs • Gills, book lungs, tracheae Metamorphosis • Reduces competition because larvae require different food and environment than adults
Arthropods (phylum Arthropoda) exoskeleton/jointed/chitin/dessication/muscle
--- are considered highly successful because: a. Have a rigid exoskeleton with freely movable jointed appendages. 1) The exoskeleton is a strong but flexible outer covering composed mainly of chitin 2) Chitin is a strong, flexible, nitrogenous polysaccharide. 3) The exoskeleton serves for protection, attachment for muscles, locomotion, and prevention of dessication 4) Because the exoskeleton is hard and nonexpandable, arthropods must molt (shed) the exoskeleton to GROW larger. i. Before molting, the body secretes a larger soft and wrinkled exoskeleton underneath. ii. Enzymes partially dissolve and weaken the old exoskeleton. iii. breaks the old exoskeleton open and wriggles out. iv. The new exoskeleton then quickly expands and hardens. b. Segmentation can be observed because each segment has a pair of jointed appendages; some segments have fused into regions (e.g., a head, a thorax, and an abdomen). 1) Jointed appendages are hollow tubes moved by muscles 2) The appendages are modified for food gathering, reproduction, locomotion. c. have a well-developed NERVOUS SYSTEM. 1) A brain is connected to a ventral solid nerve cord. 2) The head bears various sensory organs. 3) Compound eyes have many complete visual units; each collects light independently. 4) The lens of each visual unit focuses the image on the light-sensitive membranes of a few photoreceptors. 5) In simple eyes, a single lens brings the image to focus into many receptors, each of which receives only a portion of the image. 6) Many have well-developed touch, smell, taste, balance, and hearing, and display complex behaviors and methods of communication d. use a variety of respiratory organs. 1) Marine forms use gills with vascularized, thin-walled tissue specialized for gas exchange. 2) Terrestrial forms have book lungs (e.g., spiders) or air tubes called tracheae (e.g., insects). e. Metamorphosis is a drastic change in form and physiology that occurs as a larva becomes an adult. 1) Metamorphosis contributes to their success 2) A larva eats foods and lives in environments different from the adult. 3) Competition between the immature and adults of a species is reduced. 4) This reduction in competition allows more members of the species to exist at one time.
additional/appearance
-Results showed that velvet worms have the complete set of arthropod homeotic genes—no --- genes arose after the lineages diverged. -Thus, the researchers concluded that body segment diversity did not result from the --- of new homeotic genes in arthropods.
chelicerates feeding/sensory/nocturnal/numerous/
. 5. --- include spiders, scorpions, and horseshoe crabs. a. The first pair of appendages are chelicerae, the second pair are pedipalps, and the next four pairs are walking legs. 1) Chelicerae are appendages that function as --- organs. 2) Pedipalps are feeding or --- structures. b. All of the appendages attach to a CEPHALOTHORAX, a fusion of head and thoracic regions. c. The marine horseshoe crab (genus Limulus) is common along the east coast of North America. 1) Their body is covered by exoskeletal shields. 2) The anterior shield is a horseshoe-shaped carapace with two compound eyes. d. Arachnids include ticks, mites, scorpions, spiders, and harvestmen. 1) Over 25,000 species of mites and ticks have been classified. 2) Ticks are ectoparasites of various vertebrates and are carriers for Rocky Mountain spotted fever and LYME Disease. 3) When not on a host, ticks hide on plants and in the soil e. Scorpions are --- and spend the day hidden under a log or rock. f. Pedipalps are large pincerlike appendages; the abdomen ends in a stinger containing venom. g. Spiders (over 35,000 species) have a narrow waist separating the cephalothorax from the abdomen. 1) Spiders have --- SIMPLE EYES rather than compound eyes. 2) Spider chelicera are modified as fangs with ducts leading from poison glands. 3) The abdomen has silk glands; they may spin a web to trap prey.
