EXAM 3 31, 32, 33, 34

The adaptation that freed vertebrates from water for reproduction and allowed them to radiate into diverse terrestrial environments was the __________.

amniotic egg

The water vascular system of a sea star functions in __________.

movement of the tube feet

Lichens are important pioneers in areas that have been burned by fires or destroyed by lava flows because _____

they are important in the initial stages of soil formation

You are an entomologist interested in learning more about the flight motor center of the dragonfly. Which part of its body should you study?

thorax

All animals with bilateral symmetry have __________ germ layer(s)

three

Sowbugs are really crustaceans, not insects. Therefore, a sowbug does NOT have __________.

three pairs of legs

Animal tissues develop from embryonic germ layers. Triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm) and three basic body plans related to body cavities (acoelomate, pseudocoelomate, and coelomate).

A pseudocoelom has the same functions as a true coelom. A diploblast has no mesoderm. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity.

Neither (N)

Acoela

Which of the following statements is correct?

All animals share a common ancestor. It is thought to have been a protist similar to a choanoflagellate.

Which of the following statements about deuterostomes is false?

All deuterostomes exhibit radial symmetry in their bodies.

All deuterostomes have a similar pattern of early embryonic development

All deuterostomes have a coelom. All deuterostomes are triploblastic and have three tissue layers.

The following statements describe something about the body structures or functions of fungi. Identify those statements that are correct.

All fungi are heterotrophs; some species live as decomposers and others as symbionts. Some fungi secrete digestive enzymes into the environment and then absorb the digested nutrients. Some fungi can grow as either filamentous or single-celled forms. Mycelia are made up of small-diameter hyphae that form an interwoven mass, providing more surface area for nutrient absorption. All fungi are heterotrophs. Most obtain carbon compounds by decomposing organic matter, while others live in a symbiotic association with other organisms. The feeding structure of a multicellular fungus is the mycelium, which consists of numerous small-diameter filaments, or hyphae. Nutrients absorbed by the hyphae can flow throughout the mycelium in both coenocytic hyphae and septate hyphae.

Which of the following chordates is most likely to look least like other chordates?

An adult tunicate does not have a notochord (or vertebrae), a nerve cord, or a post-anal tail. The only chordate feature it retains is pharyngeal slits.

Identify the features that distinguish animals from organisms in other multicellular kingdoms.

Animals are ingestive heterotrophs.

Animals probably evolved from colonial protists. How do animals differ from these protist ancestors? (eText Concept 32.1)

Animals have more cells than their protist ancestors, and their cells show greater specialization.

Which of the following phyla contains animals that are lophotrochozoans with a mouth, anus, and true coelom?

Annelida

Leeches are members of the phylum __________ in the clade of bilaterally symmetric animals called __________.

Annelida ... Lophotrochozoa

Which of these primate groups is most closely related to hominids?

Apes, such as chimpanzees, are the primates most closely related to humans.

An unidentified species of animal displays the following characteristics: bilateral symmetry, a complete digestive system, an open circulatory system, distinct body segmentation, and a series of molting stages during growth. To which of the following animal phyla does this species most likely belong?

Arthropoda

Cup fungi are in the phylum _____.

Ascomycota Cup fungi are a type of sac fungus.

Where does meiosis occur in a mushroom?

Basidia Basidia are specialized cells in the gills of a mushroom in which haploid nuclei fuse in preparation for meiosis.

Which of the following is true?

Both larval and adult dragonflies are carnivorous.

Nematodes and arthropods are the largest ecdysozoan phyla. Which of the following statements are true?

Both nematodes and arthropods must molt in order to increase in size. Both nematodes and arthropods possess an external covering, or cuticle. Some nematodes are parasitic on humans. Arthropods possess an open circulatory system. Arthropods are named for their jointed appendages. The ecdysozoans include nematodes, arthropods, and other phyla that have tough external coats, or cuticles, that must be shed as they grow. This process of shedding, or molting, is called ecdysis. Nematodes, or roundworms, are unsegmented pseudocoelomate worms that lack a circulatory system. Although most nematodes are free-living, some well-known nematodes, such as hookworms and pinworms, are parasitic. Arthropods have a reduced coelom and an open circulatory system. Arthropods have segmented bodies that enable specialization of body structures such as appendages.

