17.1 Section Objectives – page 443 Evaluate the history, purpose, and methods of taxonomy. Section Objectives: 17.1 Explain the meaning of a scientific name. Describe the organization of taxa in a biological classification system.

Section 17.1 Summary – pages Biologists want to better understand __________ so they organize them. One tool that they use to do this is ____________—the grouping of objects or information based on _____________.

Section 17.1 Summary – pages Biologists who study taxonomy are called ____________. ________ (tak SAH nuh mee) is the branch of biology that groups and names organisms based on studies of their different _____________.

Section 17.1 Summary – pages He classified all the organisms he knew into two groups: _____ and ________. The Greek philosopher ___________ ( B.C.) developed the first widely accepted system of biological classification.

Section 17.1 Summary – pages He grouped animals according to various characteristics, including their _______ and ________ differences. He subdivided plants into three groups, _____, ______, and ______, depending on the size and structure of a plant.

Section 17.1 Summary – pages As time passed, more organisms were discovered and some did not fit easily into Aristotle’s groups, but many __________ passed before Aristotle’s system was replaced. According to his system, birds, ____, and flying insects are _______ together even though they have little in common besides the ability to ____.

Section 17.1 Summary – pages Linnaeus’s system was based on _______ and ________ similarities of organisms. In the late eighteenth century, a Swedish botanist, Carolus __________ ( ), developed a method of grouping organisms that is still used by scientists today. As a result, the groupings revealed the __________ of the organisms.

Section 17.1 Summary – pages This way of organizing _______ is the basis of modern classification systems. Eventually, some biologists proposed that ________ similarities reflect the evolutionary _________ of species.

Section 17.1 Summary – pages In this system, the first word identifies the _____ of the organism. Modern classification systems use a two-word naming system called ______ __________ that Linnaeus developed to identify species. A _____ (JEE nus) (plural, genera) consists of a group of similar species.

Section 17.1 Summary – pages Thus, the scientific name for each species, referred to as the species name, is a combination of the ______ name and specific _______. The second word, which sometimes describes a characteristic of the organism, is called the ______ ______. Homo sapiens

Section 17.1 Summary – pages Scientific names should be _________ in print and _______ when handwritten. Taxonomists are required to use ____ because the language is no longer used in conversation and, therefore, does not _______. The first letter of the genus name is _____, but the first letter of the specific epithet is _______. Passer domesticus

Section 17.1 Summary – pages In addition, it is confusing when a ______ has more than one common name. Many organisms have ______ names. However, a common name can be misleading. For example, a sea horse is a ___, not a _____.

Section 17.1 Summary – pages Grouping organisms on the basis of their evolutionary relationships makes it easier to understand biological _________. Expanding on Linnaeus’s work, today’s _________ try to identify the underlying ___________ relationships of organisms and use the information gathered as a basis for classification.

Section 17.1 Summary – pages For example, biologists study the relationship between ____ and __________ within the framework of classification. Taxonomists group similar organisms, both _____ and ______. Classification provides a __________ in which to study the relationships among living and extinct species. Archaeopteryx

Section 17.1 Summary – pages Classifying organisms can be a useful tool for scientists who work in agriculture, _______, and medicine.

Section 17.1 Summary – pages Anyone can learn to identify many organisms using a ________ key. A key is made up of sets of numbered statements. Each set deals with a ______ characteristic of an organism, such as leaf ______ or ___________.

Section 17.1 Summary – pages It often happens that the discovery of new sources of lumber, medicines, and energy results from the work of taxonomists. The characteristics of a familiar _______ are frequently similar to those found in a new, related species.

Section 17.1 Summary – pages For example, if a __________ knows that a certain species of pine tree contains chemicals that make good ___________, it’s possible that another pine species could also contain these useful substances.

Section 17.1 Summary – pages In any classification system, items are _________, making them easier to find and discuss. Although biologists group organisms, they _________ the groups on the basis of more specific ________. A group of organisms is called a ______ (plural, taxa).

Section 17.1 Summary – pages Organisms are ranked in taxa that range from having very ______ characteristics to very _________ ones. The broader a taxon, the more _______ its characteristics, and the more _______ it contains.

Section 17.1 Summary – pages The smallest taxon is ____. Organisms that look alike and successfully _______ belong to the same species. The next largest taxon is a ____—a group of similar species that have similar ______ and are closely ______.

Section 17.1 Summary – pages Compare the appearance of a ____, Lynx rufus, a ____, Lynx canadensis, and a mountain ____, Panthera concolor. Lynx Mountain lion Bobcat

Section 17.1 Summary – pages Domain Kingdom Phylum Class Order Family Genus Species Eukarya Animalia Chordata Mammalia Carnivora Felidae Lynx rufus Lynx canadensis Bobcat Lynx

Section 2 Objectives – page 450 Section Objectives 17.2 Explain how cladistics reveals phylogenetic relationships. Describe how evolutionary relationships are determined. Compare the six kingdoms of organisms.

Section 17.2 Summary – pages ____________ relationships are determined on the basis of ________ in structure, ______ behavior, _______ distribution, chromosomes, and biochemistry.

Section 17.2 Summary – pages Structural similarities among _______ reveal relationships. The presence of many shared physical structures implies that ______ are closely related and may have evolved from a common ancestor.

Section 17.2 Summary – pages For example, plant _________ use structural evidence to classify dandelions and sunflowers in the same family, Asteraceae, because they have similar flower and fruit structures.

Section 17.2 Summary – pages Taxonomists observe and compare features among members of different ____ and use this information to infer their evolutionary history.

