Chapter 1 - Introduction: Exploring Life
NEW AIM: What are the major characteristics of life?
Figure 1.1
Chapter 1 - Introduction: Exploring Life
AIM: What are the major characteristics of life?
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of
Life
lifethe
organized?
AIM: How
Whatisare
major characteristics of life?
Biology?
The study of life (organisms and how they interact with the biotic and
abiotic components of their environments or surroundings)
How does one define life or living?
Chapter 1 - Introduction: The
Scientific
Exploring
Life Study of Life
AIM: How
all life
Whatis are
theunited?
major characteristics of life?
Characteristics of Life
(Living vs. Non-Living)
Chapter 1 - Introduction:
Exploring Life
1. Organization/order
All life is ordered/organized, which
is why energy is always needed
(must maintain this order). The
atoms that make us up can be
arranged in a countless number of
ways, but only a handful of those
will result in you…a working
organism. Any arrangement outside
of this handful results in death.
Recall
the
2nd law
of the universe
With
every
transfer
of energy,
thermodynamics…
becomes
more disordered. There are MANY
energy transfers within and around you
resulting in disorder, and therefore you must
constantly be maintaining order.
Fig. 1.3
Chapter 1 - Introduction:
Exploring Life
1. Organization
Hierarchy of Life
Going from the basic level of
subatomic particles (protons,
electrons, neutrons, etc…) to the
more complex level of
ecosystems
Emergent Properties
Notice as we move up the hierarchy, new
properties come to be that were not there
before. For example, atoms alone like carbon,
nitrogen, oxygen, hydrogen and phosphorus
cannot store information to build organisms, but
combine them to form a molecule called DNA
and you now have a new property…information
Fig. 1.3
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
The hierarchy of life:
1. Atoms (carbon, nitrogen, oxygen,
hydrogen, etc…) combine to form
molecules (proteins, carbohydrates,
lipids, nucleic acids, vitamins).
2. Molecules combine to form
organelles (nucleus, ribosomes, plasma
membrane, ER, golgi, etc…)
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
The hierarchy of life:
3. Organelles combine to form cells
What is a cell?
The most basic unit of life (the lowest
level on the hierarchy that can perform
all the functions of life)
Let’s take a closer look at cells…
Chapter 1
The
Life Study of Life
4 - Introduction:
A Tour of theExploring
CellScientific
How can
is are
allwelife
united?
AIM:
What
the
major
characteristics of life?
AIM: How
observe
cells?
Cell
Theory
New cells come from pre-existing cells with the
exception of the first cell, and that the cell is the
most basic unit of all living organisms.
Credit for this theory is given to:
Theodor
(German Physiologist)
Schwann
Matthias Jakob Schleiden
(German Botanist)
Cell is basic unit of life
Rudolf Virchow
(German Doctor, Biologist,…
All cells from pre-existing ce
Chapter 1
3 - Introduction:
The MoleculesExploring
The
of Cells
Scientific
Life Study of Life
How can
is are
allwelife
united?
AIM:
What
the
major
characteristics of life?
AIM: How
observe
cells?
Scaled Size of a cell
Imagine Madison Square Garden (MSG), to be a cell…how big is a
protein in this cell?
Reminder, a protein in the cell would be like a tennis ball in MSG and
the DNA would be like a rope with a thickness of 2mm and a length of
1200 miles.
Chapter 1
The
Life Study of Life
4 - Introduction:
A Tour of theExploring
CellScientific
How is are
all life
AIM: What
theunited?
major characteristics of life?
Two major forms of cells evolved on
Earth
1. Prokaryotes (bacteria or the kingdom monera)
- Two types
A. Eubacteria
DNA in blue, ribosomes are the black d
B. Archaebacteria
- No internal membranous organelles
No nucleus, ER, golgi, lysosomes, peroxisomes, etc…
- First to evolve, simpler
Pro-, coming before. Karyo = nucleus
Chapter 1
The
Life Study of Life
4 - Introduction:
A Tour of theExploring
CellScientific
How is are
all life
AIM: What
theunited?
major characteristics of life?
Two major forms of cells evolved on
Earth
2. Eukaryotes (animals, plants, protists, fungi)
- A fusion of prokaryotes
Endosymbiotic theory
Mitochondria and Chloroplasts were once
free-living prokaryotes that at some point in
evolution cooperated with another larger
prokaryote to eventually become one…the
eukaryotic cells.