The common ancestor is likely to have been a protist that lived during the Neoproterozoic.

Cambrian This saw the culmination of the rapid diversification of animals that began in the late Precambrian.

The earliest ancestors of about half of all extant animal phyla can be traced back to the _____ explosion.

Cambrian This saw the culmination of the rapid diversification of animals that began in the late Precambrian.

Which of the following is characteristic of protostomes?

Cell fate is determined early during embryonic development.

An active marine predator is found possessing these characteristics: a series of tentacles (modified from the foot), a highly developed nervous system, and elaborate eyes. To which of the following clades does this organism most likely belong?

Cephalopoda

If an animal has segments, bilateral symmetry, pharyngeal clefts, a post-anal tail, and deuterostomic development, it must be a member of the __________.

Chordata

You are interested in attracting dragonflies to the area around your home. Doing which of the following would attract them to mate?

Creating a freshwater pond.

Which of the following is an archosaur group?

Crocodiles belong to an archosaur lineage that reaches back to the late Triassic

Cheliceriforms, which are named for their clawlike feeding appendages, called chelicerae, include sea spiders, horseshoe crabs, spiders, scorpions, ticks, and mites. Myriapods include millipedes and centipedes, which are terrestrial species.

Crustaceans are primarily aquatic animals such as lobsters, crabs, and crayfish. Insects possess three body regions (head, thorax, and abdomen), may have one or more pairs of wings, and have six legs. Insects are the largest and most diverse group of arthropods, including numerous species of butterflies, beetles, flies, ants, and many others.

Which feature of deuterostome development explains the formation of identical human twins?

Deuterostomes have indeterminate development. Most deuterostomes have indeterminate cleavage, meaning that each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo. For example, if the cells of a sea urchin embryo are isolated at the four-cell stage, each can form a complete larva. It is the indeterminate cleavage of the human zygote that makes identical twins possible. Read about protostome and deuterostome development.

Select the correct statement(s) about animal body plans.

Development in all animals is determined by the unique family of Hox genes (or other similar homeobox genes).

Deuterostomy (D)

Echinodermata, Chordata; most Arthropoda; few Mollusca, few Annelida

Which example below is a current hypothesis regarding the Cambrian explosion?

Evolution of the Hox gene complex provided developmental flexibility.

Which structure is not an innovation that occurred during vertebrate diversification?

Exoskeletons are present in groups other than the vertebrates, including some in the protostome lineage.

True or false? An organism that is radially symmetric has many well-developed head regions.

False An organism that is radially symmetric does not have a well-developed head region.

True or false? In most fungi, fertilization is complete after the cells fuse together.

False In most fungi, fertilization is a two-step process consisting of the fusion of cells and then the fusion of nuclei in the fused cells.

Which of the following occurred during the Mesozoic era?

Flight evolved in pterosaurs and birds.

Which of the following is a difference between plants and fungi?

Fungi are heterotrophic, and plants are autotrophic. Fungi are heterotrophic and absorb their nutrients, and plants are photosynthetic.

Fungi form mutualistic relationships with plants and animals. Which of the following is an example of such a relationship?

Fungi help break down plant material in the guts of grazing mammals. Endophytes in leaves produce toxins that deter herbivores. Fungi help break down wood in the guts of termites. Fungi can help increase drought tolerance in plants Fungi enter into these and many other mutualistic relationships with other organisms.

What role do pheromones play in fungal sexual reproduction?

Fungi use these chemical signals to determine whether a potential sexual partner is of a suitable mating type.

Almost all of the members of this phylum form arbuscular mycorrhizae in a mutualistic partnership with plants.

Glomeromycota Nearly all glomeromycetes form arbuscular mycorrhizae.

Which of the following pairs is NOT a correct match?

Gnathostomata, hagfish

What was the earliest hominin to have an enlarged brain (relative to body size)?

Homo habilis

The primates that spend the most time walking upright are the _____.

Humans are hominids.

