Transcript Chapter Biology in the 21st Century

Biology in the
Century
Biology I(1)
Mr. Scott
st
21
1-1 The Study of Life
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Earth is home to an
incredible diversity of
life.
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The biosphere includes
all living things and all the
places they are found.
1-1 The Study of Life
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Earth is home to an incredible diversity of life.
Every part of the biosphere is connected with every other part.
The biosphere includes many environments.
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Land environments
Water environments
Your body?
1-1 The Study of Life
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The biosphere includes
many environments.
n
n
Saltwater and freshwater
environments
Portions of the
atmosphere
Tidepool
Estuary
1-1 The Study of Life
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Biodiversity is the variety of life.
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Generally increases from the poles to the equator.
Greater in areas with consistently warm temperatures.
1-1 The Study of Life
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A species is one
particular type of living
thing.
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Members of a species can
interbreed to reproduce.
There are about 2 million
different living species
have been identified.
1-1 The Study of Life
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Biology is the scientific
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study of all forms of life.
All organisms share
certain characteristics.
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Organisms can be single
celled or multicellular
1-1 The Study of Life
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An organism is any individual living thing.
All are made of one or more cells.
 All need energy for metabolism.
 All respond to their environment.
 All have DNA that they pass on to offspring.
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1-2 Unifying Themes of Biology
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All levels of life have systems of related parts.
A system is an organized group of interacting
parts.
A cell is a system of chemicals and processes.
 A body system includes organs that interact.
 An ecosystem includes living and nonliving things
that interact.
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Biologists study many different systems.
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DNA to ecosystems
1-2 Unifying Themes of Biology
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Structure and function are
related in biology.
Structure determines
function.
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Proteins with different
structures perform different
functions.
Heart muscle cells have a
different structure and function
than stomach muscle cells.
Different species have
different anatomical structures
with different functions.
1-2 Unifying Themes of Biology
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Organisms must
maintain homeostasis to
survive in diverse
environments.
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Homeostasis is the
maintenance of constant
internal conditions.
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Sweating
Heart rate
Sugar levels
1-2 Unifying Themes of Biology
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Homeostasis is usually
maintained through
negative feedback.
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Negative feedback
systems return a
condition to its normal
(set) point.
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Temperature
Respiration
Heart Rate
1-2 Unifying Themes of Biology
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Behaviors and
adaptations can help
maintain homeostasis.
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Reptiles sun themselves
Hogs roll in mud
Blood flow in walrus
1-2 Unifying Themes of Biology
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Evolution explains the unity and diversity of life.
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Evolution is the change in living things over time.
The genetic makeup of a population of a species changes.
 Evolution can occur through natural selection of
adaptations.
 Adaptations are beneficial inherited traits that are passed
to future generations.
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1-2 Unifying Themes of Biology
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Evolution accounts for both the diversity and
the unity of life.
Cells have similar structures and chemical processes
 However, they also perform different functions
 Humans and bacteria have similar structures but
perform different tasks as part of their lives
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1-3 Scientific Thinking and Processes
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Like all science, biology is a
process of inquiry.
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Scientists make careful and
systematic observations.
Scientists record observations
as data.
Scientists form a hypothesis as
a possible answer to a question.
Scientists test their hypotheses
and analyze their data.
1-3 Scientific Thinking and Processes
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Biologists use
experiments to test
hypotheses.
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Observational studies
allow scientists to
describe a phenomenon.
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Observing/watching
Cameras
Computers
1-3 Scientific Thinking and Processes
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Observations provide data
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Data allows observations to be analyzed
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Quantitative Data – data that can be measured or counted
Qualitative Data – data that describes the characteristics or qualities
of a situation or phenomenon
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Observations also help generate hypotheses
(hypothesis)
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A hypothesis is a proposed explanation for a question (an
educated guess).
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Specific and testable
1-3 Scientific Thinking and Processes
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Experimental testing
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Experiments allow for testing of a hypothesis to see
if it is valid
In science, usually testing one time is not enough
 Validity and Reliability
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Statistics are used to evaluate the data
Nonsignificant – data shows a small or no effect so that the
results may have happened by chance
 Statistically significant – data shows an effect that is not due
to chance
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Probability – mathematical determination of significance
1-3 Scientific Thinking and Processes
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Experimental studies
allow scientists to
determine what causes a
phenomenon.
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Independent variables are
manipulated (x-axis)
Dependent variables are
observed and measured
(y-axis)
Constants are conditions
that are kept the same.
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Controlled experiment
1-3 Scientific Thinking and Processes
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A theory explains a wide range of observations.
Theories explain a wide range of observations and
experimental results.
 A theory is supported by a wide range of scientific
evidence.
 Theories can change based on new evidence.
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Humours vs. Germ Theory
1-4 Biologists’ Tools and Technology
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Imaging technologies
provide new views of
life.
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A microscope provides an
enlarged image of an
object.
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Light microscopes (LM)
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1500x
Staining
1-4 Biologists’ Tools and Technology
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Imaging technologies
provide new views of
life.
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Electron microscopes
(100,000x)
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Scanning electron
microscope – cans the
surface (3D image)
Transmission electron
microscope – beam passes
through a slice
1-4 Biologists’ Tools and Technology
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Imaging technology is
used in medicine.
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X-rays
CT Scans
MRI
PET Scans
1-4 Biologists’ Tools and Technology
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Complex systems are
modeled on computers.
Computer models are used to
study systems that cannot be
studied directly.
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Normal heartbeat
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Heart attack
heart attacks
effect of medicines on body
movement of water molecules
into/out of a cell
spread of a disease through a
population
Computer models are used
when experiments are not
safe, ethical, or practical.
1-4 Biologists’ Tools and Technology
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The tools of molecular genetics give rise to new
biological studies.
Through our understanding of DNA, we can
study genetics on a molecular level.
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Molecular genetics – the study and manipulation
of DNA molecules
 Genomics – the study and comparison of genomes
within/across species
1-5 Biology and Your Future
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Your health and the health of the environment depend on your
knowledge of biology.
Knowledge of biology helps you understand your health.
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food allergies
potential effects of obesity
1-5 Biology and Your Future
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Knowledge of Biology
also helps understand
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Cancer
Effects of alcohol,
tobacco, and other drugs
Child development
1-5 Biology and Your Future
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Knowledge of biology
can help you understand
environmental issues.
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Interactions in ecosystems
Pollution
Biodiversity
1-5 Biology and Your Future
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Biotechnology offers great promise but also
raises many issues.
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Biotechnology is the use and application of living
things and biological processes.
Making bread/beverages
 Medicine
 Agriculture
 Forensic science
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1-5 Biology and Your Future
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Biotechnology also helps
us understand living
things
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DNA testing in medicine
and forensics
transgenic (genetically
modified) crops
transgenic bacteria
1-5 Biology and Your Future
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Questions are raised about the use of
biotechnology.
Safety of genetically modified crops
 Spread of undesirable genes
 Decrease in biodiversity
 Ethical considerations
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1-5 Biology and Your Future
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Biology presents many
unanswered questions.
Over the past 50 years,
biological knowledge has
greatly increased.
There are still many
questions to answer in
biology.
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How are memories stored in
the brain?
How do viruses mutate?
Does life exist on planets other
than Earth?