Chapter 1
The
Life Study of Life
4 - Introduction:
A Tour of theExploring
CellScientific
How is are
all life
AIM: What
theunited?
major characteristics of life?
Two major forms of cells evolved on
Earth
1. Eukaryotes (animals, plants, protists, fungi)
- A fusion of prokaryotes
- Membranous organelles
Nucleus, ER, golgi, lysosomes,
peroxisomes, etc…
- More complex
Eu-, true. Karyo = nucleus
DNA found inside the purple nucle
Chapter 1
The
Life Study of Life
4 - Introduction:
A Tour of theExploring
CellScientific
How is are
all life
AIM: What
theunited?
major characteristics of life?
Two major forms of cells evolved on
Earth
EUKARYOTIC CELL
PROKARYOTIC CELL
DNA
Membrane
(no nucleus)
Membrane
Cytoplasm
Organelles
Figure 1.8
Nucleus (contains DNA)
1 µm
Chapter 1
The
Life Study of Life
4 - Introduction:
A Tour of theExploring
CellScientific
How
all life
AIM:
are
theunited?
major characteristics
of life?
NEW What
AIM:isHow
are
eukaryotic
cells organized?
Does more complex mean
better?
More complex means more that can
break, more to maintain against the
2nd law of thermodynamics, more to
form(longer development time),
etc…
Both types of cell exist on Earth and therefore they both work. If it works it
works…neither is “better”. If eukaryotes go extinct, then you might say the
prokaryotes were better, but only better in the environment that caused
Chapter 1
The
Life Study of Life
4 - Introduction:
A Tour of theExploring
CellScientific
How
all life
AIM:
are
theunited?
major characteristics
of life?
NEW What
AIM:isHow
are
eukaryotic
cells organized?
Does more complex mean
better?
Chapter 1
The
Life Study of Life
4 - Introduction:
A Tour of theExploring
CellScientific
How is are
all life
AIM: What
theunited?
major characteristics of life?
The Basketball, The
Size Comparison Analogy
Battery and the Pin Head
Eukaryotic cell (1/100th to 1/10th mm)
Prokaryotic
cell
1/1000th to 1/100th mm
Virus (just the
pin head)
1/20,000th mm
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
The hierarchy of life:
Figure 1.5
Figure 1.5 – a eukaryotic cell undergoing mitosis. Chromosomes (DNA plus associated proteins) are
stained blue, microtubules are green and the cytoskeleton is red. The left panel is anaphase and the
right is telophase.
Let’s briefly focus on the chromosomes / DNA…structure and function?
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
The hierarchy of life:
Structure of DNA:
Figure 1.7
DNA nucleotide monomers (A,C,T,G) combine
to form the double-stranded DNA polymer.
DNA (deoxyribonucleic acid) – two stranded
polymer of nucleotides A, T, C and G forming
a double helix.
Base pairs between strands:
A pairs with T
C pairs with G
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
The hierarchy of life:
Figure 1.7
Structure of DNA:
DNA nucleotide monomers (A,C,T,G) combine
to form the double-stranded DNA polymer.
Structure determines function…
The structure of a hammer determines its function to hit nails. Likewise, the structure of a
pencil allows for its function to write.
How does the structure of DNA relate to its function?
Chapter 1
3 - Introduction:
The MoleculesExploring
The
of Cells
Scientific
Life Study of Life
Howdoisorganisms
all life
AIM:
build/break
macromolecules?
AIM:How
What
are
theunited?
major
characteristics
of life?
1. Organization
The hierarchy of life:
Function of DNA / chromosomes:
DNA (a chromosome) is a book written
in only 4 letters!!
The DNA, like all books, stores information. What is
this information?
Instructions to build every RNA and
polypeptide (protein) in the cell.
DNA is found in the nucleus of eukaryotic cells or the nucleoid region of
prokaryotic cells. Each piece called a chromosome. They are books making
the nucleus of eukaryotic cells the library. All of the chromosomes in a cell is
called the genome.
Chapter 1
3 - Introduction:
The MoleculesExploring
The
of Cells
Scientific
Life Study of Life
Howdoisorganisms
all life
AIM:
build/break
macromolecules?