Which of the following events occurs first in the development of a spore into a mature mushroom?

Hyphae are produced by mitosis. The spore undergoes mitosis to produce hyphae, which then form a filamentous network called a mycelium.

Which of these anthropoid groups consists of primates who are mostly tree dwellers and whose forelimbs and hind limbs are about equal in length?

In addition to these characteristics many monkeys have tails.

All chordate embryos exhibit four derived characters: a notochord; a dorsal, hollow nerve cord; a muscular, post-anal tail; and pharyngeal slits or clefts.

In many chordates, these characters develop into different structures or are reduced in form as the animal continues its development. For example, the pharyngeal slits develop into gill slits in aquatic vertebrates, and a jointed skeleton forms around a reduced notochord in most vertebrates.

What is the importance of the extended dikaryotic stage in the life cycles of basidiomycetes and ascomycetes?

It allows for more genetic recombination.

Tunicates and lancelets are two groups of chordates. Both possess the four derived characters of chordates during their development. However, whereas adult lancelets retain all four of these characters, adult tunicates retain only one (pharyngeal slits).

Lancelets swim by contracting a series of muscles located along the side of the notochord, which results in a motion similar to the swimming motion of fishes. Larval tunicates are mobile, using their tail muscles and notochord to propel themselves through the water; adult tunicates are sessile or float with the current. Adult lancelets and tunicates use their pharyngeal slits to filter suspended food particles from the water.

A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A postdoctoral student thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus?

Look for cell walls under a microscope. Fungal cells have cell walls, and animal cells do not.

Which of the following statements about the phylum Echinodermata is true?

Many species possess an internal calcareous skeleton and spiny dermal projections. Larval forms show evidence of bilateral symmetry, which is mostly lost in the adult form. One of the clades in this phylum is Asteroidea, which includes the sea stars and sea daisies. All possess a water vascular system, which permits movements via tube feet.

Which structure is not involved in the reproduction of at least one major group of fungi?

Mycelium A mycelium is a network of filaments that forms the body of a fungus.

Which structure allows the growing mushroom to nourish itself?

Mycelium The mycelium is a mass of filaments with a high surface-area-to-volume ratio, which allows for efficient nutrient absorption.

You can buy mycorrhizal fungus to add to soil when you plant trees and other plants. Why would you want to do this?

Mycorrhizal fungi assist plants in the absorption of essential nutrients.

All animals can trace their lineage to a common ancestor that lived in the _____.

Neoproterozoic era The common ancestor is likely to have been a protist that lived during the Neoproterozoic.

Which of these primate groups lives in trees in Central and South America and have nostrils that are wide open and far apart?

New World monkeys You might recall that the Western Hemisphere is also referred to as the New World.

Triploblasts have tissues derived from three embryonic germ layers: endoderm inside, ectoderm outside, and mesoderm in the middle. The three basic body plans of triploblasts relate to the presence or absence of a body cavity.

No body cavity: acoelomate Body cavity lined on the inner side by endoderm-derived tissue and on the outer side by mesoderm-derived tissue: pseudocoelomate Body cavity lined entirely by mesoderm-derived tissue: coelomate

What is the key difference between a coelom and a pseudocoelom?

Only a coelom is fully lined with mesoderm tissue. A coelom is formed from mesoderm tissue, whereas a pseudocoelom is formed from mesoderm and endoderm and is not fully lined with mesoderm. Read about body cavities.

Which statements about the phylogenetic tree are true?

Organism (a) is a common ancestor of all chordates. Rays and frogs have a vertebral column. Birds and ray-finned fishes have a notochord and jaws. Mammals and turtles are more closely related than are lungfishes and sharks. Descendants of organism (d) have legs.

Fungi have diverse ecological niches, with most fungi being decomposers.

Other fungi exist in mutualistic associations. For example, it is estimated that over 85% of plants have mycorrhizal fungi living on their roots; the fungi provide the plants with inorganic nutrients, while receiving organic nutrients in return. Still other fungi are parasites, causing harm to the organisms they live with.

__________ fungi absorb nutrients from living organisms.

Parasitic Mutualistic

Which structure can be used for feeding and gas exchange?