Section 17.2 Summary – pages Sometimes, _______ behavior provides important clues to relationships among species. For example, two species of frogs, Hyla versicolor and Hyla chrysoscelis, live in the same area and look similar. During the breeding season, however, there is an obvious difference in their ______ behavior. Scientists concluded that the frogs were two separate species.

Section 17.2 Summary – pages Crushing Bills Probing Bills Grasping Bills Ancestral Species Parrot Bills Seed Feeders Cactus Feeders Insect Feeders Fruit Feeders

Section 17.2 Summary – pages These ______ probably spread into different _____ on the volcanic islands and evolved over time into many distinct species. The fact that they share a ______ ancestry is supported by their __________ distribution in addition to their genetic similarities.

Section 17.2 Summary – pages Both the number and structure of ___________, as seen during ______ and ______, provide evidence about relationships among species.

Section 17.2 Summary – pages For example, cauliflower, cabbage, kale, and broccoli look different but have __________ that are almost identical in structure.

Section 17.2 Summary – pages Therefore, biologists propose that these plants are related.

Section 17.2 Summary – pages Powerful evidence about relationships among species comes from _________ analyses of organisms. Closely related species have similar ___ sequences and, therefore, similar ______. In general, the more inherited _________ sequences that two species share, the more _______ related they are.

Section 17.2 Summary – pages The evolutionary history of a species is called its ___________ (fy LAH juh nee). A classification system that shows the evolutionary history of species is a ____________ classification and reveals the evolutionary relationships of species.

Section 17.2 Summary – pages One biological system of classification that is based on phylogeny is _________ (kla DIHS tiks). Scientists who use cladistics assume that as groups of organisms ______ and _______ from a common ancestral group, they retain some unique inherited characteristics that taxonomists call _____ traits.

Section 17.2 Summary – pages Cladistics Theropods Allosaurus Sinornis Velociraptor Archaeopteryx Robin Light bones 3-toed foot; wishbone Down feathers Feathers with shaft, veins, and barbs Flight feathers; arms as long as legs

Section 17.2 Summary – pages However, an important difference between cladograms and pedigrees is that, whereas pedigrees show the ______ ancestry of an organism from two parents, cladograms show a _____ evolution of a group of organisms from ancestral groups.

Section 17.2 Summary – pages One type of model resembles a ___. Unlike a cladogram, a fanlike model may communicate the time organisms became ______ or the relative number of species in a group. A fanlike diagram incorporates ____ information and the knowledge gained from ________l, embryological, ______, and cladistic studies.

Section 17.2 Summary – pages Life’s Six Kingdoms

Section 17.2 Summary – pages The six kingdoms of organisms are archaebacteria, ________, protists, _____, plants, and _______. In general, differences in ______ structures and ______ of obtaining energy are the two main characteristics that distinguish among the members of the six kingdoms.

Section 17.2 Summary – pages The ________, organisms with cells that lack distinct nuclei bounded by a membrane, are microscopic and ____________. Some are _______ and some are __________.

Section 17.2 Summary – pages In turn, some prokaryotic autotrophs are ____________, whereas others are _____________. There are two kingdoms of prokaryotic organisms: __________ and __________.

Section 17.2 Summary – pages There are several hundred species of known archaebacteria and most of them live in _______ environments such as swamps, deep-ocean hydrothermal vents, and seawater evaporating ponds. Most of these environments are ___________.

Section 17.2 Summary – pages All of the other prokaryotes, about 5000 species of bacteria, are classified in Kingdom ___________. Eubacteria have very ______ cell walls and a less complex ______ makeup than found in archaebacteria or eukaryotes.

Section 17.2 Summary – pages They live in most _______ except the extreme ones inhabited by the archaebacteria. Although some eubacteria cause diseases, such as _____ throat and _________, most bacteria are h______ and many are actually helpful.

Section 17.2 Summary – pages Kingdom _______ contains diverse species that share some characteristics. A protist is a ________ that lacks complex organ systems and lives in moist environments. Cilia Oral groove Gullet Micronucleus and macronucleus Contractile vacuole Anal pore A Paramecium

Section 17.2 Summary – pages Although some protists are unicellular, others are ______________. Some are ________ autotrophs, some are _________ heterotrophs, and others are ________ heterotrophs that produce reproductive structures like those of fungi.

Section 17.2 Summary – pages Organisms in Kingdom ____ are heterotrophs that do ___ move from place to place. A ______ is either a unicellular or multicellular eukaryote that _____ nutrients from organic materials in the environment.

Section 17.2 Summary – pages There are more than 50,000 known species of fungi.

Section 17.2 Summary – pages All of the organisms in Kingdom ________ are multicellular, photosynthetic eukaryotes. _____ moves from place to place.

Section 17.2 Summary – pages A plant’s cells usually contain ________ and have cell walls composed of ______. Plant cells are organized into _____ that, in turn, are organized into _____ and organ ________.

Section 17.2 Summary – pages The _____ plant fossils are more than 400 million years old. However, some scientists propose that plants existed on Earth’s landmasses much ______ than these fossils indicate.

Section 17.2 Summary – pages There are more than 250,000 known ______ of plants. Although you may be most familiar with ________ plants, there are many other types of plants, including ______, ferns, and _________.

Section 17.2 Summary – pages Animals are ___________ heterotrophs. Nearly all are able to _____ from place to place. Animal cells __ ___ have cell walls.

Section 17.2 Summary – pages Their cells are organized into tissues that, in turn, are organized into organs and complex organ systems. Animals first appeared in the ______ record about 600 million years ago.

End of Chapter 17