Unit OneThe Science of Biology

Mr. Greene

List five issues in the area of biology that you believe are important in the world today.

How can someone practice scientific thought?

What are universal laws in science?

How do ethics apply to science?

Why should someone who is not planning to become a scientist study science?

BREATHING EXERCISE SLEEP AND SCHOOL

Have students record how many times each breathes in 1 minute.

Have students suggest how exercise will affect the number.

Have them note the number of breaths they think they will take in the same time period after jogging in place for 1 minute.

Carry out exercise of students who volunteer.

“Does the amount of sleep affect how well you do in school?”

Design an experiment State the problem Form a hypothesis Experiment Describe how the results

could be recorded and analyzed

a way of knowing

about the physical

world

SCIENCE BIOLOGY Chemistry Physics Astronomy Geology Biology

Botony Ecology Genetics Zoology Ornithology Marine Biology

the study of

life

Scientific thought involves making observations using evidence to draw conclusions being skeptical about ideas being open to change when new discoveries are

made.

Scientists carefully observe the world and then ask questions about what they observe.

Scientific thought requires skepticism. Skepticism is a habit of mind in which a person questions the validity of accepted ideas.

Science is governed by truths that are valid everywhere in the universe. These truths are called universal laws.

Though branches of science address different aspects of the natural world, universal laws apply to all branches of science and every person.

Ethics are a system of moral principles and values.

Scientific experimentation and discovery can have serious ethical implications. Because of this, scientific investigations require ethical behavior.

Scientists performing investigations must report only accurate data must allow peers to review their work must behave ethically with the people involved in their

investigations

The same critical thinking process that scientists use is a tool that you can use in your everyday life.

By applying scientific thinking to a problem, you can help yourself and improve the world around you.

Scientific thought involves making observations, using evidence to draw conclusions, being skeptical about ideas, and being open to change when new discoveries are made.

Science is governed by truths that are valid everywhere in the universe. These truths are called universal laws.

Scientific investigations require ethical behavior.

An understanding of science can help you take better care of your health, be a wiser consumer, and become a better-informed citizen.

Imagine that all of the birds around the school are dying. How might you investigate the problem?

Write a brief description of your investigation.

Which stages of a scientific investigation are represented in your answer?

How do scientific investigations begin?

What are two methods scientists can use to test hypotheses?

What is the difference between a theory and a hypothesis?

the act of noting or perceiving objects or events by using one or more of the senses.

Essential!!!!

Inference – a logical interpretation based on prior knowledge

MEASUREMENTS

Quantitative expressed as a number

Qualitative expressed as a

description

a possible explanation to a problem that might be true

an educated guess

based in facts

not complicated or convoluted

always gives a ‘yes’ or ‘no’ answer

must be testable

“if…, then…”

Visual Concept: Hypothesis

Designed with an idea for an expected result.

Isolate a key factor responsible for an effect.

In every experiment, you need…control group standard comparison for the variable

variable one condition which is different

DEPENDENT VARIABLEthe one being measured

INDEPENDENT VARIABLEthe one causing the change

Visual Concept: Controlled Experiment and Variable

Visual Concept: Independent and

Dependent Variables

Writing down the events of the experiment

Confirms, rejects, or modifies the hypothesis

Publish the findings in a variety of ways in order to allow other individuals to learn the information you discovered

There are often cases in which experiments are not possible or not ethical.

In these cases, researchers perform studies.

In a study, researchers gather data about a system by making observations rather than by manipulating independent variables.

A widely accepted explanation for a broad range of observations.

A collection of related hypotheses that have been tested many times.

Can be revised if new evidence is discovered.

A law-like statement that generalizes across a set of conditions.

Visual Concept: Scientific Method

Designing an Experiment

Observations/State the Problem

Form a Hypothesis

Set Up a Controlled Experiment

Record Results

Forming Conclusions

Publish Results

Theory

Law

Every person has his or her own point of view. A particular point of view is called a bias.

Scientists try to prevent bias from affecting their work, but bias can still influence an experiment.

