Domain Bacteria

1. Organizing Life’s Diversity Chapter 17 17.3 Domains and Kingdoms Domain Bacteria • Eubacteria are prokaryotes whose cell walls contain peptidoglycan. • Eubacteria are a diverse group that can survive in many different environments. Classifying Using Biotechnology

2. Organizing Life’s Diversity Chapter 17 17.3 Domains and Kingdoms Domain Archaea • Archaea are thought to be more ancient than bacteria and yet more closely related to our eukaryote ancestors. • Archaea are diverse in shape and nutrition requirements. • They are called extremophiles because they can live in extreme environments.

3. Organizing Life’s Diversity Chapter 17 17.3 Domains and Kingdoms Domain Eukarya • All eukaryotes are classified in Domain Eukarya. • Domain Eukarya contains Kingdom Protista, Kingdom Fungi, Kingdom Plantae, and Kingdom Animalia.

4. Protists are eukaryotic organisms that can be unicellular, colonial, or multicellular. Organizing Life’s Diversity Chapter 17 17.3 Domains and Kingdoms Kingdom Protista • Protists are classified into three different groups—plantlike, animal-like, and funguslike.

5. A fungus is a unicellular or multicellular eukaryote that absorbs nutrients from organic materials in its environment. Organizing Life’s Diversity • Member of Kingdom Fungi are heterotrophic, lack motility, and have cell walls. Chapter 17 17.3 Domains and Kingdoms Kingdom Fungi

6. Organizing Life’s Diversity • Most plants are autotrophs, but some are heterotrophic. Chapter 17 17.3 Domains and Kingdoms Kingdom Plantae • Members of Kingdom Plantae form the base of all terrestrial habitats. • All plants are multicellular and have cell walls composed of cellulose.

7. Organizing Life’s Diversity Chapter 17 17.3 Domains and Kingdoms Kingdom Animalia (vertebrates or invertebrates) • All animals are heterotrophic, multicellular eukaryotes. • Animal organs often are organized into complex organ systems. • They live in the water, on land, and in the air.

8. Organizing Life’s Diversity Chapter 17 17.3 Domains and Kingdoms

9. Dichotomous Keys • Dichotomous key: is a tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish • Keys consist of a series of choices that lead the user to the correct name of a given item. "Dichotomous" means "divided into two parts" • Therefore, dichotomous keys always give two choices in each step

10. READING A DICHOTOMOUS KEY • Always read both choices, even if the first seems to be the logical one at first, then move to the next step • Be sure you understand the meaning of the terms involved. Do Not Guess! • When measurements are given, use a calibrated scale. Do Not Guess! • Since living things are always somewhat variable, do not base your conclusion on a single observation. Study several specimens to be sure your specimen is typical. • If the choice is not clear, for whatever reason, try both divisions. If you end up with two possible answers, read descriptions of the two choices to help you decide. • Having arrived at an answer in a key, do not accept this as absolutely reliable. Check a description of the organism to see if it agrees with the unknown specimen. If not, an error has been

11. Example of a Key • a. wings covered by an exoskeleton ………go to step 2 b. wings not covered by an exoskeleton ……….go to step 3 Step 2 needs to consist of a pair of statements that will allow for the identification of the ladybug and the grasshopper: 2. a. body has a round shape ……….ladybug b. body has an elongated shape ……….grasshopper Step 3 needs to consist of a pair of statements that will allow for the identification of the housefly and dragonfly: 3. a. wings point out from the side of the body ……….dragonfly b. wings point to the posterior of the body ……….housefly

13. Making a Key • Each step involves making choices between 2 characteristics • Each step either identifies (names) an object OR gives directions as to where to go next in the key • There is ALWAYS 1 less step in the key as there are objects to be identified • Observe objects to be keyed and find specific, visible characteristics • Characteristics must be: visible, physical, concrete, NOT opinions; LIMIT objectives • Start with general characteristics and move towards more specific

14. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification Phylogenic Species Concept • Phylogeny is the evolutionary history of a species. • The phylogenic species concept defines a species as a cluster of organisms that is distinct from other clusters and shows evidence of a pattern of ancestry and descent.

15. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification Characters • To classify a species, scientists construct patterns of descent by using characters. • Characters can be morphological or biochemical.

16. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification Morphological Characters • Shared morphological characters suggest that species are related closely and evolved from a recent common ancestor. • Analogous characters are those that have the same function but different underlying construction. • Homologous characters might perform different functions, but show an anatomical similarity inherited from a common ancestor.

17. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification Birds and Dinosaurs • Compare birds and dinosaurs: • Hollow bones Haliaeetus leucocephalus • Theropods have leg, wrist, hip, and shoulder structures similar to birds. • Some theropods may have had feathers. Oviraptor philoceratops

18. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification Biochemical Characters • Scientists use biochemical characters, such as amino acids and nucleotides, to help them determine evolutionary relationships among species. • DNA and RNA analyses are powerful tools for reconstructing phylogenies.

19. The similar appearance of chromosomes among chimpanzees, gorillas, and orangutans suggests a shared ancestry. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification

20. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification Molecular Clocks • Scientists use molecular clocks to compare the DNA sequences or amino acid sequences of genes that are shared by different species.

21. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification • The differences between the genes indicate the presence of mutations. • The more mutations that have accumulated, the more time that has passed since divergence.

22. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification The Rate of Mutation is Affected • Type of mutation • Where the mutation is in the genome • Type of protein that the mutation affects • Population in which the mutation occurs

23. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification Phylogenetic Reconstruction • Cladistics reconstructs phylogenies based on shared characters. • Scientists consider two main types of characters when doing cladistic analysis. • An ancestral character is found within the entire line of descent of a group of organisms. • Derived characters are present members of one group of the line but not in the common ancestor.

24. Organizing Life’s Diversity Chapter 17 17.2 Modern Classification Cladograms • The greater the number of derived characters shared by groups, the more recently the groups share a common ancestor.