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1.1 Biology… It Begins!Chp 1, pg 2-31

+Why is biology important?

Questions you’ve asked yourself? Why can birds fly? How do I work? What makes me who I

am? How did life begin?

All things biology tries to answer. Unfortunately, biology

cannot answer all of these.

+Some disclaimers

NOT a collection of never-changing facts. As technology opens up new possibilities, more in-

depth experimenting can occur.

Facts are observable, repeatable, and testable. If these steps cannot be done, and inference is

made.

Theories are well-tested explanation that unifies many observations and hypotheses.

Though theories may be the dominant view among the majority of scientists, no theory is considered absolute truth.

+Some disclaimers

New evidence can revise or replace a theory with a more useful explanation.

Open-mindedness is important. We must always be questioning and be able to accept new evidence.

Science is subject to biased, based on what scientist want to believe.

Do not just take your teachers word for it! Do your own research!

+What science is and is not…

Goals of science: provide natural explanations for events in the natural

world. use those explanations to understand patterns in nature

and to make useful predictions about natural events.

+The scientific method

Observing and asking questions

Making inferences and forming hypotheses

Conducting controlled experiments

Collecting and analyzing data

Drawing conclusions.

Observing and Asking Questions Begin with observation - act of noticing and

describing events in a careful, orderly way.

For example, researchers observed that marsh grass grows taller in some places than others. This observation led to a question: Why do marsh grasses grow to different heights in different places?

Inferring and Forming a Hypothesis Scientists use observations to make

inferences - logical interpretations based on what is already known. Inference lead to a

hypothesis - a scientific explanation for a set of observations that can be tested in ways that support or reject it.

Based on their knowledge of

salt marshes, they hypothesized

that marsh grass growth is limited

by available nitrogen.

Designing Controlled Experiments Design experiment that keeps track of

Variables - various factors that can change.

Examples of variables include temperature, light, time, and availability of nutrients.

In the hypothesis and experiment, only one variable is changed.

All other variables should be unchanged, or controlled. This type of experiment is called a controlled experiment.

Controlling Variables The variable that is deliberately changed is called the

independent variable (also called the manipulated variable).

The variable that is observed and that changes in response to the independent variable is called the

dependent variable (also called the responding variable).

**

Control and Experimental Groups Two groups: control & experimental groups. Control group - does not receive the

independent variable. Experimental group receives the

independent variable. Which is the control? Experimental?

Designing Controlled Experiments For example, researchers selected plots of grass with similar

plant density, soil type, and input of freshwater. The plots were divided into control and experimental groups.

Which plot receives the independent variable? Added nitrogen fertilizer (the independent variable) to the

experimental plots. Observed the growth of marsh grass in both experimental and

control plots. What is the dependent variable?

Amount of growth

Collecting and Analyzing Data Collect data – information from recorded observations Two types:

Quantitative data - numbers obtained by counting or measuring. Ex) number of plants per plot, plant sizes, and growth rates.

Qualitative data - descriptive and involve characteristics that cannot usually be counted. Ex) foreign objects in the plots, or whether the grass was growing

upright or sideways.

Data

Drawing Conclusions Use experimental data as evidence to support,

refute, or revise the hypothesis being tested, and to draw a valid conclusion.

Conclusion: Nitrogen helps these marsh plants grow.

Lesson Overview1.2 Science in Context

THINK ABOUT IT • The scientific method is the heart of science. • But that “heart” is only part of the full “body” of

science. • Other important parts of science include the

scientific community and society.

Exploration and Discovery: Where Ideas Come From What scientific attitudes

help generate new ideas?

Curiosity, skepticism, open-mindedness, and creativity

Good scientists share scientific attitudes that lead them to exploration and discovery.

Curiosity • Curiosity keeps us questioning.• You may look at a salt marsh and ask, “What’s that plant?

Why is it growing here?”

• Often, results from previous studies lead to new questions.

• For example: We find out that marsh grass grows in salt marshes because of the high levels of nitrogen.

