Transcript 1 chapter 1 Core 2nd modx

Chapter
1
An Introduction to
the Study of Life
Lecture Presentation
by Wendy Kuntz
© 2015 Pearson Education, Inc.
Chapter 1 An Introduction to the Science of
Life: Module Hyperlinks
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1.1 Properties of life
1.2 Levels of life
1.3 Process of science
1.4 Scientists try to control for variables
1.5 Scientific thinking
1.6 Tables and graphs
1.7 Major themes in biology
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Chapter Table of Contents
1.1 Biology is the
scientific study of life
•Biologists
recognize life
through a series of
properties shared by all
living things.
•Biologist consider an
object to be alive if, and
only if, it displays all of
these properties.
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1.1 Properties of life:
•Reproduction:
• All
organisms reproduce their
own kind. ‘like begets like’
• Cells are capable of repair
•Growth
and
development:
• Information carried by genes
controls the pattern of growth in
all organisms.
Elephants only give birth to
baby elephants—never baby
lions.
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1.1 Properties of life:
•Energy
use:
• Every
organism takes in
energy, converts it to useful
forms, and expels energy.
•Order:
• Each
living organisms has a
complex but well-ordered
structure.
• Living organisms are
composed of organic
molecules
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1.1 Properties of life:
• Cellular
• The
basic unit of
life is a cell
• Some organism
consist only of a
single cell
• Some organisms
are multicellular
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1.1 Properties of life:
• Response
•
to the environment:
organisms can regulate their
internal environment
• All
organisms respond to changes
in the external and internal
environment.
• Organisms
respond to stimuli
• Many
of these
responses help to
keep an organism’s
internal environment
within narrow limits.
Homeostasis, is the property of a
system in which variables are
regulated so that internal
conditions remain stable and
relatively constant.
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1.1 Properties of life:
•Evolution: Individuals with traits that help them
survive and reproduce pass the genes for those
traits to offspring, driving the evolution of
populations. Organisms adapt and evolve.
• Elephants and woolly mammoths share a common
ancestor
Elephants and woolly mammoths share a common ancestor.
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1.1 Mammoths, Asian Elephants and African
elephants
• Elephant
evolution
• Elephants and
woolly mammoths
look similar but
they are different
species
• But they had a
common ancestor
1.2 properties of life and viruses
A virus responds to stimuli, it is composed of organic
molecules, it shows growth and development, it
uses energy, it adapts and evolves and has its own
genetic material
There are many specific types of viruses. For
example the HIV virus is a RNA virus which causes
AIDS, The polio virus causes polio. Each type of
virus has its own genome.
However, a virus is not composed of cells, it cannot
reproduce on its own, viruses do use energy but
cannot produce their own they need obtain energy
from its host. Viruses must have a host cell
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1.2 Opening Question: What about a
virus?
• Using
our criteria for living things,
decide whether a virus is classified
as alive.
• Here are some fun facts:
•
A virus cannot reproduce on its
own.
•
A virus is not composed of cells.
Would you consider a virus alive?
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Chapter Table of Contents
Levels of organization
• Biosphere,
Ecosystem,
Community, Population,
Organisms
• Organ
systems, Organs,
Tissues
• Cells,
Organelles, Molecules,
Atoms
1.2 Life can be studied at many
levels.
The biosphere
consists of all life
on Earth.
An ecosystem consists
of the living and
nonliving components.
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1.2 ecosystems contain communities and
communities are composted of populations
• A community
consists of all the
interacting
populations in an
ecosystem
• A population
is a
group of interacting
individuals of one
species.
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1.2 organisms are composed of organ
systems
An organism is an
individual living being
• Organism
An organ system is a
group of organs that
work together.
• Organ
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systems
1.2 organs are composed of
tissues
An organ consists of multiple
tissues that cooperate to
perform a specific task.
A tissue is an integrated
group of similar cells
that work together
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Tissues are composed of cells and
cells contain organelles
The cell is the fundamental
unit of life.
An organelle is a component
of the cell that performs a
specific function.
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1.2 Organelles contain molecules
which contain atoms
A molecule is a group of
atoms bonded together
in a specific ratio.
An atom is a fundamental
unit of matter. An atom is
the smallest unit of an
element that retains its
properties
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1.3 What is science?
• Observation
is the
first step in science.
• The scientific
method serves
as a guideline for
a scientist to
understand an
observation.
The scientific method
depends on hypotheses.
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THE PROCESS OF SCIENCE
•
There are two main scientific
approaches:
• Discovery science is mostly about
describing nature.
• Hypothesis-driven science is mostly
about explaining nature using
experiments
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Scientific Methodobservational studies
•Observational (discovery) studies
discover new organisms, collect
data, record behavioral
relationships
•Data observations that are both
qualitative and quantitative )
•Also record behavioral
relationships
1.3 Scientists investigate the world using
two types of scientific methods
• Discovery
science and Experiment driven
• Discovery science provides data used to
describe the natural world.
Biologists take
measurements
and record data
to help us better
understand the
natural world.
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Scientific Methods
• Terms
• Data (observations that are both qualitative and
quantitative )
• Hypothesis
• Observation(s)
• Experimentation
Control group
• Experimental group(s)
• Independent and dependant variables
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• Data
collection, analysis of data and conclusions
• Theory
1.3 How can scientists narrow down the
variables?
