UNIT 10 CHAPTER 19 Kingdoms and Domains

1. UNIT 10 CHAPTER 19 Kingdoms and Domains

2. Introduction to Kingdom and Domains -- Categories of Biological Classification • Taxonomy is the science of naming and classifying organisms. • More than 2,000 years ago, the Greek philosopher and naturalist Aristotle grouped plants and animals according to their structural similarities. As time went by, some of the groups became too large, and some organisms did not fit into either of the two categories. • In the 1750s, Swedish biologist Carl Linnaeus developed a new system that used a polynomial system to classify organisms. This system is still in use today.

3. Scientific Names • Linnaeus included a two-word Latin name for each species. This system is known as binomial nomenclature. • Binomial nomenclature is a system for giving each organism a two-word scientific name that consists of the genus name followed by the species name, which are written in Latin and italicized. • An example of binomial nomenclature is the two-part scientific name for the common house cat – Felix catus.

4. Scientific Names • The unique two-part name for a species is now referred to as its scientific name. • The scientific name of an organism consists of its two-part (binomial) name known as the genus species name. • The genus species name is always italicized or underlined.

5. Scientific Names • The first word in a scientific name is the genusto which the organism belongs. The first letter of the genus name is always capitalized. • Organisms in a genus share important characteristics and are closely related. • The second word in a scientific name is called a species. • A species is the basic biological unit in the Linnaean system of classification that identifies one particular kind of organism within the genus. • The first letter of the species name is always lowercase.

6. Classification Levels • Linnaeus worked out a broad system of classification for plants and animals in which an organism’s form and structure are the basis for arranging specimens in a collection. • The different groups into which organisms are now classified include eight levels. • Similar genera are grouped into a family. • Similar families are combined into an order.

7. Classification Levels • Orders with common properties are assigned to a class. • Classes with similar characteristics are assigned to a phylum. • Similar phyla are collected into a kingdom. • Similar kingdoms are grouped into domains. • All living things are grouped into one of three domains: Archaea, Bacteria, and Eukarya.

11. Classification based on similarities should reflect an organism’s phylogeny, or evolutionary history. • However, not all features are inherited from a common ancestor. • Organisms that appear similar may not share a recent common ancestor. • Through the process of convergent evolution, similarities evolve in organisms not closely related to one another often because the organisms live in similar habitats. • Analogous characters are similarities that arise through convergent evolution. Evolutionary History

12. Organisms that appear similar may not share a recent common ancestor.

13. Cladistics is a method of analysis that reconstructs phylogenies by inferring relationships based on shared characters. • Cladistics can be used to hypothesize the sequence in which different groups of organisms evolved. • Cladistics focuses on the nature of the characters in different groups of organisms. Cladistics

14. An ancestral character is a character that evolved in a common ancestor of both mammals. • When considering the relationship between birds and mammals, a backbone is an example of an ancestral character. • A derived character is a character that evolved in an ancestor of one group but not the other. • An example of a derived character when considering birds and mammals is that feathers evolved in an ancestor of birds that was not also ancestral to mammals. Cladistics

15. Cladistics is based on the principle that shared derivedcharacters provide evidence that two groups are relatively closely related. Shared ancestralcharacters, however, do not. • A biologists using cladistics constructs a branching diagram called a cladogram which shows the evolutionary relationships among groups of organisms. • Organisms that share derived characteristics are grouped together on the cladogram, and new derived characters will appear on the cladogram as groups evolve. Cladistics

17. In evolutionary systematics, taxonomists give varying degrees of importance to characters and thus produce a subjective analysis of evolutionary relationships. • These evolutionary relationships can be displayed in a branching diagram called a phylogenetic tree. • A phylogenetic tree is a branching diagram that shows how organisms are related through evolution. • A phylogenetic tree and a cladogram are similar in that each represents a hypothesis of evolutionary history which must be inferred because it was not observed. Phylogenetic Trees

