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Q How have flowering plants come to dominate Earth’s landscapes? From the mosses that live in Antarctica to these flowering protea plants of South Africa, the plant kingdom is diverse. Proteas are native to one region of South Africa, called the Cape floristic region, which can go through long periods of drought. This small region is home to over 9000 plant species, including at least 6000 that are found nowhere else on Earth.

R e a d i N G T o o l b o x This reading tool can help you learn the material in the following pages.

USING LANGUAGE Your Turn Classification As you read the chapter, make distinc- Use information that you read in the chapter to answer tions between general words that describe categories and the following questions. specific words that describe individuals within a category. 1. What are two types of seedless vascular plants? Words that name categories are more general than words 2. What is the general term identifying the category that that describe individuals. includes mosses, liverworts, and hornworts?

Chapter 20: Plant Diversity 591 CorrectionKey=B DO NOT EDIT--Changes mustbemadethrough “File info” 592

FIGURE seed pollen grain lignin system vascular stomata cuticle plant VOCABULARY competition amongorganisms commensalism, mutualism, and including predation, parasitism, animals; 12Ainterpret relationships, bacteria, protists, fungi,plants, and taxonomic groups, including archaea, 8C compare characteristics of of diversity inandamongspecies; adaptation andto thedevelopment relationship ofnatural selection to 7E analyze andevaluate the molecular, anddevelopmental; homologies, includinganatomical, fossil record, biogeography, and among groups isprovided by the how evidence ofcommon ancestry ancestor ofall plants. living relatives of thecommon and are thoughtto betheclosest They are called charophyceans found inmanylakes andponds. al Unit 7: Plants gae ofthegenus Chara can be 7Aanalyze andevaluate 1.1 20.1

Multicellular green 7A, 7E, 8C, 12A Origins ofPlant Life Land plants evolved plants Land from green algae. animal life aswe know itwould not exist onland. sources. Green protea beetles even live insideofprotea flowers. Withoutplants, flowers. Various birds, rodents, andinsectsrely onprotea andpollen nectar asfood The flowering proteas shown ontheprevious page are not justplants withbeautiful Connect to Your World ke became a

y of plants. all that contain cellulose, acomplex carbohydrate that is found walls cell inthe starch use they as astorage product. Most have green also algae walls cell oftypes chlorophyll. Another feature green and both algae plants share is that plants that we are familiar with—green. Green and algae plants have same the photosynthesis. Chlorophyll is what makes algae—and these most of the eukaryotes. have They chlorophyll that captures from energy sunlight during and have adapted to life on land. plants, Like green are algae photosynthetic lar eukaryotes, most of which produce own their through food photosynthesis es plant evolved, species as shown in individuals that could withstand Eventually, longer periods. dry first true the shallow water that out dried from to time time. Natural likely selection favored All • originated incharophyceans. embryos that remain attached to female the parent develop. as they algae in algae would asspecies classified amember be of class the Charophyceae, like the thatalgae is common the ancestor of plants. all If it were alive today, this • • MAI MAI

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A mul Repr which allowswalls, cells to communicate with each other chemically A meth Evidence from genetic analysis points to one ancient of species green Today, charophyceans are common infreshwater habitats. Scientists hypoth- Plants evolve withother organisms intheirenvironment. Plants have adaptations that allow themto live onland. Land plants evolved from green algae. green share algae characteristics certain with plants. N n N ID c ID e oduction that involves traveling sperm to and an fertilizing cell egg figure 1.1. dapted to land. p ticellular body, to which led specialization the of cells and tissues E E t A od ofod division cell that produces channels cells with small intheir AS

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plant grow parts, upright, and reproduce without free-standing water. low t plant life In on turn, Earth. many land plants have evolved adaptations that al and developing offspring out. from drying allowing for reproduction and dispersal. Finally, water prevents eggs, sperm, algae, water provides amedium through and which sperm spores can travel, photosynthesis. The buoyancy of water supports weight the of most algae. For land plants, are algae constantly surrounded by water, for which is needed Life on land presents different challenges thanlife does water. inthe Unlike time, descendants the of plants these were able to live areas. ineven drier similar to that of moss, keeping low to ground the to retain moisture. Over duc reliedmosses, they on droplets of water that brought to eggs pro sperm tr MAI Millions of years ago ue plants probably grewon edges the of lakes and streams. modern-day Like 500 400 300 200 100 present day The c The earliest plant fossils date to more than 450million years ago. The first e the nexte the generation of plants. had afairly also They simple structure

