Unit Overview – pages 366-367 • How is music grouped in a store? • What is the advantage to doing • this?
Unit Overview – pages 366-367 Change Through Time Organizing Life’s Diversity Classification
Section 17.1 Summary – pages 443-449 How Classification Began • Biologists want to better understand organisms so they organize them. • One tool that they use to do this is classification • Classification is the grouping of objects or information based on similarities.
Section 17.1 Summary – pages 443-449 How Classification Began • Taxonomy is the branch of biology that groups and names organisms based on studies of their different characteristics. • Biologists who study taxonomy are called taxonomists.
Section 17.1 Summary – pages 443-449 Aristotle’s system • The Greek philosopher Aristotle (384-322 B.C.) developed the first widely accepted system of biological classification. • He classified all the organisms he knew into two groups: plants and animals.
Section 17.1 Summary – pages 443-449 Aristotle’s system • He subdivided plants into three groups, herbs, shrubs, and trees, depending on the size and structure of a plant. • He grouped animals according to various characteristics, including their habitat and physical differences.
Section 17.1 Summary – pages 443-449 Aristotle’s system • According to his system, birds, bats, and flying insects are classified together even though they have little in common besides the ability to fly. • As time passed, more organisms were discovered and some did not fit easily into Aristotle’s groups, but many centuries passed before Aristotle’s system was replaced.
Section 17.1 Summary – pages 443-449 Linnaeus’s system of binomial nomenclature • In the late eighteenth century, a Swedish botanist, Carolus Linnaeus (1707-1778), developed a method of grouping organisms that is still used by scientists today. • Linnaeus’s system was based on physical and structural similarities of organisms. • As a result, the groupings revealed the relationships of the organisms.
Section 17.1 Summary – pages 443-449 Linnaeus’s system of binomial nomenclature • Eventually, some biologists proposed that structural similarities reflect the evolutionary relationships of species. • This way of organizing organisms is the basis of modern classification systems.
Section 17.1 Summary – pages 443-449 Linnaeus’s system of binomial nomenclature • Binomial nomenclature is a modern classification system using a two-word naming system that Linnaeus developed to identify species. • In this system, the first word identifies the genus of the organism. • A genus is a group of similar species.
Section 17.1 Summary – pages 443-449 Linnaeus’s system of binomial nomenclature • A specific epithet is the second word, which sometimes describes a characteristic of the organism • Thus, the scientific name for each species, referred to as the species name, is a combination of the genus name and specific epithet. Homo sapiens
Section 17.1 Summary – pages 443-449 Scientific and common names • Scientific names should be italicized in print and underlined when handwritten. • The first letter of the genus name is uppercase, but the first letter of the specific epithet is lowercase. Passer domesticus
Section 17.1 Summary – pages 443-449 Scientific and common names • Taxonomists are required to use Latin because: • the language is no longer used in conversation and, therefore, does not change • a common name can be misleading. • it is confusing when a species has more than one common name.
Section 17.1 Summary – pages 443-449 Modern Classification • Expanding on Linnaeus’s work, today’s taxonomists try to identify the underlying evolutionary relationships of organisms and use the information gathered as a basis for classification. • Grouping organisms on the basis of their evolutionary relationships makes it easier to understand biological diversity.
Section 17.1 Summary – pages 443-449 Taxonomy: A framework • Taxonomists group similar organisms, both living and extinct. Classification provides a framework in which to study the relationships among living and extinct species. • For example, biologists study the relationship between birds and dinosaurs within the framework of classification. Archaeopteryx
Section 17.1 Summary – pages 443-449 Taxonomy: A useful tool • Anyone can learn to identify many organisms using a dichotomous key. • A key is made up of sets of numbered statements. Each set deals with a single characteristic of an organism, such as leaf shape or arrangement.
Section 17.1 Summary – pages 443-449 How Living Things Are Classified • In any classification system, items are categorized, making them easier to find and discuss. • Although biologists group organisms, they subdivide the groups on the basis of more specific criteria. • A group of organisms is called a taxon (plural, taxa).
Section 17.1 Summary – pages 443-449 Taxonomic rankings • Organisms are ranked in taxa that range from having very broad characteristics to very specific ones. • The broader a taxon, the more general its characteristics, and the more species it contains.
Section 17.1 Summary – pages 443-449 Taxonomic rankings • The smallest taxon is species. Organisms that look alike and successfully interbreed belong to the same species. • The next largest taxon is a genus—a group of similar species that have similar features and are closely related.
Section 17.1 Summary – pages 443-449 Taxonomic rankings • Compare the appearance of a lynx, Lynx rufus, a bobcat, Lynx canadensis, and a mountain lion, Panthera concolor. Mountain lion Lynx Bobcat
Section 17.1 Summary – pages 443-449 Domain Eukarya Kingdom Animalia Chordata Phylum Class Mammalia Carnivora Order Felidae Family Lynx Genus Species Lynx canadensis Lynx rufus Lynx Bobcat
Most Inclusive to Least Inclusive Place the following groups in the appropriate level: Mammals, Man, Primates, Vertebrates, Animals A B C D E
Most Inclusive to Least Inclusive Add the following groups to the appropriate level on the Venn Diagram: Kingdom Plantae, Division Angiospermae, All Organisms, Order Rodentia, Tulip, Kingdom Animalia A B C D E F
Most Inclusive to Least Inclusive Complete the Venn Diagram with the following groups: Family Vespidae (yellow jacket), Phylum Arthropoda, Order Lepidoptera (butterflies), Class Insecta, Order Hymenoptera (bees, wasps) A B C D E
Most Inclusive to Least Inclusive Draw a Venn Diagram to represent the following groups: Kingdom Animalia Class Osteichthyes (Bony Fish) Phylum Chordata (animals with backbones) Class Chondrichthyes (Cartilaginous Fish) Family Sphyrnidae (Hammerhead Shark)
Section 1 Check Question 1 How did Aristotle group organisms such as birds, bats, and insects? A. by their common genus B. by their analogous structures C. by their common species D. by their homologous structures
Section 1 Check The answer is B. The organisms were grouped together because of their wings, which, in this case, are analogous structures.
