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00.indd 170 169-182 GHSB RESG-874600.indd 170 3/17/06 1:36:18 PM 3/17/06 1:36:18 PM What principles did Darwin use? Darwin developed a theory for how one species could change to become multiple new species. Darwin based his theory on four principles. Principle 1 Individuals in a population show differences, even among ...
-874600.indd 171 3/17/06 1:36:21 PM 3/17/06 1:36:21 PM 15 section ● Evolution Evidence of Evolution 2 Multiple lines of evidence support evolution. What You’ll Learn how fossils provide evidence of evolution evidence of evolution from morphology how physiology and biochemistry provide evidence of evolution State Main I...
that birds evolved from dinosaurs. Scientists divide traits into two classes. Derived traits are newly evolved traits that have not appeared in common ancestors. Ancestral traits are traits that are shared by species with a common ancestor. In Archaeopteryx, teeth are an example of an ancestral trait. What does anatom...
a common ancestor. The more closely related two organisms are, the more similar their molecules will be. Scientists have observed this pattern for DNA and RNA sequences, as well as for the amino acid sequences of proteins. Scientists now use similarities in DNA and RNA sequences to determine evolutionary relationships...
traits increase ﬁ tness? Not all features of organisms are adaptations that increase ﬁ tness. Some features arise because they are unavoidable consequences of other evolutionary changes. For example, human babies are born helpless at an earlier stage of development than other primates. Many scientists believe that ear...
frequency of alleles in populations does not change unless the frequencies are acted on by some factor that causes change. When the frequency of alleles remains the same, the population is in genetic equilibrium. A population in genetic equilibrium does not evolve. 176 Chapter 15 Evolution Reading Essentials. 169-182 ...
that result from genetic drift are not always the best ones for the environment. Sometimes, important adaptations can be lost by genetic drift. Reading Essentials 3. Draw Conclusions What population would be most likely to experience genetic drift? (Circle your answer.) a. 4000 mice living in a meadow b. 30 rabbits li...
frequencies in a population and violate genetic equilibrium. Occasionally, a mutation provides an advantage for an organism. The mutation will become more common in future generations. Mutations are the raw material in which natural selection works. 4. Deﬁ ne What happens in a bottleneck? 5. Evaluate What is a problem...
When rain returns, average beak size decreases because smaller beak size is a better ﬁ t for the environment. What is disruptive selection? Disruptive selection removes individuals with the average form of a trait. It creates two populations with extreme forms of a trait. Disruptive selection occurs in water snakes on...
a similar appearance and live in overlapping areas. However, the two species use different mating songs and do not interbreed. Time is another factor that can be a reproductive barrier. For example, closely related species of ﬁ reﬂ ies mate at different times of night. Different species of trout live in the same strea...
PM 3/17/06 1:36:45 PM 12. Deﬁ ne What happens in adaptive radiation? 13. Compare Which statement describes two organisms that emerged by convergent evolution? (Circle your answer.) They have similar a. morphology. b. They are closely related. When does adaptive radiation occur? Adaptive radiation occurs when one speci...
-874600.indd 182 169-182 GHSB RESG-874600.indd 182 3/17/06 1:36:47 PM 3/17/06 1:36:47 PM 16 section ● Primate Evolution Primates 1 Before You Read Have you ever watched a monkey or an ape in a zoo or on television? On the lines below, list some humanlike behaviors you might have observed. Then read the section to learn...
the two subgroups of primates. How do forward-looking eyes beneﬁ t primates? Most primates rely more on vision than on smell. Their eyes are on the fronts of their faces. This creates overlapping ﬁ elds of vision called binocular vision. Forward-looking eyes provide depth perception and enable primates to judge distan...
16 Primate Evolution Reading Essentials 183-196 GHSB RESG-874600.indd 184 183-196 GHSB RESG-874600.indd 184 3/17/06 1:39:13 PM 3/17/06 1:39:13 PM Strepsirrhines The table below lists characteristics of some strepsirrhines. Strepsirrhines are the only primates that rely mostly on smell for hunting and social interactio...