Pharyngeal gill slit . A pharyngeal gill slit is an opening into the throat that can be used for feeding and gas exchange

Which term describes the fusion of cytoplasm from two individuals?

Plasmogamy Plasmogamy is the fusion of cytoplasm from different individuals.

Protostomy (P)

Platyhelminthes, Rotifera, Nematoda; most Mollusca, most Annelida; few Arthropoda

The animal phylum most like the protists that gave rise to the animal kingdom is _____.

Porifera Evidence that supports this includes the lack of true tissue in sponges and the close similarity between choanocytes and choanoflagellates.

_____ are the oldest known primate group.

Prosimian fossils date back to the end of the dinosaurs.

Which of the following correctly lists probable ancestors of modern humans from the earliest to the most recent?

Sahelanthropus, Ardipithecus, Australopithecus, Homo

__________ are members of the phylum __________ and feed by __________.

Sea anemones ... Cnidaria ... using stinging cells to capture small animals that venture too close to them

The body of a multicellular fungus consists of a network of hyphae, which form an interwoven mass called a mycelium.

Some hyphae, called septate hyphae, are divided into cells by crosswalls, or septa. Coenocytic hyphae do not have septa; these hyphae consist of a continuous cytoplasmic mass that contains many nuclei and organelles.

Animal bodies may exhibit symmetry or a lack of symmetry (asymmetry).

Some symmetrical animals exhibit radial symmetry, in which the body is wheel- or spoke-shaped, with no obvious front, back, right, or left. Other symmetrical animals exhibit bilateral symmetry, in which the body has left and right sides, a front and back, and a top and bottom.

Which of the following statements about vertebrates is true?

The development of an amniotic egg and internal fertilization allowed vertebrates to reproduce away from water. Reptiles and their descendants reproduce on land via an amniotic egg, which prevents the embryo from drying out.

Which of the following statements about fungi is/are true?

The dominant stage of the life cycle is usually haploid. The haploid nuclei of dikaryotic hyphal cells fuse to form a diploid zygote. Many species obtain their nutrients from decaying organic matter. Spores germinate and then mitotically divide to form a mycelium.

Insects and their relatives are the most species-rich group of living organisms. The diversity of characteristics such as wing shape, mouthparts, and reproductive tactics enable insects to live in most terrestrial and freshwater habitats.

The evolutionary tree below shows the relationship between the phyla and subphyla within the clade Ecdysozoa, which includes animals with tough outer coverings that must be shed for growth to occur. Myriapods, cheliceriforms, crustaceans, and insects and their relatives (hexapods) together comprise the phylum Arthropoda, which is marked by jointed appendages, segmented bodies, and hard exoskeletons. Note that the tree does not show all phyla in the clade Ecdysozoa, nor does it show all orders of insects and their relatives in the subphylum Hexapoda.

Select the correct statement about the evolution of animals.

The oldest generally accepted fossils of large animals range in age from 565 to 550 million years old. The Ediacaran biota was a group of early animals. Some are sponges, whereas others may be related to living cnidarians. Still others of these fossil organisms have proven difficult to classify. Read about this biota.

The phylogenetic tree shown above represents the evolutionary relationships between the major clades of chordates. The hatch marks on the tree indicate derived characters shared by all the groups to the right of each mark. For example, all chordates have a notochord, and all mammals produce milk.

The phylogenetic tree also shows the degree of relatedness of particular groups of chordates. For example, mammals are more closely related to hagfishes than to lancelets.

Which characteristics define a chordate?

The presence of four specific morphological traits Chordates are defined by the presence of four morphological traits: a notochord, a dorsal nerve cord, pharyngeal gill slits, and a tail behind the anus.

Which characteristic distinguishes echinoderms from the other two deuterostome lineages?

Their body plan Echinoderms exhibit a unique body plan characterized by an endoskeleton and a water vascular system.

Which of the following allows dragonflies to maneuver so well?

Their wings can move independently of one another

Which of the following is characteristic of the phylum Platyhelminthes?

They are dorsoventrally flattened. This is why they are also called flatworms.

