Presentation on theme: "Chapter Intro-page 442 What Youll Learn You will identify and compare various methods of classification. You will distinguish among six kingdoms of organisms."— Presentation transcript:
Chapter Intro-page 442 What Youll Learn You will identify and compare various methods of classification. You will distinguish among six kingdoms of organisms.
17.1 Section Objectives – page 443 Evaluate the history, purpose, and methods of taxonomy. Section Objectives: 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 organisms so they organize them. One tool that they use to do this is classificationthe grouping of objects or information based on similarities. How Classification Began
Section 17.1 Summary – pages Biologists who study taxonomy are called taxonomists. How Classification Began Taxonomy (tak SAH nuh mee) is the branch of biology that groups and names organisms based on studies of their different characteristics. Click image to view movie.
Section 17.1 Summary – pages He classified all the organisms he knew into two groups: plants and animals. Aristotles system The Greek philosopher Aristotle ( 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 habitat and physical differences. Aristotles system He subdivided plants into three groups, herbs, shrubs, and trees, 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 Aristotles groups, but many centuries passed before Aristotles system was replaced. Aristotles system aka Artificial Classification System Aristotles system aka Artificial Classification 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.
Section 17.1 Summary – pages Linnaeuss system was based on physical and structural similarities of organisms. Linnaeuss system of binomial nomenclature In the late eighteenth century, a Swedish botanist, Carolus Linnaeus ( ), developed a method of grouping organisms that is still used by scientists today. As a result, the groupings revealed the relationships of the organisms.
Section 17.1 Summary – pages This way of organizing organisms is the basis of modern classification systems. Linnaeuss system of binomial nomenclature Eventually, some biologists proposed that structural similarities reflect the evolutionary relationships of species.
Section 17.1 Summary – pages In this system, the first word identifies the genus of the organism. Linnaeuss system of binomial nomenclature Modern classification systems use a two-word naming system called binomial nomenclature that Linnaeus developed to identify species. A genus (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 genus name and specific epithet. Linnaeuss system of binomial nomenclature The second word, which sometimes describes a characteristic of the organism, is called the specific epithet. Homo sapiens
Section 17.1 Summary – pages Scientific names should be italicized in print and underlined when handwritten. Taxonomists are required to use Latin because the language is no longer used in conversation and, therefore, does not change. The first letter of the genus name is uppercase, but the first letter of the specific epithet is lowercase. Passer domesticus Scientific and common names
Section 17.1 Summary – pages In addition, it is confusing when a species has more than one common name. Scientific and common names Many organisms have common names. However, a common name can be misleading. For example, a sea horse is a fish, not a horse.
Section 17.1 Summary – pages Grouping organisms on the basis of their evolutionary relationships makes it easier to understand biological diversity. Modern Classification Expanding on Linnaeuss work, todays taxonomists try to identify the underlying evolutionary 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 birds and dinosaurs within the framework of classification. Taxonomists group similar organisms, both living and extinct. Classification provides a framework in which to study the relationships among living and extinct species. Archaeopteryx Taxonomy: A framework
Section 17.1 Summary – pages Taxonomy: A useful tool Classifying organisms can be a useful tool for scientists who work in agriculture, forestry, and medicine.
Section 17.1 Summary – pages Taxonomy: A useful tool Anyone can learn to identify many organisms using a biological (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 Taxonomy and the economy 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 species are frequently similar to those found in a new, related species.
Section 17.1 Summary – pages Taxonomy and the economy For example, if a taxonomist knows that a certain species of pine tree contains chemicals that make good disinfectants, its possible that another pine species could also contain these useful substances.
Section 17.1 Summary – pages 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 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 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 genusa group of similar species that have similar features and are closely related.
Section 17.1 Summary – pages Compare the appearance of a lynx, Lynx rufus, a bobcat, Lynx canadensis, and a mountain lion, Panthera concolor. Lynx Mountain lion Bobcat Taxonomic rankings
Section 17.1 Summary – pages Domain Kingdom Phylum Class Order Family Genus Species Eukarya Animalia Chordata Mammalia Carnivora Felidae Lynx rufus Lynx canadensis BobcatLynx
Section 2 Objectives – page 450 Section Objectives 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 similarities in structure, breeding, behavior, geographical distribution, chromosomes, and biochemistry. How are relationships determined?
Section 17.2 Summary – pages Structural similarities among species reveal relationships. Structural similarities The presence of many shared physical structures implies that species are closely related and may have evolved from a common ancestor.
Section 17.2 Summary – pages 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. Structural similarities
Section 17.2 Summary – pages Structural similarities Taxonomists may observe and compare features among members of different taxa and use this information to infer their evolutionary history.