AIM:How
What
are
theunited?
major
characteristics
of life?
1. Organization
The hierarchy of life:
Function of DNA / chromosomes:
DNA is the hereditary molecule of life
Sperm cell
Nuclei
containing
DNA
Figure 1.6
Egg cell
Fertilized egg
with DNA from
both parents
Embyro’s cells
with copies of
inherited DNA
Proteins [and in certain cases RNA] built you, but the information to
build them is stored in the DNA. The books are passed on to the next
generation (heritable)…
Offspring with traits
inherited from
both parents
Chapter 1
3 - Introduction:
The MoleculesExploring
The
of Cells
Scientific
Life Study of Life
Howdoisorganisms
all life
AIM:
build/break
macromolecules?
AIM:How
What
are
theunited?
major
characteristics
of life?
1. Organization
The hierarchy of life:
Function of DNA / chromosomes:
Genetic Variation
We all obviously have slightly different books
(chromosomes) that code for slightly different
proteins/RNA that will in turn build us slightly
differently.
Why is genetic variation important?
Because the environment is changing around us. If we
were all identical, a change that caused one of us to
die would cause all of us to die….
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
The hierarchy of life:
3. Organelles combine to form cells
(muscle cells, neurons, blood cells, etc…)
4. In multicellular organisms, cells
combine to form tissues: muscle tissue,
nervous tissue, connective tissue, and
epithelial tissue (there are only 4 types).
5. Tissues combine to form organs like the
heart, lungs, pancreas, liver etc…
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
The hierarchy of life:
The regents focuses mainly on the immune,
reproductive and endocrine systems
6. Organs combine to form the organ systems:
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
Function is to obtain nutrients – proteins,
carbohydrates, lipids, nucleic acids, vitamins,
minerals.
Nutrients are first ingested, then digested (large
molecules broken down into smaller ones –
protein to amino acids, polysaccharides to
monosaccharides, nucleic acids to nucleotides,
etc… so they can be absorbed by the small
intestines into the blood for transport). All
undigestable material
(roughage/fiber/cellulose) will be egested.
Fig. 20.9
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
Serves for gas exchange. Bring in
molecular oxygen (O2) to your blood,
which will be used to perform cell
respiration by your cells. Get rid of CO2
and H2O waste (excrete) in the blood
coming from cell respiration.
Fig. 20.9
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
The heart pumps blood around your body in
hollow tubes made of cell called arteries (take
blood away from heart), veins (bring blood toward
heart), and capillaries (where nutrients and waste
diffuse to cells). These would be the roadways of
your body. The blood also carries other substance
like white blood cells (WBC’s – immune system)
and red blood cells (carry oxygen).
Fig. 20.9
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
Cleans the blood of metabolic waste (waste from
chemical reactions) like H2O from cell respiration, and
urea (form of nitrogenous waste) from deamination.
The kidney are “blood filters”, removing urea, excess
salt or excess water and other undesirable chemicals
from the blood.
Although not shown, the respiratory system has
excretory function in the elimination of CO2 since it is
a gas along with the skin, which will release some
urea, salt and water as sweat.
Fig. 20.9
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
CELLS TALK TO EACH OTHER (cell signaling)…
Your cells must be able to talk to each other in order to cooperate to maintain homeostasis,
and to be able to survive and reproduce…
***Homeostasis is NOT EQUILIBRIUM!!
In order to be alive, we cannot be at equilibrium. Homeostasis maintains a specific internal
environment (order), which is far from equilibrium. Think about your body
temperature…is this at equilibrium?
We are endotherms (warm-blooded) and maintain a body temp not at equilibrium with
our surroundings typically.
Fig. 20.9
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
Your cells must be able to talk to each other. For
example, insulin from the pancreas instructs the liver
to take up glucose from the blood.
The endocrine system uses hormones (special
chemicals – usually amino acid based - ex. Insulin, or
steroid (lipid) based – ex. testosterone) put into the
blood by endocrine cells. The hormone will bind to
receptor proteins on target cells and signal them to
perform certain functions. This system is typically
slow and long term – takes a while for the hormones
to circulate and they will stay around a while…
CELLS TALK TO EACH OTHER (cell signaling)…
Fig. 20.9
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
The nervous system is also all about cellular
communication, but instead of using chemicals
released into the blood, it uses cells that act like
wires called neurons that transmit electrical
signals. These signals are extremely fast (up to
120 m/s) and are typically short lived. An
example would be moving your finger or any
other skeletal muscle. The electrical signal is
sent from your brain, down your spinal cord
and out to the muscle in your finger.