fixed/one/mouth/radial/atop/fusion
1) Animals that have three tissue layers are either protostomes or deuterostomes. d. Protostomes 1) SPIRAL cleavage, in which the cells divide without an increase in size. 2) The fate of the cells is --- —each contributes to development in only --- particular way. 3) The blastopore is associated with the --- 4) A coelom forms by splitting of the mesoderm, which has arisen from cells near the blastopore. e. Deuterostomes 1) --- cleavage, where the new daughter cells sit --- the previous cells; the fate of these cells is indeterminate. 2) The blastopore is associated with the anus; the mouth appears later. A coelom forms by the --- of mesodermal pouches from the primitive gut
pseudocoelum/pork/DOGS/lymphatic/pinworm
1. The ecdysozoans include roundworms and arthropods A. Roundworms 1. Roundworms (phylum Nematoda) are NONSEGMENTED worms that are prevalent in almost any environment. 2. The internal organs lie within a --- —a body cavity that is incompletely lined with mesoderm. 3. Parasitic roundworms a. In Ascaris lumbricoides, males are smaller than females and their posterior end curves to a point. b. These worms move by WHIPLIKE motions because only longitudinal muscles lie next to the body wall. c. Mating produces eggs that mature in the SOIL; therefore, most are limited to warmer climates. d. When eggs are swallowed, larvae burrow through the intestinal wall to the liver, heart, and/or lungs. e. In the lungs, the larvae molt; after 10 days they migrate up the windpipe to the throat and are swallowed. f. Back in the intestine, mature worms mate and the female deposits eggs that are lost with feces. g. Feces must reach the mouth of the next host to complete a life cycle; therefore, proper sanitation easily prevents infection. 4. Trichinosis is a serious infection caused by Trichinella spirallis. a. Humans contract Trichinella spirallis by eating raw --- with encysted larvae. b. After maturation, the adult female burrows into the wall of the small intestine and produces living offspring that are carried by the bloodstream to skeletal muscles where they encyst. 5. Filarial worms cause various diseases. a. In the U.S., a filarial worm is a parasite of --- b. It lives in the heart and the arteries that serve the lungs and thus is called heartworm disease. 6. Elephantiasis occurs in tropical Africa. a. It is caused by a filarial worm (Wuchereria bancrofti) that utilizes the mosquito as a secondary host. b. Adult worms reside in and block the --- vessels; ultimately this results in the limbs of an infected individual swelling to monstrous size. c. It is treatable only in the early stages but not after scar tissue has blocked the lymphatic vessels. 7. --- are the most common nematode in the United States. a. Adult parasites live in the cecum and large intestines. b. Females migrate to anal region at night to lay their eggs. c. Scratching an infected area can contaminate the area with eggs. The eggs are swallowed and the life cycle begins again.
rRNA
1. The phylogenetic tree of animals is based on MOLECULAR and MORPHOLOGICAL data. 2. It is assumed that the more closely related two organisms, the more --- nucleotide sequences they will have in common. a. DNA b. RNA c. rRNA d. rDNA
closed/
18.10 Annelids Are Segmented Worms (1 of 3) •Annelids (phylum Annelida) have -segmentation, the subdivision of the body along its length into a series of repeated parts, -a nervous system, and -a --- circulatory system in which blood remains enclosed in vessels throughout the body. Many invertebrates, such as molluscs and arthropods, have an open circulatory system in which blood is pumped through vessels into open body cavities.
ticks/ecdysis
18.11 Arthropods Are Segmented Animals with JOINTED Appendages and an Exoskeleton •There are over a million species of arthropods (phylum Arthropoda), including CRAYFISH, lobsters, crabs, barnacles, spiders, ---, and insects. •Their diversity and success are due to their segmentation, hard exoskeleton, and jointed appendages, for which the phylum is named. •As an arthropod grows, it must periodically SHED Bits old exoskeleton and secrete a larger one, a complex process called molting, or ---.
increase/master
18.13 Scientific Thinking: The Genes That Build Animal Bodies Are Ancient (1 of 3) •How did the arthropod body plan, with its variety of distinct body segments, evolve? -One hypothesis proposes that an --- in the number of homeotic genes, the --- control genes that direct animal development, led to the diversity of segment and appendage types. -To test this hypothesis, a team of scientists compared homeotic genes in arthropods with VELVET WORMS, their closest living relatives.
