Bio 94 Midterm #3
A, Placental mammals provide considerable maternal care, increasing offspring survival.
A placenta and viviparity are most likely adaptations for increasing ______. A) parental care and offspring survival B) the amount of yolk available to offspring C) the number of offspring produced D) the chance that the offspring will be female
C, Lampreys are a basal vertebrate taxon.
An example of a vertebrate is a(n) _____. A) acorn worm B) sea urchin C) lamprey D) tunicate
D
Animals that feed primarily or exclusively on plants and algae are classified as _______. A) omnivores B) carnivores C) detritivores D) herbivores
A, Yes. Time to get out the butter and lemon and eat some fried crickets!
Crustacea (the group that contains crustaceans like lobsters, crabs, shrimp, and isopods) used to be considered a monophlyetic group. However, recent molecular work suggests that it is paraphyletic, containing traditional crustaceans and which of the following other arthropod groups? A) insects B) chelicerates C) onychophorans D) myriapods
D, Both have internal skeletons, so they can both be considered endoskeletons.
Do echinoderms and vertebrates both have endoskeletons? Explain. A) The five fused or separate plates in an echinoderm are not equivalent to the many bones of a vertebrate's endoskeleton. B) Even though the echinoderm's calcium carbonate plates are underneath the skin, they should be considered an exoskeleton since they are outside all the internal parts. C) Echinoderms have calcium carbonate plates, while vertebrates have bones mostly made of calcium phosphate. Therefore, echinoderms do not have true endoskeletons. D) Echinoderms have a calcium carbonate endoskeleton, and vertebrates have a bony endoskeleton made of calcium phosphate.
A, In some cases, as much as 20 percent of the sugar molecules produced by a plant are transferred to symbiotic fungi.
Experiments with isotopes used as tracers showed that some fungi _____. A) obtain sugars from plants in exchange for phosphorus, nitrogen, and other soil nutrients B) help plants by providing them with sugar C) take carbon dioxide from plants D) take nutrients from plants
D, The large surface area of a fungal mycelium is fundamental to an absorptive mode of life.
Fungal mycelia _____. A) have a set morphology when mature and rarely change size or shape B) have a very specific evolutionary preserved structure C) are found almost exclusively in dry areas D) have a large surface area composed of branching hyphae
D, Fungi can absorb nutrients from the host and benefit the host in another fashion.
Fungi often live in close association with other organisms in a nondetrimental fashion known as ______. A) predation B) parasitism C) pathology D) mutualism
B, they got bigger 4heads over time thats embarassing
How did the forehead and brow ridge of hominin skulls change through time? A) The forehead and brow ridges became broader and wider in later skulls than in earlier skulls. B) The forehead became much larger, and the face became "flatter"; the brow ridges are less prominent in later skulls than in earlier skulls. C) The forehead remained the same size, but the brow ridges became less prominent in later skulls than in earlier skulls. D) The forehead became taller and the brow ridges are more prominent in later skulls than in earlier skulls.
B, In insects with hemimetabolous metamorphosis, juveniles resemble miniature adults. In insects with holometabolous metamorphosis, there is a distinct larval stage.
How do hemimetabolous and holometabolous metamorphosis differ? A) In hemimetabolous metamorphosis, juveniles are a dispersal stage. In holometabolous metamorphosis, juveniles are sessile. B) Hemimetabolous metamorphosis is incomplete, while holometabolous metamorphosis is complete. C) In hemimetabolous metamorphosis, juveniles are a feeding stage. In holometabolous metamorphosis, only adults can feed. D) In hemimetabolous metamorphosis, juveniles are sexually mature. In holometabolous metamorphosis, only adults can reproduce.
B, The reproductive structures and mycelia of fungi are composed of thin filaments called hyphae.
