Transcript What - Cy-Fair High School Biology

What IS science?
True or False? What’s your opinion?
•Science is a method for inventing new devices.
•Science uses supernatural explanations if necessary.
•A scientific fact is absolute, fixed, permanent.
•Scientists have solved most of the major mysteries of nature.
•All scientific problems are solved by the Scientific Method.
•Science can be done poorly.
•Science can be influenced by race, gender, nationality, or religion of the
scientists.
•Science is most concerned with collecting facts.
MUST HAVE….
How can we tell the difference between science and non-science?
CONPTT
Consistency
Observability
Natural
Predictability
Testability
Tentativeness
Consistency
The results of repeated observations and/or experiments are the
same.
Professor Earl
gets the same
results as
Professor
Hfuhruhurr
Who gets the
same results as
Professor Timmy
Observability
The event under study can be observed or
explained by the basic human senses.
Observation
video
Observation or Inference?
1. There are 8 people in the photo.
2. The man on the far right is the leader of the team?
3. The people are happy.
4. All people have dark hair.
Natural
A natural cause must be used to explain why or
how the naturally occurring event happens.
Predictability
The natural cause of the naturally occurring
event be used to make testable predictions.
Testability
The natural cause of the naturally occurring event must be testable
through the processes of science (controlled experiments).
What characteristics do you notice
about this unidentified creature?
What are the
differences between
DNA and RNA?
Design an experiment to test if
these 2 animals are related.
Tentativeness
Scientific theories are subject to revision and
correction, even to the point of the theory
being wrong.
Geocentric Theory
Peer-reviewed journals
Flat Earth Theory
Good Science Follows the Scientific
Method
1. Observation -information obtained by the five sense
2. Hypothesis- testable idea to explain observations
3. Variable-What is changed and measured
4. Control- What stays the same
5. Data-Information gathered from experiment
6. Conclusion- Confirmation or rejection of hypothesis
with summary of results
Example of Good science
The Theory of Biogenesis
vs.
The Theory of Spontaneous Generation
Does life only come from life?
OR
Can life come from non-life?
Hmm, every time I leave the
meat out for a few days maggots
appear on it.
Francesco Redi
Observation 1: Maggots, which are alive, come
out of meat, which is dead.
Hypothesis 1: Life can come from non-life (aka
spontaneous generation).
Hmm, every time I leave the
meat out for a few days maggots
appear on it.
• Observation 2: Flies land on the meat that is
left uncovered. Later, maggots appear on the
meat.
• Hypothesis 2: Flies produce maggots.
• How can I test which hypothesis is correct?
The Experiment
Uncovered jars
Covered jars
Several
days pass
Maggots appear
No maggots appear
Conclusion: Maggots only form when flies come in contact with
meat. Spontaneous Generation did not occur.
A word on variables…
Uncovered jars
Maggots appear
Controlled
Variables:
jars, type of
meat,
location,
temperature,
time
Manipulated
(What you
changed!)
Variables:
gauze covering
that
keeps flies away
from meat
(1 at a time)
Covered jars
No maggots appear
Responding (What you
measure! )Variable:
whether maggots
appear
Components of The Experiment
Covered jars
Uncovered jars
Several
days pass
Maggots appear
No maggots appear
1. Observation
2. Hypothesis
3. Variable
4. Control
5. Data
6. Conclusion
Can result in…
A THEORY!
Conclusion: Maggots only form when flies come in contact
with meat. Spontaneous Generation did not occur.
Theory is a well-established, thoroughly tested, highlyreliable explanation that unifies a broad range of
observations. NOT absolute truth.
What’s the difference between a theory and a law?
Theory
Law
Explains an entire group
of related
phenomena
A result of the scientific
method
Describes a single action
Can be expressed in
mathematical
equation
Studying Life
Biology is the study of life.
bios means “life”
-logy means “study of”
Is it alive?
7 characteristics of life
Structure from Genetic Code
(DNA)
1. . Living things are based on
a universal genetic code =
DNA (deoxyribonucleic
acid). Directions for
inheritance.
Made of Cells
1. Unicellular – one cell
2. Multicellular – many
cells, some cells
specialized to perform a
different function.
7 characteristics of life
1.
Internal Balance A.K.A. HOMEOSTASIS
Living things maintain
internal balance through
homeostasis.
Example: Keeping the body
constant.
ex: 98.6 degrees F
ex. sweating vs.
shivering
7 characteristics of life
Energy Used
1. Autotrophic – use sun
2. Heterotrophic –
must consume
food
3. Decomposers –
energy from dead
remains of
organisms
Needs to Reproduce
1. Sexual reproduction =
cells from different parents
unite to form a new cell
2. Asexual reproduction =
single parent
7 characteristics of life
Change and grow
1. Unicellular grows in size
2. Multicellular changes
through differentiation, a
change in shape and size
Environment Stimulates
Response
1. A stimulus is a signal to
which an organism
responds (temp, light,
smell)
ex: migration
7 Characteristics of Life
tructure from genetic material (DNA)!
ells!
Just
remember
SCIENCE!
nternal balance AKA homeostasis!
nergy!
eeds to Reproduce!
hange and grow!
nvironment stimulates response!
Virus – Is it Alive???
Do:
1. Contain genetic info
2. Evolve over time, so they transform and change
3. Able to reproduce WITH A HOST ONLY
NOT:
1.
2.
3.
4.
Made of cells
Obtain and use energy (parasites)
Respond
Reproduce
Studying Life
Is it alive?
Characteristics of Life
You will be given several cards with pictures on them.
Your assignment is to group them in 3 or more
groups. You decide the categories.
HINT: Think about what we just learned!
Cell Theory - Timeline
• 1838 Matthias Schleiden – German botanist stated that all
plants are made of cells
• 1839 Theodor Schwann – German biologist stated that all
animals are made of cells.
• 1855 Rudolf Virchow – concluded that new cells are
produced from the division of existing cells.
Cell Theory
• All living things are
composed of cells
• Cells are the basic units
of structure and
function in living things.
• New cells are produced
from existing cells.
Tools and Procedures
Results need to be repeatable! We need...
A. A Common Measure System – metric
system (SI)
1. Multiples of ten
2. Length – meters
3. Volume – liters
4. Mass – grams
5. Temperature – Celsius (0-100)
B. Record data in tables and graphs
ex. Water released and absorbed by
tree
When graphing variables…
DRY
Dependent
Responding
Y-axis
(What you
MEASURE)
MIX
Manipulative
Independent
X-axis
(What YOU CHANGED)
C. Microscopes –
1. Light Microscopes –
produce magnified images
by focusing visible light
rays. Magnify up to 1000x
Can observe live specimens
2. Electron Microscopes – produce magnified images by
focusing on beams of electrons. Cannot observe live
specimens .
a. TEM – transmission electron microscope
Electrons pass through the sample
b. SEM – scanning electron microscope
Electrons scan back and forth across a surface
Laboratory Techniques
1. Cell Cultures – a
laboratory technique in
which one cell is able to
reproduce a group of cells
2. Cell Fractionation – a
laboratory technique in
which cells are ruptured
then parts are separated
Studying Life
III. Branches of Biology
1. Zoologists – study animals
2. Botanists – study plants
3. Paleontologist – study ancient life
Levels of Organization…
• LARGE
• SMALL
Oxygen
Air
Water
Dirt
Plants
Giraffe
Elephants
Smaller Levels of Organization
CELL-smallest unit of life
TISSUE- group of specialized cells
ORGAN- group of tissues with specific function
ORGAN SYSTEM- multiple organs doing the
same function
ORGANISM- many
organ systems make
up a single living
thing