Chapter 1. The Science of Biology

Honors BiologyMs. Watson

Chapter 1.1 What is science?Guide for Reading

Key Concept What is the goal of

science?

Vocabulary Science Observation Data Inference Hypothesis

What science is and is not

The goal of science is to investigate and understand the natural world, to explain in the natural world, and to use those explanations to make useful predictions.Science deals only with the natural world.Collect and organize information in a careful orderly way, looking for patterns and connections.Science – an organized way of using evidence to learn about the natural world.

Thinking like a Scientist

Scientific thinking usually begins with observation….Observation – the process of gathering information about events or processes in a careful orderly way. Involves using the senses, especially sight

and hearing.Data – the information gathered from observations is called data.

Thinking like a Scientist (cont’d)

Quantitative data – expressed as numbers, obtained by counting or measuring.Qualitative data – descriptive and involve characteristics that can’t usually be counted.Scientist may use data to make inferences.Inference – a logical interpretation based on prior knowledge or experience.

With the Data….

Scientist make inferences!Inference – a logical interpretation based on prior knowledge or experience.

Statement Observation Inference

Object A is round and orange.

Object A is a basketball.

Object C is round and black and white.

Object C is larger than Object B.

Object B is smooth.

Object B is a table-tennis ball.

Each object is used in a different sport.

Observation or inference???

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Make an observation….

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Make and observation…

Then make an inference…

Give an example of qualitative and quantitative data.

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Explaining and Interpreting Evidence

Scientists try to explain events in the natural world by interpreting evidence logically and analytically.Hypothesis – a proposed scientific explanation for a set of observations (use prior knowledge, logical inference, and informed, creative observation).Must be able to be tested.Perform controlled experiments or gathering more data.Some hypotheses can be ruled out.To be valid, a conclusion must be based on logical interpretation of reliable data.

Science as a Way of Knowing

Science is an ongoing process – ask questions, observing, making inferences, and testing inferences.Good scientists are skeptics, which means they question both existing ideas and new hypothesis.Science has limits.Focus on living systems, from invisibly small to size of our entire planet.

Chapter 1.2 How Scientists WorkGuide for Reading

Key Concepts How do scientists test

hypotheses? How does a scientific

theory develop?

Vocabulary Spontaneous

generation Controlled experiment Manipulated variable Responding variable Theory

Designing an Experiment

State the Problem

Form a Hypothesis

Set Up a Controlled Experiment

Record Results

Analyze Results

Draw a Conclusion

Publish Results

Designing an Experiment (cont’d)

Asking a Question How do new living things, or organisms, come

into being?Forming a Hypothesis Life could arise from nonliving matter

(spontaneous generation) 1668, Francesco Redi formed a new

hypothesis – Flies produce maggots.

Designing an Experiment (cont’d)

Setting up a controlled experiment Factors that can change are called variables

(equipment used, type of material, amount of material, temperature, light, and time.

Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time.

Controlled experiment – an experiment in which all variables are kept unchanged except for one.

Manipulated variable - the variable that is deliberately changed.

Responding variable – the variable that is changed in response to the manipulated variable

Designing an Experiment (cont’d)

Recording and Analyzing Results Scientists usually keep written records of their

observations, or data.Drawing a Conclusion Use the data from an experiment to evaluate

the hypothesis and draw a valid conclusion

“Science can be repeated – results should always be the same”

When Experiments are Not Possible

Observing animals in the natural habitatDetermining the effect on people of a chemical suspected of causing cancerMust design alternative investigations.

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How a Theory Develops

A particular hypothesis may become so well supported that scientists consider it a theoryTheory – applies to a well tested explanation that unifies a broad range of observations.Makes accurate predictions

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Chapter 1.3 Studying LifeGuide for Reading

What are some characteristics of living things?How can life be studied at different levels?

Vocabulary Biology Cell Sexual reproduction Asexual

reproduction Metabolism Stimulus Homeostasis Evolution

Continued

Key Concepts Which

measurement system do scientists use?

How are light microscopes similar? How are they different?

Vocabulary Metric system Microscope Compound light

microscope Electron

microscope Cell culture Cell fractionation

Characteristics of Living Things

Living things share the following characteristics Living things are made up of units called cells Living things reproduce Living things are based on a universal genetic code Living things grow and develop Living things obtain and use materials and energy Living things respond to their environment Living things maintain a stable internal environment Taken as a group, living things change over time

Made up of CellsCell – collection of living matter enclosed in barrier that separates the cell from its surroundingsSmallest unit of an organism that can be considered alive.Complex and highly organizedOrganisms can be unicellular and multicellularEx. Human body made up of 85 different cell types

Reproduction

All organisms produce new organisms through a process of reproduction.Sexual reproduction – cells from two parents unite to produce the first cell of the new organismAsexual reproduction – the new organism has a single parent.

Based on a Genetic Code

Asexual reproduction – offspring have the same traitsSexual reproduction – offspring differ from their parents in some waysDirections for inheritance carried by deoxyribonucleic acid, or DNA.

Growth and Development

All living things grow for at least part of their livesSome increase in size, others undergo developmentDevelopment – a single fertilized egg divides again and again to produce the many cells of mature organisms (differentiation)

Need for Materials and Energy

Metabolism – the combination of chemical reactions though which an organism builds up or breaks down materials as it carries out its life processesSome organisms can make their own food from the sun – photosynthesisOther organisms get their food by eating other organisms.