Hyphae are _____. A) reproductive cells B) thin filaments C) dead at maturity D) cross-walls
D, Feathers evolved (most likely to aid in thermoregulation) in a series of steps, beginning with simple projections from the skin ("dinofuzz") that evolved into the complex, branched feathers of living birds. rawr
In which vertebrates did feathers first evolve? A) Pterosaurs B) Birds C) Bats D) Non-avian dinosaurs
A, Cephalopods have a mantle lined with muscle. When the cavity surrounded by the mantle fills with water and the mantle muscles contract, a stream of water is forced out the siphon, propelling the squid or octopus backward.
Long before humans invented it to power aircraft, jet propulsion evolved in _____. A) cephalopod mollusks B) adult insects C) snails and chitons D) chelicerate such as spiders and scorpions
C, The lophophore is a specialized structure that rings the mouth and functions in suspension feeding.
Lophotrochozoan phyla have a lophophore, a specialized structure for _____. A) reproduction B) predator evasion C) suspension feeding D) movement
D, DNA sequence data support this classification.
Lophotrochozoan phyla include _____. A) sponges, comb jellies, and jellyfish B) roundworms, tardigrades, and velvet worms C) sea stars, sea urchins, and sea cucumbers D) mollusks, annelids, and flatworms
A, The mushrooms need time to mature and release their spores.
Many poisonous mushrooms are extremely colorful. One hypothesis is that the colors serve as a warning to prevent animals from eating the mushrooms, much like the bright yellow and black stripes on wasps help to deter potential predators. Why do mushrooms need to deter predators when the majority of a mushroom consists of the underground mycelium? A) The aboveground mushroom is the reproductive part of the life cycle. B) If the aboveground mushrooms are destroyed, the underground mycelium cannot make new mushrooms. C) The aboveground mushroom provides nutrients to the underground mycelium. D) The underground mycelium will die if the mushroom is eaten.
B
Many protostomes appear quite similar at first glance, with several groups exhibiting worm-like morphology. However, this superficial similarity can be misleading, as worms are present in both major groups of protostome, the lophotrochozoa and the ecdysozoa. Which of the following features is most likely to be present in a segmented worm (a lophotrochozoan) and absent in a round worm (an ecdysozoan)? A) the blastopore develops into the mouth during gastrulation B) spiral cleavage during development C) radial cleavage during development D) the blastopore develops into the anus during gastrulation
A, These structures possess basidia which produce sexual spores.
Mushrooms, brackets, and puffballs are examples of structures used for _____. A) reproduction B) photosynthesis C) nutrient absorption D) food storage
B & C
Select the feature(s) common to ecdysozoans. (Choose one or more.) A) spiral cleavage B) waxy cuticle C) intermittent growth with molting D) continuous growth
D, Ovoviviparous means "egg-live-bearing." Ovoviviparous animals retain eggs within their body, but the developing embryo is nourished by yolk inside the egg and not by nutrients transferred from the mother.
Species that retain fertilized eggs internally, nourish the embryo with a yolk, and give birth to live young are said to be _______. A) oviparous B) undergoing direct development C) viviparous D) ovoviviparous
C, The inner tube is the individual's gut, with a mouth at one end and an anus at the other, and the outer tube forms the nervous system and skin.
The basic bilaterian body form plan can be thought of as simply _____. A) a series of boxes B) several joined rings C) a tube within a tube D) many concentric circles
A, Spores are the resistant dispersal stage in the fungal life cycle and are produced during both asexual and sexual reproduction.
The fundamental reproductive cell produced by fungi is the _______. A) spore B) basidium C) swimming gamete D) ascus
D, Prosimians include lemurs, found in Madagascar, and lorises, pottos, and tarsiers from Africa and south Asia.
The lemurs of Madagascar are _____. A) hominins B) Old World monkeys C) anthropoids D) prosimians
C
The main trait that animals have in common with plants and fungi is that they are all multicellular eukaryotes. Which of these traits distinguishes animals from plants and fungi? A) Only animals have organs. B) Animals are heterotrophs. C) Animals usually ingest their food first, before they digest it. D) Animals, like Arthropods, use chitin as a structural molecule.