19. This phylogenetic tree focuses on the relationships between marine organisms.

21. The Kingdoms of Life • Biologists have organized living things into large groups called Kingdoms. See page 412 for more information. • Biologists group organisms into sixkingdoms based on RNA and DNA sequencing and similarities: • Cell Type • Organisms are either prokaryotes or eukaryotes. Scientists generally recognize two kingdoms of prokaryotes and four kingdoms of eukaryotes. • Cell Walls • In four of the six kingdoms organisms have cell walls. In one of the six kingdoms, organisms lack cell walls. In the remaining kingdom, some organisms have cell walls and some do not. • Body Type • Organisms are either unicellular or multicellular. • Nutrition • Organisms are either autotrophs or heterotrophs.

22. The 6 Kingdoms of Life Protista is the only kingdom that contains both unicellular and multicellular organisms.

23. The 3 Domains of Life This phylogenetic tree is based on rRNA sequences that demonstrate the division of all living things into three broad domains. All living organisms are classified into three superkingdoms or domains: Archaea, Bacteria, and Eukarya.

24. The 3 Domains of Life • The domain thought to be the oldest is Bacteria, which is composed of the organisms in the kingdom Eubacteria. • Archaea is the second prokaryotic domain and is also composed of single kingdom Archaebacteria. • The third domain, Eukarya, contains all four of the eukaryotic kingdoms: Animalia (animals), Fungi (fungi), Plantae(plants), and Protista (protists).

25. The Domain Bacteria • The Domain Bacteria contains a single kingdom, Eubacteria. • Some scientists call this kingdom Bacteria. • Bacteria are prokaryotes and have no internal compartments and no nuclear membranes. • Bacteria are found in practically every environment on Earth.

26. Characteristics of Bacteria Bacteria have strong exterior cell walls made of peptidoglycan, a web-like molecule complex made of carbohydrate strands cross-linked by short peptide bridges.

27. Kinds of Bacteria • Some bacteria can cause disease, while others are used by humans to process food. • Bacteria are used to control agricultural pests, to produce various chemicals, and perform genetic engineering. • Some bacteria obtain energy from inorganic compounds such as hydrogen sulfide, ammonia, and methane (chemosynthesis).

28. Kinds of Bacteria • Some bacteria are photosynthetic and are found in ocean and freshwater ecosystems. • Some heterotrophic bacteria are able to live in the absence of oxygen (anaerobic). • Heterotrophic bacteria are also important decomposers and help to recycle phosphorusand other minerals back to the soil.

29. Shapes of Bacteria A bacterial cell is usually one of three basic shapes: coccus - round-shaped bacillus – rod-shaped spirillum – spiral-shaped Species that form filaments are indicated by the prefix strepto-. Species that form clusters are indicated by the prefix staphylo-.

30. Members of the kingdom Eubacteria have a cell wall. • Outside the cell wall and membrane, many bacteria have a gel-like layer called a capsule. • Members of kingdom Archaebacteria often lack cell walls. • Some bacteria form thick-walled endospores around their chromosomes and a small bit of cytoplasm when they are exposed to harsh conditions. This also makes these bacteria resistant to heat and cold, and more difficult to destroy. • A few kinds of bacteria aggregate into strands.

31. Bacterial Reproduction • Many bacteria reproduce by binary fission, a form of asexual reproduction where the cell simply splits into. • Bacteria exhibit an extremely wide variety of metabolic types. • Some bacteria are autotrophs and produce their own food by photosynthesis. Other bacteria use inorganic compounds as a source of energy.

32. Can you identify the three types of bacteria? spirillum bacillus coccus

33. The Domain Archaea • The Domain Archaea contains a single kingdom, Archaebacteria. • Archaebacteria are prokaryotes that have diverged very early from bacteria. • They are more closely related to eukaryotes than to bacteria.

34. Characteristics of Archaebacteria Cell Wall and Membrane • The cell walls of archaebacteria do not contain peptidoglycan like the cell walls of bacteria. • Archaebacteria contain lipids very different from those of bacteria or eukaryotes. Gene Structure and Translation • The ribosomal proteins of archaebacteria are very similar to those of eukaryotes and different from those of bacteria.