Response to the Environment

Stimulus – a signal to which an organism responds.Ex. Light, temperature

Maintaining Internal Balance

Homeostasis – keeping internal conditions, such as temperature and water content, fairly constant to surviveInvolves internal feedbackEx. Shivering, sweating, feelings of thirst

Evolution

As a group any given kind of organism can evolve, or change over time.Over a few generations, the changes in a group may not seem significant

Test Yourself…Do you know???Characteristic ExamplesLiving things are made up of units called cells.Living things reproduce.

Living things are based on a universal genetic code.Living things grow and develop.

Living things obtain and use materials and energy.

Living things respond to their environment.Living things maintain a stable internal environment.

Taken as a group, living things change over time.

Many microorganisms consist of only a single cell. Animals and trees are multicellular.Maple trees reproduce sexually. A hydra can reproduce asexually by budding.Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees.Flies begin life as eggs, then become maggots, and then become adult flies.Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat.Leaves and stems of plants grow toward light.

Despite changes in the temperature of the environment, a robin maintains a constant body temperature.Plants that live in the desert survive because they have become adapted to the conditions of the desert.

Branches of Biology

No single biologist could study all this diversity, so biology is divided into different fields.Ex. Zoologists (animals), botanists (plants), paleontologists (ancient life)

Branches of Biology

Biosphere – The part of the Earth that contains all ecosystemsEcosystem – Community and its nonliving surroundingsCommunity – Populations that live together in a defined areaPopulation – group of organisms of one type that live in the same areaOrganism – Individual living thingGroups of Cells – tissues, organs, and organ systemsCells – smallest functional unit of lifeMolecules – Groups of atoms; smallest unit of most chemical compounds

Biology in Everyday LifeHelps you understand your pets.DinosaursThe food you need and methods for sustaining the world’s food supply.Condition of good healthBehaviors of the diseases that can harm you.Identifies environmental factors that might threaten you.Understand what affects the quality of your life.Help understand that humans are capable of predicting and trying to control their future and that of the planet.

A Common Measurement SystemMost scientists use the metric system when collecting data and performing experiments.Metric system – a decimal system of measurement whole units are based on certain physical standards and are scaled on multiples of 10.International System of Units, or SI

A Common Measurement System

Common Metric Units – Appendix C

Length 1 meter (m) = 100 centimeters (cm) 1 meter = 1000 millimeters (mm) 1000 meters = 1 kilometer (km)

Mass 1 kilogram (kg) = 1000 grams (g) 1 gram = 1000 milligrams (mg) 1000 kilograms = 1 metric ton (t)

Volume 1 liter (L) = 1000 milliliters (mL) 1 liter = 1000 cubic centimeters (cm3)

Temperature 0oC = freezing point of water 100oC = boiling point of water

A Common Measurement System

Can you remember?????

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A Common Measurement System

A Common Measurement System

If you convert from a larger unit to a smaller unit the number increases by the correct factor of 10Ex. 10 decameters to metersMove the decimal place one space to the right and 10 decameters becomes 100 meters

A Common Measurement System

If you convert from a smaller unit to a larger unit the number decreases by the correct factor of 10Ex. 100 deciliters to litersMove the decimal place one space to the left and 100 deciliters becomes 10 meters

Let’s Practice…

If meter (m) is the base unit then how many centimeters are in one meter?

Convert 60.4 decameters to meters.

Convert 5 centimeters to hectameters.

1.4 Studying LifeAnalyzing Biological Data

Record data in a table and then make a graph.Graph of data makes recognizing patterns easier.Scientists use computers to sort data.

Water Released and Absorbed by Tree

TimeAbsorbedby Roots

(g/h)

Releasedby Leaves

(g/h)8 AM

10 AM12 PM

2 PM4 PM6 PM8 PM

52

101496411

121716103

Water released by leaves

Water released by leaves

Rel

ativ

e R

ates

(g/h

)20

Time

0

15

10

5

8 AM 10 AM 12 PM 2 PM 4 PM 6 PM 8 PM

MicroscopesMicroscope – a device that produces magnified images of structures that are too small to see with the unaided eyeLight Microscopes

Focus visible light rays Magnification about 1000x Compound Light

Microscope – allow light to pass through the specimen and use two lenses to form an image

study dead organisms and their parts and also when they are alive

Microscopes

Electron Microscopes Focuses a beam of

electrons, rather than light, to produce images.

1000x more detail than light microscopes

Transmission Electron Microscopes (TEM) – through the specimen, detailed information inside the specimen

Scanning Electron Microscope (SEM) – across the surface of the specimen, produces a 3-D image

Specimens are non-living

Scanning Electron Microscope Images

Blood Cells

Beetle

Transmission Electron Microscope Images

Plant Cell 22,500X Muscle Cells

Laboratory Techniques

Cell Cultures Used to obtain additional

culture The cell is able to

reproduce so a that a group of cells develop from the original cell

Cell Fractionation Separates one part of the

cell from the others Separates cell parts Cells are broken apart,

placed in a centrifuge, and then specific part is selected

Laboratory Techniques – Cell Fractionation

Working Safely in Biology

Scientists must be carefulWorking with flames or heating, elements, electricity, chemicals, hot liquids, sharp instruments, and breakable glassware.Always follow your teacher’s instructions and the textbook directions exactlyYOU are responsible for your own safety as well as your teacher and classmates.Safety rules – Appendix B (pg 1068)