C, The foot is most often used for locomotion in mollusks.
The molluscan body plan is based on three major components: the mantle, the visceral mass, and the _______. A) shell B) jointed limbs C) foot D) gills
D, Increased surface-to-volume ratios developed to increase the efficiency of gas exchange.
The water-to-land transition occurred independently several times in the protostomes. Which of these is not an example of an adaptation for terrestrial living that may have arisen by convergent evolution? A) Internal respiratory structures B) Internal fertilization C) Eggs with a covering that minimizes water loss D) Decreased surface-to-volume ratios to increase the efficiency of gas exchange in air
A, Acorn worms are a member of the phylum Hemichordata.
There are three recognized phyla of deuterostomes: Echinodermata, Chordata and _____. A) Hemichordata B) Rotifera C) Molluska D) Arthropoda
A, Body heat is internally generated in endotherms by oxidizing large amounts of food and generating large amounts of heat.
To be endothermic means that ______. A) body heat is internally generated B) the body is covered with an outer shell C) the body is lacking fur or feathers for insulation D) body heat comes from an external source
C, After modern humans left Africa, they probably interbred with Neanderthals in the Middle East before migrating through Europe and Asia.
Use the out-of-Africa hypothesis to explain why it is possible that some or none of your genome may be derived from Neanderthals. A) After modern humans left Africa, they probably interbred with Neanderthals in Europe. Humans with European origins often have less than 15 percent Neanderthal alleles. Humans with purely African or Asian origins do not have any Neanderthal alleles. B) Modern humans and Neanderthals are different species; therefore, they could not have interbred. No Neanderthal alleles are in the modern human genome. C) Homo sapiens originated in Africa, then interbred with Neanderthals and migrated to Europe and to the rest of the world. If you have purely African heritage, you would not have any Neanderthal alleles in your genome, but if your heritage is from anywhere else or mixed, you are probably 1 to 4 percent Neanderthal. D) Modern humans and Neanderthals both originated in Africa; therefore, all modern humans have some alleles in common with Neanderthals.
D, Internal respiratory structures are inefficient in aquatic organisms unless there is abundant water flow through the structures.
Use your understanding of insect evolution to predict which of these characteristics is an adaptation for terrestrial living that occurred in spiders. A) Spiders have a pair of clawlike appendages called chelicerae, located near the mouth, that are adapted for feeding on terrestrial prey. B) Spiders have long, jointed legs for walking and climbing on land without the buoyancy of water. C) Spiders have a hard exoskeleton that provides support against gravity. D) Spiders have internal respiratory structures that minimize water loss.
A, Ecdysozoa are defined by a clear synapomorphy: They grow intermittently by shedding the exoskeleton, or external covering. (Ecdysis is another term for molting.)
What characterizes an ecdysozoan? A) Ecdysozoans grow by molting. B) Ecdysozoans reproduce clonally. C) Ecdysozoans are sessile in the adult stage. D) Ecdysozoans practice suspension feeding.
C, In a dikaryotic mycelium, pairs of unlike nuclei may eventually fuse to form diploid zygotes.
What does it mean to say that a hypha is dikaryotic? A) Two gametes fuse together during fertilization to form a new mycelium with dikaryotic hyphae. B) When the hyphae of two different individuals fuse after karyogamy, a new dikaryotic hypha develops with two independent nuclei in each cell. C) When the hyphae of two different individuals fuse after plasmogamy, a new dikaryotic hypha develops with two independent nuclei in each cell. D) After karyogamy, two nuclei in a basidium cell fuse together to form a diploid nucleus. The basidium develops into a dikaryotic hypha.
A, Unlike deuterostomes, which made the transition once, each lineage of protostomes that includes terrestrial members made an independent transition.
What does phylogenetic evidence tell us about protostomes? A) There were multiple transitions from water to land. B) There was one transition from land to water. C) There were multiple transitions from land to water. D) There was one transition from water to land.
A, Lophophores are found in bryozoans (moss animals), brachiopods (lamp shells), and phoronids (horseshoe worms).
