Chapter 1: The Science of Life

The Science of LifeChapter 1

Table of Contents• Section 1 The World of Biology

– What is biology? What are the properties of life?

• Section 2 Themes in Biology

– How is life diverse? What is interdependence? What is evolution?

• Section 3 The Study of Biology

– How are problems solved in biology?

• Section 4 Tools and Techniques

– What do you know about the microscope?

Section 1 The World of BiologyChapter 1

Biology

• What is Biology?• the study of life • The study of living things• Questions that biologists (scientists that study

biology) have:• How do living things work?• How do living things interact?• How do living things change over time?• How diverse are living things?

Section 1

Chapter 1

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Biology

Section 1 The World of Biology

Section 1 The World of BiologyChapter 1

Characteristics of Life

• Living things share the same 7 characteristics

1. Cellular organization

2. Reproduction & Heredity

3. Metabolism

4. Homeostasis

5. Response to stimuli

6. Growth and development

7. Evolve

Section 1 The World of BiologyChapter 1

Characteristics of Life, continued• Cellular Organization

– Organization is the high degree of order within an organism’s internal and external parts and in its interactions with the living world.

– A cell is the smallest unit of an organism that can perform all life’s processes.

Section 1 The World of BiologyChapter 1

Characteristics of Life, continued

• Organization and Cells– Multicellular organisms are made up of many

cells and show a hierarchy of organization going from the smallest unit of matter, the atom, to the actual organism

• Atom, biological molecule, organelle, cell, tissue, organ, organism

Section 1 The World of BiologyChapter 1

Characteristics of Life, continued

• Reproduction– Living organisms produce new organisms like

themselves– Is essential for the continuation of the species

Section 1 The World of BiologyChapter 1

Characteristics of Life, continued

• Heredity• During reproduction, organisms transmit

hereditary information to their offspring• Hereditary information is contained in genes on

strands of DNA

Section 1 The World of BiologyChapter 1

Characteristics of Life, continued

• Metabolism– Metabolism is the sum of all the chemical

reactions that take in and transform energy and materials from the environment.

– Includes photosynthesis, cellular respiration, digestion etc.

Section 1 The World of BiologyChapter 1

Characteristics of Life, continued

• Homeostasis– All living things have mechanisms that allow them

to maintain stable internal conditions. Homeostasis is the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing.

– How do we maintain 98.6 degrees when we are cold?– How do we maintain 98.6 degrees when we are hot?

Section 1 The World of BiologyChapter 1

Characteristics of Life, continued

• Response to Stimuli– Another characteristic of

life is that an organism can respond to a stimulus—a physical or chemical change in the internal or external environment.

Section 1 The World of BiologyChapter 1

Characteristics of Life, continued

• Growth and Development– The growth of living things results from the division

and enlargement of cells.– Development is the process by which an

organism becomes a mature adult.

Section 1 The World of BiologyChapter 1

Characteristics of Life, continued

• Change Through Time– Populations of living organisms evolve or change

through time.

Section 2 Skip

Section 3

Section 3 The Study of BiologyChapter 1

Science as a Process

• Steps of the Scientific Method– The scientific method is a way scientists solve

problems– There are 7 steps

7 Steps of the scientific method

1. Observation/ Question/ Problem

2. Research

3. Hypothesis

4. Predictions – predict based on a true hypothesis

5. Controlled experiment – only one variable is manipulated

6. Analysis of data

7. Conclusion

Chapter 1

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Scientific Method

Section 3 The Study of Biology

Chapter 1

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Controlled Experiment and Variable

Section 3 The Study of Biology

Section 3 The Study of BiologyChapter 1

Designing an Experiment, continued

• Performing the Experiment– The control group provides a normal standard

against which the biologist can compare results of the experimental group.

– The experimental group is identical to the control group except for one factor.

Section 3 The Study of BiologyChapter 1

Designing an Experiment, continued

• Performing the Experiment– The experimenter manipulates the independent

variable. (manipulative variable)– The experimenter measures the dependent

variable because it is is affected by the independent variable. (responding variable)

Chapter 1

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Independent and Dependent Variables

Section 3 The Study of Biology

Section 3 The Study of BiologyChapter 1

Drawing Conclusions

• Making Inferences– An inference is a conclusion made on the basis of

facts and previous knowledge rather than on direct observations.

Section 3 The Study of BiologyChapter 1

Constructing a Theory

• A theory is a set of related hypotheses confirmed to be true many times, and it can explain a great amount of data.

• Examples of theories:• Cell theory

• Theory of evolution

• With advanced knowledge and scientific tools, it may be possible to disprove a theory

• Example: spontaneous generation theory

Francisco Redi

• Didn’t believe the spontaneous generation theory that living things can spontaneously come to life from nonliving things – maggots from meat

Section 4

Section 4 Tools and TechniquesChapter 1

Microscopes as Tools

• Light Microscopes– A compound light microscope is a microscope

that shines light through a specimen and has two lenses to magnify an image.

– Four major parts of a compound light microscope are the ocular lens, objective lens, stage, and light source.

Section 4 Tools and TechniquesChapter 1

Microscopes as Tools

• Light Microscopes– The eyepiece magnifies the image.– The objective lens enlarges the specimen.– The stage is a platform that supports slides with

specimens.– The light source is a light bulb that provides light

for viewing images.

Section 4 Tools and TechniquesChapter 1

Microscopes as Tools, continued

• Magnification and Resolution– Magnification is the increase of an object’s

apparent size.– Resolution is the power to show details clearly in

an image.

Section 4 Tools and TechniquesChapter 1

Object Size and Magnifying Power of Microscopes

Section 4 Tools and TechniquesChapter 1

Microscopes as Tools, continued

• Electron Microscopes– In an electron microscope, a beam of electrons

produces an enlarged image of the specimen. – Electron microscopes provide greater

magnification and resolution than light microscopes.

Section 4 Tools and TechniquesChapter 1

Microscopes as Tools, continued

• Electron Microscopes– Scanning electron microscopes pass a beam of

electrons over the specimen’s surface for better viewing the external surface of a specimen.

– Transmission electron microscopes transmit a beam of electrons through a thinly sliced specimen for better viewing the internal structures of a specimen.