Which characteristic below is shared by plants, fungi, and animals?

They are multicellular eukaryotes.

Which statement below about zygosporangia is/are true?

They are multinucleate formations. They are resistant to freezing and drying. They are produced through plasmogamy. They are metabolically inactive.

Which of the following is/are characteristic of sponges?

They consist of two layers of cells with a noncellular gelatinous layer between them. They have holes, or pores, in specialized cells, through which water enters. They have collar cells.

What is one visible feature that makes it easy to identify sea cucumbers as echinoderms?

They have five rows of tube feet.

Which of the following is NOT a characteristic of all animals?

They have tissues, organs, and organ systems. Sponges are considered animals, and they lack these levels of organization.

Which of the following is true about the phylum Cnidaria?

They may use a gastrovascular cavity as a hydrostatic skeleton.

Which of the following is true of annelids?

They perform gas exchange across their skin. Cutaneous respiration occurs across their skins. Polychaetes have lateral extensions, called parapodia, which provide even more surface area for cutaneous respiration.

True or false? Most of the cells in a mushroom contain haploid nuclei.

True A mushroom consists mainly of hyphae that are heterokaryotic, which means they have two distinct haploid nuclei per cell; these nuclei may fuse in specialized cells called basidia and become diploid in preparation for meiosis and spore production.

__________ arose very early in hominid evolution; __________ evolved more recently.

Upright posture ... large brains

Which of the following is a trait shared by protostomes and deuterostomes?

a body cavity

A true coelom is __________.

a body cavity lined with mesoderm

A major characteristic of arthropods is __________.

a chitinous exoskeleton

Sponges lack __________.

a complete digestive tract true tissues a nervous system the ability to make organic compounds from CO2 and water

Which of the following is radially symmetrical?

a doughnut A doughnut has no front, no back, no left, and no right.

"Cephalization" refers to having _____.

a head

During the development of most animals, cleavage leads to __________.

a multicellular blastula

An ascus is _____.

a saclike structure containing spores

A feature of bony fish not found in sharks is __________.

a swim bladder

Humans and lorises share many traits that probably evolved in our early primate ancestors; one such trait is __________.

a thumb that is relatively mobile and separate from the fingers

In most insects, gas exchange is accomplished by __________.

a tracheal system

Fungi obtain nutrients through _____.

absorption Fungi are heterotrophs that acquire their nutrients by absorbing small molecules from the surrounding medium.

Listed below are four adaptations of terrestrial vertebrates. Which is a characteristic only of truly terrestrial animals with no need to return to water at any stage of the life cycle?

amniotic eggs In contrast to the shell-less eggs of amphibians, amniotic eggs (of most reptiles, and a few mammals) have a shell that retains water and can be laid in a dry place.

Some digestion in sponges takes place in the __________.

amoebocytes

Habitat loss, the spread of a fungal disease, climate change, and pollution are causing severe population declines and extinction in __________.

amphibians

The first vertebrates to live on land were __________.

amphibians

Most members of which of the following groups are most closely associated with a wet or moist environment?

amphibians Amphibians typically have a water-permeable skin that does not easily resist drying. Thus, amphibians tend to be found in moist environments.

According to this phylogenetic tree, the animals most closely related to reptiles and mammals are _____.

amphibians The branching pattern of the phylogenetic tree makes it clear that amphibians are most closely related to reptiles and mammals

A dramatic example of the pathogenicity of certain fungi is the dramatic decrease of the American chestnut tree by _____.

an ascomycete

The diagnostic feature of Chondrichthyes is _____.

an endoskeleton of calcified cartilage The cartilaginous skeleton of sharks and their relatives is reinforced with calcium.

Molecular evidence suggests that fungi _____.

and animals have a common ancestor

A marine biologist dredges up a small animal from the bottom of the ocean. It is uniformly segmented, with short, stiff appendages and soft, flexible skin. It has a complete digestive system and a closed circulatory system, plus multiple true coeloms. Based on this, you determine that the animal must be a(n) _____.

annelid The description matches the characteristics of annelids.

