Transcript Chapter 1 – The Science of Biology!

Chapter 1 – The Science of
Biology!
What words do we associate with science?
The goal of science is to investigate and
natural world to explain events,
understand the ______________,
and to use those explanations to make
___________________
useful predictions
To simplify, science is
an organized way of
using evidence to learn
about the natural world
Science can also just refer to the
knowledge scientists have complied
Scientific thinking usually
observation
starts with an
________________
An observation
is just gathering
info in an
orderly way
Data
_______=
the information gathered through
observations
There are 2 main types of data:
qualitative and quantitative
Quantitative = results from experiments that use
__________________________—
counts or measurements numerical data  can
be used to make graphs, tables, or charts.
observational data
Qualitative =____________________—written
descriptions of what scientists observe.
Qualitative
Quantitative
Inference = a logical interpretation based on
____________
prior knowledge or experience
So we have made our observation, now what?
Scientists come up with a
hypothesis – a proposed
______________
explanation for a set of
observations
Hypothesis’ must be able to be
tested – some through
controlled
experiments and
________________________
some through further
collection of data
Biology can be
considered a way of
knowing – it is an
ongoing process
because things
continue to change
(we don’t leave
things alone!!!)
Biological research can lead to
all sorts of different things;
new medical treatments,
new sources of fuel,
different uses for waste
Observations lead to questions – we need a way
to test those questions. That’s where an
experiment comes in.
The basic steps in designing an experiment:
1.
2.
3.
4.
5.
Ask the question
Form a hypothesis from the question
Set up a controlled experiment
Record and analyze results
Draw a conclusion
To help understand each step, let’s look at some
well-known experiments from history
Aristotle had the idea that
living things could come
from nonliving things –there
were special “vital” forces
that brought this about –
this became known as
spontaneous generation
This idea persisted for
a while – it was only
challenged some 400
years ago
These ideas were questioned because of simple
observations: maggots on meat, mice on grain,
beetles in poo (step 1)
(stepan
2)Italian physician, came up with a different
Redi,
hypothesis as to why maggots appear on meat
__________ they laid eggs
Redi came up with a controlled experiment (step 3)
Controlled experiment = an
experiment in which only
one variable is changed
_______________
at a time  all others are
kept unchanged (controlled)
The independent variable (IV) is what you are
changing/controlling/know
The dependent variable (DV) is what you are
observing/counting/watching
What is the IV?
What is the DV?
What is the IV?
What is the DV?
We like pictures, but hate numbers, so why do we
hate graphs? Its just a picture of our numbers!
Dependent
Reactive
Y-axis
What is the IV?
What is the DV?
Manipulated
Independent
X-axis
Types of Graphs
Line Graph: shows change over time
Bar Graph: compares similar but separate
categories
Circle/pie Graph: part of a whole thing (%)
In Redi’s experiment, he predicted that keeping
flies away from meat would prevent maggots, so
the variable he changed (IV) was the flies access to
the meat
Redi thought that if flies couldn't get to the meat
there would be no maggots, so he set up meat in
2 sets of jars – most factors were the same: the
jar, type of meat, location, temp, time – the only
thing that changed was
the gauze over the jar
Redi recorded his data in notebooks for future
generations of scientists (step 4)
supported his hypothesis – if the
Redi’s finding ___________
flies couldn’t get to the meat, there were no
maggots (step 5)
A key assumption in science is that experimental
results can be reproduced
Experiments are often repeated to make sure that
results are valid
Sometimes it’s not always
possible to do an experiment
to test a hypothesis
Field studies are used as a way
_______________
to make observations and gather
further information to help
support a hypothesis
When there is enough evidence from several
investigations and a hypothesis is very well
supported it is considered a theory
Some people might try to criticize something
because it is “just a theory”, but in science, a
theory is a well tested explanation that unifies a
broad range of observations
We ask questions all the time; how, what, when,
where, why?
This is exactly what biologists do – they ask
questions about living things
Biology is just the study of life
Bio = life
Logy = the study of
So how do we classify living things; what
characteristics do they have?
All living things (___________)
organisms share the following
characteristics, they are:
1. Are made up of units called cells
Cell = a collection of living matter enclosed by a
_______
barrier
_____________
that separates the cell from its
surroundings
2. Reproduce
_____________________
Sexual reproduction = cells from 2 parents unite
to produce the first cell of the new organism
Asexual
reproduction the new organism has a
______________________=
single parent  it divides in half to form 2 new
organisms
3. Based on a universal genetic code
Organisms inherit traits from their parents
through DNA – the genetic code
This code determines the inherited traits of every
organism on Earth
4. Grow and develop
growth is just
For some single-celled organisms, _________
an increase in size
All of the changes that take place during the life of
an organism = development
5. Obtain and use materials and energy
Organisms need material and energy just to stay
alive!
Metabolism the combo of chemical reactions
_____________=
through which an organism builds up or breaks
down materials during life processes
6. Respond to their environment
Stimulus
_________= a signal to which an organism responds
internal and external
Organisms can react to both _____________________
stimuli
7. Maintain a stable internal environment
Homeostasis = the process by which organisms
_______________
keep internal conditions constant for survival
Organisms go to great lengths to maintain
conditions (temp and water content)
8. As a group, change over time
100s or 1000s of years for these
It can take ________________
changes to really be apparent
Ex. Desert plants have evolved and adapted to
living in very hot, dry climates
Since there is a very large range of living things,
there are many branches of Biology
Some of the levels that biology can study are…
Biospheres
Communities
Organisms
Ecosystems
Molecules
Populations
Cells
Groups of cells
Section 1-4:
Tools and Procedures
Scientists use all sorts of tools to help make
measurements
observations and take
_____________________
common system
We need a _________________
of
measurement so that
_________________
scientists all over the world
can understand it
metric system is a decimal system of
The ________________
measurement whose units are scaled on multiples
of 10
A revised version of the metric system is the
International System of Measurement (SI)
Measurement
Unit
Symbol
Length
meter
m
Mass
kilogram
kg
Time
second
s
Temperature
Kelvin
K
Amount of
substance
mole
mol
Microscopes devices that produce
_______________=
magnified images of structures that are
too small to see with the naked eye
Light microscopes produce an image by
____________________
focusing visible light rays
Compound light
two
microscopes use ______
lenses to form an image
They can magnify an
object by about 1000 times
Electron
microscopes produce an image by
______________________
focusing beams of electrons
Images can get 1000 times more detailed than that
of a light microscope
There are 2 main types of electron microscopes:
transmission electron (TEM) and scanning
electron (SEM)
TEM
•Shines light through
thin specimen
•Specimen is NOT living
•Used to view details in
the specimen
SEM
•Scans surface of
specimen
•Specimen is NOT living
•Creates a 3D image of
the specimen
Lab
safety should always be practiced as biologists
__________
work with a variety of materials, living and dead
Eye Safety
Sharp Object
Safety
Chemical Safety
Clothing Protection
Safety
P.1066-1076 – reference
page for safety procedures
P.1068 in book – reference
page for safety symbols