cord/rod/slits/tail
18.15 Our Own Phylum, Chordata, Is Distinguished by Four Features (1 of 2) •Chordates (phylum Chordata) are defined by -a dorsal, hollow nerve --- -a flexible, supportive, longitudinal ---, the notochord, -pharyngeal ---, and -a muscular post-anal ---.
filter/painkiller/pollinated
18.16 Connection: Invertebrate Diversity Is a Valuable but Threatened Resource •Invertebrates play critical roles in natural ecosystems and provide valuable services to humans. For example; -Freshwater mussels --- and improve water quality in natural ecosystems and reduce the cost of water treatment for human uses. -Reef-dwelling cone snails produce a powerful --- in their venom. -Most flowering plants are --- by animals, chiefly insects.
billion/ediacaran/soft/cambrian/hard
18.2 Animal Diversification Began More Than Half a --- Years Ago (1 of 2) •The oldest animal fossils are from the late --- period and are about 560 million years old. All are impressions of ----bodied animals that varied in shape and length. •Animal DIVERSIFICATION appears to have accelerated rapidly during the --- explosion from 535 to 525 million years ago. In contrast to the uniformly soft-bodied Ediacaran animals, many Cambrian animals had --- body parts such as shells and spikes.
phylogenetic/record
18.4 Body PLANS and Molecular Comparisons of Animals Can Be Used to Build --- Trees (1 of 2) •Biologists make hypotheses about the phylogeny of animal groups using evidence from -body plan 4 characteristics, -the fossil ---, and -molecular data, chiefly D N A sequences.
radial/stinging/radial/two/cavity/polyp
18.6 Cnidarians Are --- Animals with Tentacles and --- Cells (1 of 2) •Cnidarians (phylum Cnidaria) -are characterized by ---symmetry, -have ---true tissue layers, -have a gastrovascular (GV) ---, and -have two body forms: 1.--- (such as hydras) and 2.medusa (such as jellies).
body/planarian (worm)/parasitic
18.7 Flatworms Are the Simplest BILATERAL Animals (1 of 2) •Flatworms (phylum Platyhelminthes) are bilateral animals with no --- cavity. •A ---(worm) has a gastrovascular cavity and a simple nervous system. •Flatworms live in marine, freshwater, and damp terrestrial habitats. •Flukes and tapeworms are --- flatworms with complex life cycles.
cavity/tract/roundworms/cuticle
18.8 Nematodes Have a Body --- and a Complete Digestive --- (1 of 2) •Nematodes, or --- (phylum Nematoda), have -bilateral symmetry, -three tissue layers, -a nonliving protective --- that is shed periodically, and -a complete digestive tract with a MOUTH and ANUS •Some nematodes are free-living decomposers, while others are plant or animal parasites.
muscular/mass/
18.9 Diverse Molluscs Are Variations on a Common Body Plan •Molluscs (phylum Mollusca) have -a --- foot, which functions in locomotion, -a visceral --- containing most of the internal organs, -a mantle, which may secrete a shell that encloses the visceral mass, and -a circulatory system. •Many molluscs feed with a rasping radula, used to scrape up food.