Section 17.2 Summary – pages 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. Breeding behavior
Section 17.2 Summary – pages Geographical distribution Crushing Bills Probing Bills Grasping Bills Ancestral Species Parrot Bills Seed Feeders Cactus Feeders Insect Feeders Fruit Feeders
Section 17.2 Summary – pages These finches probably spread into different niches on the volcanic islands and changed over time into many distinct species. The fact that they share a common ancestry is supported by their geographical distribution in addition to their genetic similarities. Geographical distribution
Section 17.2 Summary – pages Both the number and structure of chromosomes, as seen during mitosis and meiosis, provide evidence about relationships among species. Chromosome comparisons
Section 17.2 Summary – pages Chromosome comparisons For example, cauliflower, cabbage, kale, and broccoli look different but have chromosomes that are almost identical in structure.
Section 17.2 Summary – pages Chromosome comparisons Therefore, biologists propose that these plants are related.
Section 17.2 Summary – pages Powerful evidence about relationships among species comes from biochemical analyses of organisms. Biochemistry 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 The evolutionary history of a species is called its phylogeny (fy LAH juh nee). Phylogenetic Classification: Models 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 One biological system of classification that is based on phylogeny is cladistics (kla DIHS tiks). Cladistics 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 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 direct ancestry of an organism from two parents, cladograms show a probable evolution of a group of organisms from ancestral groups. Cladistics
Section 17.2 Summary – pages One type of model resembles a fan. Another type of model Unlike a cladogram, 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 Lifes Six Kingdoms Lifes Six Kingdoms
Section 17.2 Summary – pages The six kingdoms of organisms are archaebacteria, eubacteria, protists, fungi, plants, and animals. The Six Kingdoms of Organisms 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 The prokaryotes, organisms with cells that lack distinct nuclei bounded by a membrane, are microscopic and unicellular. Prokaryotes Some are heterotrophs and some are autotrophs.
Section 17.2 Summary – pages Prokaryotes In turn, some prokaryotic autotrophs are chemosynthetic, whereas others are photosynthetic. There are two kingdoms of prokaryotic organisms: Archaebacteria and Eubacteria. Ameoba
Section 17.2 Summary – pages There are several hundred species of known Archaebacteria and most of them live in extreme environments such as swamps, deep- ocean hydrothermal vents, and seawater evaporating ponds. Most of these environments are oxygen-free. Prokaryotes
Section 17.2 Summary – pages Prokaryotes All of the other prokaryotes, about 5000 species of bacteria, are classified in Kingdom Eubacteria. Eubacteria have very strong cell walls and a less complex genetic makeup than found in archaebacteria or eukaryotes.
Section 17.2 Summary – pages Prokaryotes They live in most habitats except the extreme ones inhabited by the archaebacteria. Although some eubacteria cause diseases, such as strep throat and pneumonia, most bacteria are harmless and many are actually helpful. Staphylococcus
Section 17.2 Summary – pages Protista: A diverse group Kingdom Protista contains diverse species that share some characteristics. A protist is a eukaryote 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 Protista Although some protists are unicellular, others are multicellular. Some are plantlike autotrophs, some are animal-like heterotrophs, and others are funguslike heterotrophs that produce reproductive structures like those of fungi. Lycogala
Section 17.2 Summary – pages Fungi: Earths decomposers Organisms in Kingdom Fungi are heterotrophs that do not move from place to place. A fungus is either a unicellular or multicellular eukaryote that absorbs nutrients from organic materials in the environment.
Section 17.2 Summary – pages Fungi: Earths decomposers There are more than 50,000 known species of fungi.
Section 17.2 Summary – pages Plants: Multicellular oxygen producers All of the organisms in Kingdom Plantae are multicellular, photosynthetic eukaryotes. None moves from place to place.
Section 17.2 Summary – pages Plants: Multicellular oxygen producers A plants cells usually contain chloroplasts and have cell walls composed of cellulose. Plant cells are organized into tissue that, in turn, are organized into organs and organ systems.
Section 17.2 Summary – pages The oldest plant fossils are more than 400 million years old. However, some scientists propose that plants existed on Earths landmasses much earlier than these fossils indicate. Plants: Multicellular oxygen producers
Section 17.2 Summary – pages There are more than 250,000 known species of plants. Although you may be most familiar with flowering plants, there are many other types of plants, including mosses, ferns, and evergreens. Plants: Multicellular oxygen producers
Section 17.2 Summary – pages Animals: Multicellular consumers Animals are multicellular heterotrophs. Nearly all are able to move from place to place. Animal cells do not have cell walls.
Section 17.2 Summary – pages Animals: Multicellular consumers Their cells are organized into tissues that, in turn, are organized into organs and complex organ systems.
The Species and the Kind Linnaeus - first thought number of species was set at creation –later thought they could change He and his students named about 10,000 plants and animals
Today There are now over 1.5 million known living species It is estimated that there are 5 to 10 million undiscovered
The Species The definition for species is not adequate Two things to consider when defining a species –Member of a species are structurally similar but do have a degree of variation –Members of a species can interbreed and produce viable and fertile offspring under natural conditions
Problems with Species Concept 1) Artificial characteristics –environment can affect an organisms characteristics (ex - tiger salamander, Ambystoma tigrinum) –a cross between two species makes a new combination, not a new species (ex - coyote + dog = coydog)
2) Interbreeding –Some species do not reproduce sexually –Organisms of the same species may not necessarily be able to interbreed (St. Bernard and Chihuahua; the green spotted grass frog) –ecotypes - organisms that appear the same but are suited for one environment and often cannot interbreed
Gods primary purpose in creating different organisms was to have them perform specific functions in specific ways in specific places, not to make them easy to classify.