CELLS TALK TO EACH OTHER (cell signaling)…
Fig. 20.9
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
There are millions upon millions of bacteria,
fungi, parasitic worms, etc… that would love
nothing more than to take your organic
molecules and make them lunch.
Luckily you have an immune system. This
systems protects your body from foreign
substance. White blood cells are responsible
for the destruction of these substances. They,
like all blood cells, are born in the bone
marrow and secrete antibodies (a type of
protein) that will stick to foreign molecules
called antigens on bacteria, viruses, etc...
Anything antibodies stick to will be eaten
by other white blood cells.
Fig. 20.9
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
What is life without a reproductive
system? Nonexistent. This one if
fairly self-explanatory. It is also the
only system not required for the
organism itself to survive.
Gametes (sex cells = sperm and
egg/ovum) are made in the gonads
(testes and ovaries).
Fig. 20.9
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
The muscular system is composed of all the
skeletal muscles of the body. The skeletal
muscles allow the body to move when
combined with signals from the nervous
system (and a lot of ATP of course).
Ligaments attach bone to bone.
Tendons attach muscle to bone.
Muscle cells can ONLY contract (get shorter) –
you cannot signal a muscle to extend.
Life is simply a series of movements (energy transfers).
Fig. 20.9
Chapter
- Introduction:
The
Exploring
Scientific
Life Study
of Life
Chapter120:
Unifying Concepts
of Animal
Structure
and Function
How
all life
AIM:
are
theunited?
major
characteristics of life?
AIM: What
Howisare
animals
organized?
Organs cooperate to build organ systems:
The skeletal system serves to support the body
(without it you would be a blob on the floor),
protects vital organs like your lungs, brain, spinal
cord and heart, and contains marrow that produces
blood cells.
The integumentary system is composed of the
skin, hair and nails (feathers and scales), all of
which are mostly non-living. This system serves to
waterproof, cushion and protect the deeper tissues,
excrete wastes, regulate temperature, is the
attachment site for sensory receptors to detect pain,
sensation, pressure and temperature, and may
attract a mate.
Integere means “to cover” (latin)
Fig. 20.9
Chapter
Introduction:
The
Life Study of Life
Chapter 51--Energy
and the Exploring
Cell Scientific
How is are
all
AIM: Describe
thelife
process
of active
transport.
AIM:
What
theunited?
major
characteristics
of life?
Comparing single to multicellular organisms
Function
Gas Exchange
Transport
Nutrition
Excretion
Single Cell
Multicellular
Chapter
Introduction:
The
Life Study of Life
Chapter 51--Energy
and the Exploring
Cell Scientific
How is are
all
AIM: Describe
thelife
process
of active
transport.
AIM:
What
theunited?
major
characteristics
of life?
Comparing single to multicellular organisms
Function
Single Cell
Multicellular
Gas Exchange
Cell Membrane
Respiratory
System
Transport
Cytoplasm
(cyclosis)
Circulatory
System
Nutrition
Lysosomes
Digestive System
Excretion
Cell membrane
Excretory System
and others
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
Organ systems cooperate:
Ex. Nutrients from digestive system are transported to cells by circulatory
system
Ex. Hormones from the endocrine system regulate the reproductive system
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
Organ systems cooperate:
Ex. When body temp drops, nerve impulses from brain signal muscles to
contract and shiver
Ex. Waste products from chemical reactions are transported by the
circulatory system to the kidney/lungs/skin for removal (excretion).
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
The hierarchy of life:
7. Organ systems combine to form organisms
8. Organisms that can reproduce with each
other collectively form a population (species)
9. Different populations combine to form
communities (squirrels, birds, humans all living
in an area).
10. Communities (biotic-living) combine with the
rest of the abiotic (non-living) substances like
soil, water, air to form the ecosystem.
Let’s take a closer look at ecosystems…
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
NEW What
How
AIM: is
How
allare
life
organisms
united?
to the environment?
AIM:
are
the
majorconnected
characteristics
of life?