/17/06 1:39:15 PM 3/17/06 1:39:15 PM What traits do New World monkeys share? New World monkeys live in the tropical forests of Mexico, Central America, and South America. New World monkeys include marmosets and tamarins. These unique primates do not have ﬁ ngernails or opposable digits. Some squirrel monkeys and spider...
primates. They spend more time on the ground than in trees. Orangutans are the only great ape species that lives exclusively in Asia. Gorillas are the largest primates. Like all great apes, they spend most of their time on the ground. They walk on all four limbs, using their front knuckles for support. They use sticks...
alongside dinosaurs about 85 mya. One of the earliest fossil primates, called Altiatlasius (al tee aht lah SEE us), was a small, nocturnal animal that used its hands and feet for grasping. About 50 mya, anthropoids branched off from tarsiers. By the end of the Eocene, 35 to 30 mya, anthropoids had evolved widely. Abou...
of various australopithecine species Read to Learn Hominoids Hominoids (HAH mih noydz) include all nonmonkey anthropoids—gibbons, orangutans, chimpanzees, gorillas, and humans. By comparing DNA of living hominoid species, researchers conclude that gibbons likely branched from anthropoids ﬁ rst. Next to the branch were...
below highlights some important hominin discoveries. The brains of hominins are larger than those of other hominoids and have more capacity for high-level thought. The hominin face is thinner and ﬂ atter. The teeth are smaller. Longer thumbs and more ﬂ exible wrists increase manual dexterity. Identify a body character...
and back. Because walking upright opposes gravity, it requires more energy than walking on all four limbs. Why did hominins become bipedal? At the time hominins evolved, Africa was changing. Many scientists suggest that bipedalism was an adaptation to the new savanna environment. Food sources were sparse and far apart...
, long arms, and curved ﬁ nger bones. But her hip and knee joints showed clearly that Lucy walked upright. A few years later, Mary Leakey found fossilized footprints that supported the theory that australopithecines were bipedal. How can hominin evolution be described? Hominin fossils show a patchwork of human and apel...
had lighter skeletons, ﬂ atter faces, and smaller teeth. Homo species were the ﬁ rst to control ﬁ re and to use stone tools. As they evolved, they developed language and culture. How did Homo habilis differ from its ancestors? The ﬁ rst Homo species for which fossils exist is Homo habili. Homo habili, which means “han...
evolved from H. ergaster. This species includes “Java Man,” discovered in Indonesia, and “Peking Man,” discovered in China. Unlike earlier species, H. erectus adapted to many types of environments. H. erectus was taller than H. habilis. It had a bigger brain and more humanlike teeth. H. erectus featured a long skull, ...
near the end of the Pleistocene ice age. They hunted, used ﬁ re, and made complex shelters. Evidence suggests that they cared for their sick and buried their dead. In some areas, Neanderthals overlapped with modern humans. However, DNA tests on fossil bones show that Neanderthals were not part of the human gene pool. ...
evolved only once, in Africa, and then migrated to all parts of the world, replacing other hominins. Picture This 6. Highlight Use a marker to highlight the direct ancestor of today’s human beings. 7. Draw Conclusions Scientists found the widest variation in mitochondrial DNA in Africans. What conclusion could they dr...
accepted system of biological classiﬁ cation. Aristotle classiﬁ ed organisms as either animals or plants. Animals were classiﬁ ed by their habitat and their morphology. Morphology relates to the physical characteristics and structures of organisms. Animals were also classiﬁ ed by the presence of red blood. Aristotle’s...
Because of this understanding, Aristotle’s classiﬁ cation did not account for evolutionary history or relationships. Also, many organisms have been discovered that do not ﬁ t Aristotle’s classiﬁ cation system, such as birds that do not ﬂ y and frogs that live on land and in water. Aristotle’s system was used for many ...
iﬁ es the species. Latin is often used for binomial nomenclature because Latin is a language that is unchanging. Historically, Latin has also been the language of science. The meaning of Latin words can be understood by scientists who speak different languages. Why do scientists use scientiﬁ c names? Biologists use sci...