crustaceans
2. --- have a hard, crusty exoskeleton, which contains calcium carbonate in addition to chitin. a. The head usually bears COMPOUND EYES and FIVE PAIRS of appendages. 1) The first two appendages are antennae and antennules; in front of the mouth, they have sensory functions. 2) The next three pairs (mandibles, first and second maxillae) lie behind the mouth and are used in feeding. b. Biramous appendages have two branches; one branch is a gill and the other is the leg branch. c. Copepods and krill feed on algae; numerous, they are an important link in marine food chains. d. Barnacles have a thick, heavy shell and are SESSILE 1) Stalked barnacles attach by their stalk; stalkless barnacles attach directly to the shell. 2) Barnacles begin as free-swimming larvae and become sessile on wharf pilings, rocks, etc. 3) They extend feathery structures (cirri) to filter feed. e The head and thorax of a crayfish are fused into a cephalothorax, which is covered on the top and sides by a nonsegmented carapace. f. Abdominal segments have a pair of swimmerets, small paddlelike structures. 1) The first two pairs of swimmerets in the male (claspers) stronger to pass sperm to the female. 2) The last tail segments are the uropod and the telson, which together make a fan-shaped tail. 3) A crayfish awaits prey and uses its claws to carry it to the mouth. 5) Crayfish have gills that lie above the walking legs and are protected by the carapace. 6) The crayfish stomach has two main regions. i. The anterior gastric mill with chitinous teeth grinds food. ii. A posterior region filters coarse particles before absorption in the digestive glands. g. Green glands in the head area excrete metabolic wastes through a duct at the base of the antennae. h. The coelom is reduced in arthropods and forms the space about the reproductive system. i. The heart pumps hemolymph containing bluish hemocyanin into a hemocoel where it washes around the organs. j. A brain is connected to a ventral nerve cord; periodic ganglia give off lateral nerves. k. The sexes are separate in crayfish. 1) The male has a coiled sperm duct that opens to the outside at the base of its fifth walking leg. 2) The female's ovaries open at the base of the third walking legs. 3) The fold between the bases of the fourth and fifth pair of legs serves as a seminal receptacle. 4) Following fertilization, the eggs are attached to the swimmerets of the female.
pattern/first/segments/Hox/bind/region/shared/ancestor
2. Body plans are determined by the --- of genes being expressed or not expressed, at different times and regions of the developing embryo. 3. In the --- stages of development, the anterior and posterior ends of the embryo are defined. 4. In animals that have bilateral symmetry and segments, the next step in development is diving the embryo into --- 5 After the segmentation pattern is established, the --- (homeotic) genes determine what each segment will be. a. Hox genes --- to the genetic area that determines the body plan during development. b. Each Hox gene determines the developmental fate of a particular --- of the body. c. Hox genes are found in all animals and there is a --- similarity among animal groups. d. Hox genes have evolved from a common ---
HOX/EXPRESSION
2. Slight shifts in genes called --- (homeotic) genes are responsible for the major differences between animals that arise during development. a. Maybe the changes in the --- of Hox developmental genes explain why all the animal groups of today had representations of the Cambrian seas.
molting/non-segmented/
28.4 Diversity of the Ecdysozoans • Protostomes • Shed outer covering by --- • Contains roundworms and arthropods • Roundworms (phylum Nematoda) ---, generally colorless worms Several parasitic roundworms infect humans Contain a PSEUDOCOELOM: A "false" body cavity that is incompletely lined by mesoderm Provides a space for internal organs and can serve as hydrostatic skeleton • Parasitic Roundworms Ascaris - Intestinal roundworm Trichinella - Trichinosis Filarial worms- Heartworms Wuchereria - Elephantiasis
arthropods/one/carnivorous/cylindrical
3. Centipedes and millipedes are other examples of --- a. There are about 3,000 species of centipedes ("hundred-leggers"). 1) The body is composed of a head and trunk with many segments; each segment has --- pair of legs. 2) Centipedes are ---; the head bears antennae and mouthparts with poison fangs. b. The millipedes ("thousand-leggers") have a --- segmented body. 1) Some body segments are fused with two pair of legs on each resulting segment. 2) They possess more legs than centipedes, although not one thousand as the name states. 3) Millipedes dwell in the soil, feeding on dead organic matter.
DIPLOID/MONOPHYLETIC/same
3. Many animals have the --- life cycle, and usually reproduce sexually. 4. Muscle and nerve tissues characterize animals. a. The evolution of these tissues enabled many types of animals search actively for their food and prey on other organisms. 5. Animals are --- —meaning both invertebrates and vertebrates can trace their ancestry to the --- ancestor.