7 N hem to retain moisture, transport water and other resources between What evidence suggests that green algae are close relatives of land plants? plants? land of relatives close algae are green that suggests evidence What a

ID 1.2 What category of plants evolved recently? plants most of category What hallenges of living on land drier have pressures as selective acted for E e A

volution ofPlants charophyceans 7E mosses and relatives ferns and relatives cone-bearing plants flowering - plants

algae colors. theirdistinct pigments give various typesof protists. Photosynthetic and Fungi that algae are plantlike Recall from thechapter Protists A adaptation: challenge: adaptation: challenge: adaptations to these challenges. life onland andplants’ notes aboutthechallenges of Use amainidea web to take T lga A CO K R I E NNE N e ADI G challenges living onland. Chapter 20:Plant Diversity N C Early plants faced O T N

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Retaining Moisture Plants will die if they dry out from exposure to air and sunlight. The surfaces of plants are covered with a cuticle. A cuticle is a waxy, waterproof layer that helps hold in moisture. As figure 1.3 shows, there are tiny holes in the cuticle, called stomata (singular, stoma). Special cells allow stomata to close to prevent water loss, or to open to allow air to move in and out. Without stomata, the movement of air would be prevented by the cuticle. Transporting Resources CONNECT TO Taller plants often have more access to sunlight than do shorter plants, but Human Biology growing tall presents another challenge. While plants must get sunlight and carbon dioxide from the air, they must also get water and nutrients from the A plant’s vascular system is similar in function to a human’s soil. A structure for moving these VISUAL VOCAB circulatory system. You will learn resources to different parts of the more about the human plant evolved in the form of a vascu- A vascular system allows circulatory system in the chapter lar system. A vascular system is a water, mineral nutrients, and Respiratory and Circulatory sugars to be Systems. collection of specialized tissues that transported to bring water and mineral nutrients up various parts from the roots and disperse sugars of a plant. down from the leaves. A vascular water and system allows a plant to grow higher mineral off the ground. nutrients sugars Growing Upright Plant height is also limited by the ability of a plant to support its own weight. Plants need structure to support their weight and provide space for vascular tissues. This support comes from a material called lignin (LIHG-nihn), which hardens the cell walls of some vascular tissues. Lignin is also responsible for the strength of wood and provides stiffness to the stems of other plants. As a result, plants can retain their upright structure as they grow toward the sun. Reproducing on Land In all plants, eggs are fertilized within the tissue of the parent plant. There, the fertilized egg develops into an embryo, the earliest stage of growth and development for a plant. Some plants reproduce with the help of rainwater or dew, while others do not need free-standing water to reproduce. Pollen and seeds are adaptations that allow seed plants to reproduce completely free of water. A pollen grain is a two-celled structure that contains a cell that will divide to form sperm. Pollen can be carried by wind or animals to female reproductive structures. A seed is a storage device for a plant embryo. A seed has a hard coat that protects the embryo from drying wind and sunlight. Once a seed encounters the right conditions, the embryo can develop into an adult plant. Analyze Discuss why the four challenges on this page do not apply to most algae.

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(tl) ©Magdalena Bujak/ShutterStock; (tr) ©John Walmsley/Education Photos/Alamy Ltd of life onland. Land plants have evolved to adapt to thechallenges FIGURE VI CRI higher offtheground. plant. Avascular system allows plants to grow resources upanddown to different ofthe parts Vascular tissues form “pipelines” that carry vascular andconductsupport fluids. walls ofplant tissues that provide Tough ligninisfound inthecell lig leaves from dryingout. A cuticle isawaxy coating that protects plant and theatmosphere. allow for gas exchange between theplant Stomata are small openings inthecuticle that s embryos. nutrients for developing Seeds protect andprovide divide to form sperm. contains onecell that will or animals. Each pollen grain Pollen can becarried by wind poll E t WI T oma n ICAL N i en n 1.3 G t a a

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inside theflower. isproducednectar 30cmdown blooming orchid whose It isthepollinator ofanight- between in.). 30and35cm(10–14 has atongue tha FIGURE 20.1 Unit 7: Plants 3. 2. 1. Re

