Ch 1: Introduction to Biology

Biology – the study of life Studies origins and history of life and once-living things Studies structures of living things Studies how living things interact with each other Study how living things function

Copyright Cmassengale What do biologists do? Study diversity of life Research disease Develop technologies Improve agriculture Preserve the environment Copyright Cmassengale

Characteristics of Life Copyright Cmassengale

Organism – anything that has ALL the characteristic of life Made of one or more cells (basic unit of structure and function) Displays organization (cell-tissues-organs-organ system-organism) Grows and develops (growth = increase in mass; development = changes that take place during the organisms life)

4. Reproduces (essential for the survival of a species) 5. Responds to stimuli 6. Requires energy (made themselves or consumed) 7. Maintains homeostasis (regulation of internal conditions) 8. Adaptations evolve over time (inherited characteristics which result in changes to a species)

The Nature of Science What is science? Scientists Body of knowledge based on the study of nature (observation) Scientists Make observations and draw conclusions Expand knowledge through reevaluation of current theories Challenge accepted theories Test claims Undergo peer review (experimental results are evaluated by other scientists in the field)

The Nature of Science Theory vs. Law Ethics Psuedoscience Theory – explanation of a natural phenomenon supported by many observations and experiments over time. Law – explains relationships under certain condition in nature, but doesn’t have to explain why (gravity) Ethics Morals and values held by humans Ethical issues must be addressed by society based on the values it holds important Psuedoscience Questionable or fraudulent science - astrology

Scientific Method Ask a Question Form a hypothesis Scientific inquiry begins with observation which leads to making inferences (combining what you know with what you have learned to make a conclusion) Form a hypothesis A testable explanation of a situation

Scientific Method Experiment Control group – group used for comparison Experimental group – group exposed to the factor being tested Independent variable – only one factor can change at a time; factor being tested Dependent variable – results from or depends on changes to the independent variable.

Scientific Method Collect Data Data – information gathered from observations Quantitative data – NUMERICAL – measurements of time, temp., length, mass, area, volume, etc. Qualitative data – WORDS – descriptions of what our senses detect

Scientific Method Metric System: system of measurement which uses units with divisions that are powers of ten SI units of measure: Length – meter Mass – gram Volume – liter Time – seconds SI (International System of Measurement) are commonly used in science for consistency and ease of communication. Metric prefixes: Kilo – 1000 Deci – tenths 1/10 Centi – hundreths 1/100 Milli-thousanths 1/1000

Scientific Method Analyze Data Report Conclusions Graph of the data makes the pattern easier to grasp Report Conclusions The conclusion compares the data with the hypothesis