Welcome to Regents Biology The Living Environment with

Welcome to Regents Biology: The Living Environment, with Mr. Gardner 1

Chpt 1: The Science of Biology n Section 1 -1: What is Science? ¨ People have always wondered how things work. ¨ Magic or legend in ancient times versus actual evidence in present times. n Science is investigating and understanding nature’s events so that we can make useful predictions. ¨ Deals with the natural world (no ¨ Info is collected in an organized n Looking for patterns and trends. n mythology). and meaningful way. Explanations can be tested by examining evidence. 2

Why is Biology important to you: n Helps to explain the natural world ¨ Why your body changes as you grow ¨ Why diseases spread rapidly (in schools? ) n Prepares you for a career ¨ Many n jobs may have biology related topics Makes you an informed citizen ¨ Reduce, reuse, recycle and involve your family and friends 3

Making Observations: n Using your senses to gather info/data ¨ Quantitative: Quantity, amount or number Ex. there are 20 students n Ex. He made 87% of his free throws n ¨ Qualitative: Quality or appearance Ex. They are very tall n Ex. She has red hair n 4

Making an Inference: n a logical interpretation of the observations based on prior knowledge and experience ¨ Ex. If home base, 2 nd base and left field are all saturated with water, I can infer that a storm recently occurred. n Class Activity-5 senses: Write out an observation and an inference that could go with it: (Think back to past experiences) ¨ Sight/Sound/Smell/Touch/Taste* 5

Section 1 -2: How Scientists Work: n People once wondered if you could get something from nothing…ex, Maggots from meat. Known as spontaneous generation ¨ Needed to design an experiment to prove/solve this n In 1668, Francesco Redi proved spontaneous generation inaccurate with his maggot and meat experiment. ¨ 6

The Scientific Method: PHEOC(R) State the Problem or question you are wondering. Form a Hypothesis, or educated guess, about your problem. Set up a controlled Experiment to test your hypothesis. n n n Variables: Factors that can change such as equipment, temperature, light and time ¨ n n n ¨ Manipulated or independent variable: the one that is deliberately changed. (Always on the ‘X’ axis in a graph) Responding or dependent variable: observed and changes in response to the manipulated or independent variable (‘Y’ axis) It is important to only change one variable at a time Controls: factors that stay the same in an experiment. 7

The Scientific Method Continues: n Record data and analyze results through Observations. ¨ ¨ ¨ n Documentation of observations during an experiment. Kept in notebook, journal or online database. Graphs, charts, and tables are used to better visualize the data and trends that are occurring. Draw a Conclusion. ¨ ¨ Helps to support or refute the hypothesis. Should relate to the original problem. 8

The Scientific Method Continues: Repeat the investigation. n ¨ ¨ Helps to make sure the experimental design and procedures were without flaws. Another person should be able to re-create the outcome with similar materials. n Needham, Spallanzani and later Pastuer repeated Redi’s experiment and determined spontaneous generation to be an unlikely occurrence ¨ New organisms are only produced from existing organisms 9

Impossible Experiments: n Sometimes it is not possible to carry out an experiment. ¨ Animals n n n in the wild, ethical drug testing on humans etc. Field studies may allow for better understanding of the subject. Large groups of subjects must be studied. Reliable patterns can add to scientific knowledge. 10

Scientific Theory: n n A well tested explanation that unifies a broad range of observations. Allows scientists to make accurate predictions. May become the dominant view among a majority of scientists. Is not considered an absolute truth (ex. evolution). ¨ May be revised or replaced as more evidence is uncovered. 11

Section 1 -3: Studying Life Biology: Biologists use the scientific method to study living things n What makes something living? n Write down 5 things that you feel quantify something as being ‘alive’ or living. n 12

8 Characteristics of living things: n Made up of units called cells ¨ ¨ ¨ Living matter enclosed in a barrier that separates it from its surroundings A cell is the smallest unit of an organism that can be considered alive Organisms may be single(unicellular) or multicellular n n Humans have ~85 different cell types Reproduce ¨ May be sexual or asexual(one parent, without sex) 13

8 Characteristics of living things: n Based on universal genetic code ¨ ¨ n Offspring resemble parents DNA determines traits inherited from parent Grow and develop ¨ ¨ Typically refers to size of organism May also include developmental stages n ¨ Cells may differentiate or specialize n ¨ Ex. Metamorphosis of a butterfly Become specialized for one system Stops with the death of the organisms 14

8 Characteristics of living things: n Obtain and use materials and energy ¨ Typically through ingestion or taking in food n n ¨ n All energy is originally from the sun (photosynthesis) Decomposers obtain by consuming dead organisms Metabolism: breaking down and building up materials to carry out life processes Respond to their environment ¨ Variables result in lifestyle changes of organisms n Ex. birds fly south for winter, plants grow more with rains in spring 15

8 Characteristics of living things: Maintain a stable internal environment n Homeostasis: conditions inside kept relatively stable Constantly affected by the environment ¨ ¨ n Drought/rains, high/low temperatures If not maintained, can lead to death ¨ n Ex. Blood vessels may dilate on hot days to allow for heat to be radiated away from body, while they constrict on cold days to conserve body heat. Change over time (as a group): Evolution n What does it mean to adapt to a situation? ¨ n ¨ Adjusting by making small changes in how you act/feel Populations may evolve over time to their surroundings 16

Branches of Biology: n n n n Molecular: smallest unit of a chemical compound Cellular/Cells: smallest units of life Multicellular/Groups of cells: tissues, organs, body systems Organisms: individual living thing Population: A group of one type of organism in an area Community: Different populations in one area Ecosystem: A community and its non-living surroundings (rocks, water, air) Biosphere: Contains all the ecosystems 17

Measurement: Tools and Procedures: n n n In order to retest and replicate experiments, a common system of measurement is needed: The Metric System Based on multiples of 10 Numbers in science without units mean NOTHING and have no inherent value ¨ n All numbers need meaningful units SI units (System International) are used ( w/ root words) n Volume Liter Mass gram Length meter Temperature degrees Kelvin (Celsius used also) Time seconds n grams, liters, meters = ROOT or BASE WORDS n n 18

Microscopes: (See Appendix D in textbook for reference) n n Used to magnify images or objects that are too small to be seen by the unaided eye. Compound Light Microscope: visible light aimed onto object ¨ Used to observe both dead and living specimens up to 1000 X 19

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Microscopes continued: n Electron Microscope: Beams of electrons are aimed onto object ¨ Used to observe only dead organisms, but at a much high magnification than a compound scope (about 1, 000 X) ¨ Two kinds: TEM and SEM n n n TEM can only view thin slices of object (Microtome) SEM can view whole organism What is an advantage to viewing a living specimen over a dead one? 21

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Lab techniques: Used to study cells n Cultures: Sample taken and grown in a nutrient solution (ex. agar in a Petri dish) ¨ n Fractionation: Breaking cells up to study certain parts ¨ n Done at the doctors for strep throat Blender used first to break cells apart into their components Centrifugation: used to separate materials based on density ¨ ¨ Follows fractionation to collect specific parts of the cell Blood components may be separated this way 23