Unit 1: Biology

1. Unit 1: Biology Objectives: I can … • Explain the goals of science and the function of scientific instruments • List the characteristics of life • Distinguish between sexual and asexual reproduction and the significance of each • Evaluate the relationship between adaptation and evolution • Differentiate between the dependent & independent variable and also the control group & the experimental group, quantitative & qualitative data, etc. in a controlled experiment. • Design a controlled experiment accurately using the scientific method • Use a microscope accurately and identify its parts • Compare/contrast the advantages and disadvantages of using each type of microscope • Accurately collect data using the metric system

2. Vocabulary: Biology, Anatomy, Physiology, Morphology, Taxonomy, Phylogeny, Botany, Zoology, Ecology, Genetics, unicellular, multicellular, cell, tissues, organs, homeostasis, autotrophs, heterotrophs, herbivores, omnivores, carnivores, natural selection, “survival of the fittest”, zygote, divergent & convergent evolution , analogous, homologous, scientific sample, qualitative data, quantitative data, milli, centi, kilo, scientific method, hypothesis, controlled experiment, independent (manipulated) variable, dependent (responding) variable, control group, experimental group, operational definition, Inference, theory, law, magnification, resolution, Darwin, natural selection, objective lens, ocular lens, stage, turret, diaphragm

3. Biology Bio - “life” -ology = “the study of” Biology is the study of both unicellular and multicellular organisms and includes several subcategories such as: Anatomy - the study of structure (Literally “to cut apart”) Physiology - the study of function Morphology - outer shape or appearance; used in taxonomy. Taxonomy - classification of organisms according to their “relatedness” Phylogeny - ancestry/evolutionary history of organisms Genetics - the study of inheritance Botany - the study of plants Zoology - the study of animals Ecology - study of interactions between organisms and their environment AND MANY MORE

4. Characteristics of Life • All living things are composed of one (unicellular) or more cells (multicellular - allows “specialization” of cells). Cell = basic unit of life and contains the “genetic code” • Living things are organized at both the cellular level (organelles have specific tasks) and the multicellular level: cells -> tissues -> organs -> organ systems And they can maintain their internal conditions (homeostasis) • Living things respond to their environment • Grow by cell division and/or enlargement • Have the potential to reproduce • Use energy for growth and maintenance • Autotrophs - make their own food (Ex: plants photosynthesize) • Heterotrophs - eat other organisms • Herbivores - eat mostly plants • Omnivores -eat plants and animals • Carnivores - eat mostly meat • Adapt to their environment and as a species, may evolve Is movement a characteristic of all life? NO !!!!!!

5. All areas of biology believe in evolution - the theory that specieschange over time as they adapt to their environment. Charles Darwin proposed that natural selection, or “survival of the fittest” occurred when organisms with the “right” traits (adaptations) survived to reproduce. Organisms can reproduce through either: 1) Sexual reproduction - genetic information in egg and sperm combine to form a zygote. Sexual reproduction increases genetic variability in a population. 2) Asexual reproduction - an organism simply divides into two. Offspring are genetically identical (clones) to parents. How might the consequences of being infected by ONE sexually reproducing organism differ from ONE that asexually reproduces? An asexual organism could create 1000’s of offspring over time. Without a partner, sexually reproducing organisms can’t multiply.

6. To better study groups of organisms, scientists often classify them into related groups (taxonomy). Initially this was done by their morphology (shape/outer appearance). But evolutionary adaptations can fool us: 1) Homologous organs - physical features look quite different but developed from similar structures. This is known as divergent evolution. (Ex: a bat’s wing, a whale’s flipper, and a human hand.) 2) Analogous organs - features look similar but came from quite different structures. This is called convergent evolution. (Ex: a butterfly wing and a bird wing, a panda’s “thumb” and a human thumb)

7. To study large populations of organisms, scientists may use smaller groups. This is known as scientific sampling. This is similar to surveys where a smaller number of people are asked their opinion to determine how the overall population feels about an issue. Understanding populations of organisms also requires observing those organisms. Observations may be qualitative (ex: color, texture - non-numerical qualities) or quantitative, numericaldata (ex: 5 cm tall, 110 grams). Worldwide, the metric system (similar to the Systeme Internationale, SI system)is most commonly used for collecting numerical data. It is based on multiples of 10. Base units: distance - meter, mass - gram, volume - liter Prefixes: milli- 1/1000th (.001), centi- 1/100th (.01), deci- 1/10th (.1), deka - 10, hecto- 100, kilo- 1000

8. The scientific method is usually followed during experiments. It includes: 1) Problem statement /question (Ex: How fast do E. coli bacteria reproduce at 10 degrees Celsius?) 2) Gathering background information (Ex: According to Smith & Jones, E. coli can double in numbers in 15 minutes at 15 degrees Celsius.) 3) Forming a hypothesis. This must be TESTABLE to be useful. A hypothesis is an educated guess as to what will likely happen based on your background research. (Ex: If E. coli doubles in number in 15 minutes at 15o C (Smith & Jones), then it will probably take 30 minutes to double in number at 10 degrees because bacteria populations do not grow as fast at low temperatures (Jason & Kline).