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leaves during its development. butterfly of has atype chemical protection as aresult of eating milkweed adults,larvae, and taste evento eggs bad potential predators. In way, this the Milkweed plants species. milkweed produce achemical that makes monarch oftage. monarch The larvae butterflies, for example, exclusively feed on that produce spines even sharper or thorns or even more toxic chemicals. ofeffects defensive plant adaptations. In turn, natural favors selection plants eating predators. Natural favors selection herbivores that can overcome the plantsOther produce defensive chemicals that as against pesticides act plant- Thethem. spines on acactus and thorns the on arose stem are examples. Plants have avariety of adaptations that discourage animals from eating Interactions Plant-Herbivore in 30 and 35cm(10–14in.)long must pollinator. the be That moth, shown very long, tubular flower He parts. predicted that moth with anocturnal atongue or For fruit. example, inMadagascar, noticed avariety of orchids Darwin with dispersal. Inor animals turn, seed these are fed by plant’s the nectar, pollen, and help fungi the bacteria while plant the get mineral nutrients from soil. the of andprovide Roots fungi bacteria. ahabitat for and fungi these bacteria, Mutualisticbenefit. relationships exist plant between roots and types certain Mutualism an interaction describes species inwhich two both species between Mutualisms tween plant and species animal the that species eat them. Some of relationships these are cooperative, others while have evolved be- Plants have coevolved with other terrestrial organisms for millions of years. MAI F Som Man igure 1.4, 7E N ID e insects use defensive use e insects chemicals produced by plants to advan- their y flowering plants animal for on depend species specific pollination 5. 4. C

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©Harold Taylor/Getty Images classification ofplants andfungi. term phylumfor the sometimes used instead ofthe of Life that theterm divisionis Recall from thechapter TheTree C fruit flower cone angiosperm gymnosperm pollination VOCABULARY fungi, plants, andanimals including archaea, bacteria, protists, characteristics oftaxonomic groups, reproductive success; 8 resources, result indifferential finite supply ofenvironmental offspring thancan survive, anda population to produce more variation, thepotential ofa selection, includinginherited how theelements ofnatural epithelium; 7 such asblood, muscle, and leaves ofplants; andanimal cells cells, includingr among groups; 8 similarities anddifferences shared classification system based on organisms usingahierarchical la CO ss NNE 5 i B f 20.2 examine specialized ica C D T anal

T oots, stems, and t C O io compar yze andevaluate 5 B n , 7 B ca D e , 8 tegorize Classification ofPlants B , 8 C nonvascular plants. relatives their and Mosses are seedless reveal new relationships that keep taxonomists updating theplant family tree. found. plants All belong to thekingdom Plantae. However, DNAanalysis continues to have described about300,000plant species,andmanymore probably remain to be the plants that grow inyour neighborhoodandinplaces you regularly Scientists visit. How manydifferent typesofplants You can you thinkof? are probably familiar with Your to World Connect ke

y the thallose liverwort, shown liverwort, in thallose the produced on umbrella-like structures of oflobes aliver flat on ground. the Eggs are which like look liverworts, the to thallose or leafy.thallose The name liverwort refers worts can have one of two basic forms: other areas with plenty of moisture. Liver- wet rocks, ingreenhouse flowerpots, and in of soil. the are They often found growing on and get moisture directly from surface the Most live liverworts indamp environments Liverworts are Hepatophyta, the liverworts, and Anthocerophyta, the hornworts. one of the three phyla of nonvascular plants. The other phyla in this category allow their sperm to swim to and fertilize eggs. Mosses belong to Bryophyta, absorb water and nutrients directly. rely also They on free-standing water to grow closeto ground the or on where can surfacessuch they as tree trunks, plants do not produce have They seeds. systems. no vascular Instead, they In adamp forest, mosses lend an emerald green color to landscape. the These are most often arranged in three rows. leaflike structures. These leaflike structures common. have liverworts Leafy stemlike and are liverworts recognize, leafy much more may liverworts easierThough to be thallose MAI MAI