Humans, apes, and monkeys are classified together as __________.

anthropoids

All species of New World monkeys are __________.

arboreal

What is the major feature of glomeromycetes?

arbuscules

Members of the phylum Mollusca _____.

are soft-bodied and often covered by a shell Members of the phylum Mollusca are soft-bodied and are often covered by a shell.

The mushroom in a basidiomycete life cycle serves the same function as the _____ in the ascomycete life cycle, which is to _____.

ascocarp ... scatter sexually produced spores

Two of the most common mycoses (fungal infections) in humans are _____.

athlete's foot and Candida (yeast) infections

Which of the following traits distinguishes hominins from other apes?

bipedalism (upright walking)

What structure is responsible for gas exchange in most spiders?

book lungs The extensive surface area of book lungs is a structural adaptation that enhances the exchange of O2 and CO2 between the hemolymph and air.

Which of the following are lophotrochozoans that have a lophophore?

brachiopods

Jaws evolved _____.

by modification of the skeletal rods that previously supported the anterior pharyngeal gill slits According to a leading hypothesis, this marked a reduction in the number of pharyngeal gill slits and a change in the function of gills from feeding to respiration.

Which of the following animals is an amphibian?

caecilian

Which of the following features is associated with bilateral symmetry?

cephalization

Fungi are __________ organisms

chemoheterotrophic

The cell walls of fungal cells are composed of _____.

chitin

Fungi that consist of a continuous mass containing hundreds or thousands of nuclei are known as _____.

coenocytic The coenocytic condition results from the repeated division of nuclei without cytoplasmic division.

The asexual spores produced by members of the phylum Ascomycota are called _____.

conidia These spores are not formed within sporangia.

Which of the following is among the earliest known vertebrates?

conodonts

You are an entomologist specializing in the closest relatives of the dragonflies. What do you study?

damselflies

Hyphae with two nuclei per cell are called _____.

dikaryotic

While hiking through a forest, you discover a fungus growing on the remains of a decaying tree trunk. You hypothesize that it is a basidiomycete fungus because it resembles a mushroom in shape and size. If your logic is correct, microscopic analysis of the tissue found in the stalk of this fungus will reveal the presence of _____.

dikaryotic cells with haploid nuclei Environmental cues, such as rain and temperature changes, induce the dikaryotic mycelium (containing two haploid nuclei) to form compact masses that develop into basidiocarps, or mushrooms.

Karyogamy produces a _____.

diploid zygote Karyogamy is the fusion of nuclei.

Which of the following is a characteristic of cnidarians?

ectoderm and endoderm

Which of the following groups has a true coelom, a lophophore, and no distinct head?

ectoprocts

Which of the following characteristics is NOT shared by extant birds and extant reptiles?

endothermic metabolism

Complete metamorphosis __________.

features a larval stage that looks different from the adult

Sponges feed by __________.

filtering small particles from water

Which of the following animals does NOT have a body cavity?

flatworm Flatworms are acoelomates, even those that are not classified as acoels.

Evidence that mycorrhizae, the mutualistic relationship between plants and fungi, existed from the beginning of the colonization of land comes from _____.

fossils

The diploid phase of the life cycle is shortest in which of the following?

fungus Most fungi are haploid except for a very brief diploid stage that is seen only when a fungus reproduces sexually.

Which of the following is a characteristic of cnidarians?

gastrovascular cavity The gastrovascular cavity, characterized by a single opening, is the digestive compartment of cnidarians.

Consider the following list of animals: giant squid, earthworm, largemouth bass, snail, tapeworm, coral, and starfish. The two that belong to the same phylum are the __________, and their phylum is __________.

giant squid and snail ... Mollusca

Included among the modern groups of apes are __________.

gibbons, orangutans, gorillas, chimpanzees, and bonobos

Fungi produce _____ spores.

haploid Fungal spores are haploid.

An important trend in animal evolution was cephalization. An animal is said to show cephalization when it _____.

has an aggregation of sensory neurons at the anterior end Cephalization is an evolutionary trend toward the concentration of sensory equipment at the anterior end. It is associated with bilateral symmetry.