9. 4) Experimenting and experimental design - This is often done as a controlled experiment. Here, only a singlevariable (variation from “normal”) is tested in an experimental group. A control group, where nothing has changed (everything is “normal”, or “standard”) is used as a comparison. (Ex: Two groups of E.coli bacteria are exposed to the same amount of light, heat, etc., but the experimental group gets 10 minutes of radiation exposure each day and the control group does not.) In this example, the variable that the scientist “manipulated” was the exposure to radiation. This is the independent (manipulated) variable. Whether or not the bacteria died or grew, or ??? due to the radiation exposure, is known as the dependent (responding) variable. The independent variable and the expected outcome (dependent variable) should always be stated in the experimental design. An operational definition should also be given if needed. Ex: growth means an increase in number of bacteria, or growth means an increase in size of individual bacteria)

10. The experimental design should give a clear step by step account of how to conduct the experiment and also describe the size of the sample population used (Ex: 10 colonies of bacteria will be used in the control group and 10 colonies in the experimental group) and other factors such as gender, age, etc, when applicable. 5) Data collection - Both qualitative and quantitative observations are made. Quantitative data may be put in graphs, charts, etc. However, it is important to use the right type of graph for the data! How might qualitative data be quantified?

11. 6) Analysis and Conclusion - This is made based on the data collected. It should briefly summarize the data and how it either supported or refuted the hypothesis. “Sources of Error” should be included here. (Ex: Since only 2 bacterial colonies were used in this experiment, the sample size was too small to generalize the findings to all bacteria exposed to radiation.) Beware of making inferences, stay strictly with what was actually observed (seen, heard, smelled, etc) Inferences are assumptions (Ex: I hear yelling in hall - I infer there must be a fight) 7) Sharing of the experimental findings - the experimental design should be reproducible so that other people can review the findings and re-create the experiment to either support the findings or find flaws with them (refute them). This may lead to new discoveries! If a hypothesis is found true over & over again and it pertains to natural phenomenon, it may become a theory. This is a well-tested explanation that “unifies a range of observations.” Theories that hold true may become “laws”.

12. One of the many tools used by biologists is the microscope.

13. Microscope parts: Ocular lens (eyepiece) - magnifies (usually 10x) Objective lenses - each lens has a different magnification. The shortest lens magnifies the least. These usually ride on a turret (revolving nosepiece) Diaphragm - adjusts the amount of light Stage - flat platform to place slides Coarse adjustment - used for main focus. Do NOT use on high power. Fine adjustment - used to focus on higher powers Note: Always put object into focus on low power ( shortest objective) first, then work up to medium, readjusting focus if needed, then high if needed. Energy source - we use light microscopes but other sources of energy, like electrons can be used. Because both an ocular and objective lens are used, it’s called a compound light microscope.

14. Total magnification can be found by multiplying the power of the ocular lens by the power of the objective lens in place. Ocular lens x Objective = Total magnification 10 x 10 = 100 10 x 40 = 400 10 x 100 = 1000 Resolution is different than magnification. It’s the clarity or ability to show distinct detail. (Ex: Two dots close together - if seen as 2 separate dots, the resolution is better than if seen as 1 dot.)

15. Electron Microscopes Electrons are bounced off the object to create an image. This increases magnification many times greater than is possible with compound light microscopes. 1) Scanning Electron Microscope (S.E.M.) - shows surface of object in 3 dimensions. 2) Transmission Electron Microscope (T.E.M.) - greatly magnifies thin sections of material. 3) Scanning Tunneling E. M. (STEM) - has the highest magnification of all. Magnifies up to 100 million times. (Can even see DNA) Uses computer to create image. Electron Microscope Advantages: 1) Magnification of 300,000x or more 2) Very high resolution

16. Disadvantages of Electron Microscopes: 1) Very expensive 2) S.E.M. requires thin coating of gold over objects. 3) T.E.M. requires skilled person to cut super thin section (often use a laser knife) 4) Requires a vacuum chamber within microscope. Dust inside scope would completely block view. 5) Except for STEM, can only view dead organisms Of course many other instruments are used by biologists, such as a special blender to break cells apart (cell fractionation) and separate their parts or a centrifuge to spin blood, separating the liquid plasma from the solid cells.