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“ground pines.” (RY-zohmz). Their large leaves, shown in ferns grow from underground stems rhizomes called erous with about period, alive 12,000species today. Most “scouringcalled rush,” pots. to scrub compound colonial silica, plant, the settlers used called also horsetails’ Because period. contain walls cell arough much larger and more common Carboniferous in the around atubular stem. club Like mosses, horsetails were streams. have They leaves tan, scalelike that grow inwhorls closely related to ferns. and leaves, DNA analysis indicates that whisk ferns are tropicsin the and subtropics. roots Although lack true they grouped together inone phylum. Whisk ferns grow mostly Ferns and relatives, their whisk ferns and horsetails, can be Whisk onethe shown in living genus of club moss is Lycopodium. SomeLycopodium such species, as ous climate but cooled, One some common of survived. species smaller the than ten stories giant These tall. plants were out wiped Carbonifer- the when plants.vascular Some ancient trees, looked likegrowing species modern more Club mosses, which are not mosses, belong true to oldest the living group of Club Mosses grow higherabove ground the and get materials still from need soil. the they water for reproduction. However, system avascular allowsplants these to plants. vascular seedless nonvascular Like modern plants, on depend they a fossil fuel. gradually turned intothey This coal. is why coal we call plants were pressed and heated underground, where plants.vascular time,remains dead the Over of these shallow swampsperiod, were home to enormous seedless About 300million years ago, during Carboniferous the over three stories tall. tree ferns, liveOthers, called tropics inthe and can grow grow.uncurl as they Some ferns are grown as houseplants. fronds.called Newly-forming fronds, fiddleheads, called MAI

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(t) ©Chris Jones/photolibrary/Jupiterimages; (bl) ©Science Pictures Limited/Photo Researchers, Inc.; (br) ©Joseph Malcolm Smith/Photo Researchers, Inc. habitat tropical inthese areas. are species cycad endangered of because slow their growth and loss of grow intropical areas Americas, inthe Asia,and Australia. Africa, Many of era this is commonlyperiod Age the called of Cycads. the Today, cycads years ago. plants These provided for food dinosaurs. In Jurassic the fact, forests of grewduring cycads Mesozoic the era, 248million to 65million Ginkgo biloba (phylum Ginkgophyta), and conifers (phylum Coniferophyta). There are three living phyla (phylum cycads of gymnosperms: Cycadophyta), cones, which protect eggs. fertilized developalso of on female scales the are produced infemale cones. Seeds is produced cones, inmale eggs while contains hard protective Pollen scales. structure of It most gymnosperms. shown in saurs lived. Only one species lives today, Like cycads, ginkgoes were abundant while the dino- G Cycads trees with like look large palm cones, as shown in Cycads areseeds enclosedinfruit. grouped according to their whether million years ago. plants Seed can be million years ago. Fossil suggests evidence plants that seed evolved about 360 fr urban landscaping. grown around the world in gardens and used in the oldest living species of seed plants. Today, it is this species a living fossil. In fact, the ginkgo may be closely resembles its fossil ancestors, Darwin called Buddhist monks since the year 1100. Because it so and it has survived in part due to its cultivation by A woody A woody ing and evergreen, such as pine trees. • •

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What adaptation of seed plants allows sperm to reach and fertilize fertilize and to reach allows sperm plants seed of adaptation What 5. 4. C the conifers—familiarthe trees with leaves, needlelike such in as those By far, most the diverse and common alive today gymnosperms are Conifers f CorrectionKey=A few lose their needles in the winter. inthe needles their few lose Conifers are well adapted to high large tree farms help produce to enough demand. meet wood cardboard, housing lumber, and grow They plywood. quickly, and to phylum. this Conifers supply most for of used timber the paper,

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i CO st the evolution of seed plants? climate change likely play in What role did this global becoming hotter and drier. when Earth’s climate was to 360 million years ago, re According to the fossil cord, seed plants date back ory NNE HMDScience.com Self-check Online 7 C