Haeckel, introduced classiﬁ cation systems based on evolutionary relationships to organize biological diversity. Categories used in modern classiﬁ cation are based on Linnaeus’s system but have been changed to show evolutionary relationships. Taxonomic Categories Taxonomists classify organisms by dividing them into sm...
organized. Picture This 8. Determine At what level on the pyramid of taxa is the American black bear distinguished from the Asiatic black bear? Systematics Applications Systematicists are scientists who study classiﬁ cation. They provide detailed guides that enable other people to identify organisms. Many times, ﬁ eld...
of that species. When another specimen was found that was different from the type specimen, it was classiﬁ ed as a different species. Evolution causes species to change. Because there is a lot of variation among members of some species, the typological species concept has been replaced. Some of its traditions such as ...
t Typological species concept classiﬁ cation by the comparison of physical characteristics with a type specimen Alleles produce a wide variety of features within a species. Biological species concept classiﬁ cation by similar characteristics and the ability to interbreed and produce fertile offspring Some organisms th...
Their hip, leg, wrist, and shoulder structures are similar to those of birds. These morphological characters suggest that birds are related more closely to theropod dinosaurs than to other reptiles. Summarize Why might African elephants be two species, instead of one? Picture This 5. Compare What physical characterist...
difﬁ cult to read. Scientists are trying to ﬁ nd genes that mutate at a relatively consistent rate throughout a range of organisms. Even though molecular clocks have limitations, they can be a valuable tool for helping to determine the time when a new species evolved. The molecular clock is often used along with the f...
branches of a cladogram show hypothesized phylogeny. The hypothesized phylogeny shown in a cladogram depends on information from DNA and RNA sequences, bioinformatics, and morphological studies. Places where branching occurs are called nodes. The common ancestor at the nodes is rarely a known organism, species, or fos...
together to develop a comprehensive tree of life. Knowing how organisms are related would beneﬁ t industry, agriculture, and medicine biologygmh.com Chapter 17 Organizing Life's Diversity 207 197-212 GHSB RESG-874600.indd 207 197-212 GHSB RESG-874600.indd 207 3/18/06 3:38:22 PM 3/18/06 3:38:22 PM 17 section ● Organizi...
HR ee uh) are prokaryotes whose cell walls contain peptidoglycan (pep tih doh GLY kan). Peptidoglycan is a polymer that contains two kinds of sugars. The amino acids on these sugars form a netlike structure that is porous and strong. 208 Chapter 17 Organizing Life's Diversity Reading Essentials. 197-212 GHSB RESG-87460...
ukarya All organisms with membrane-bound organelles are classiﬁ ed in Domain Eukarya and are called eukaryotes. Domain Eukarya contains Kingdom Protista, Kingdom Fungi, Kingdom Plantae, and Kingdom Animalia. 1. Apply What is a good deﬁ nition of the term anaerobic? 2. Explain Why are archaebacteria sometimes called ext...
i also have hyphae (HI fee). Hyphae are threadlike strands that enable the fungi to grow, feed, and reproduce. More than 70,000 species of fungi have been identiﬁ ed. Most fungi, such as mushrooms, are multicellular. A few fungi, such as yeasts, are unicellular. Fungi are heterotrophs. Unlike other heterotrophic organi...
, such as digestive, circulatory, and nervous systems. Animals range in size from a few millimeters to many meters. Animals live in water, on land, and in the air. Most animals are able to move. A few animals such as coral cannot move in their adult form. Is there an exception to the classiﬁ cation system? If you have ...
autotrophic live in many environments can move live in many environments can move autotrophic and heterotrophic live in moist environments can move heterotrophic live in many environments cannot move most are autotrophic that perform photosynthesis; some are heterotrophic heterotrophic live in water and on land cannot...
an Outline Make an outline of the information you learn in this section. Start with the headings. Include the boldface terms. 1. Apply Prokaryotes that live in the Great Salt Lake belong to which domain? (Circle your answer.) a. Bacteria b. Archae Chapter 18 Bacteria and Viruses 213. 213-222 GHSB RESG-874600.indd 213 ...
214 213-222 GHSB RESG-874600.indd 214 3/18/06 1:54:40 PM 3/18/06 1:54:40 PM How do bacteria beneﬁ t from their size? Prokaryotes are small, even when viewed with a microscope. Small cells have a larger surface-area-to-volume ratio than larger cells. As a result, nutrients and other important substances can diffuse to ...
and separate the cell into two identical cells. 4. Describe the three shapes of prokaryotes. 5. Apply Why do doctors use Gram stains Reading Essentials Chapter 18 Bacteria and Viruses 215 213-222 GHSB RESG-874600.indd 215 213-222 GHSB RESG-874600.indd 215 3/18/06 1:54:42 PM 3/18/06 1:54:42 PM Picture This 6. Label Wri...