What is a lophophore? A) A specialized tuft that rings the mouth and functions in suspension feeding B) A synapomorphy that defines lophotrochozoans C) A body cavity where body fluids bathe the organs directly in an open circulatory system D) A distinctive type of larva with a band of cilia
C, The width of the body allowed for the evolutionary loss of the coelom. Return to Assignment
What is one of the greatest evolutionary benefits of the body plan of flatworms? A) Most flatworms have a one-way digestive system that is the common ancestor for all one-way digestive tract animals. B) The shape of flatworms allows for them to easily exist in all aquatic and terrestrial environments. C) Thin flat bodies allow for efficient exchange of gases and nutrients form the environment. D) Flatworms have well developed appendages for locomotion.
D, Larvae are specialized for feeding while adults are specialized for mating.
What is the current explanation for the benefit of complete metamorphosis in insects? A) Larvae are more mobile than adult forms. B) Adult forms are specialized for feeding. C) Larvae are specialized for reproduction. D) There is a functional specialization that separates larvae and adults.
A, ooga ooga fire ooga ooga wheel
What is the leading hypothesis on why humans evolving such large brains was beneficial? A) They evolved because of spoken language and tool use. B) They evolved because of competition with apes. C) They evolved so humans could be better at locating and securing mates. D) They evolved to help overpower other species.
B, The choanoflagellate lineage diverged before animal lineages diverged from one another.
What is the relationship between choanoflagellates and animals? A) Choanoflagellates were one of the first multicellular organisms. B) Choanoflagellates are considered an outgroup to the animal lineages. C) Choanoflagellates are a phylum of animals. D) Choanoflagellates are ancestral to animals.
A, EMF produce lignin peroxidase and degrade lignin and deliver it straight to the roots of the host via the connection between plant cells. As opposed to AMF which interact directly with the cellular membrane of the plant cells.
What is the symbiotic relationship that characterizes ectomycorrhizal fungi (EMF)? A) EMF are ecologically important because they decompose biomass to make it more available to the roots of the host plant.. B) EMF form mutualistic associations with cyanobacteria or green algae. C) EMF cause yeast infections in human hosts. D) EMF are predatory on amoebae and other unicellular protists that infect plants.
C, The relative physical separation of the muscular foot and visceral mass in snails may have enabled greater diversification of the muscular foot across the mollusk phylum.
What part of a squid is homologous to the foot of a snail? A) The hemocoel B) The siphon C) The arms (the shorter appendages) and tentacles (the two longer ones) D) The flattened fins and tail
A, The vertebrates are a monophyletic group distinguished by the following synapomorphies: a column of cartilaginous or bony structural supports called vertebrae, which form along the dorsal side of the body; and a cranium, a bony, cartilaginous, or fibrous case that encloses the brain.
What trait(s) characterize the vertebrates? A) Vertebrae and a cranium B0 Jaws and a spinal cord C) Bony endoskeleton D) Notochord and post-anal tail
B, When a cnidocyte senses a fish or other type of prey, it forcibly ejects a barbed, spear-like structure that may contain toxins. The barbs hold the prey, and the toxins subdue it until it can be brought to the mouth and ingested.
What unique trait distinguishes Cnidaria from Porifera and Ctenophora? CA) nidarians are distinguished by their spicules−−stiff spikes of silica or calcium carbonate (CaCO3) that, along with collagen fibers, give structural support in the extracellular matrix. B) Cnidarians have a specialized cell called a cnidocyte, which is used in prey capture. C) Cnidarians are mobile, while poriferans and ctenophores are sessile. D) Cnidarians have specialized sticky cells, called coloblasts, for trapping prey.
