Chapter 1 The Science of Biology

Section 1 – What is Science? The goal of science is to investigate and understand nature, to explain events in nature, and to use those explanations to make useful predictions. Science is an organized way of using evidence to learn about the natural world.

Science starts with observation! Observation involves using one or more of the senses to gather information. Data is the information gathered from observations. 2 types of observations – Qualitative – involves characteristics that cannot be easily measured or counted – Quantitative – involves numbers

Evidence must be interpreted The goal is to understand what was observed. Observations are followed by inferences. An inference is a logical interpretation based on prior knowledge and experience.

Evidence must be explained A hypothesis is a possible explanation for a set of observations or an answer to a scientific question. A hypothesis must be developed and tested in many different ways. Tests can support a hypothesis, suggest that it be revised, or even prove that is wrong.

REVIEW!!!!!! What does science study? What is qualitative data? What is quantitative data? What is a hypothesis? What is an inference?

Section 2 – How Scientists Work Designing an Experiment – Stating the Problem Identifying a problem to be solved – Forming a Hypothesis – Setting Up a Controlled Experiment – Recording and Analyzing Results – Drawing a Conclusion

Forming a Hypothesis Spontaneous generation – disproven hypothesis stating that life could arise from nonliving matter.

Setting Up a Controlled Experiment Variables – factors in an experiment that can change. Only one variable should be changed at a time. All other variables should be controlled or unchanged. Manipulated (independent) variable – the variable that is deliberately changed. Responding (dependent) variable – the variable that is observed and that changes in response to the manipulated variable.

Group Work Group 1 – Redi’s Experiment on Spontaneous Generation Group 2 – Needham’s Test of Redi’s Findings Group 3 – Spallanzani’s Test of Redi’s Findings Group 4 – Pasteur’s Test of Spontaneous Generation

Louis Pasteur Pasteur showed that all living things come from other living things. Proved that spontaneous generation was not correct.

How a Theory Develops Theory – well tested explanation that unifies a broad range of observations. Enables scientists to make accurate predictions about new situations.

Section 3 – Studying Life Living things share several characteristics. – Made up of units called cells – Reproduce – Based on a universal genetic code – Grow and develop – Obtain and use materials and energy – Respond to their environment – Maintain a stable internal environment – Living things change over time

Cells Cells are the smallest units of an organism that can be considered alive. Living things consisting of only one cell is called unicellular. – Microorganisms Living things that are made up of many cells are called multicellular. – Plants & Animals

Reproduction 2 types of reproduction – Sexual : two cells from different parents unite to produce the first cell of the new organism – Asexual: the new organism has a single parent

Genetics Offspring show characteristics of their parents The molecule of inheritance is called DNA

Growth & Development Each organism has a distinctive life cycle They grow and increase in size

Energy Organism uses energy and a constant supply of materials to live Metabolism: the combination of chemical reactions through which an organism builds up or breaks down materials

Homeostasis The process by which organisms keep their internal conditions stable. Constantly being threatened by changes in the environment.

Evolution Organisms evolve or change over time

Section 4 – Tools and Procedures Scientists use the metric system when performing experiments. Length: meter Mass: gram Volume: liter

Microscopes Light microscopes – produce magnified images by focusing visible light rays – Most common and magnifies up to 1000 times Electron microscopes – produce magnified images by focusing beams of electrons – Used to see objects that are too small to be seen by light microscopes