• Our next question could be:

Skepticism • Skeptics question existing

ideas and hypotheses, and refuse to accept explanations without evidence.

• Scientists who disagree with hypotheses design experiments to test them.

• Supporters of hypotheses also test their ideas to confirm them and to address any valid questions raised.

Open-Mindedness Open-minded - willing to accept different ideas

that may not agree with their hypothesis.

Creativity Researchers need to think creatively to

design experiments that yield accurate data.

Practical Problems • Ideas for scientific investigations may arise

from practical problems. • For example, people living on a strip of land

along a coast may face flooding and other problems.

• These practical questions inspire scientific questions, hypotheses, and experiments.

Reviewing and Sharing Ideas Why is peer review important?

Publishing peer-reviewed articles allows researchers to share ideas and to test and evaluate each other’s work.

Peer Review • Reviewers read articles

looking for oversights, unfair influences, fraud, or mistakes in techniques or reasoning.

• They provide expert assessment of the work to ensure that the highest standards of quality are met.

Sharing Knowledge and New Ideas • New research may spark new questions. • Each question leads to new hypotheses that must be

tested.

• For example, the findings thatgrowth of salt marsh grasses is limited by nitrogen suggests that nitrogen might be a limiting nutrient for mangroves and other plants in similar habitats.

Scientific Theories What is a scientific theory?

Theory - a well-tested explanation that unifies a broad range of observations and hypotheses

Enables scientists to make accurate predictions about new situations.

Science and Society What is the relationship between science

and society?

Using science involves understanding its context in society and its limitations.

Science, Ethics, and Morality Science can tell us how technology and scientific

knowledge can be applied, but not whether it should be applied in particular ways.

Example: What does the frontal lobe of the brain do? Test: Remove the frontal lobe and see what happens. Should we?

Other examples include testing medicine, chemicals in food, etc.

Avoiding Bias

The way that science is applied can be affected by… Bias - a particular point of view that is personal, rather than scientific.

Science aims to be objective, but scientists are human, too. Sometimes scientific data can be misinterpreted or misapplied by scientists who want to prove a particular point.

https://www.youtube.com/watch?v=pYPgi1oUqXA

Understanding and Using Science • Don’t just memorize today’s scientific facts

and ideas. • Instead, try to understand how scientists

developed those ideas and come up with questions of your own.

Understanding and Using Science • Understanding biology will help you realize that

we humans can predict the consequences of our actions and take an active role in directing our future and that of our planet.

• Personal example: How does food affects you?• US example: How can watersheds be cleaned?• Worldwide example: How can pollution be

reduced?

Lesson Overview1.3 Studying Life

Characteristics of Living Things What characteristics do all living things share?

1) Made up of basic units called cells 2) Based on a universal genetic code 3) Obtain and use materials and energy 4) Grow and develop

5) Reproduce6) Respond to their environment7) Maintain a stable internal

environment8) Change over time.

What characteristics do all living things share?

Characteristics of Living Things• Biology is the study of life. But what is

life?

• No single characteristic is enough to describe a living thing.

• Some things, like viruses, exist at the border between organisms and nonliving things.

Characteristics of Living Things• Living things are based on a universal

genetic code. • All organisms store the information they

need to live in a genetic code called DNA. • DNA is passed from parent to offspring and

is almost identical in every organism on Earth.

Characteristics of Living Things• Living things grow and develop.

• A fertilized egg divides again and again.

• As these cells divide, they become specialized.

Characteristics of Living Things• Living things respond to their

environment.

• Stimulus – signal an organism responds to.

• Ex) Some plants can produce unsavory chemicals to ward off caterpillars that feed on their leaves.

Characteristics of Living Things• Living things reproduce

-- Produce new similar organisms.

• Most plants and animals perform sexual reproduction

-- Cells from two parents unite to form one cell that will divide and grow.

Characteristics of Living Things• Other organisms go through asexual

reproduction -- One organism produces offspring identical to itself.

Ex) Bacteria, cuttings, etc.