Producers
= autotrophs = organisms that
make their own food (food =
organic molecules) by
photosynthesis or
chemosynthesis
Consumer
= heterotroph = steal/obtain food
(organic molecules) from the
producers or other consumers
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
AIM: How
organisms
connected
to the environment?
How are
is are
all
life
AIM:
What
theunited?
major
characteristics
of life?
What does this diagram show/tell us?
Chemicals cycle within
ecosystems
Earth is essentially not accumlating or losing
mass. Therefore, matter must be recycled and
used over and over by organisms. The
molecules your are made of were part of
countless other organisms in the past and will
be part of countless others in the future.
Energy flows through ecosystems
Energy enters for the most part as light from the
sun with the exception of rare deep sea thermal
vent and cave ecosystems. The energy of the
light is captured during photosynthesis and
stored in the electrons of organic molecules. As
energy is transferred between molecules, a
small amount is lost with each transfer.
Eventually all the energy is lost as infrared light
to outer space. Therefore energy must always
be coming into ecosystem.
Fig. 1.4
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
AIM: How
organisms
connected
to the environment?
How are
is are
all
life
AIM:
What
theunited?
major
characteristics
of life?
Explain how the atoms that make
up me could be part of you at
some point in the future.
Explain why the energy stored
within me will likely never be
used by your cells to
build/maintain/repair you.
Fig. 1.4
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
1. Organization
Reductionism vs Holism View Points
Reductionism
Complex systems like an ecosystem can be
explained by its simpler / fundamental
components like DNA in combination with the
basic laws of chemistry, physics, etc…
Holism
A complex system cannot be explained by its
simpler parts alone. It must be looked at as a
whole [“The whole is greater than the sum of its
parts” – Aristotle, emergent properties]
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
2. Regulation
(homeostasis)
Homeostasis is maintaining a stable internal environment
conducive to life.
Examples:
1. Body Temperature
- Get too hot, sweat; get too cold, shiver
2. Blood glucose levels
- Glucose too high, insulin secreted from pancreas telling liver
and muscle cells to take up glucose from blood and store as
glycogen.
- Glucose too low, glucagon secreted from pancreas telling liver
to break down glycogen and release glucose into blood.
3. Number of red blood cells
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
2. Regulation
(homeostasis)
Remember that homeostasis does not
maintain equilibrium, but in fact
prevents equilibrium as the conditions
required to maintain life are not those of
equilibrium.
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
2. Regulation
(homeostasis)
Example?
Glucose levels in the blood – eat a candy bar
and blood glucose levels rise above the
homeostatic level of 90mg/dl. Consistent high
glucose levels denature proteins and in turn
damage cells, the result of diabetes. The
pancreas (endocrine gland) senses the rise in
glucose and secretes the hormone insulin.
Hormones are chemicals secreted directly into
the blood and talk to other cells (bind protein
receptors). Insulin receptors are located on the
surface of muscle cells (myocytes – myo =
muscle, cyte = cell), fat cells (adipocytes) and
liver cells (hepatocytes). These cells are
triggered to take up glucose and store it as
glycogen (polymer of glucose) in the smooth ER
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
2. Regulation
(homeostasis)
Negative Feedback is one way and often used to maintain
homeostasis
A basic means of maintaining a certain concentration or level in a system like
the body where the product or output shuts its own production off.
Classic example – Thermostat:
1. Room is cold
2. Thermostat sends signal to furnace to generate
heat
3. Heat (output) added to the room
4. Heat shuts thermostat off (negative feedback)
at a set temperature like 72 degree F thereby
shutting its own production off, regulating the
temperature of the room
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
2. Regulation
(homeostasis)
Negative Feedback
A
General Biological Example:
Three enzymes [proteins
that catalyze reactions]
(enzyme 1, 2 and 3)
convert molecules A into
molecule D (the output).
Molecule D then binds to
enzyme 1, shutting it off,
which in turn shuts its own
production off. This
maintains/regulates a
specific level of molecule
D.
Figure 1.11
Negative
feedback
Enzyme 1
B
A
Enzyme 1
B
Enzyme 2
C
C
Enzyme 3
D
D
D
D
D
D
D
D
D
D
D
Chapter
Introduction:
The
Life Study of Life
Chapter 51--Energy
and the Exploring
Cell Scientific
Howare
is are
all life
AIM: How
enzymes
regulated
(controlled)?
