Unit 1: The Nature of Life

Chapter 1: The Science of Biology

Ms. PetrucciBiology

Chapter 1: The Science of Biology

• Vocabulary• 1-1

– Science – Observation– Data– Inference– Hypothesis

• 1-2– Spontaneous generation– Controlled experiment– Manipulated (Independent) Variable– Responding (Dependant) Variable– Theory

• 1-3– Biology– Cell

– Sexual Reproduction– Asexual Reproduction– Stimuli– Metabolism

• 1-4– Metric system– Microscopes

• Compound Light Microscopes• Electron Microscopes

– SEM– TEM

– Cell Culture– Cell Fractionation

1-1 What is Science?

Tell whether the following statements are scientific:

• Why it rains:– It rains because the clouds are crying.– Enough water vapor must be available to a cloud

for precipitation to form.• Where Babies come from:

– Fertilization can occur outside of an organism.– Storks bring babies to the new parents.

• The sun: – The sun is a really big bonfire.– You can walk on the sun in the winter

because it is not as hot.

The Goal of Science

• The goal of science is to understand the natural world. To achieve this goal, scientists make certain assumptions. They assume that:

– Nature can be understood through systematic study.

– Scientific ideas are open to revision.

– Sound scientific ideas withstand the test of time.

– Science cannot provide answers to all questions.

The Goals of Science

1. Science deals only with the natural world

The supernatural is outside of the realm of science

The Goals of Science

2. Collect and Organize Information

The Goals of Science

3. Propose explanations that can be tested

The Scientific Method

• There are basic methods of gaining knowledge that are common to all of science. At the heart of science is the scientific investigation, which is done by following the scientific method. A scientific investigation is a plan for asking questions and testing possible answers. It generally follows the steps listed in the figure:

Science Begins with OBSERVATIONS

• How good are your Observing Skills?

Think Like a Scientist…

• Make Observations• Ask a Question• Form a Possible Answer

(Hypothesis)• Test the Idea and Collect

Data (from the observations)• Make an Inference/Draw

Conclusions• Communicate the Results

Quantitative vs Qualitative

Explaining and Interpreting Evidence

• How Scientists develop a Hypothesis– Use prior knowledge– Make a logical inference– Informed, creative imagination

• Accept or reject? (Support or Refute)– Evaluating experimental results– Gathering more data

Hypothesis or Not?

• Our universe is surrounded by another, larger universe, with which we can have absolutely no contact.

• Any two objects dropped from the same height above the surface of the earth will hit the ground at the same time, as long as air resistance is not a factor.

• Occam’s Razor

Science as a Way of Knowing

• Science is an ongoing process• Scientific understanding is ever-changing

Science and Human Values

• Journal Prompt• Your journal entries should look like this:

8/25/2014 Make a list of things that you need to understand in order to protect your life and the lives of others (include at least 5 different things)

Start your list hereList each item on a new lineMake sure you have at least five items

Take 5 minutes to complete in your journal:

Make a list of things that you need to understand in order to protect your life and the lives of others (include at least 5 different things).

Make sure you include the date and the prompt in your actual journal (just like the picture) and write legibly.

1-2 How Scientists Work

• Systematically

Designing an Experiment

1. Make Observations/Ask a Question

2. Research/Form a Hypothesis

3. Set up a Controlled Experiment

4. Record and Analyze Results

5. Draw a conclusion– Communicate Results– Repeat

Set up a Controlled Experiment

– Use only one variable– Control (keep unchanged) all others– Manipulated variable is changed– Responding variable is observed

• Francesco Redi (1668)• Needham (1748)• Lazzaro Spallanzini (1765)• Louis Pasteur (1800's)

Variables

• Dependent Variable

• Independent Variable

Redi’s Experiment

• Spontaneous Generation

Needham’s Experiment

• Spontaneous generation can occur under the right conditions. Was Redi wrong!?

• 1765

• Nonliving Gravy does not produce living things.

• New organisms are produced only by existing organisms

• 1861

• Fixed the “no air” claim of Needham.

• Some flasks still sterile today.

Disproved Spontaneous Generation!

Life can only come from other life.

Three Experiments

Practice the Scientific Method

• Think about how you would test how the amount of a certain fertilizer determines if the fertilizer would grow taller plants.

Brainstorm

• Decide how you would go about conducting an experiment or investigation to study this.

• Identify the Dependant Variable and the Independent Variable

• I will provide you results

Data

Does more fertilizer = better growth?

Analyze these results.

What if you Cannot Experiment?

• When might an experiment not be possible?

• How can we answer scientific questions without experimentation?

What is a Theory??

1-3 Studying Life

• What are the Characteristics of living things?

• How can live be studies at different levels?

• Define Biology

To be classified as a living thing, an object must have all eight of the

following characteristics: • Living things:

– Are made up of units called cells– Reproduce– Are based on a universal genetic code– Grow and develop – Obtain and use materials for

energy– Respond to their environment– Maintain homeostasis– Taken as a group, change over

time (evolution)

1. Living things are made up of units called cells

• Cell - smallest unit of life– unicellular = single celled– Multicellular = many celled

2. Living Things Reproduce

• Sexual Reproduction• Asexual Reproduction

3. Living things are based on a universal genetic code

http://www.pbs.org/wgbh/nova/genome/dna.html

4. Living Things Grow and Develop

Differentiation

5. Living Things Obtain and Use Materials and Energy

6.Living Things Respond to Their Environment

7. Living Things Maintain a Stable Internal Environment

8. Living Things (Group) Change Over Time

Big Ideas in Biology

• Science as a Way of Knowing• Interdependence in Nature• Matter & Energy• Cellular Basis of Life• Information and Heredity• Unity & Diversity of Life• Evolution• Structure & Function• Homeostasis• Science, Technology & Society

Branches of Biology

• Zoology = animals• Paleontology = ancient life• Cytology = cells• Botany = plants• Entomology = insects• Microbiology = • Ecology =

Levels of Organization

• The living world can be organized into different levels. For example, many individual organisms can be organized into the following levels:

• Molecule

• Cell

• Tissue

• Organ

• Organ System

• Organism

More Organizational Levels

• There are also levels of organization above the individual organism.

• Population

• Community

• Ecosystem

• Biome

• Biosphere

Diversity of Life

biodiversity

1-4 Tools and Procedures

• What is the most dangerous thing in a Science Lab?

A Common Measurement System

• Metric System – Base 10 System– KHDDCM

How long are these snails?

How is Length measured? (what units?)

Snail 1Snail 2Snail 3

Volume

• How much space something takes up

• Usually a measure of liquids

• Use a

beaker or

graduated

cylinder.

Mass – not weight

Mass ≠ Weight

Temperature

How can a graph help biologist analyze data?

Microscopes

Steroscope Compound Microscope

Scanning Electron Microscope

Stereoscope

Light Microscopes

Electron Microscope

Laboratory Techniques

• Cell Cultures – single cell grown on nutrients will divide and form millions of cells

• Cell Fractionation – technique in which cells are broken into pieces and parts are separated.

Laboratory Techniques

Working Safely in Biology

• Lab Safety Handout

• Lab One – Using a Compound Microscope

• Chapter Test Next Week!