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Need for SEEDS

T’ g Web azin ! BIOLOGY A m Video Inquiry Plant and Pollinator Endangered Plants Cotton-Ball Bats Have you Matching Game Examine Explore a plant in your area that ever wondered what bats the adaptive features of is threatened or endangered, and are up to at night? Watch as flowers and animals, and determine how to keep it from bats are tracked through the use them as clues to match going extinct. rain forest and discover the flowers to their animal crucial role they play in the pollinators. ecosystem. ©Gunter Marx Photography/Corbis

online biology 603 HMDScience.com CorrectionKey=A DO NOT EDIT--Changes mustbemadethrough “File info” Unit 604 FIGURE years ago. killed thedinosaurs 65million after themass extinctionthat period ofadaptive radiation mammals also went through a Evolution ofPopulations that Recall from thechapter The Evolu wood dicot monocot cotyledon VOCABULARY dogwoods, shared amonggroups based onsimilarities anddifferences hierarchical classification system 8B categorize organisms usinga differential reproductive success; environmental resources, result in survive, andafinite supply of produce more offspring thancan potential ofapopulation to including inherited variation, the elements ofnatural selection, 7D analyze andevaluate how the groups inthefossil record; stasis, andsequential nature of any data ofsuddenappearance, scientific explanations concerning CO

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y today. important to success the of flowering plants long ago continue important to be of land animals such and as insects birds. The same adaptations that were happened quickly ingeologic terms and was closely to diversification the tied plants that rely on the wind to randomly transfer their pollen. plants pollinated by animals don’t need to produce nearly as much pollen as do pollen from flower to flower in a very targeted way. For this reason, flowering of the pollen brushes off onto the new flower. Thus, animal pollinators transfer gets pollen on itself. Then, when it moves to another flower for more food, some duced in the flowers of some plant species. As an animal feeds from a flower, it feed on pollen, which is high in protein, or on nectar, a sugary solution pro- butterfly hovering around the center of a flower. These insects and other animals which rely on wind for pollination. You have probably observed a bee or a Flowers allow for more efficient pollination than occurs in most gymnosperms, Flowers Pollination and in dogwoods the plantThese extinctions open niches left into which flowering plants, such as dominated Dinosaurs Earth. disappeared, as did many plant seedless species. fossil the recordperiod, reveals that amajor shifttook that place inspecies there are today. After mass the extinction event that Cretaceous ended the Up until about 65million years ago, there were far fewer flowering plants than MAI MAI

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Biology IDEO FIGURE 3.2 Adaptations of Flowering Plants V CLIP Flowers and fruits are unique adaptations of all flowering plants. HMDScience.com GO ONLINE Plants and Pollinators

Many flowering plants are pollinated Fruits protect the seeds of flowering plants and by animals. often play a role in seed dispersal. Synthesize How is each photograph showing a coevolutionary relationship? 7D

Fruits and Seed Dispersal The many types of fruits include some very unlike the kinds you see in a T’ zing! grocery store. In biological terms, a fruit is a flower’s ripened ovary, which A ma surrounds and protects the seed or seeds. For example, the shells of sunflower Video Inquiry HMDScience.com seeds and peanuts are fruits. Fruit play an important role in seed dispersal. As shown in figure 3.2, the more familiar fleshy fruits are tasty food sources for GO ONLINE animals, which digest the fruit tissue but not the seeds. Seeds pass through Cotton-Ball Bats the animal and are deposited along with a convenient supply of fecal fertilizer that is helpful during germination. Others take the form of burrs that cling to passing wildlife, or fibers that help spread seeds by wind. Infer Why is pollination by animals more efficient than wind pollination?

MAIN IDEA 8b Botanists classify flowering plants into two groups based on seed type. There are at least 300,000 identified flowering plant species. Compared with other living plant phyla—the three gymnosperm phyla have a total of 720 species—the number of flowering plants is impressive. Botanists classify flowering plants into two groups based on two basic kinds of seed: seeds with one or two cotyledons. A cotyledon (kaht-uhl-EED-uhn) is an embryonic leaf inside a seed. For this reason, cotyledons are often called “seed leaves.” As an embryo develops into a seedling, the seed leaf of some species remains inside the seed coat. In other species, cotyledons break out of the seed and turn green. (tl) ©Michael & Patricia Fogden/Corbis; (tr) ©Michael Quinton/Minden Pictures

Chapter 20: Plant Diversity 605 DO NOT EDIT--Changes must be made through “File info” CorrectionKey=A

FIGURE 3.3 Monocots and Dicots Monocots are flowering plants with one cotyledon. One cotyledon Parallel veins Flower parts in Scattered vascular multiples of three tissue

