UNIT I – UNITY & DIVERSITY OF LIFE

1. UNIT I – UNITY & DIVERSITY OF LIFE

2. Biology is . . .

3. I. “THE STUDY OF . . . “ – EXPERIMENTAL DESIGN Inquiry-based

4. I. EXPERIMENTAL DESIGN, cont • Types of Experiments • Comparative, Observational, Controlled • Setting up a Controlled Experiment • Clearly defined purpose • Valid, clear hypothesis • Testable statement or prediction • Do not use “I think …”, “My hypothesis is …”, etc! • Often written in “If …, then …” format but not required • Control Group • Benchmark or standard for comparison • Experimental or Test Group(s) • Only one factor can be changed in each test • Independent (Manipulated) Variable • Dependent (Responding) Variable

5. I. EXPERIMENTAL DESIGN, cont • Important Considerations • Controlled variables (aka control variables, constants) must be monitored • Additional factors that could change from one set-up to another • Sample Size • Potential sources of error • Is it repeatable? • Presentation of Data • Concise & Organized • Tables

6. I. EXPERIMENTAL DESIGN, cont • Graphs • Format • Descriptive title • Key • Units must be evenly spaced (line break) and labeled • Use at least half of available space • Use a RULER!!! • DRY MIX • Dependent Responsive Y-axis; Manipulated Independent X-axis • Types of Graphs • Continuous Independent Variable (time) → _Line_ Graph • Discrete Independent Variable → _Bar__ Graph • Part of a Whole → ___Pie___ Graph

7. I. EXPERIMENTAL DESIGN, cont • Graphs, cont • For Height Lab … • Mean • Median • Mode • Range • Histogram • Normal Distribution?

8. I. EXPERIMENTAL DESIGN, cont • Data Analysis • Null Hypothesis • “Statement of No Effect” • States that any differences in data sets are due to random errors that cannot be eliminated in experimental design/protocol • For example, • There are no significant differences between predicted and observed data. • There are no significant differences between control group data and test group data. • Alternate Hypothesis – it is formulated to describe the effect that we expect our data to support. • Statistical Analysis – Supports or refutes null hypothesis

9. I. EXPERIMENTAL DESIGN, cont • Standard Deviation

10. I. EXPERIMENTAL DESIGN, cont • Standard Error of the Mean

11. I. EXPERIMENTAL DESIGN, cont Examine the data below showing two different experiments in which the heart rate of 10 different individuals was measured in beats/minute.

12. I. EXPERIMENTAL DESIGN, cont Calculate the standard deviation for each data set.

13. I. EXPERIMENTAL DESIGN, cont • Is there is a significant difference between the average heart beat/minutes in the two data sets? Construct a graph to illustrate.

14. I. EXPERIMENTAL DESIGN, cont • Conclusion • Evaluate hypothesis • Was it supported, refuted, or were results inconclusive? • Assess experimental design • Was there only one independent variable? • Were sources of error minimized? • Controlled variables/constants • Repeatable? • Theory

15. II. UNITY OF LIFE • Form vs. Function • Characteristics of Life • All living things are made of _cells_. • Prokaryotic • Eukaryotic

16. II. UNITY OF LIFE, cont. • Characteristics of Life, cont • Living things obtain and use energy. • Living things respond to their environment. • Living things grow and develop. • Living things maintain homeostasis. • Living things are based on a universal genetic code. • Living things reproduce. • As a group, living things evolve.

17. III. HIERARCHY OF LIFE • Organization of Life • Biosphere • Ecosystem • Community • Population • Organism • organ system • organ • tissue • cell • Organelle • Molecule • Atom

18. III. HIERARCHY OF LIFE, cont • Classification of Life • Domain • Kingdom • Phylum • Class • Order • Family • Genus • Species

19. III. HIERARCHY OF LIFE, cont • A Closer Look at Classification • Domain _Archaea_ • Kingdom __Archaebacteria__ • Domain _Bacteria_ • Kingdom _Eubacteria__ • Domain __Eukarya__ • Kingdom _Protista___ • Kingdom __Fungi___ • Kingdom __Plantae___ • Kingdom __Animalia___

20. IV. CHALLENGING THE BOUNDARIES OF LIFE • Viruses . . . Living or Non-living? • Discovery of Viruses • First isolated by Ivanowsky in 1890s from infected tobacco leaves • Crystallized by Stanley in 1935 – proved viruses were not cells • Not capable of carrying out life processes without a host cell • Parasites

21. IV. BOUNDARIES, cont • Viruses, cont • Structures found in all viruses: • Viral genome • DNA or RNA. • May be single-stranded or double-stranded • Protein coat • Known as a capsid • Made up of protein subunits called capsomeres.