Parasitic fungi possess hyphae that are modified to penetrate and absorb nutrients from host tissue. Such modified hyphae are called _____.

haustoria

Annelids __________.

have a mouth that is separate from the anus

The arthropods superficially resemble earthworms in that both groups __________, yet the two are distinctly different because arthropods, but not earthworms, __________.

have prominently segmented bodies ... have jointed appendages

An important example of interaction between fungi and certain other organisms is mycorrhizae, in which the fungal partners _____.

help plants take up nutrients and water Mycorrhizae are mutualistic associations with the roots of plants, which enhance the absorption of nutrients.

During typical earthworm reproduction __________.

hermaphroditic individuals exchange sperm

A lamprey, a shark, a lizard, and a rabbit share all the following characteristics EXCEPT __________.

hinged jaws

During embryological development, the anus forms before the mouth in _____.

humans During gastrulation, the developing digestive tube of the embryo initially has a single opening, the blastopore. After the archenteron develops, a second opening forms at the opposite end of the gastrula. The mouth of many protostomes develops from the first opening, whereas in deuterostomes the mouth is derived from the second opening.

The body of most fungi consists of threadlike _____, which form a network called a _____.

hyphae ... mycelium Hyphae form a network called a mycelium.

Where and when does fertilization occur in the mushroom life cycle?

in a mushroom, when the nuclei of a dikaryotic cell fuse

The majority of animal species are __________.

insects

Plasmogamy

is the fusion of hyphae.

The presence of a coelom is advantageous because __________.

it allows room for the development and movement of internal organs

Which of the following groups does NOT exhibit bilateral symmetry?

jellies

During what stage of fungal reproduction are diploid cells produced?

karyogamy

What sexual processes in fungi generate genetic variation?

karyogamy and meiosis During karyogamy, the haploid nuclei fuse, and meiosis produces genetic variation in several ways.

Unlike other animals, sponges __________.

lack true tissues

The common ancestor of all these chordate groups EXCEPT the _____ probably had paired appendages.

lampreys Lampreys lack paired appendages.

A __________ is a chordate but not a vertebrate.

lancelet

Many young animals are __________, a sexually immature form that is morphologically distinct from the adult stage. These young animals undergo __________ to become __________, which resemble adults but are not yet sexually mature.

larvae ... metamorphosis ... juveniles

Fungi in the phylum Basidiomycota are the most important decomposers of wood because of their ability to break down _____.

lignin

One of the primary developmental/anatomical characteristics distinguishing the major animal phyla is the condition of the body cavity. A pseudocoelomate animal is one in which the body cavity is __________.

lined on one side by mesoderm and on the other side by endoderm

Ectoprocts and brachiopods are collectively referred to as _____.

lophophorates The lophophore is a structure common to these two phyla that bear ciliated tentacles.

The gill flap, or operculum, was an important adaptation for fish because it helps with __________.

maintaining a supply of oxygen

Which of these is the only chordate group that has hair?

mammals Hair is one of the defining characteristics of mammals.

The opossum is an example of a(n) __________ mammal.

marsupial

There are three major groups of mammals, categorized on the basis of their _____.

method of reproduction Monotremes are egg-laying mammals, marsupials are pouched mammals, and eutherians are placental mammals.

Analysis of DNA from a variety of sources has led most researchers to agree that __________.

modern humans emerged from Africa

Which of the following features is characteristic of the poriferan (sponge) body plan or life history?

motile larvae Zygotes develop into flagellated, swimming larvae that disperse from the parent.

There is a fungus in Oregon that covers 890,965 hectares! The bulk of this fungus is most likely _____.

mycelia

All mammals __________.

nourish their offspring through mammary glands

The choanocyte of a sponge and the nematocyst of a cnidarian both function in __________.

obtaining food

In fungi, the function of the mycelium is _____.

obtaining food The hyphae form an interwoven mat called a mycelium, the feeding network of a fungus.

Primates are distinguished from other mammals by __________.

opposable thumbs, nails, and good depth perception

Some species of rotifers consist solely of females. Their method of reproduction is described as _____.

parthenogenesis The females lay unfertilized eggs that develop into females.