222 GHSB RESG-874600.indd 216 3/18/06 1:54:44 PM 3/18/06 1:54:44 PM Prokaryotes Heterotrophs Autotrophs Saprotrophs Photosynthetic Autotrophs Chemoautotrophs What do chemoautotrophs use to make food? Chemoautotrophs do not need light. They use the process of chemosynthesis to break down and release inorganic materials ...
bacteria do not cause disease. In fact, many beneﬁ t humans. How do bacteria beneﬁ t plants? All organisms use nitrogen to make proteins, DNA, and RNA. Most of Earth’s nitrogen is gas in the atmosphere. Some bacteria can use nitrogen gas directly. In a process called nitrogen ﬁ xation, these bacteria convert nitrogen ...
218 3/18/06 1:54:51 PM 3/18/06 1:54:51 PM 18 section ● Bacteria and Viruses Viruses and Prions 2 Before You Read Have you ever heard of mad cow disease? On the lines below, write what you know about mad cow disease. In this section, you will read about what causes mad cow disease. Read to Learn Viruses A virus is a no...
which could be DNA or RNA but not both. Viruses are classiﬁ ed as either DNA or RNA based on the type of genetic material they contain. Smallpox, caused by a DNA virus, infected humans for thousands of years. A successful worldwide vaccination program eliminated the disease. Viral Infection A virus attaches to the hos...
replication cycle that has many parts. Human immunodeﬁ ciency virus (HIV) is a retrovirus. What is the structure of HIV? The structure of HIV is similar to other viruses. It has a protein capsid. Around the capsid is a lipid envelope that it got from the plasma membrane of the host cell. In the core of a retrovirus is...
and elk 222 Chapter 18 Bacteria and Viruses biologygmh.com 213-222 GHSB RESG-874600.indd 222 213-222 GHSB RESG-874600.indd 222 3/18/06 1:55:02 PM 3/18/06 1:55:02 PM 19 section ● Protists Introduction to Protists 1 Before You Read Suppose you want to determine if an organism is more like a plant or more like an animal....
4600.indd 223 223-236 GHSB RESG-874600.indd 223 3/17/06 1:47:48 PM 3/17/06 1:47:48 PM ■ ■ Picture This 2. Synthesize You can determine the group to which a protist belongs by its method of a. moving. b. obtaining nutrients. c. reproducing. Protist Group Animal-like protists (protozoans) Plantlike protists (algae) Fungu...
evolved from a common ancestor. Mitochondria became part of protist cells early in evolution. Chloroplasts entered later. Algae are the only protists with chloroplasts. Thus, algae are the only protists that perform photosynthesis. 3. Identify two structures within protists that might have been individual organisms at...
shaped bodies discharge spinelike structures. Scientists are not sure of the purpose of trichocysts. A paramecium might use them for defense, as a reaction to injury, to anchor itself, or to capture prey. Reading Essentials Create a Quiz As you read this section, write quiz questions based on what you have learned. Aft...
us Cytoplasmic bridge Cells separate Genetically identical paramecia form Three micronuclei in each cell disintegrate Remaining micronuclei go through mitosis Macronuclei disintegrate. 226 Chapter 19 Protists Reading Essentials 223-236 GHSB RESG-874600.indd 226 223-236 GHSB RESG-874600.indd 226 3/17/06 1:47:57 PM 3/17/...
ugation different from binary ﬁ ssion? Picture This 3. Explain What happens to the pseudopods from the left ﬁ gure to the right ﬁ gure Reading Essentials Chapter 19 Protists 227 223-236 GHSB RESG-874600.indd 227 223-236 GHSB RESG-874600.indd 227 3/17/06 1:47:59 PM 3/17/06 1:47:59 PM What are the structures of an amoeba...
movement. Recall that ﬂ agella are long whiplike projections from the cell. Can zooﬂ agellates infect humans? Some zooﬂ agellates are parasites. Some species can cause sleeping sickness in humans. Their life cycles includes two hosts. In Africa, tsetse ﬂ ies spread the disease when they feed on the blood of humans or ...
s atmosphere. Algae are plantlike, autotrophic protists. What You’ll Learn the characteristics of several phyla of algae the secondary photosynthetic pigments of some algae the differences between diatoms and most other algae Restate the Main Point As you read this section, stop after each paragraph, and put the main i...