A
What's wrong with the following perspective of primate evolution? A) Extant species don't evolve from other extant species. An evolutionary tree is a better model. B) Humans aren't the sole pinnacle of primate evolution. It would also be correct to swap chimpanzees with humans. C) It is incomplete. The absence of bonobos and orangutans is misleading. , Not Selected
A & C
Which features are synapomorphies of primates? (Select all that apply.) A) they have forward-facing eyes B) they are bipedal C) they have grasping hands D) they possess large brains
D, This method is very useful in determining the changes in gene expression during development and is sometimes called evolutionary developmental biology.
Which key innovation has provided information about patterns of gene expression and morphological change during an organism's growth from embryo to adult? A) Comparative genetics B) Fossils C) Comparative morphology D) Comparative development
B, The Amniota is a lineage of vertebrates that includes all tetrapods other than amphibians.
Which major lineages make up the living Amniota? A) Amphibians, reptiles, and mammals B) Reptiles and mammals C) All vertebrates D) Reptiles
D, Monotremes like the Platypus and Echidna lay eggs yet are mammals.
Which mammals are oviparous? A) Eutherians B) Marsupials C) Cetartiodactyls D) Monotremes
B, D, E
Which of the following are chordate synapomorphies? (Select all that apply.) A) a cranium; a bony, cartilaginous, or fibrous case that encloses and protects brains and sensory organs B) muscular post-anal tail C) openings into throat called pharyngeal gill slits D) stiff and supportive but flexible rod, called notochord, runs the length of body E) dorsal hollow nerve cord that runs the length of body, comprised of projections from neurons F) vertebrae; a column of cartilaginous or bony structures that forms along dorsal side of most species
B, C, D, G
Which of the following are members of the class Reptilia (in other words, which are reptiles)? (Select all that apply.) A) Anura (frogs and toads) B) Lepidosauria (snakes and lizards) C) Aves (birds) D) Crocodilia (crocodiles and alligators) E) Mammalia (mammals) F) Urodela (salamanders) G) Testudinia (turtles and tortoises)
B, E, F
Which of the following are true concerning echinoderms? (Select all that apply.) A) like other deuterostomes, they show pentaradial symmetry B) they possess tube feet and a water vascular system C) they lack endoskeletons D) they possess a visceral mass from which a rasp-like organ called the radula develops E) unlike other deuterostomes, they show pentaradial symmetry F) they possess endoskeletons
A & D
Which of the following features are synapomorphies of deuterostomes? (Select all that apply.) A) they possess pharyngeal slits or pouches B) during development, the deuterostome embryo's first opening develops into the mouth C) they move under their own power at some time during development D) during development, the deuterostome embryo's first opening develops into the anus
E
Which of the following geographic patterns is the DOMINANT pattern in human origins? A) humans developed mostly in Eurasia and migrated outwards from there B) humans developed mostly in North America and migrated outwards from there C) humans developed from hybridization between Asian and North American ancestors and migrated outwards from their initial points of contact D) humans developed mostly in Australia and migrated outwards from there E) humans developed mostly in Africa and migrated outward from there F) humans developed mostly in South America and migrated outwards from there G) humans developed from a globally distributed ancestor
C, This is an advantage of indirect development in insects, not of viviparity and the placenta.
Which of the following is NOT an advantage of viviparity and the placenta? A) offspring are protected B) offspring are portable — mothers are not tied to a nest C) offspring and parents specialize on different food, reducing competition D) offspring develop at a more constant, favorable temperature
B, D, E
Which of the following is NOT found in the common ancestor of all fish? (Select all that apply.) A) lungs B) limbs C) bones D) amniotic eggs E) lobed fins
C, True. Spongebob doesn't have a brain.