three/NITROGENOUS/adult
4. Insects a. Most insects live on land; some are secondarily aquatic. b. The insect body is divided into a head, thorax, and abdomen. c. The head bears sense organs and mouthparts. d. The thorax bears --- pairs of legs and one or two pairs of wings; the wings provide advantages in escaping enemies, finding food, and mating. e. A TYPICAL insect is a grasshopper. 1) In grasshoppers, the third pair of legs is suited to JUMPING 2) The front wings are protective and leathery; the thin hind pair of wings foldup. 3) Each side of the first abdominal segment has a tympanum for sound wave reception. 4) Two paired projections form an ovipositor in females used to dig a hole for laying eggs. 5) The grasshopper digestive system is complex. i. The mouth mechanically breaks apart food, and salivary secretions begin digestion. i. The crop temporarily stores food. ii. A gizzard finely grinds the food. iii. Digestion is completed in the stomach; gastric ceca cavities assist absorption of nutrients. f. The excretory system consists of Malpighian tubules. 1) The tubules extend into the hemocoel. 2) --- wastes are collected and excreted into the digestive system. 3) Formation of solid nitrogenous wastes (URIC acid) conserves water. g. The respiratory system begins with openings in the exoskeleton called spiracles. 1) Air enters into small tubules called tracheae. 2) The tracheae branch many times until they reach moist areas of gas absorption. 3) Air movement through this tracheal system is assisted by air sacs. 4) Air enters the anterior four spiracles and exits by the posterior six. 5) Breathing by tracheae is a factor that limits the size of insects. h. The circulatory system contains a slender, tubular heart. 1) This HEART lies against the dorsal wall of the abdominal exoskeleton. 2) The heart pumps hemolymph into a hemocoel where it circulates before returning to the heart. 3) Insect hemolymph is colorless—it lacks any respiratory pigment since the tracheal system transports gases. i. Grasshoppers undergo INCOMPLETE METAMORPHOSIS; the immature nymph resembles the --- j. Other insects undergo complete metamorphosis; the wormlike larvae reorganize into different adults. k. Some species (e.g., BEES and ANTS) exhibit COLONIAL SOCIAL BEHAVIOR.
oligochaete/pairs/hermaphroditic/aortic
6. The common earthworm, Lumbricus terrestris is an ---. Setae protrude in --- directly from surface of body Specialized digestive system • Food is drawn into the mouth by action of muscular pharynx • Food is stored in a crop and ground up in a gizzard • Digestion and absorption occur in a long internal intestine - Typhlosole increases the surface for absorption • Waste is eliminated through the anus • Earthworm segmentation evidenced by: Body rings Coelom divided by septa Setae arranged in pairs on segments Ganglionic swellings and lateral nerves in each segment Nephridia in each segment (The coiled nephridia tubules in most segments have two openings: one is a ciliated funnel that collects coelomic fluid, and the other is an exit through the body wall. Between the two openings, a coiled nephridia tubule removes waste from blood vessels.) Branched blood vessels in each segment Earthworm Reproduction ---, two worms lie in parallel to each other facing in opposite directions • Fused midbody segment (clitellum) secretes mucus, protecting sperm from dessication No larval stage The extensive CLOSED circulatory system has blood vessels running the length of the body and to every segment; muscular --- arches ("hearts") propel blood through the vessels.
hirudin
8. Leeches are annelids that mostly live in freshwater habitats. a. They lack setae and each body ring has several transverse grooves. b. Leeches possess a small anterior sucker around the mouth and a larger posterior sucker. c. Although some are free-living PREDATORS, most feed on body fluids. d. Leeches keep blood from coagulating by ---, an anticoagulant in their saliva.
body/number/cavity
Animals Can Be Characterized by Basic Features of Their "--- Plan" •body plans may vary in (4): - --- of tissue layers (two or three), - symmetry (radial or bilateral), - presence of a body ---, and - embryonic development (protostome or deuterostome).