It gives toothpaste its gritty texture 230 Chapter 19 Protists Reading Essentials 223-236 GHSB RESG-874600.indd 230 223-236 GHSB RESG-874600.indd 230 3/17/06 1:48:08 PM 3/17/06 1:48:08 PM How do dinoﬂ agellates move? Dinoﬂ agellates (DI nuh ﬂ a juh layts) are plantlike protists of the phylum Pyrrophyta (puh RAH fuh tu...
similar to a paramecium. They have an eyespot to detect light and ﬂ agella to move toward food or light. The contractile vacuole expels water to maintain homeostasis. What pigments color the chrysophytes? Members of the phylum Chrysophyta (KRIS oh fyt uh) are called chrysophytes (KRIS oh fytz). They get their yellow o...
. The ﬂ agella of all cells beat at the same time to move the colony. Smaller daughter colonies form balls inside the larger colony. When the daughter cells have matured, they digest the parental cell and become free-swimming. What pigment gives red algae their color? Red algae, of phylum Rhodophyta (roh dah FI duh), g...
asexually. Algae alternate between a diploid (2n) form and a haploid (n) form. Each form is a generation. How does alternation of generations work? Follow the arrows in the ﬁ gure below to review how the two generations alternate. The haploid form is called the gametophyte generation because it produces gametes. Gamet...
. The cell walls of fungi are made of chitin (KI tun), a complex carbohydrate. The cell walls of funguslike protists contain cellulose or similar compounds, instead of chitin. Slime molds are found in many colors. They usually grow in damp, shady places among decaying matter such as decaying leaves or wood. Slime molds...
When food or moisture becomes limited, the slime mold produces spores that are spread by the wind. When the spores are in water, the cycle repeats. How do cellular slime molds differ? The phylum Acrasiomycota (uh kray see oh my COH tuh) contains cellular slime molds. These funguslike protists spread over moist soil, f...
nutrients from the water or soil around them. Others obtain nutrients from other organisms. Like fungi, water molds enclose their food with a mass of threads and absorb nutrients through their cell walls. Water molds differ from fungi in two main ways. Their cell walls are made of different materials, and the reproduc...
Ask your teacher to help you with anything that you still do not understand. Take Notes Make a layered Foldable, as shown below. As you read, take notes and organize what you learn about the characteristics of fungi. Characteristics of Fungi Major Features Reproduction Nutrition Chapter 20 Fungi 237. 237-246 GHSB RESG...
nutrients from dead organisms or organic wastes back into food webs. Picture This 2. Label two septa in the diagram. 1. The structural units of a fungus are hyphae. The cell walls of hyphae are made of chitin Large food molecule Small food molecule Enzyme 2. The hyphae release enzymes into a food source. 3. The enzyme...
ed? Fungi are classiﬁ ed by the type of fruiting body, or sporophore, 4. List three features of spores that help them survive. they produce. For example, some fungi produce spores in a sac or case called a sporangium (spuh RAN jee uhm) (plural, sporangia). The sporangium protects the spores and keeps them from drying ...
spores have ﬂ agella. For this reason, scientists ﬁ rst thought that chytrids were a type of protist. Studies of chytrid molecules, however, suggest a closer relationship to fungi than to protists. Also, like other fungi, chytrids have chitin in their cell walls. Scientists think that chytrids might have been the ﬁ rs...
B RESG-874600.indd 241 237-246 GHSB RESG-874600.indd 241 3/17/06 1:52:07 PM 3/17/06 1:52:07 PM How does sexual reproduction take place? Fungi are not divided into males and females. Instead, they have plus (+) and minus (–) mating strains. The hyphae of a plus mating strain and a minus mating strain grow together. Each...
dee uh forz) produce chains or clusters of spores called conidia at their tips. Wind, water, and animals spread the spores. How do sac fungi reproduce sexually? In sexual reproduction, the hyphae from plus and minus mating strains fuse. One nucleus from each strain pairs off in a separate cell. The cell contains two h...