Sources of funding, personal involvement in a product, and other conflicts of interest can affect an experiment.

It is wise to view all scientific claims in their context and think critically about them.

Most scientific investigations begin with observations that lead to questions.

Scientists can conduct controlled experiments and perform studies in order to test a hypothesis.

The main difference between a theory and a hypothesis is that a hypothesis is a specific, testable prediction for a limited set of conditions, while a theory is a general explanation for a broad range of data.

Examine the SI units below.

How many meters are there in a kilometer? How many centigrams are in a gram?

How many milliliters are in 20 liters?

Why do scientists use SI units for measurement?

What are some tools and techniques that scientists use in the laboratory?

What can you do to stay safe during an investigation?

Metric system – a decimal system based on a multiple of 10

Length – meterMass – gramVolume – liter

 1 meter = 100 centimeters = 1,000

millimeters1000 meters = 1 kilometer

Water Released and Absorbed by Tree

TimeAbsorbedby Roots

(g/h)

Releasedby Leaves

(g/h)

8 AM

10 AM12 PM2 PM

4 PM6 PM8 PM

52

10

1496

411

12

171610

3

Water released by leaves

Water absorbed by rootsR

ela

tiv

e R

ate

s (

g/h

)

20

Time

0

1510

5

8 AM10 AM

12 PM2 PM

4 PM6 PM

8 PM

Making a Graph From A Data Table

Scientists use microscopes to view objects and organisms that are too small to see with the unaided eye.

Sterile technique is a method of keeping unwanted microorganisms out of a lab in order to minimize the risk of contamination.

Scientists also collect data remotely using devices such as satellites. These devices help scientists conduct research that would not have been possible in the past.

Cells were first seen in the 1600's with the invention of the microscopes.

There are various types with their own strengths.

Two Main Conceptsmagnification - the ability

to make an image appear larger

resolution - the ability to distinguish objects that are close to one another

Micrograph – a picture taken using one of the various microscopes

1) COMPOUND LIGHT it has two lenses a beam of light shines

underneath specimen and passes through objective lens through the eyepiece

both lenses magnify the image

eyepiece (ocular lens) is 10x the objective lens is 40 x

= 400 x!!!

good for very thin objects and living cells

commonly use stains to enable specific organelles to be seen

affordable magnifies up to 1,000

x objects that are larger than 0.2 micrometers

Visual Concept: Types of Microscopes

Visual Concept: Parts of a Light Microscope

2) ELECTRON MICROSCOPES

Specimen must be dead EM’s reveal details not

visible with Light Microscopes

Expensive, less available

2A) TRANSMISSION ELECTRON (TEM) uses beam of electrons to form

images against a fluorescent screen

object is thinly sliced into sections and stained which block electrons

the beam of electrons passes through the specimen, revealing internal structures

offers high magnification and resolution

no 3D information magnifies up to 200,000 x

2B) SCANNING ELECTRON (SEM) study the 3D surface of

object no slicing occurs object put on small metal

cylinder and coated with thin layer of metal

electrons move back and forth and bounce off and an image can be seen

living cells cannot be viewed because this must take place with no pressure

B/W - one wavelength of electrons

3) SCANNING TUNNELING (STM) ultra fine electron-

emitting probe that measures differences in voltage due to electrons that leak, or tunnel, from the surface of the object being viewed

computer tracks the movement of the probe

skim objects and shows contours of object

view living cells

4) STEREOMICROSCOPE

study of living objects that are too large to fit in Light Microscopes

Compound Light Transmission Electron

Stereomicroscope

Scanning Electron

3

2

1

4

Compound LightTransmission

Electron

Stereomicroscope

Scanning Electron

Scientists must use caution when working in the lab or doing field research to avoid

chemical burns exposure to radiation exposure to infectious disease animal bites poisonous plants

The International System of Units is used by scientists because scientists must share a common measurement system. SI is scaled in multiples of 10, which makes the system easy to use.

In the lab, scientists keep detailed and accurate notes and perform precise measurements. Scientists also use specialized tools and procedures.

