CHAPTER 1 The Science of Life

Section 1-1 The Study of Life Objectives List six unifying themes in biology. Explain how organisms get the energy they need. Describe the main difference between the structure of a living thing and a nonliving thing.

In the beginning . . . First forms of life on earth arose 3.5 bya prokaryotic, unicellular, heterotrophic

Themes in Biology Cell structure and function unicellular vs. multicellular What is differentiation? prokaryotic vs. eukaryotic common cell parts

Themes in Biology Stability and Homeostasis Organisms must control conditions such as temperature, water content, food intake, and pH Homeostasis – constant internal environment

Themes in Biology Reproduction and Inheritance The molecule of heredity is DNA Gene – section of DNA that codes for the development of a trait Two types of reproduction Sexual and Asexual

Themes in Biology Evolution Populations of organisms change over time Natural selection is the mechanism by which evolution occurs

Themes in Biology Interdependence of Organisms Ecology is the study of the interactions of organisms with one another and with their environment Ecosystems – environmental communities

Themes in Biology Matter, Energy , and Organization Autotrophs vs. Heterotrophs

Section 1-2 The World of Biology Objectives List six characteristics of life. Describe how a living things is organized. Explain why all living things on Earth are not yet well understood.

Characteristics of Life Cells Unicellular Multicellular

Characteristics of Life Organization Organism System Organ Tissue Cells Organelles Molecules Atoms Biosphere Biome Ecosystem Community Population

Characteristics of Life Energy Use Metabolism- the sum of all the chemical processes that occur in an organism Two Types Anabolism building complex molecules from simpler ones ex: photosynthesis Catabolism breaking down complex molecules into simpler ones ex: cellular respiration

Characteristics of Life Flow of Energy in an Ecosystem Solar energy Chemical energy Mechanical energy AUTOTROPHS HETEROTROPHS

Characteristics of Life Homeostasis Necessary for survival A reaction (response) to a change in the environment (stimulus) helps us to maintain homeostasis

Characteristics of Life Growth Results from Cell enlargement Cell division Is necessary for the development of an adult organism

Characteristics of Life Reproduction Is necessary for the survival of the species Two types Asexual One parent cell divides to form two identical daughter cells. Sexual Two cells unite to form a new organism, different from either parent cell.

The Living World Difficulties involved in studying all living things Inaccessibility to all organisms Some organisms are so small Few of some species exist

Section 1-3 Scientific Methods Objectives 1. Define and give examples of observing, measuring, organizing and analyzing data, inferring, and modeling. 2. Explain the relationship between hypothesizing, predicting, and experimenting. 3. Explain why good communication is so important in science. 4. Describe the methods that scientists use in their work.

Scientific Methods Observing

Scientific Methods Asking a Question/Stating the Problem Collecting Data/Background Information 1. Observing 2. Measuring 3. Sampling 4. Organizing data using graphs, charts, tables, or maps

Scientific Methods Hypothesizing Hypothesis – TESTABLE statement Prediction – a statement made in advance that states the results that will be obtained from testing a hypothesis, if the hypothesis is supported If . . . Then . . .

Scientific Methods Experimenting Process by which a hypothesis is tested under controlled conditions Data which is collected and organized must then be analyzed

Scientific Methods Drawing Conclusions If data are reliable, the hypothesis is supported If data are NOT reliable, the hypothesis is rejected Modeling and inferring may be used to help draw conclusions

?? What is the difference between Scientific Methods A hypothesis that is repeatedly tested and supported may become a THEORY! ?? What is the difference between a theory and a law ??

Scientific Methods Communicate the results review

Controlled Experiments Two Groups Control Group Differs from the experimental group in only ONE way Is used as a standard for comparison Experimental Group Differs from control group by one factor called the INDEPENDENT VARIABLE The DEPENDENT VARIABLE is observed or measured in both groups review

Section 1-4 Microscopy & Measurement Objectives 1. Compare light microscopes and electron microscopes in terms of magnification and resolution 2. Explain the advantage of using the International System of Units (SI)

Microscopes Magnification and Resolution Magnification – the apparent increase in an object’s size Resolution – the ability to see detail

Microscopes Light microscopes Electron microscopes Uses light and lenses to illuminate and magnify the image Electron microscopes Uses a beam of electrons to magnify the image

Measurement Base Units Derived Units Other Units Length, mass, time chart Derived Units Area, volume, mass density, specific volume, temperature Other Units Minute, hour, day, liter, metric ton