• Controlled
experiments investigate a hypothesis
by changing only one variable. The control group
serves as a comparison to the experimental
group(s)
Ideally, all other
variables are
held constant,
except the
experimental
variable
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1.4 Independent vs. dependent variables
• The
independent variable is what is being manipulated
as a potential cause.
• The dependent variable is the response, output, or effect
under investigation.
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1.4 A control group establishes a baseline
for an experiment.
• A negative
control is a group for which no change is
expected.
• Changing the oven
• A positive
control is a group for which a change is
expected.
• Doubling the amount of butter
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1.4 Performing experiments blind can
reduce bias.
• In
a blind experiment, information
is withheld from participants
(single-blind) or from both
participants and experimenter
(double-blind).
• The
placebo effect is a phenomenon in which a
patient feels better after merely believing treatment
was given, even if none actually was given.
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1.3 Hypothesis vs. theory
A hypothesis is a
proposed explanation
for an observation.
• A valid hypothesis
must be testable.
A theory is much
broader in scope and
explains a great many
observations.
• Theories are
supported by a large
and growing body of
evidence.
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1.3 Theory vs. theory
• Scientists use theory with a specific
meaning.
In everyday language how do people
often use the word theory?
Common Language:
Conjecture
• Speculation
• Opinion
•
Scientific Language:
Well-supported
• Testable ideas
• Objective data
•
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1.5 The scientific process depends upon
peer review.
• Peer
review is the
evaluation of work by
impartial, qualified, often
anonymous experts who
are not involved in that
work.
• Through peer review,
outside authorities can
help verify the validity of
scientific results.
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1.5 For reliability, consider the source of the
information.
• A primary
source is
original material presented
for the first time by the
person who performed the
research.
• A secondary source is a
description or review of
primary sources, often
containing commentary.
Examples of primary sources are peer-reviewed
journal articles, technical reports, and dissertations
Examples of secondary sources are websites,
books, newspapers, encyclopedias, and magazines.
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1.6 Opening Questions: Which cookie wins?
• As
part of a local “bake-off,” 100 students were
asked to taste two cookies and choose a winner.
Is there a clear winner?
Cookie Bake-off
Number of times chosen as winner
100
90
80
70
60
50
40
30
20
10
0
Cookie A
Cookie B
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1.6 Scientists communicate data using
tables and graphs.
• A scientific
table is
an efficient way to
present a lot of data
in a small amount of
space.
• Graphs
are a
means of displaying
data visually, which
can help to
summarize and
compare
information.
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1.6 Tables are read in columns and
rows.
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1.6 Different graphs are used to present
specific kinds of data.
Line Graph
Bar Graph
Pie Chart
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1.3 Process of science as a social process
Scientists share information with
each other
(meetings, seminars, websites,
personal communication)
Scientists share information with the
public
In St. Louis St. Louis Zoo;
Science Museum and the world
famous Missouri Botanical garden
Scientists work in groups and mentor
Belong to scientific associations
For example I belong to
American Association for the
Advancement of Science (AAAS)
Human Anatomy & Physiology
Society (HAPS)
1.7 Major themes underlie the study
of biology at all levels.
• Focusing
on these themes helps us organize and make
sense of all the information in biology.
Information Flow
Interconnections
Structure and
function
Evolution
Energy and
Matter Pathways
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Major themes underlie the
study of biology at all levels.
•Major
themes of biology
•Structure and function of
chemicals and cells, energy and
matter pathways, information flow
and genetics, interconnections
(evolution and ecology)
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1.7 Evolution by natural selection is
biology’s unifying theme
•Evolution
is the core theme of biology.
• All
life on Earth is connected through a shared
evolutionary history that stretches back over 3 billion
years.
All life on Earth is
connected through a
shared evolutionary
history that stretches
back over 3 billion
years.
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1.7 The theory of evolution through natural
selection is biology’s unifying theme.
• Evolution,
the descent with gradual
modifications of ancestral species to modernday ones, explains the common
characteristics throughout living things.
Evolution through natural
selection helps to explain
the development of
antibiotic-resistant bacteria.
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1.7 Structure and function correlate at all
levels of biological organization.
• Within
biological systems, structure (the shape
of something) and function (what it does) often
provide insight into each other.
The millions of tiny sacs in your lungs
provide a structure that correlates with
the function of gas exchange.
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1.7 Living organisms regulate the
transformation of energy and matter.
• All
activities of the cell require energy and matter to proceed.
The sun provides the
energy that drives nearly
every ecosystem.
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1.7 Information flow is apparent at all levels
of biological organization.
• The
information in all genes is encoded in an
identical chemical language common to all
organisms.
• Many inherited diseases result from improper
information in the form of a gene mutation.
People with Parkinson’s disease have
a gene
with faulty information.
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1.7 The interconnections within and
between the levels of biological
systems
• There
are many interconnections within and between the different
levels of biological systems.
• At
each new level, novel properties emerge that are absent from the
preceding one.
A cell displays as emergent, which is
not apparent in the individual parts that
make up the cell.
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1.8 Natural selection in action
•Antibiotics
were first
discovered in the
1940s.
•Today, some
antibiotics have
become virtually
useless because
bacteria have
evolved resistance.
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