bilateral/radial/gastrovascular cavity
Checkpoint question Flatworms and cnidarians differ in symmetry, with flatworms being _____ and cnidarians being _____, but the animals of both phyla have a _____. 1. radial/bilateral/ GVx cavity 2. radial/bilateral/no GVx cavity 3. bilateral/radial/gastrovascular cavity
cavity/tract
Checkpoint question Tapeworms (FLATW) and bloodsucking leeches (ANNELIDS) are parasites. What are the key differences between these two? Checkpoint Question Response Whereas both are composed of repeated segments, the segments of a TAPEWORM are filled mostly with reproductive organs and are shed from the POSTERIOR end of the animal. Tapeworms are flatworms with NO BODY cavity and, in their parasitic lifestyle, not even a gastrovascular cavity. Leeches have a body --- and a complete digestive ---
circulation/
Checkpoint question What are three functions of a cnidarian's gastrovascular cavity? Digestion, --- (transport of oxygen, nutrients, and wastes), and physical support and movement
bilateral/
Checkpoint question What shared derived character separates bilaterians from cnidarians? Checkpoint Question Response --- symmetry
tissues/protists
Checkpoint question Why is it thought that sponges represent the earliest branch of the animal kingdom? Sponges lack true ---, and their choanocytes resemble certain flagellated ---
tubular/cnidocytes/
Cnidaria --- animals that most often reside in shallow marine waters • Polyp and medusa body forms • Specialized stinging cells (---) - Fluid-filled capsule, nematocyst • Two-layered body sac - Outer layer - Protective epidermis - Inner layer - Gastrovascular cavity
2.segmentation/coelom/repetition/hydrostatic/independent/bristles/
E. Annelids 1. Annelids are the only trochozoan with --- and a well-developed --- 2. Segmentation is the --- of body parts along the length of the body. 3. A well-developed, fluid-filled coelom and tough integument act as a --- skeleton. 4. Using a hydrostatic skeleton, partitioning the coelom allows for --- movement of the segments so it can not only burrow but crawl on the surface. 5. Setae are --- that protrude from the body wall, can anchor the worm, and help it move: oligochaetes have few setae, polychaetes have many setae. 6. The common earthworm, Lumbricus terrestris is an oligochaete. Earthworms ingest soil and extract nutrients, aerating soil and improving its texture 1.non segmet/cavity/non repetition/partial/dependent/spicules 2.segmentation/coelom/repetition/hydrostatic/independent/bristles/ 3.segment/coelom/non repetition/hydrostatic/independent/spicules
endoderm/mouth
Embryonic Development • Diploblastic - Two tissue layers (e.g., cnidarians) (ectoderm and ---) • Triploblastic - Three tissue layers - Protostomes - First embryonic opening becomes the mouth - Deuterostomes - Second embryonic opening becomes the ---
tubular/stimuli/cells
Hydra Freshwater cnidarian • Small --- poly body about one-quarter inch in length - Gastrovascular cavity is central cavity • Tentacles can respond to --- • Can reproduce sexually and asexually • Nerve net - Interconnected nerve ---
animals/tissues/choanocytes
INVERTEBRATES (96% of animals) 18.5 Sponges Have a Relatively Simple, Porous Body (1 of 2) •Sponges (phylum Porifera) -are the simplest of all ---, -do not have true ---, -usually LACK BODY SYMMETRY, and -are usually marine, although some are found in fresh water. •Their flagellated --- filter food from water passing through pores in the body.
three/sinuses/open
MOLLUSC • Molluscs (phylum Mollusca) Have ---part body plan • Visceral Mass - Contains internal organs • Mantle - May secrete shell and/or contribute to development of gills or lungs • Foot - Muscle adapted for locomotion, attachment, or food capture 1. The radula in the mouth bears many rows of teeth and is used for feeding; a radula is not present in all molluscs. 2. In molluscs, the true coelom is reduced and limited to the region around the heart. 3. Nutrients and oxygen diffuse into the tissues from the --- INSTEAD of being carried into the tissues by capillaries. 4. Most molluscs have an --- circulatory system: a heart pumps hemolymph through vessels into a hemocoel.
lack/cellular/asexual/sexual/spicules/predators/toxic/
SIMPLEST INVERTABRATE = Sponges 1. Only level of animal to --- TRUE TISSUES and to have a --- LEVEL of organization 2. Saclike bodies perforated by many pores 3. Beating of flagella produces water currents that flow through pores into central cavity and out osculum 4. Sessile filter feeders 5. Reproduction • --- reproduction by fragmentation or budding • --- reproduction produces a flagellated larva that may swim to a new location b. The endoskeleton of sponges also contains ---, which are tiny needle-shaped structures with one to six rays, depending on chemical structure. c. Sponges have few ---, due to spicules, and the production of foul smelling and --- substances that discourage predators.