22. IV. BOUNDARIES, cont • Viruses, cont • Structures/adaptations that may be present: • Viral envelope • Typically derived from host cell membrane • Exception is Herpes virus, synthesized from nuclear envelope of host cell • Aid in attachment. Envelope glycoproteins bind to receptor molecules on host cell • Most viruses that infect animals have envelope • Tail – Found in some viruses to aid in attachment

23. IV. BOUNDARIES, cont

24. IV. BOUNDARIES, cont • Viruses, cont. • Bacteriophage • Infect bacteria • Bacterial Defense Mechanisms • Restriction Enzymes • Coexistence

25. IV. BOUNDARIES, cont – Viral Replication 1. Virus enters; is uncoated; releases viral genome and capsid proteins 2. Host enzymes replicate the viral genome 3. Host enzymes replicate viral genome 4. Viral genomes and capsids self-assemble into new viral particles; exit the cell

26. IV. BOUNDARIES, cont – Viral Replication Viral Entrance into Host Cell

27. IV. BOUNDARIES, cont – Viral Replication LYTIC CYCLE 1. Lytic Cycle – Results in death of host cell.

28. IV. BOUNDARIES, cont – Viral Replication LYSOGENIC CYCLE

29. IV. BOUNDARIES, cont – Human Viruses • DNA Viruses • No envelope • Papilloma Virus • Warts, cervical cancer • With envelope • Smallpox Virus - cowpox • Herpesvirus • Herpes simplex I and II – cold sores, genital sores • Epstein-Barr virus – mono, burkitt’s lymphoma • Varicella zoster – shingles, chicken pox

30. IV. BOUNDARIES, cont – Human Viruses RNA Viruses

31. IV. BOUNDARIES, cont – Human Viruses • RNA Viruses • No envelope • Rhinovirus – common cold • Envelope • Coronavirus - SARS • Filovirus – Ebola (hemmorrhagic fever) • Influenza virus - flu • HIV • Belongs to a group of viruses known as _Retroviruses__ • Contain RNA, reverse transcriptase • Converts _RNA_ to _DNA_

32. IV. BOUNDARIES, cont – HIV • A Closer Look at Human Immunodeficiency Virus • Infects WBCs known as Helper T cells • Can reside in lysogenic-like cycle for years • Active, symptomatic = AIDS

33. IV. BOUNDARIES, cont – HIV, cont

34. IV. BOUNDARIES, cont • Viroids • Single, circular RNA molecule; lack protein • Parasitize plants • Prions • Infectious proteins; lack nucleic acid • Cause Mad Cow Disease, Creutzfeldt-Jakob Disease • Very long incubation period • No treatment

35. V. THE DIVERSITY OF LIFE

36. IV. THE DIVERSITY OF LIFE

37. VI. PROKARYOTES – A CLOSER LOOK

38. VI. PROKARYOTES, cont • Archaebacteria • Examples include methanogens, thermoacidophiles, halophiles • Taq DNA polymerase

39. VI. PROKARYOTES, cont Eubacteria • Ubiquitous • May be pathogenic • Most are harmless • Classification • Shape • Cocci • Bacilli • Spirilla • Gram Stain Reaction • Positive • Negative

41. Gram + Streptococcus pneumoniae

42. Gram - E.coli – gram negative; rod-shaped Neisseria gonorrhoeae – gram negative; coccus shaped

43. VI. PROKARYOTES – EUBACTERIA, cont • Nucleoid region • Plasmids • Asexual reproduction • Binary fission

44. VI. PROKARYOTES – EUBACTERIA, cont • Adaptations • Capsule • Adherence • Protection • Associated with virulence • Pili • Adherence • Conjugation • Endospore • Bacterial “hibernation” • Motility (flagella, slime,

45. Spore formation– adaptation seen in some bacteria that allows them to survive adverse conditions. A hard, protective wall forms around the DNA of the bacteria – and the bacteria can survive for centuries. When favorable conditions return, the spores revive, and the bacteria is able to revive and germinate. Ex. Bacillus anthracis; Clostridium botulinum Bacillus anthracis

46. VI. PROKARYOTES – EUBACTERIA, cont Adaptations, cont Quorum Sensing/Biofilms Fairly recent discovery Bacteria exchange chemical communication signals Multicellularity??? “Sexual Reproduction” Genetic Recombination Occurs by: Transformation Transduction Conjugation

47. Transformation– external DNA incorporated into cells – can come from dead bacteria

48. Transduction– transfer of genes between a bacteria and a virus vector – the virus inserts new genes into the bacteria…. This method is used in biotechnology to create bacteria that produce valuable products such as insulin.

49. Conjugation– a form of sexual reproduction in which there is a direct transfer of a plasmid from one bacteria to another (through pili) before the bacteria divides – results in offspring with new genes/traits. • - Plasmid - smaller ring of DNA that functions in antibiotic resistance or • metabolism; replicates independently of the entire DNA

50. VI. PROKARYOTES – EUBACTERIA, cont • Metabolism • Nitrogen fixation • Conversion of atmospheric nitrogen (N2) to ammonium (NH4+) • Metabolic Cooperation • Biofilms • Oxygen relationships • Obligate aerobes • Facultative anaerobes • Obligate anaerobes