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Introductory Comments (chapter 1)

Introductory Comments (chapter 1). Why study Biology?. Overall the reason is to begin to develop biological literacy so that you can: gain an understanding of life. But what is life?. Life is more easily understood by looking at the characteristics of living organisms, which are as follows:.

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Introductory Comments (chapter 1)

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  1. Introductory Comments (chapter 1)

  2. Why study Biology? Overall the reason is to begin to develop biological literacy so that you can: gain an understanding of life.

  3. But what is life? Life is more easily understood by looking at the characteristics of living organisms, which are as follows:

  4. The possession and inheritance of DNA from parent to offspring.

  5. The ability to get, convert, and use energy E.g.: photosynthesis & aerobic respiration

  6. Homeostasis - the maintenance of a fairly constant environment.

  7. Reproduction or the production of offspring

  8. Adaptation to the environment

  9. The ability of populations of living organisms to evolve

  10. Response to stimuli

  11. A higher level of organization than non-living objects and composed of one or more cells.

  12. Why study Biology? In order to understand how scientists conduct research

  13. Levels of organization

  14. Molecules

  15. Subcellular structures

  16. Cell

  17. Tissue

  18. Organ

  19. Organ System

  20. Organism

  21. Population

  22. Community The cats, mice, grass, insects etc. that all live in a given area

  23. Ecosystem The living organisms of the community + the abiotic factors that affect them

  24. Biosphere

  25. Regardless of the area of interest, scientists make their discoveries by:

  26. Observations where they document some phenomenon (e.g., Jane Goodall’s work with chimpanzees)

  27. Controlled experiments which often involve hypothesis testing. Steps:

  28. Make observation(s)

  29. Propose hypotheses. Make sure that they are falsifiable and testable. Alternative – statement that there is a difference between the experimental and control groups Null – statement that there is no difference between the experimental and control groups King snakes in West Virginia are immune to venom of sympatric rattlesnakes but not to venom of allopatric rattlesnake venom. King snakes in West Virginia are immune to venom from sympatric and allopatric rattlesnakes.

  30. Design predictions (if-then statements) and an experiment If king snakes from West Virginia are immune to venom of both sympatric and allopatric rattlesnakes, then a bite from any rattlesnake will not harm or kill the king snake. Experiment design- Collect 40 king snakes Collect 20 sympatric and 20 allopatric rattlesnakes Randomize sample Put king snakes with rattlesnakes and observe the king snakes response to bites by rattlesnakes

  31. Conduct the experiment with appropriate control group (the group that is held constant for comparison), dependent (measured variables) and independent variables (manipulated variables). Bias should be prevented by considering the placebo effect, utilizing a blind or a double blind design (so the subjects and the researchers do not know if they are in the experimental group or the control group), and randomizing the subjects.

  32. Analyze Data Apply the appropriate statistical tests (determined a priori or before the data were collected)

  33. Make inferences based on the results and reject or fail to reject the null hypothesis. Never prove

  34. Objectively report the results and inferences (write a paper and/or give a presentation)

  35. Why study Biology? to understand how biology applies to you and then integrate what you have learned into your decision making

  36. Medical applications, human genome project, the search for a vaccine for AIDS, and genetic engineering. Understanding our impact on current and future biodiversity and ultimately on our own species. Human induced extinctions and decreases in genetic variability are occurring. Understanding our impact on the environment (and again on biodiversity) and ultimately the survival of our own species.

  37. Biodiversity and Domains

  38. Definitions I Biodiversity - number of species of living organisms in a given area

  39. Definitions II A species is composed of organisms that appear to be similar (in looks) and that are capable of interbreeding with other like individuals. This is the Biological Species Concept proposed by Ernst Mayr.

  40. Definitions III Autotrophs are organisms that are capable of building their own large organic molecules by using CO2 and energy from their environment. Photosynthetic autotrophs use sunlight energy Chemosynthetic autotrophs use energy from chemical reactions involving I norganic molecules.

  41. Definitions IV Heterotrophs are organisms that are not capable of synthesizing their own food and thus obtain their nourishment from autotrophs, other heterotrophs or from organic wastes (e.g., decomposers).

  42. Definitions V A theory is generated by a related set of insights supported by evidence. It explains some aspect of nature and is a valued entity (e.g., evolution). Evolution is just a theory.

  43. Biodiversity

  44. Viruses. Not considered to be living (they cannot reproduce on their own) by many biologists, they are worth mentioning. A virus is a noncellular infectious agent possessing a nuclei acid core that cannot reproduce itself. Viruses may be composed of DNA or RNA within the protein coat (but

  45. Domains Archaea and Bacteria bacteria all are prokaryotic (meaning that they do not possess membrane-bound organelles), autotrophs (photosynthetic and chemosynthetic) and heterotrophs. Archaea is the domain containing the greatest metabolic diversity. Bacteria were the first living organisms, they prepared the environment for other organisms, all other living organisms originated (evolved) from bacteria, and they are ubiquitous (they live throughout the entire biosphere). Prokaryotes are unicellular.

  46. Protists -mostly single-celled eukaryotes but there are some colonial forms as well as some that are truly multicellular (the algae). Some are heterotrophs & some are photosynthetic autotrophs.

  47. Kingdom Fungi (Myceteae) predominantly multicellular eukaryotes. They have external digestion and all are heterotrophs.

  48. Kingdom Plantae plants. All are eukaryotic and they are photosynthetic autotrophs. They are multicellular, the cells have cell walls, and they are sessile (they do not move)

  49. Kingdom Animaliae animals ranging from sponges to humans. They are multicellular eukaryotes and all are heterotrophic. They all move at some time in their life cycles. There are no cell walls and the vast majority of the animals are invertebrates.

  50. Classification Domain Kingdom Phylum Class Order Family Genus species Genus + species (maybe subspecies) makes up the Scientific name

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