The Science of Biology Notes Chapter 1

1-1 What is Science? What science is & is not Goals of Science: To investigate & understand the natural world To explain events in natural world To use explanation to make useful predictions

Features of Science: Deals only with natural world Scientists collect & organize info in a careful orderly way Scientists propose explanations that can be tested Science – an organized way of using evidence to learn about the natural world

Thinking like a Scientist Observation – gathering info about events or processes in a careful orderly way Uses the senses especially sight & hearing Produces data – info gathered from observations Quantitative – expressed as numbers obtained by counting Qualitative – descriptive & can’t be counted Used to make inferences – logical interpretations based on previous knowledge

Explaining & Interpreting Evidence Hypothesis – proposed scientific explanation for a set of observations “testable statement” Many times is a prediction Come up with hypothesis by Prior knowledge Logical inference Creative imagination Must be able to be tested Use controlled experiments Gather more data

Researchers work in teams Meet regularly Analyze, review & critique one another Helps ensure data is valid

Science as a Way of Knowing Is an ongoing process Scientists need to be open-minded Whole physical universe is a collection of parts & processes that interact Basic laws of nature govern all events & objects Biologists focus on living systems Science & Human Values-must work together based on society, morals & laws

1-2 How Scientists Work Designing an experiment Ask a question – about an observation Form a hypothesis ex: Redi’s experiment Set up a controlled experiment 1. Controlled =only 1 variable is tested at a time 2. Variables – factors that can change ex: type of material used, light, time, etc. a. Manipulated ( independent) variable-factor that is deliberately changed b. Responding (dependent) variable-factor that changes in response to the independent factor and is observed.

Recording & Analyzing Results Keep a written record of observations or data May include drawings, measurements, etc. Repeating Investigations 1. Nature behaves in a consistent manner a. 1 variable manipulated in a given set of variables → results should be the same. b. communication & experiment description is necessary. 2. Scientists publish reports→ others look for flaws & repeatability

Some experiments are not possible Practical & ethical considerations prevent controlled experiments Alternative investigations Field study – observe animal interactions Study large groups Tries to identify as many relevant variables as possible How a theory develops Theory – well tested explanation that unifies a broad range of observations Uses evidence from numerous investigations Allows scientists to make accurate predictions about new situations No theory is absolute; can be revised or replaced

1-3 Studying Life Biology – study of life Characteristics of Living things: Are made of cells Reproduce Sexual – 2 parents Asexual- 1 parent Have universal genetic code Grow & develop Have metabolism- obtain & use energy Respond to their environment Homeostasis- stable internal environment Evolution- a species changes over time

Big Ideas in Biology (Themes) Science is a way of knowing Job of Science – to use observations, questions & experiments to explain the natural world in terms of natural forces & events Interdependence in Nature All forms of life are interconnected → flow of energy and cycling of matter Matter & Energy – life’s most basic requirements Matter- nutrients to build body structures Energy- fuel process

Cellular basis of Life Cells – complex & highly organized Unicellular – one cell Multicellular- > than one cell Information & Heredity – DNA is the info; heredity –is passing of info to offspring Unity & diversity of Life – all life is basically alike at the molecular level; but there are a variety of forms Evolution- species change over time Structure & Function: Each structure has certain function. Wing = allows flying Homeostasis – stable internal environment; allows organisms to adapt to external changes Science, technology & society: If we have the knowledge & tools, should we always do it?

Some Branches of Biology : Zoology Botany Paleontology Ecology

Levels of Organization ( Large to Small) Biosphere – part of the Earth in which life exists Ecosystem – community + physical environment Community – populations of all species living in the same space Population – group of individuals of the same species living in the same space Organism – individual made of interdependent groups of cells Groups of cells – cells that do specific jobs- tissue Cell – basic unit of life Molecules – smallest unit of most compounds

Biology in Everyday & Issues in biology Helps you understand what affects the quality of your life Gives you info to make informed decisions

Tools & Procedures Common system of measurement 1. needed to replicate experiments accurately 2. metric – decimal system based on multiples of 10 B. Analyzing Biological Data 1. Use tables & graphs 2. Graphs allow patterns to be seen easier C. Microscopes – device that magnifies images of structures too small to be seen with unaided eye. 1. Light Microscope- most common uses visible light rays Compound scope – uses two lenses Can study dead organisms & tiny alive organisms Chemical stains (Dyes) can show specific structures

Electron Uses beam of electrons to produce image studies objects smaller than 0.2µm ~ 1000x more detailed than light microscope Must be viewed in a vacuum- no living specimens 2 types = TEM & SEM Lab Techniques – many 1. cell culture – group of cells grown in nutrient solution from a single original cell 2. cell fractionation – separating different cell parts

E. Working Safely 1. Before beginning any activity, read all steps. 2. Most important: always follow teacher instructions & textbook directions exactly!