What is science? an organized way of investigating and using evidence to learn about the natural world

Science always starts with an observation. An observation is …. using 1 or more of the 5 senses to gain information about an object or event

Qualitative Observations – are descriptive – color, odor, sound,…. Quantitative Observations – involve the use of numbers

What are some sub disciplines of science? Zoology Botany Ecology Dermatology Genetics Geology Chemistry

What is biology? Why study biology? How do we use biology in our everyday life? What are some problems that have been solved or are being worked on by scientists?

How do scientists approach scientific study? Scientific Method 1. State the problem 2. Preliminary research 3. Develop a hypothesis 4. Experiment (collect data) *can be qualitative or quantitative 5. Draw a conclusion

What is a theory? an explanation, supported by evidence that seems to hold true over time and attempts to explain a set of natural phenomena What are some scientific theories?

It is important for scientists to conduct controlled experiments… Controls - what is consistent throughout the groups Variables – what varies between the groups (this is what is being tested)

Independent (manipulated) Variable – what you manipulate/change about the groups Dependent (responding) Variable – what you measure or observe about the groups Control Group(s) – used as a standard, used as a basis for comparison Experimental (variable) Group(s) – groups that are different from the control group(s) Virtual Lab – Dependent v. Independent variable

What distinguishes a living thing (an organism) from a nonliving thing? (an object) Intro Video (5:31)

All living things…have cells… Cell – smallest unit of a living thing Unicellular – 1 cell Multicellular – more than 1 cell PROKARYOTE - (PRO - meaning “before”) primitive cell that lacks a nucleus & membrane-bound organelles EUKARYOTE – (EU - meaning “true”) complex cell that has a nucleus and membrane-bound organelles

All living things grow and develop.... Growth – an increase in size Development – a change in form and function as an organism matures

ALL Living Things (LT) ARE ORGANIZED… At the chemical level – all LT are composed of chemicals especially C, H, O, N, P, S At the cellular level – all LT have one or more cells Some LT have tissues, organs and organ systems

All living things need and use energy …. Photosynthesis – process of using light to make food Cellular Respiration – process of breaking down food to release energy ATP – adenosine triphosphate chemical substance – stores energy in its chemical bonds

All living things reproduce… Asexual reproduction production of offspring by 1 parent (1 set of genetic information) Sexual reproduction – production of offspring by 2 parents (2 sets of genetic information)

All living things maintain homeostasis…. HOMEOSTASIS – ability of a cell (or an organism) to maintain a stable internal environment “an internal balance” What things must we keep stable?

All living things have a universal genetic code… DNA (deoxyribonucleic acid) – a chemical substance that contains the instructions for the activities and functions of a cell (or a living thing)

All living things respond to stimuli Responses to internal and external stimuli Organisms adaptations will evolve over time

Living or Nonliving?

What were the first living things (organisms) and how are they different? BACTERIA – prokaryotic, unicellular

What are some tools used by biologists?

MEASUREMENT Scientists use the international system (SI system) of measurements This system is different because….it is based on units of 10

MICROSCOPE AN INSTRUMENT USED TO FORM AN ENLARGED IMAGE OF AN OBJECT “MICRO” = SMALL “SCOPE” = TO LOOK AT

Magnification and Resolution Magnification The ability to make an object appear larger Resolution The ability to make an object appear clear

LIGHT MICROSCOPE uses a beam of light to form an image can view preserved and living specimens limitations specimen must be thin so that light can pass through degree of magnification and resolution

COMPOUND LIGHT MICROSCOPE Uses 2 lenses to magnify an object: 1. the ocular (eyepiece) lens(es) 2. the objective lens(es)

STEREOMICROSCOPE lower magnification 2 ocular lenses provides 3D image What types of objects can be studied? larger objects through which light does not pass, however, only surface details can be studied

ELECTRON MICROSCOPE uses a beam of electrons focused by magnets to form an enlarged image

transmission electron microscope (TEM) – electrons pass through thin sections of an object/specimen scanning electron microscope (SEM) – scans the surface of an object/specimen – provides a 3D image

advantages greater magnification and resolution can view larger specimens can view viruses and cell parts disadvantages/limitations more expensive and very large objects to be viewed cannot be living