The Biblical Kind Organisms that reproduce after their own kind (Gen 1:20-25) Linnaeus was the first to use the term species (kind-latin)
Some species can successfully interbreed making a hybrid organism – evoltion or not?
Natural System of Classification A system based on biochemical similarities Example - Humans, frogs, gorillas As researchers decode genomes they hope to show the relationships between organsims
Migration and Adaptation are not Evolution Migration - the moving of organisms from one area to another Adaptation - the change of an organism that allows it to survive in a new environment (limited to the organisms genetic makeup)
Section 2 Check Which of the following is NOT a way to determine evolutionary relationships? Question 1 D. geographical distribution C. specific epithets B. biochemistry A. chromosome comparisons C
Section 2 Check How does a cladogram differ from a pedigree? Question 2 Answer Pedigrees show the direct ancestry of an organism from two parents. Cladograms show a probable evolution from an ancestral group.
Section 2 Check Why do taxonomists use Latin names for classification? Question 3 Answer Latin is no longer used in conversation and, therefore, does not change.
Section 2 Check What is the relationship between cladistics and taxonomy? Question 5 Answer Cladistics is one kind of taxonomy that is based on phylogeny.
Chapter Summary – 17.1 Although Aristotle developed the first classification system, Linnaeus laid the foundation for modern classification systems by using structural similarities to organize species and by developing a binomial naming system for species. Classification Scientists use a two-word system called binomial nomenclature to give species scientific names.
Chapter Summary – 17.1 Classification provides an orderly framework in which to study the relationships among living and extinct species. Classification Organisms are classified in a hierarchy of taxa: domain, kingdom, phylum or division, class, order, family, genus, and species.
Chapter Summary – 17.2 Biologists use similarities in body structures, breeding behavior, geographic distribution, chromosomes, and biochemistry to determine evolutionary relationships. The Six Kingdoms
Chapter Summary – 17.2 Kingdoms Archaebacteria and Eubacteria contain only unicellular prokaryotes. The Six Kingdoms Kingdom Protista contains eukaryotes that lack complex organ systems. Kingdom Fungi includes heterotrophic eukaryotes that absorb their nutrients.
Chapter Summary – 17.2 Kingdom Plantae includes multicellular eukaryotes that are photosynthetic. The Six Kingdoms Kingdom Animalia includes multicellular, eukaryotic heterotrophs with cells that lack cell walls.
Chapter Assessment Domain Kingdom Phylum Class Order Family Genus Species Eukarya Animalia Chordata Mammalia Carnivora Felidae Lynx rufus Lynx canadensis Bobcat Lynx Question 1
Both organisms are members of the same kingdom, phylum, class, order, family, and genus but belong to different species. Chapter Assessment
Question 2 Which taxon contains the others? D. family C. genus B. class A. order The answer is B.
Chapter Assessment Question 3 Which of the following pairs of terms is NOT related? D. Aristotle – evolutionary relationships C. biology – taxonomy B. binomial nomenclature – Linnaeus A. specific epithet – genus The answer is D.
Chapter Assessment Domain Kingdom Phylum Class Order Family Genus Species Eukarya Animalia Chordata Mammalia Carnivora Felidae Lynx rufus Lynx canadensis Bobcat Lynx Question 4
Bobcats are more closely associated with lynxes as cats than as mammals. Domain Kingdom Phylum Class Order Family Genus Species Eukarya Animalia Chordata Mammalia Carnivora Felidae Lynx rufus Lynx canadensis Bobcat Lynx Chapter Assessment
Question 5 What two main characteristics distinguish the members of the six kingdoms? The two characteristics are differences in cellular structures and methods of obtaining energy.
Chapter Assessment Question 6 Which of the following is NOT true of both the animal and plant kingdoms? D. cells contain cell walls C. cells are organized into tissues B. tissues are organized into organs A. both contain organisms made up of cells D
Chapter Assessment Question 7 Which of the following describes a fungus? D. heterotrophic prokaryote C. unicellular autotroph B. unicellular or multicellular heterotroph A. autotrophic prokaryote
The answer is B, unicellular or multicellular heterotroph. Chapter Assessment
Question 8 What is the definition of a species? Answer: a group with members that resemble each other and that can interbreed to produce fertile offspring
Question 9 What is meant by the biblical kind? Answer: organism that reproduces after its own kind
Question 10 What is a natural classification system? Answer: a system based on biochemical similarities
Photo Credits NOAA PhotoDisc Mark Steinmetz Corbis Digital Stock Alton Biggs
End of Chapter 9 Show Tropical Red-eyed tree frog