flagellated/preceded/any/unicellular/
The colonial flagellate hypothesis states that 1. animals are descended from an ancestor that resembled a HOLLOW SPHERICAL colony of --- cells. • Individual cells within the colony become SPECIALIZED • Two tissue layers could have arisen by INFOLDING of certain cells into a hollow sphere 2. that RADIA symmetry --- bilateral symmetry in the history of animals. a. In a RADIALLY symmetrical animal, --- longitudinal cut produces 2 IDENTICAL HALVES b. In a bilaterally symmetrical animal, ONLY ONE longitudinal cut yields two identical halves. 3. The choanoflagellates (collared flagellates) most likely resemble the LAST --- ANCESTOR of living animals, and molecular data illustrates that they are the closest living relatives of animals. 4. A choanoflagellate is a single cell, 3-10 μm in diameter, with a flagellum surrounded by a collar of 30-40 microvilli. 5. As the water moves through the microvilli, they engulf bacteria and debris from the water.
WHEEL/sessile/ALL/complementary/forward/CEPHALIZATION
a. Asymmetry means there is no particular body shape (e.g., sponge). b. Radial symmetry describes body parts arranged AROUND AN AXIS, like spokes of a --- (e.g., starfish, jellyfish). 1) Radially symmetrical animals may be --- (i.e., attached to a substrate or less motile). 2) This symmetry enables an animal to reach out in --- directions from one center. c. Bilateral symmetry describes a body having a right and left, or --- halves. 1) Only ONE longitudinal cut down the center produces mirror halves. 2) Bilaterally symmetrical animals tend to be active and to move --- at an anterior end. 3) The development of a head to localize the brain and sensory organs at the anterior end is called ---
crustaceans calcium/
• --- Hard, crusty exoskeleton containing --- carbonate and chitin Most have compound eyes and five pairs of appendages Majority live in marine and aquatic environments Decapods are the most familiar and numerous • Shrimp, lobsters, crayfish, and crabs
cylindrical
• Centipedes Each body segment has a pair of walking legs Live in moist environments Head includes paired antennae and mandibles Appendages on the first trunk segment are jaws that kill or immobilize prey • Millipedes Four thoracic segments each have one pair of legs Abdominal segments have two pairs of legs --- bodies Tough chitinous exoskeleton
brains
• Cephalopods Squids and octopi Head Footed • Force water out mantle cavity for propulsion Tentacles and arms capture prey by adhesive secretions or suckers Beak is used to tear prey apart d. Well-developed sense organs include focusing camera-type eyes. e. Cephalopods, particularly octopuses, have well-developed --- with a capacity for learning.
2. NO/one/incomplete/no
• Flatworms (phylum Platyhelminthes) Flat body --- specialized circulatory or respiratory structures Sac body plan with --- opening (and thus an --- digestive tract) --- body cavity 1. incomplete/no/complete/no 2.no/one/incomplete/no 3. full/two/complete/one
calcareous/
• Gastropods Largest class of molluscs Slugs, snails, whelks, conchs, limpets, nudibranchs Have an elongated, flattened foot Most have a one-piece coiled shell Well-developed head region • Cerebral ganglion and eyes on the ends of tentacles d. Land snails are hermaphroditic. 1) In pre-mating behavior, they meet and shoot --- darts into each other's body wall. 2) Each inserts a penis into the other's vagina; this provides sperm for future fertilization of eggs. 3) Eggs are deposited in soil and development proceeds without the formation of a larvae.