Section 1 Check Question 2 Which taxon contains the fewest species? A. genus B. family C. order D. phylum The answer is A, genus.
Section 1 Check Question 3 For which of the following species names does the specific epithet mean “handy?” A. Homo sapiens B. Homo erectus C. Australopithecus anamensis D. Homo habilis The answer is D.
Section 1 Check Question 4 What is the difference between “classification” and “taxonomy?” Answer Classification is the grouping of objects or information based on similarities. Taxonomy is the branch of biology that classifies and names organisms based on their different characteristics.
Section 1 Check Question 5 What are the two parts that make up binomial nomenclature? Answer Binomial nomenclature comprises a genus name followed by a specific epithet.
Section 2 Objectives – page 450 1. Put these animals into 3 groups.2. What characteristics did you use for your system of classification?
Unit Overview – pages 366-367 Change Through Time Organizing Life’s Diversity The Six Kingdoms
Section 17.2 Summary – pages 450-459 How are evolutionary relationships determined? • Classification systems today are based on evolutionary relationships. • This means extinct animals can also be included in classification schemes.
Section 17.2 Summary – pages 450-459 How are evolutionary relationships determined? • Evolutionary relationships are determined on the basis of: • similarities in structure • breeding behavior • geographical distribution • chromosomes • biochemistry
Section 17.2 Summary – pages 450-459 Structural similarities • For example, plant taxonomists 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 450-459 Breeding behavior • Sometimes, breeding 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 mating behavior. • Scientists concluded that the frogs were two separate species.
Section 17.2 Summary – pages 450-459 Geographical distribution Probing Bills Grasping Bills Crushing Bills Feeders Cactus Insect Feeders Seed Fruit Feeders Parrot Bills Feeders Ancestral Species
Section 17.2 Summary – pages 450-459 Chromosome comparisons • For example, cauliflower, cabbage, kale, and broccoli look different but have chromosomes that are almost identical in structure. • Therefore, biologists propose that these plants are related.
Section 17.2 Summary – pages 450-459 Biochemistry • Powerful evidence about relationships among species comes from biochemical analyses of organisms. • Closely related species have similar DNA sequences and, therefore, similar proteins. • In general, the more inherited nucleotide sequences that two species share, the more closely related they are.
Section 17.2 Summary – pages 450-459 Phylogenetic Classification: Models • Phylogeny is the evolutionary history of a species • A classification system that shows the evolutionary history of species is a phylogenetic classification and reveals the evolutionary relationships of species.
Section 17.2 Summary – pages 450-459 Cladistics • Cladistics is a biological system of classification that is based on phylogeny. • Scientists who use cladistics assume that as groups of organisms diverge and evolve from a common ancestral group, they retain some unique inherited characteristics that taxonomists call derived traits.
Section 17.2 Summary – pages 450-459 Cladistics • A cladogram is a branching diagram used to identify a group’s derived traits; it is a model of phylogeny of a species • Cladograms are hypothetical evolutionary trees.
Section 17.2 Summary – pages 450-459 Cladistics Allosaurus Velociraptor Robin Archaeopteryx Sinornis Theropods Flight feathers; arms as long as legs Feathers with shaft, veins, and barbs 3-toed foot; wishbone Dry scales Light bones
Section 17.2 Summary – pages 450-459 Cladistics • Organisms are assigned to a group on a cladogram by a unique characteristic they share in common with other members of that group. • A derived character is a unique trait, such as dry skin, that is used to assign an organism to a group.
Section 17.2 Summary – pages 450-459 Another type of model • One type of model resembles a fan. • A fanlike model may communicate the time organisms became extinct or the relative number of species in a group. • A fanlike diagram incorporates fossil information and the knowledge gained from anatomical, embryological, genetic, and cladistic studies.
Section 17.2 Summary – pages 450-459 Life’s Six Kingdoms
Section 17.2 Summary – pages 450-459 The Six Kingdoms of Organisms • The six kingdoms of organisms are archaebacteria, eubacteria, protists, fungi, plants, and animals. • In general, differences in cellular structures and methods of obtaining energy are the two main characteristics that distinguish among the members of the six kingdoms.
Section 17.2 Summary – pages 450-459 Prokaryotes • The prokaryotes, organisms with cells that lack distinct nuclei bounded by a membrane, are microscopic and unicellular. • Some are heterotrophs (eat other organisms) and some are autotrophs (make their own food).
Section 17.2 Summary – pages 450-459 Prokaryotes • In turn, some prokaryotic autotrophs are chemosynthetic, whereas others are photosynthetic. • There are two kingdoms of prokaryotic organisms: Archaebacteria and Eubacteria.