AIM:
What
theunited?
major characteristics
of life?
Positive Feedback
Opposite of negative feedback.
When the output of a system goes back (feeds back)
and further enhances its own production (in the
positive direction) leading to more output and in turn
more enhancement and even more output, etc…
Such a condition is considered unstable and does not maintain
homeostasis…
Chapter
Introduction:
The
Life Study of Life
Chapter 51--Energy
and the Exploring
Cell Scientific
Howare
is are
all life
AIM: How
enzymes
regulated
(controlled)?
AIM:
What
theunited?
major characteristics
of life?
Positive Feedback
Examples:
1. Hypothetical – if your house thermostat worked
based on positive feedback, the output (heat) would
further activate the thermostat, which would instruct
the release of more heat, which would even further
activate thermostat, etc…
2. Child Birth contractions – the hormone oxytocin
stimulates contration of the uterus. This will cause the
baby to press up against the uterus, which causes
more oxytocin release, more contractions, more
pushing of the baby, more oxytocin, even harder
contractions, etc… until baby and placenta are out and
Chapter
Introduction:
The
Life Study of Life
Chapter 51--Energy
and the Exploring
Cell Scientific
Howare
is are
all life
AIM: How
enzymes
regulated
(controlled)?
AIM:
What
theunited?
major characteristics
of life?
Positive Feedback
Examples:
3. Sneezing
- You initially have to somewhat sneeze, which causes
you to feel more like you have to sneeze, and then
more, and more, and aaaaaaahhhhhhh
choooooooooooooo!
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
2. Regulation
Positive Feedback
(homeostasis)
W
General Biological Example:
Three enzymes [proteins
that catalyze reactions]
(enzyme 4, 5 and 6)
convert molecule W into
molecule Z (the output).
Molecule Z then binds to
enzyme 5, speeding it up,
causing more molecule Z
to be produced.
W
Enzyme 4
Positive
feedback
X
X
Enzyme 5
Enzyme 5
Y
Y
Enzyme 6
Z
Enzyme 6
Z
Z
Z
Figure
1.12
Enzyme 4
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
3. Growth and Development
After fertilization (sperm and egg also known
as gametes/sex cells fuse), you underwent
mitosis (one cell divides into two genetically
identical cells), many times as you grew. Your
original cells, called stem cells, differentiated
(turned into) all the different types of cells
that make up you by having their genes
turned on and off** (differential gene
expression) in order to grow/develop.
**Your eyes cells do not make insulin and therefore this gene
is turned off. ALL of your cells have the same DNA, what is
different is gene expression (which genes are on and their
protein being made).
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
4. Energy Utilization
What is energy?
An object has energy when it is able to accelerate
(speed up or slow down) itself or another object.
We obviously accelerate ourselves around
and move around other objects. Therefore
we use energy…where do we get energy
from**?
We are heterotrophs (eat others) and must
eat plants, which are autotrophs (organisms
that make their own food) or we eat animals
that have eaten autotrophs. The organic
molecules autotrophs contain, like fat
(triglycerides) and sugar (glucose/sucrose),
have energy…how did these molecules get
energy?
**Energy can’t be created or destroyed (1st law of thermodynamics).
You can’t magically give something the ability to move objects. It must
get this ability from somewhere. Ex. A ball on the ground will not be able
to move another ball next to it unless…
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
4. Energy Utilization
How did these molecules get energy?
Most autotrophs – also known as producers
because they produce their own food and the
food for others, like plants, do photosynthesis –
make organic molecules** that have energy,
like glucose, from inorganic ones (CO2 and
H2O) that do not have readily accessible
energy. The energy put into CO2 and H2O to
rearrange them into glucose is from sunlight!!
**Organic molecules are molecules that contain BOTH carbon and
hydrogen
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
4. Energy Utilization
How do we get the energy from these
molecules?
We “burn” them similar to burning a piece
of wood, but we do it slowly using many,
many chemical reactions known as…
cellular respiration.
What is the name we give to ALL the
chemical reactions in an organism
including those involved in cellular
respiration?
metabolism
Examples of chemical reactions (metabolism):
1. Cellular respiration
2. Photosynthesis
3. Protein synthesis by the ribosome
4. Glycogen synthesis and breakdown by the liver
5. Cholesterol synthesis
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
4. Energy Utilization
What is a chemical reaction?