i 243 237-246 GHSB RESG-874600.indd 243 237-246 GHSB RESG-874600.indd 243 3/17/06 1:52:14 PM 3/17/06 1:52:14 PM 20 section ● Fungi Ecology of Fungi 3 Lichens have distinct characteristics. What You’ll Learn the features of mycorrhizal relationships the positive and negative effects of fungi on humans Before You Read Th...
areas. On the tundra, grazing animals feed on lichens that cover the ground. Lichens can survive droughts. When there is little water, lichens dry out and stop photosynthesizing. Dry pieces can break off, blow away, and form new colonies where they land. When the rain returns, lichens absorb the moisture and start pho...
nutrients from dead organisms back into food webs. How are fungi used in medicine? Fungi have many medical uses. A type of fungi is the source of penicillin, a life-saving antibiotic. Chemicals found in some fungi can reduce bleeding and lower high blood pressure. How are fungi used in foods? Fungi contribute to human...
plants have tissues where photosynthesis occurs. Organs such as roots that anchor plants to the soil or to another object also have speciﬁ c functions. Primitive land plants ﬁ rst appeared about 400 million years ago. Biochemical and fossil evidence suggests that freshwater green algae are the ancestors of land plants...
icle that gives some plant leaves their gray appearance. The cuticle helps keep water from evaporating from the plant tissues. The cuticle also stops microorganisms from invading the plant. 2. Conclude Why do land plants need to conserve water 248 Chapter 21 Introduction to Plants Reading Essentials 247-258 GHSB RESG-8...
, a diploid zygote forms. The zygote goes through mitosis repeatedly to form a multicellular sporophyte. The sporophyte generation produces spores. The spores can grow to form the next gametophyte generation. 3. Explain how the cuticle and stomata function together. 4. Name the two plant generations Reading Essentials ...
Plants 2 Nonvascular plants are small and only grow in damp environments. What You’ll Learn the structures of nonvascular plants the differences among the nonvascular-plant divisions Identify Plant Divisions Underline or highlight the name of each nonvascular plant division. Say the name aloud. Then circle the words o...
without damage. Some mosses can survive drought and begin growing again when water returns. What is the smallest division of nonvascular plants? Anthocerophytes (an tho SAIR uh ﬁ tes) are the smallest division of nonvascular plants. Members of division Anthocerophyta are commonly called hornworts because of their horn...
es and ferns. Club mosses are small plants. They are usually less than 30 cm tall. Tropical tree ferns can grow to a height of 25 m. An adaptation seen in the sporophytes of many seedless vascular plants is the strobilus (STROH bih lus). A strobilus is a cluster of structures that produce spores. What is the dominant g...
te produced? The fern gametophyte is a tiny, thin structure. It grows from a spore and has male and female reproductive structures. After fertilization, the sporophyte grows from the gametophyte. Ferns that live in dry areas have an adaptation that allows them to produce sporophytes without fertilization. The sporophyt...
seed plants and the plants you have read about in the last two sections. Seeds are an adaptation that helps seed plants succeed in different environments, including places with little water. Structures known as cotyledons (kah tuh LEE dunz) either store food or help take in food for the seed. Plants with seeds that ar...
grains produce male gametophytes. Female cones contain the female gametophytes. Male reproductive structures and female reproductive structures are on separate cycad plants. What is the natural cycad habitat? Cycads grew in abundance about 200 million years ago. Today, there are only about 250 species of cycads. They ...
to identify the tree or shrub. Conifers are trees and shrubs with needlelike or scalelike leaves. The leaves are covered with cutin—a waxlike coating. Cutin is an adaptation that reduces water loss. What is an evergreen plant? Most evergreen plants in the northern temperate region are conifers. In tropical regions, ev...
now classify dicots as eudicots or dicots, based on the structure of the pollen. About 75 percent of anthophytes are eudicots. Most trees, shrubs, and garden plants are eudicots. Monocots are the second largest group and include grass, onions, and palms. Oaks, maples, and sycamores are examples of dicots. What are the...
a large central vacuole. Most plant cells also have chloroplasts. However, there are many types of plant cells that carry out speciﬁ c functions. Plant cells have one or more adaptations that make it possible for these cells to perform their functions. For example, some plant cells lose their cytoplasm and organelles ...
ma cells? Sclerenchyma (skle RENG kuh muh) cells differ from parenchyma and collenchyma cells. Mature sclerenchyma cells lack cytoplasm and other living components, but their rigid cell walls remain. Sclerenchyma cells support the plant and help transport materials within the plant. Plants can have two types of scleren...