Scientists use caution to avoid hazards such as chemical burns, exposure to radiation, exposure to infectious disease, animal bites, or poisonous plants.

List all the characteristics that you have in common with a beetle.

What are some of the branches of biology?

What are seven characteristics that all living things share?

All living organisms share certain properties.

Cellular Organization

All living things are made of one or more cells.

A cell is the smallest unit capable of all life processes.

Homeostasis

All living organisms must maintain a stable internal environment in order to function properly.

The maintenance of a stable internal environment in spite of changes in the external environment is called homeostasis.

Metabolism

The sum of all the chemical reactions carried out in an organism is called metabolism.

Almost all of the energy used by living things originally comes from the sun.

Responsiveness

In addition to maintaining a stable internal environment, living organisms respond to their external environment.

Reproduction

Most living things can reproduce. Reproduction is the process by which organisms make more of their own kind from one generation to the next.

Heredity

When an organism reproduces, it passes on its own traits to its offspring in a process called heredity.

Inherited characteristics change over generations. This process is called evolution

Click above to play the video.

Growth

All living organisms grow.

As organisms grow, many change. This process is called development.

Development differs from evolution because development refers to change in a single individual during that individual’s life.

Branches of biology include biochemistry, ecology, cell biology, genetics, evolutionary theory, microbiology, botany, zoology, and physiology.

The seven properties of life are cellular organization, homeostasis, metabolism, responsiveness, reproduction, heredity, and growth.

nonliving things produce living things 

People believed that meat produced maggotsIt became a big question during age of discovery when food needed to be

preserved for long periods of time.

FRANCESCO REDI1660’S

an Italian doctor challenged spontaneous

generation used meat which people knew

had maggots after a time he allowed meat to decay in

an open box and within several days maggots appeared

he kept watching the maggots and after about 20 days he saw that there were hard shells and then flies emerged.

HENCE, maggots were an early stage in the life cycle of flies.

flies laid eggs on meat

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.

HYPOTHESIS: Flies produce maggots.

PROCEDURE

Controlled Variables:jars, type of meat,location, temperature,timeManipulated Variables:gauze covering thatkeeps flies away from meat

Uncovered jars Covered jars

Several days pass

Maggots appear No maggots appear

Responding Variable: whether maggots appear

CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Redi’s Experiment on Spontaneous Generation

ANTON VON LEEUWENHOEK1765

invented one of the 1st microscopes

looked at rainwater and pond water, blood capillaries and cells

‘animalcules’/ ‘cavorting beasties’

it was hard to explain the growing number of microorganisms

he thought it arose from water left 247 microscopes completed

when he died scientists could not agree where

they come from

JOHN NEEDHAM1748

said spontaneous generation could occur under the right conditions

knew that heat killed microorganisms

he boiled gravy then sealed the container with a cork

- control - one that was open to air

- both containers - microorganisms reappeared in open one

- microorganisms appeared in “sealed one” later

microorganisms come from nonliving gravy

LAZZARO SPALLANZANI

read of John Needham's experiment and found some flaws

repeated them with some changes1 - boiled broth for an hour2 - better seals (melted

glass) no microorganisms present nonliving gravy did not produce

living things. They were offspring of microbes that entered the jar through the air.

critics said heating it would destroy the "active principle" or “life force”

Gravy is boiled.Flask isopen.

Gravy is teeming with microorganisms.

Gravy is boiled. Flask issealed.

Gravy is free of microorganisms.

Spallanzani’s Experiment

LOUIS PASTEUR proved spontaneous generation does

not produce microorganisms placed clear broth in long-necked glass

flasks, heated the necks of each flask, and bent them into S-shaped curves

heated the flask to kill microorganisms flasks were cooled and water droplets

condensed in the curved necks dust with microorganisms settled in

the water droplets air could pass in and out of the flask no microorganisms in the flask!!! tipped the flask and microorganisms

from neck got into flask spontaneous generation disappeared

about 20 years later

Broth is boiled. Broth is free ofmicroorganismsfor a year.

Curved neckis removed.

Broth is teeming with microorganisms.

Pasteur’s Experiment