Dicots are flowering plants with two cotyledons. Two cotyledons Netlike veins Flower parts in Ringed vascular multiples of four tissue or five

Monocots R E ADI N G TO OLB ox Flowering plants whose embryos have one seed leaf are called monocotyle- dons, or monocots (MAHN-uh-kahts). As figure 3.3 shows, monocot plants VOCABULARY generally have parallel veins in long, narrow leaves, such as those of an iris or Mono- and di- are prefixes lily. Their flower parts usually occur in multiples of three, and bundles of meaning “one” and “two.” The word cot is a shortened form vascular tissues are scattered throughout the stem. The cereal plants we of the word cotyledon. depend on—corn, wheat, rice—are monocots, as are all other grasses, irises, Therefore, monocots have one and lilies. cotyledon and dicots have two. Dicots Dicotyledons, or dicots (DY-kahts), are flowering plants whose embryos have two seed leaves. In contrast to monocots, dicots have leaves with netlike veins. Flower parts in dicots usually occur in multiples of four or five, and bundles of vascular tissue are arranged in rings. Most deciduous trees, which lose their leaves in the fall, are dicots. Peanuts are also dicots. Each “half” of a peanut that has been removed from its shell is a cotyledon. Predict Would you expect that cotyledons are green inside a seed? Explain.

MAIN IDEA 8b Flowering plants are also categorized by stem type and lifespan. Flowering plants can also be categorized by stem type and lifespan, as shown in figure 3.4. These characteristics help describe mature flowering plants and are commonly used by botanists, gardeners, landscape designers, and horticulturists.

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iris ©Lynn Watson/ShutterStock; wheat ©Matt/ShutterStock; foxglove ©BananaStock/Jupiterimages; oak ©Yare Marketing/ShutterStock; bluestem ©Ross Frid/Alamy Ltd herbaceous, Iris Contrast 20.3 3. 2. 1. Re wood, such andwood, cacti, as cucumbers, marigolds, are herbaceous plants. called Trees, shrubs, and most vines have stems. woody Plants that do not produce branches. Wood accounts also for thickness the of many plant woody stems. of cells thick and these Woody stiff. plants therefore have stems stiff and some plants. High concentrations of and lignin make cellulose walls cell the fibrous material made up of cells that dead are system of part vascular the of lifespan is an important life trait. history It is helpful for biologists to plants classify interms of lifespans, their since T Some flowering plants develop stems, woody others while do not. Woody or Herbaceous Stems • • •

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are shown inTable 1. found insome common fruits.These data A class counted thenumberofseeds Model the data set, itisagood idea to studythese data pointsmore closely. Some data sets have more thanonemode.Ifthere are several modesthat dominate The modeisthevalue that occurs most frequently. Itisnot affected by outliers. affect the median, this may be a good measure to use with a data set that includes outliers. data points, the median is the average of the two middle numbers. Since outliers do not points are ordered from least to greatest. If there is an even number of The vary greatly from all oftheother pointsinthedata set. range ofdata andistherefore affected by outliers—data pointsthat dividing by thenumberofdata points.Themean considers thefull The mean iscalculated by adding all ofthedata pointstogether and they may each point out different characteristics of a data set. mode. It is often helpful to look at all three of these measures because common measures of central tendency are the mean, median, and are measures that indicate the center of a data set. The three most One way to analyze data is to use measures of Mode and Median, Mean, 7:

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CHAPTER 20 G N I D A E R

water loss while allowing for gas exchange.” could write “Together, the cuticle and stomata prevent For example, for theterms cuticle andstomata, you two to clearly explain how theterms are connected. For e V R 20.1 vo Chapter 10. 12. 11. 8. 6. 4. 2. 5. 9. ocabulary Connections 3. 7. 1. eviewing

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Critical Thinking 24. Analyze Aquatic plants, which evolved from land plants, Analyzing Data Measure Central Tendency have adaptations that allow them to live in the water. Valencia oranges, which likely originated in Spain or Some aquatic plants grow completely submerged in Portugal, are now the most widely planted orange water. What challenges might these plants face that do variety in the world. Use the data below on the number not apply to plants that live entirely on land? of California Valencia oranges per tree to answer the 7E next three questions. 25. Analyze The sperm of seedless plants are flagellated, while those of seed plants are not. How do the sperm of California valencia oranges per tree seed plants reach eggs without flagella? 8b 596, 402, 489, 708, 374, 548, 640, 585, 518, 450