along the stems of most monocots. Lateral meristems The two types of lateral meristems produce an increase in root and stem diameter. Nonﬂ owering plants, eudicots, dicots, and a few monocots have secondary growth produced from this meristematic tissue. Vascular cambium (VAS kyuh lur • KAM bee um) is a thin cylinder o...
the plant. It is composed of vessel elements and tracheids (TRA kihdz). Each mature vessel element and tracheid consists of just its cell wall, as shown below. Water can ﬂ ow freely through these cells because the cytoplasm and other living parts are gone. Vessel elements are tubular cells that form strands of xylem. ...
PM 3/17/06 2:08:49 PM 22 section ● Plant Structure and Function Roots, Stems, and Leaves 2 Before You Read On the lines below, name the parts of a plant you have seen recently. Describe the function of one of the parts. In this section you will read more about the functions of plant parts. Read to Learn Roots For most...
the cortex. This layer of cells creates a waterproof seal around the root’s vascular tissue. Water and dissolved minerals are forced to pass through the cells of the endodermis to reach the vascular tissue. Next to the endodermis is the pericycle (PER ih si kul). It is the tissue that produces lateral roots. In some p...
provides additional support for the plant. Most of the increase in diameter is due to an increase in cell size. Cells produced in the vascular cambium of some plants cause the increase in stem diameter. Xylem and phloem, produced throughout the year, also increase stem diameter. They produce the annual growth rings fo...
through its stem to the leaves. Some water is used in photosynthesis. Some water evaporates from the inside of the leaf to the outside through the stomata in a process called transpiration. What differences in leaves help people identify plants? Some people identify plants by the differences in size, shape, color, and...
cells to get longer. The auxin, indoleacetic (IHN doh luh see tihk) acid, is produced in apical meristems, buds, and other tissues that grow rapidly. This hormone moves from one parenchyma cell to another, always moving away from where it was produced. The effect of auxin varies widely depending on the concentration a...
is. Plant Responses Events such as vines climbing a pole and trees dropping their leaves are plant responses to their environments. A response of a plant that causes movement independent of the direction of the stimulus is a nastic response. A Venus ﬂ ytrap plant exhibits a nastic response. Its leaves snap shut when it...
potato can be cut into pieces. Each piece with an eye (bud) can be planted and grown into a new potato plant. A few cells of plant tissue can also be used to grow some plants, using a technique called tissue culture. The life cycle of mosses, ferns, and conifers includes alternation of generations. What You’ll Learn f...
ophytes live apart from the gametophyte. 2. Identify Which stage produces haploid spores? Picture This 3. Explain to a partner the alternation of generations using the ﬁ gure. Cell divisions occur Sporophyte Diploid cells (2n) Cell divisions occur Fertilization forms zygote (2n) Reproductive cells develop Male gamete (...
the gametophyte plant, and the cycle repeats. Picture This 5. Highlight the area where eggs are produced. Circle the area where sperm are produced Reading Essentials Chapter 23 Reproduction in Plants 271 269-282 GHSB RESG-874600.indd 271 269-282 GHSB RESG-874600.indd 271 3/17/06 2:14:02 PM 3/17/06 2:14:02 PM Picture T...
8. Compare What is the male gametophyte of a conifer? 9. Summarize pollination in conifers. Conifer Reproduction and Life Cycle Pine trees are examples of the sporophyte generation of conifer plants. Conifers are heterosporous. Heterosporous (he tuh roh SPOR us) plants make two types of spores that develop into male a...
mature seeds biologygmh.com Chapter 23 Reproduction in Plants 273 269-282 GHSB RESG-874600.indd 273 269-282 GHSB RESG-874600.indd 273 3/17/06 2:14:08 PM 3/17/06 2:14:08 PM 23 section ● Reproduction in Plants Flowers 2 Flowers are the reproductive structures of anthophytes. What You’ll Learn about complete, incomplete,...
iosis and then mitosis to form pollen grains. Two sperm eventually form inside each pollen grain. The female reproductive structure of a ﬂ ower is the pistil. In the center of a ﬂ ower is one or more pistils. A pistil usually has three parts—a stigma, a style, and an ovary. The style connects the stigma to the ovary. T...

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