Which of the following is a synapomorphy of most, but not all, animal phyla: A) multicelluar B) they move under their own power at some point in their life cycle C) they have neurons D) they are heterotrophs
C
Which of the following is true about how fungi interact with the ecosystems they inhabit? A) Neither A nor B B) A: They are important decomposers that speed up the carbon cycle, especially for plant compounds like lignin and cellulose C) Both A and B D) B: They are important symbionts, especially in mutualisms with plant roots
A & D
Which of the following is true of ALL mammals? (Select all that apply.) A) they possess hair or fur B) hey have placentas C) they bear live young D) they possess lactation
A
Which of the following is true of the evolution of animal phyla and animal body plans: A) The majority of animal body plans and phyla evolved over a comparatively short timespan in the Cambrian period around 540 million years ago in an event paleontologists call the Cambrian Explosion. B) Animal body plans and phyla diversified during the Jurassic period and through the Cretaceous period, from around 200 million years ago until 65 million years ago, when the Cretaceous-Paleogene extinction event halted their progress. C) Animal body plans show a slow, but constant, progression, with new body plans and new phyla evolving since the Proterozoic Era 2.5 billion years ago until relatively recent times. D) The majority of animal body plans and phyla evolved over a comparatively short timespan in the Cretaceous period around 200 million years ago in an event paleontologists call the Cretaceous Explosion. , Not Selected
A
Which of the following is unique to mollusks? (Choose one or more.) A) the radula B) the lophophore feeding organ C) spiral cleavage D) trochophore larvae
C, Yes. This is the definition of radial symmetry. Bilaterians have bilateral symmetry
Which of the following isn't a feature of bilaterian animals differentiating them from other animals: A) they are triploblasts B) they exhibit cephalization C) they have the property of being divisible into symmetrical pieces across multiple planes of symmetry situated around a central axis D) they have the property of being divisible into symmetrical halves on either side of only a single plane
A
Which of the following isn't a feature of bilaterian animals differentiating them from other animals: A) they have the property of being divisible into symmetrical pieces across multiple planes of symmetry situated around a central axis B) they exhibit cephalization C) they are triploblasts D) they have the property of being divisible into symmetrical halves on either side of only a single plane
B
Which of the following pairs of fungi form a monophyletic grouping? A) basdiomycetes and chytrids B) basdiomycetes and ascomycetes C) chytrids and zygomycetes D) zygomycetes and ascomycetes
A, The four membrane-bound sacs are still present in placental mammal eggs but are in modified or reduced form.
Which of these characteristics is the same in amniotic eggs and placental mammal eggs? A) Placental mammal eggs have all four membrane-bound sacs found in amniotic eggs but no shell. B) The chorion's gas exchange functions in amniotic eggs are replaced by the placenta in placental mammal eggs. C) Amniotic eggs and placental mammal eggs both have a hard or leathery outer protective covering. D) The embryos in amniotic eggs and placental mammal eggs both rely on the yolk for most of their nutrients.
C, spiders also get 8 solo movies where they're played by 3 diff actors
Which of these is not a difference between insects and spiders? A) Some insects eat plants, while all spiders are predators. B) An insect has three body regions, while a spider only has two. C) Insects have compound eyes, while spiders have multiple simple eyes called chelicerae. D) Most insects have six legs, while spiders have eight legs.
C, The exoskeleton cannot expand. Periodically, the ecdysozoans must molt their exoskeleton, pump up their bodies to expand their size, and form new, larger exoskeletons.
Which of these is not an advantage of the arthropod exoskeleton? A) The stiff exoskeleton provides support against gravity on land. B) A stiff body covering provides an effective structure for muscle attachment. C) The cuticle of the exoskeleton is strong but flexible, allowing the body to expand as the body grows. D) The hard covering provides protection.
A, Snails on land or in water have a similar muscular foot for movement.
Which of these is not how a land-dwelling snail might differ from a snail that lives in water? A) Snails on land would have a muscular foot using contractions for movement. B) Snails on land would likely have desiccation-resistant eggs. C) Snails on land would likely have gills or lungs inside the body or otherwise be protected from drying out. D) Snails on land would likely have thinner shells that are less heavy.
B, Muscles and organs are derived from mesoderm.