35. Kinds of Archaebacteria • Methanogens • These archaebacteria obtain energy by combining hydrogen gas and carbon dioxide to form methane gas. • Methanogens live deep in the mud of swamps and are poisoned by even traces of oxygen. • Extremophiles • A group of extremophiles called Thermophiles lives in very hot places. • Halophiles inhabit very salty lakes that can be three times as salty as seawater. • Other extremophiles live in very acidic places or under enormous pressure. • Nonextreme Archaebacteria • These grow in all the same environments that bacteria do.

36. Kinds of Archaebacteria • Methanogens

37. The Domain Eukarya • Eukarya is made up of four kingdoms: • Protista • Fungi • Plantae • Animalia • Members of this domain are eukaryotes.

38. Characteristics of Eukarya • Highly Organized Cell Interior • All eukaryotes have cells with a nucleus and other internal compartments. • Multicellularity • The activities of individual cells are coordinated and the cells themselves are in contact with each other, which occurs only in eukaryotes. • Sexual Reproduction • Meiotic cell division forms haploid gametes and two gametes unite to form a diploid cell in fertilization. • Genetic recombination during meiosis and fertilization causes the offspring of eukaryotes to vary widely, providing for evolution.

39. Kinds of Eukarya • A wide variety of eukaryotes are unicellular. • Most unicellular eukaryotes are in the kingdom Protista. • Protists contain both unicellular and multicellular organisms, and many are aquatic. • Fungi are heterotrophs that are mostly multicellular. • Many fungi live on and decompose dead organisms, and many others are parasitic.

40. Kinds of Eukarya • Plants and Animals are all multicellular. • Almost all plants are autotrophs and have cells with cell walls composed of cellulose. • All animals are heterotrophs composed of cells that do not have cell walls. • Most plants and animals have tissues and organs.

41. Kingdom and Domain Characteristics

42. Chapter 19 Section 2: Advent of Multicellularity

43. Advent of Multicellularity • Colonies • A colonial organism is a group of cells that are permanently associated but do not communicate with one another. • Aggregations • An aggregation is a temporary collection of cells that come together for a period of time and then separate. • True Multicellularity • A multicellular organism is an organism composed of many cells that are permanently associated with one another. • This enables cells to specialize in different functions. • Complex Multicellularity • Plants and animals have complex multicellularity. • The specialized cells of most plants and animals are organized into structures called tissues and organs.

44. Kingdom Protista • Of the six kingdoms of organisms, Protista is the most diverse. • They are eukaryotes that are not fungi, plants, or animals. • Many are unicellular. • All single-celled eukaryotes (except yeasts) are protists. • Some protists, such as some kinds of algae, have cell specialization. • Most are microscopic, but some are as large as trees.

45. Kinds of Protists • Biologists recognize six groups of protists based on physical or nutritional characteristics. • 1.) Protists That Use Pseudopodia Amoebas are protists that have flexible surfaces with no cell walls or flagella. Amoebas move by using extensions of cytoplasm calledpseudopodia. Forams have porous shells through which long, thin projections of cytoplasm can be extended. • 2.) Protists That Use Flagella Many protists move by using flagella, which are long whip-like tails.

46. Amoebas

47. Kinds of Protists • 3.) Protists with Double Shells • Diatoms are photosynthetic protists with unique double shells made of silica. • 4.) Photosynthetic Algae • These algae are distinguished by the type of chlorophyll they contain. • Many algae are multicellular and reproduce sexually. • 5.) Fungus-like Protists • Slime molds and water molds are often confused with fungi because they aggregate in times of stress to form spore-producing bodies.

48. Diatoms

49. Kinds of Protists • 6.) Spore-Forming Protists • Sporozoans are nonmotile unicellular parasites that form spores. • Sporozoans are responsible for many significant diseases, including malaria, and have complex life cycles.

50. Slime Molds Paramecium