What is Science?

 The goal of science: is to investigate and understand the natural world, to explain events and use those explanations to make predictions.

 1. Observation – gather info in an orderly way.  2. Collect data  Quantitative – numbers  Qualitative – descriptive  3. Data allows us to make inferences – interpreting our data using our prior knowledge.  4. Hypothesis – An explanation for a set of observations. “educated guess”

 Designing an experiment  Ask a question  Form a hypothesis (prediction & reason)  Set up a controlled experiment  manipulated – variable that is changed  responding – variable that reacts to the change  controlled – variables (need 2) that stay the same  Record and Analyze Results  Draw a conclusion  Publish/Repeat experiment

 Validity – Something you do in the experimental procedure to get accurate data.  Reliability – Repeating an experiment  Constraint – a problem you encounter while designing a solution to a scenario.  Limitation – an explanation of your solution to the scenario -

 When evidence from numerous investigations builds up a hypothesis may become so well supported that we call it a theory.  Theory – WELL TESTED explanation that unifies or explains a broad range of observations.  Example: Why are marsupials (kangaroo) only found in Australia? Both the theory of plate tectonics and the theory of evolution work together to answer this question.

 Characteristics of Living Things  1. Living things are made up of cells. Animal Cells – Cheek cells Plant cells - Elodea

 2. Living things reproduce.  Sexual – 2 different cells unite  Asexual – single parent, cell divides in half (bacteria)

 3. Living things are based on a universal genetic code. D.N.A.  4. Living things grow and develop.  differentiation – where cells look different and perform different functions. Nerve cell Skin cell

 5.Living things obtain and use materials and energy.  Metabolism – the building up or breaking down materials to carry out life processes.

 6. Living things respond to their environment.  Stimulus – a signal to which an organism responds. Examples: Temperature, Light Low blood glucose in animals = hunger

 7. Living things maintain a stable internal environment.  Homeostasis – the ability to keep internal conditions constant.

 8.Living things, taken as a group, change over time.  Evolution – change over time.

 Different branches of Biology study living systems at different levels of organization

 Metric system – based on the number 10.  100 cm = 1 meter  10 cm =____ meter  12 mm = ____ centimeters Which one doesn’t belong?

 Light – magnify by focusing visible light  Electron – magnify by focusing beams of electrons. Require a vacuum to operate so they can only look at preserved specimens. 2 Types 1.SEM – Scanning (external detail) 2.TEM – Transmission (internal detail)

A-D Scanning Electron Microscope E Transmission Electron Microscope F Light Microscope Can you identify which type of microscope took pictures A-F?

Laboratory Techniques  Cell culture – take a single cell, add a nutrient solution and grow more cells….  Cell fractionation – this technique is used when you want to study one part of a cell so you have to separate the cell parts. Steps  blend cells  add liquid  put in centrifuge tube and spin  cell parts will separate by density