Characteristics of Living Things• Living things maintain a stable internal

environment

• Homeostasis - Expend energy to keep conditions inside cells stable.

• Ex) Kidneys, lysosomes, etc.

Characteristics of Living Things• Living things obtain and use energy.

• Metabolism - Reactions through which an organism builds up or breaks down materials.

• Ex) How we use food.

Characteristics of Living Things• Living things are made up of cells — the

smallest units considered fully alive.

• Cells are complex and highly organized.

• The human body is made up of over 100 trillion cells.• And there 10x that many microorganisms in our

intestines!

Characteristics of Living Things• Over generations, groups of organisms

evolve• Or change over time.

• Beaks changeover time dependingon what food isavailable.

What are the central themes of biology?

• The cellular basis of life• Information and

heredity• Matter and energy• Growth, development,

and reproduction• Homeostasis

• Evolution• Structure and function• Unity and diversity of life• Interdependence in

nature• Science as a way of

knowing.

Cellular Basis of Life • Living things are made of cells.

• Unicellular organisms - consist of only a single cell

• Multicellular organisms – Made of many cells. These cells display many different sizes, shapes, and functions.

Information and Heredity Living things are based on a universal

genetic code.

The DNA inside your cells right now can influence your future—your risk of getting cancer, the amount of cholesterol in your blood, and the color of your children’s hair.

Matter and Energy • Life requires matter for nutrients to build

body structures, and energy that fuels life’s processes.

• Plants obtain energy from sunlight and take up nutrients from air, water, and soil.

• Animals eat plants or other animals to obtain both nutrients and energy.

• Interdependent – All living things are connected.

Growth, Development, and Reproduction

• All living things reproduce, grow, and develop.

• Cells become more specialized for particular functions.

• Different cells for your brain, muscles, liver, etc.

Homeostasis • Living things keep a stable internal

environment.

• If homeostasis fails, it can be fatal.

• Kidney filters blood. Waste exits the body. People exhale CO2. If these processes stopped, we would die.

Evolution • Groups of living things evolve.

• Fact or theory: Evolutionary change links all forms of life to a common origin more than 3.5 billion years ago.

• Organisms change to better suit their environment.

Structure and Function • Organisms have evolved structures that

make particular functions possible.

• This helps species adapt to life in different environments.

Unity and Diversity of Life • Life takes many forms, but life is similar

at the molecular level.

• All organisms use DNA, protein, and enzymes to carry out their functions.

• People and bacteria both have DNA, use proteins to transfer materials, and have enzymes to help proteins.

Interdependence in Nature • All life is connected into a biosphere, or

“living planet.”

• Organisms are linked to each other and the non-living environment around them.

• Relationships between organisms and their environments depend on the cycling of matter and the flow of energy.

Science as a Way of Knowing

• Job of science:• Explain the natural

world using natural forces.

• Done through observation, questioning, and experimenting.

Fields of Biology How do fields of biology differ in

their approach to studying life?

Different fields use different tools to study life.

Microbiologist vs. ecologist

• Global Ecology • Global ecologists study

our global impact.

• Ex) How does pollution affect the climate?

• How does overfishing affect marine life?

• Biotechnology • Biotechnology includes

rewriting the genetic code.

• Replace damaged genes

• Prevent disease• Genetically engineer

bacteria to produce medicine.

• Raises ethical, legal, and social questions.

Ecology and Evolution of Infectious Diseases • Host and pathogen relationships are

constantly changing.

• The pathogen environment includes our bodies, medicines, and interactions with each other and the environment.

• Why can’t we find a cure for the common cold?

Genomics and Molecular Biology • Focus on DNA and molecules inside

cells.

• What can we do with this information?• Help us understand aging, cancer, and

the history of life on Earth.

Performing Biological Investigations How is the metric system important in

science?

The metric system is used to collect data and perform experiments.

Scaled on multiples of 10.

Scientific Measurement: Common Metric Units

The metric system makes it easy to convert to large and small units.

Which would you rather do?

How many ounces in 3.4 lbs?

How many milligrams in 3.4 g?