THE STUDY OF LIFE

Biology

Science is a gas, it rocks, it rules, its da bomb

Two types of science studied at Nashua High school are life sciences and physical sciences:

Biology is a graduation requirement and a prerequisite for other life science courses.

Life Sciences Physical Sciences

BiologyAnatomy and physiologyBiotechnologyEnvironmental scienceZoologyPlant science

Physical SciencePhysicsChemistryAerospace scienceAstronomyBiotechnology

Theories and Laws are not “beliefs”

Biology, like all sciences investigates the natural world and uses data collected to try to explain natural events, describe natural phenomena, and make useful predictions

Scientific Theories Scientific Laws

•Explanations of the “whys and hows” of natural phenomena•Derived from much data collected from repeatable experiments•Falsifiable•Ex: Cell theory

•Describe natural phenomena•Often modeled with mathematical formulas that represent predictable relationships •Ex:Newton’s Universal Law of Gravitation

A Law you can’t break

A falsifiable theory

Cell Theory:•All life forms are made from one or more cells. •Cells only arise from pre-existing cells. •The cell is the smallest form of life.

Scientific Habits of Mind

Observant-details matter!Curious- question why and how things happen in natureRational-make inferences by connecting prior knowledge

and experience to new situations in a logical way.Skeptical-Scientific people question their own inferences

and other’s continually to assess value of data.Open minded-Scientists always try to understand other’s

interpretations of data and are always on the lookout for new ideas and data to incorporate into his or her knowledge base.

Ethical-we have a responsibility to consider the effects of our work and to be honest in data reporting and analysis.

Knowledge is a process

Science does not fail when new information proves old ideas to be wrong, it is demonstrating growth and advancement.

Scientific Method: Observe, question, hypothesize, experiment, analyze, conclude, retest, analyze, revise (hypothesis or experiment), retest, analyze revise, retest………..

Variables in an experiment

Variable: something that varies or changes or can be changed in a situation.

Controlled variable: what the scientist controls so that is does not affect the experiment

Manipulated variable: what the scientist changes in one of his or her test groups in order to cause a change to occur.

Responding variable: what changes because of the manipulated variable, depending on whether or not the test group has been manipulated.

Redi’s experiment 1668

Needham’s disagreed with Redi… 1745

Life from broth??!!

Spallanzani ..1768 Louis Pasteur 1864

Louis Pasteur

Contributed to the development of Germ Theory, which explains what causes infection and contamination, before Pasteur doctors didn’t even wash their tool or hands!

Developed a boiling process we use to keep milk from spoiling: PASTEURIZATION

Developed the first vaccines for rabies and anthraxDiscovered anaerobiosis: bacteria that live without

air..**The “Pasteur effect” is that fermentation slows in presence of air.

Aerobic:with air Anaerobic: without air

Life is cells, but what does life do differently than non-life?

Life reproducesLife has a genetic code that all life on earth shares (DNA)Life grows larger and develops in stagesLife must obtain energy for chemical reactions and raw

materials (matter) for needed life chemicals. (metabolism)

Life must perceive and respond to its environment .Life has a different internal environment from its outside

environment and must maintain this difference. (homeostasis)

As a group life must change over time to survive environmental changes. (Evolution)