Which of these is not part of the human tube-within-a-tube body plan? A) One end (head) cephalized with sensory organs and brain (derived from ectoderm) B) Muscles and organs derived from endoderm C) A bilaterally symmetrical, elongated body with an inner tube (gut and associated organs) derived from endoderm D) An outer tube (mostly skin) derived from ectoderm
B, The protostomes are the most diverse and abundant lineage of animals on Earth. Of the more than 30 animal phyla known to exist, at least 22 are protostomes. Deuterostomes transitioned to the land long after the protostomes were well established.
Which of these is not true about both protostomes and deuterostomes living on land? A) Protostomes and deuterostomes living on land both have mechanisms for preventing their eggs from drying out. B) Protostomes and deuterostomes living on land have been equally successful in diversifying and spreading. C) Protostomes and deuterostomes living on land both have mechanisms for preventing their skin from drying out. D) Protostomes and deuterostomes living on land both have mechanisms for keeping their respiratory surfaces from drying out.
A, Even though the major body plans arose during the Cambrian period, evolution did not stop within any of the lineages.
Which of these major animal body plans evolved since the Cambrian period about 550 million years ago? A) Almost all the major phylum-level body plans arose rapidly during the Cambrian. B) Cephalization with nervous system C) Segmentation D) Body symmetry
C, Echinoderm means "spiny-skin."
Which phylum is exclusively marine and is named for having many spines and spikes? A) Xenoturbellidans B) Hemichordates C) Echinoderms D) Urochordates
A, Birds are reptiles and most reptiles are ectothermic. Therefore, endothermy arose independently in birds and mammals.
Which statement is true about endothermy in mammals and birds? A) Endothermy arose independently in these two lineages. B) Birds are more closely related to mammals than to reptiles. C) Birds are reptiles and all reptiles are ectothermic. D) They both inherited this trait from a common tetrapod ancestor.
C, All animals share a common ancestor that was multicellular. Choanoflagellates are unicellular or colonial.
Which synapomorphy (shared, derived trait) distinguishes animals as a monophyletic group, distinct from choanoflagellates? A) Multiple germ layers B) Cephalization C) Multicellularity D) Bilateral symmetry
A
Which the following types of fungi have no heterokaryotic phase in their life cycle? A) Chytrids B) Ascomycetes C) Zygomycetes D) Basdiomycetes
B, Some fungi have evolved the ability to digest lignin and cellulose, which are the two most common organic polymers on Earth.
Why are fungi so important to the carbon cycle? A) Fungi produce O2 and make it available to nearby plants for use in the carbon cycle. B) Fungi accelerate the carbon cycle by breaking down wood and thus freeing up carbon atoms. C) Fungi fix carbon and produce O2 just like plants do during photosynthesis. D) Fungi release water from the soil and break it up into its constituent elements, thus freeing up hydrogen atoms for the carbon cycle.
C, The mammalian placenta is rich in blood vessels that facilitate the flow of oxygen and nutrients from the mother to the developing embryo in place of the yolk.
Why is the relative size of the yolk sac in a mammal egg much smaller than that found in an amniotic egg? A) The embryos of animals with amniotic eggs like reptiles are larger than the embryos of placental mammals, so they need more nutrients. B) Amniotic eggs require larger yolk sacs to support longer maturation times compared to mammal eggs that develop more quickly. C) The yolk sac is relatively smaller in the mammal because its function in an amniotic egg (source of nutrients) has been taken over by the placenta. D) Because amniotic eggs develop outside the body, they require larger yolk sacs to support embryos exposed to variable environmental temperatures. Mammal eggs develop at a more constant, favorable temperature inside the body.
A, Molecular data have overturned this view, suggesting that segmentation arose independently in these groups.
Why were annelids and arthropods thought to be closely related before phylogenetic analyses in the late 1990s? A) Both annelids and arthropods have segmented bodies, unlike other protostomes such as flatworms and nematodes. B) Both annelids and arthropods have bilateral symmetry and triploblastic embryonic tissues. C) Annelids have bristle-like appendages (setae) that extend from lobe-like appendages (parapodia) that are homologous to the limbs of arthropods. D) Annelids have a coelom and fully developed digestive tract with a mouth and anus like arthropods.