Which of the following chordate characteristics contributes most to suspension-feeding devices in many invertebrate chordates?

pharyngeal slits or clefts

Which of the following chordate characteristics contributes most to the formation of your ears?

pharyngeal slits or clefts

Tapeworms are highly specialized worms that make their living as endoparasites. To which of the following phyla do the tapeworms belong?

phylum Platyhelminthes

Which choice below generally represents the correct order of events in fungal sexual reproduction?

plasmogamy, karyogamy, meiosis, germination

Some cnidarians go through both a motile stage and a sessile (attached) stage during their life cycle. The attached stage is called a(n) __________

polyp Sessile polyps are cylindrical forms that attach to a substratum and extend their tentacles, waiting for prey.

Gastrulation is the process that directly forms the _____.

primary germ layers Gastrulation gives rise to either two or three germ layers.

An animal with a true coelom that has __________ cleavage must be a(n) __________.

radial ... deuterostome

Which of the following sets of animals contains only gnathostomes?

rays, turtles, pigeons, and tuna

The proglottids of a tapeworm contain an elaborate __________ system.

reproductive

This phylogenetic tree indicates that mammals are most closely related to _____.

reptiles

Indeterminate cleavage produces embryonic cells that __________.

retain the capacity to develop into a complete embryo

From the human perspective, which of the following kinds of fungi would be considered the least useful or beneficial?

rusts Rusts include destructive plant parasites.

Fungi of the phylum Ascomycota are recognized on the basis of their production of _____ during sexual reproduction.

saclike structures The production of saclike structures during sexual reproduction is characteristic of the phylum Ascomycota.

Which of the following animals is most closely related to spiders?

scorpions

Which of the following are thought to be most closely related to humans?

sea stars Humans and sea stars are deuterostomes.

Which of the following statements about hominin evolution is correct? As hominins have evolved, _____.

sexual dimorphism was significantly reduced Reduced sexual dimorphism is associated with pair-bonding.

The zygotes of many protostomes undergo __________ cleavage and __________ cleavage.

spiral ... determinate

Lichens are _____.

symbiotic associations of photosynthesizers and fungi

Through what means do coral animals capture their food?

tentacles that trap food particles All cnidarians, including coral, are predators.

In the embryo of a shark, ectoderm gives rise to __________; mesoderm gives rise to __________; endoderm gives rise to __________.

the central nervous system ... muscle ... the lining of the digestive tube

In arthropods, molting is necessary because __________.

the chitinous exoskeleton cannot grow

Which of these contains two haploid nuclei?

the heterokaryotic stage of the fungal life cycle The heterokaryotic stage is produced by plasmogamy.

A unique feature of craniates is _____.

the neural crest The neural crest is the band of embryonic cells, which contribute to the formation of a wide variety of different adult tissues.

Which of the following is the defining characteristic of the clade Ecdysozoa for which this group is named?

the secretion of stiff external skeletons that must be shed to permit growth

Some species of rotifers undergo parthenogenesis, which means that __________.

the species consist only of females that produce more females from unfertilized eggs

Fungal species are assigned to particular phyla based on _____.

the type of sexual structure they form

Some sharks are viviparous, which means that __________.

the young develop within the female's body

Which of the following groups of worms is/are completely parasitic?

trematodes

Which one of these chordate groups lacks a post-anal tail and a notochord as adults?

tunicates While larval tunicates have a post-anal tail and a notochord, adult tunicates do not.

Which of the following can be found in vertebrates but NOT in lancelets and tunicates?

two or more clusters of Hox genes duplications of genes that produce signaling molecules and transcription factors neural crest

What do lampreys, sharks, snakes, turtles, and cats have that a hagfish lacks?

vertebrae Hagfish do not have a vertebral column.

Which of the following is NOT a diagnostic feature of the Chordata?

vertebrae Lancelets and tunicates are two subgroups of chordates that lack vertebrae. Hagfishes do, too.

Cephalopods are the only molluscs __________.

with a closed circulatory system

Which feature below is unique to chytrids?

zoospores (flagellated spores)

Which of the following correctly lists the embryonic stages in the order that they develop

zygote, blastula, gastrula, larva