2. billaterally/three/protostome/coelom/rotifers
• Lophotrochozoa --- symmetrical Embryos have --- germ layers --- pattern of development Adults have the organ level of organization Some have a true --- Divided into two groups • Lophophorans (bryozoans, brachiopods, phoronids) • Trocohozoans (flatworms, ---, molluscs, annelids 1. radially/two/deuterostome/cavity/profira 2. billaterally/three/protostome/coelom/rotifers 3. no symmetry/zero/deuterostome/cavity/rotifers
setae/hirudin/
• Other annelids: Most annelids are marine polychaetes • Setae are in bundles on parapodia • Have sex organs only during the breeding season Leeches • Usually found in freshwater habitats • Same body plan as other annelids - No --- - Each body ring has several transverse grooves - Two additional suckers » Keep blood flowing and prevent clotting by means of ---, a powerful anticoagulant
scolex
• Parasitic flatworms are flukes (trematodes) and tapeworms (cestodes) Well-developed nerves and gastrovascular cavity are unnecessary Absence of cephalization • Flukes Reproductive system well developed Usually hermaphroditic Tapeworms Have anterior region with modifications for attachment to intestinal wall of host Behind head region ---, a long series of proglottids are found that contain a full set of both male and female sex organs Complicated life cycles usually involve several hosts
arrow/hermaphroditic
• Planarians (genus Dugesia) Live in freshwater habitats Head is bluntly --- shaped • Auricles function as sense organs • Two light-sensitive eye spots Three kinds of muscle layers: • Outer circular layer • Inner longitudinal layer • Diagonal layer • Planarians, (cont.) Excretory organ functions in osmotic regulation and water excretion Can reproduce asexually or sexually --- • Practice cross-fertilization Have undergone cephalization Ladder-type nervous system
growth/spiral/ALL/outpocketing
• Protostomes vs. Deuterostomes 1. Cleavage - Cell division without --- • Protostomes - --- cleavage • Deuterostomes - Radial cleavage 2. First opening • Protostomes - First opening becomes the mouth • Deuterostomes - First opening becomes the anus, and the second opening becomes the mouth 3. Certain protostomes and --- deuterostomes have a true coelom • Protostomes - Coelom forms by a SPLITTING of the MESOderm • Deuterostomes - Coelom forms by an --- of primitive gut
changes/regulation
•An alternative hypothesis proposes that --- in the regulation of homeotic gene expression led to the diversity of segment and appendage types. -To test this hypothesis, researchers compared gene expression patterns in the embryos of a centipede and a velvet worm. -The results support the hypothesis that the diversification of arthropods occurred through changes in the --- of homeotic gene expression.
lack/ingestion/life
•Animals -are eukaryotes, -are multicellular heterotrophs, and -have cells that --- cell walls. •Animals also use ---, the eating of food. •Animal --- cycles and embryonic development also distinguish animals from other groups of organisms.
calcium/
•Echinoderms have -an endoskeleton of hard ---containing plates under a thin skin, -a water vascular system based on a network of water-filled canals that branch into extensions called tube feet, and -the ability to regenerate lost arms. Checkpoint question, Contrast the skeleton of an echinoderm with that of an arthropod. An echinoderm has an endoskeleton; an arthropod has an exoskeleton.
PUPA
•Insect life cycles often include metamorphosis, during which the animal takes on different body forms as it develops from larva to adult. -More than 80% of insect species undergo COMPLETE metamorphosis, in which a free-living larva transforms from a pupa into an adult. -Other insect species undergo INCOMPLETE metamorphosis, in which the transition from larva to adult is achieved through multiple molts, but WITHOUT forming a ---
color/homeotic
•Specialized appendages and protective --- patterns have also played a major role in this group's success. •These traits frequently result from evolutionary changes in the timing and location of --- gene expression.
SHORT/
•The extraordinary success of insects is due to -body segmentation, -an exoskeleton, -jointed appendages, -flight, -a waterproof cuticle, and a complex life cycle with --- generations and large numbers of offspring
leeches
•The two major clades of annelids are -errantians (mostly mobile marine worms) and -sedentarians (less mobile worms, including earthworms, ---, and many tube-dwellers).
backbone/soft/present
•only one phylum includes vertebrates, animals with a ---. •Roughly 96% of animals are INVERTEBRATES, animals that lack a backbone. Checkpoint question, What are two major differences between the fossil animals from the Ediacaran and the Cambrian periods? Checkpoint Question Response Ediacaran animals were all ----bodied; many Cambrian animals had hard parts such as shells. Few Ediacaran animals can be classified as members of present-day groups; many Cambrian animals are clearly related to ----day groups.