26. Compare When a plant reproduces, it is important for Source: California Agricultural Statistics Service its offspring to disperse so that they do not compete directly with the parent plant. Compare the structures 33. Calculate What are the mean, median, and mode for that allow seedless plants and seed plants to disperse to this data set? Round the mean to the nearest whole new locations. 8B number. 27. Synthesize Some experts predict that the Amazon 34. Analyze Does this data set contain outliers? Explain rain forest will be completely destroyed within the next your answer. century due to human activities. What resources would potentially be lost along with this ecosystem? 35. Evaluate Which measure of central tendency best represents this data set? Explain your answer. 28. Infer Some types of flowers have special markings on their petals that act as guides to the pollen or nectar for their pollinators. How could such markings have evolved Making Connections through natural selection? 7d 36. Write About Seeds From the viewpoint of a plant embryo, write about the importance of a seed. What 29. Analyze What evolutionary advantage do the seeds of does the seed provide for you? In what ways does 7E dandelions have over the seeds of pine trees? it help you? What advantages do you have over 30. Synthesize How might an increase in the use of nonseed plants? insecticides affect flowering-plant populations in the 37. Synthesize The flowering proteas of South Africa are area? adapted to a dry climate that receives as little as 600 mm (23.6 in) of rain each year. However, plants must Interpreting Visuals retain moisture in order for photosynthesis to occur. Use the illustration below to answer the next two Describe the adaptations that allow these plants to questions. retain moisture in their leaves while still allowing for air 31. Analyze What parts of this plant could to move in and out. 7E you examine to determine whether it is a monocot or a dicot? 32. Apply Is this plant likely a monocot or a dicot? Explain your reasoning.

614 Unit 7: Plants Biology End-of-Course Exam Practice

Record your answers on a separate piece of paper. A Corn that expresses this gene cannot convert MULTIPLE CHOICE sugar to starch. B This gene causes corn to convert sugar to 2C, 3F starch when picked. 1 In the 1940s, Barbara McClintock observed C Plants with this gene produce less sugar. patterns of inheritance in corn plants that could D This gene works in conjunction with other not be explained by the current gene theory. The genes to convert sugar to starch. conclusions of her work were not widely accepted for years until further supported by the work of THINK THROUGH THE QUESTION other scientists. What does this scenario Think about the process by which plants produce demonstrate about science? sugars. You can eliminate any answer choices that A Data that are more than 50 years old should be would result in plants with less sugar. discarded. B Data that do not fit a scientific theory should be discarded. 7E C Theories may be modified as additional data 4 The beak shape shown below likely evolved as a leads to new conclusions. result of the birds that could get food most D The repetition of results by many scientists is efficiently with this adaptation — not necessary to validate a theory. A dying in the absence of long, tubular flowers B not attracting a mate 2G, 11B C being able to eat a 2 wide variety of food, Tomato Plant Growth Per Week (cm) such as nuts, insects, Plot Condition Average Growth and berries 1 full sun 9 cm D being more likely to 2 part sun 7 cm survive and reproduce 3 full shade 2 cm

7B, 7E, 11B Gardeners are testing three plots of land with 5 Rock from the Cretaceous period contains the similar soil to find out which is best for growing fossils of a variety of dinosaurs and seedless tomato plants. Which of the following plants. The fossil record afterwards includes the conclusions is best supported by their data? fossils of many flowering plants and smaller A Plot 1 received the most nutrients. animals, but no dinosaurs. Which of the B Tomato plants grow best in full sun. following statements is supported by this C Tomato plants cannot grow in the shade. evidence? D The data are not reliable because there is no A Dinosaurs had begun to die out during the control. Cretaceous period. B A mass extinction at the end of the Cretaceous 2G, 6D period made new niches available for flowering 3 The sugar in corn quickly converts to starch after plants. the corn has been picked. After picking, corn that C The Cretaceous environment was less favorable has the Sh2 gene in its DNA was found to have to seedless plants than to flowering plants. more sugar and less starch than corn without this D Dinosaurs evolved around the end of the gene. Which of the following statements is most Cretaceous period. likely true about corn with this gene?

Chapter 20: Plant Diversity 615