When chemicals called reactants are rearranged into new chemicals called
products. In the above example, carbon dioxide and water are the reactants. They
are rearranged (bonds broken and reformed) into the products glucose, oxygen and
water by proteins called enzymes that speed up chemical reactions.
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
5. Response to the Environment
This one should be obvious. ALL
organisms do science and collect data
about their surroundings. We use the five
senses. Based on this data, the organism
will react.
Example:
You are in the street and a car is heading
at you resulting in you moving out of the
way.
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
6. Reproduction
All organisms must reproduce either sexually* or asexually** in order to maintain
the species. This is the only characteristic NOT required by the individual
organism itself to survive.
*sexual reproduction – two parents, each contributes half their DNA (sperm and egg) to the offspring
resulting in very different DNA in the offspring compared to each parent (genetic diversity)
**asexual reproduction – (prefix a- means without) one parent, genetically identical offspring, little
genetic diversity – offspring known as CLONES
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
7. Evolution
The DNA of populations (population = smallest unit that can evolve) will change
over time via…
microevolution (genetic drift, gene flow, mutation, natural selection, and sexual
selection) resulting in the structure/function of the species changing over time and
potentially new species arising. Why is it important that a species maintains genetic
diversity?
Because the environment is always changing, selecting for/against certain combinations of DNA
(organisms). Species need to be able to keep up with the environmental changes.
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
7. Evolution
Charles Darwin did not figure out the Theory of Evolution (or descent with modification as he
called it), he figured out one way in which evolution works…
The Theory of Natural Selection
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
7. Evolution
The Theory of Natural Selection
Nature acts like a filter and only “allows”
certain organisms to survive and reproduce.
The DNA (genes) of these organisms get
passed on and the genes of the others that
do not survive and reproduce get erased.
Only those organisms best suited to the
current environment make it…
Will we all survive? Will we all reproduce? Will we
have the same number of offspring? Think about
what is happening to you right now.
Fig. 1.21
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
7. Evolution
Population
of organisms
The Theory of Natural Selection
Remember:
Populations have Individual Variation already.
Populations will always reproduce beyond their
capacity (overproduction) resulting in competition.
Certain individuals will be better adapted to the
environment than others resulting in unequal
reproductive success.
Adaptations are characteristics in the population that
vary like beak size. Successful traits will become more
Figure 1.20
frequent in the population adapting the population =
evolutionary adaptation.
Hereditary
variations
Overproduction
and struggle for
existence
Differences in
reproductive success
Evolution of adaptations
in the population
Fig. 1.20
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
7. Evolution
The Theory of Natural Selection
Examples:
1.
There are humans who cannot get HIV. These people were
here before HIV. They did NOT arise because of HIV.
2.
Likewise, there are bacteria that are resistant to antibiotics
just by chance. The antibiotics did not cause them to arise,
it just SELECTS for them.
Fig. 1.21
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
7. Evolution
The Theory of Natural Selection
“Survival of the fittest”
Who is the “fittest”?
The fittest organism is the one who passes the most of his/her
genes into the next generation (you can say the most offspring,
but its more than that...)
Who is more fit, a person who lives to 95
years old with two offspring or a person who
lives to 22 with six offspring?
The 22 year old…more offspring.
Fig. 1.21
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
Living things
Life Characteristics
exhibit all 7
1. Organization
characteristics
2. Regulation
3. Growth and Development
4. Energy Utilization
5. Response to Environment
6. Reproduction
7. Evolution
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
How is are
all life
AIM: What
theunited?
major characteristics of life?
Fig. 1.2
Chapter 1 - Introduction: Exploring Life
NEW AIM: How is all life united?
Unity in Diversity
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
Unity in Diversity
There are currently ~2,000,000 known species
with an estimated 30,000,000 species on Earth
and guess what…
We are all essentially the same
We are all composed of cells that have DNA,
which code for RNA/proteins, which build us,
etc…
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
NEW How
AIM:
AIM:isHow
all life
is all
united?
life united?
Unity in Diversity
How is it that all life is so similar?
time
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
AIM: How is all life united?
All life is connected by a common ancestor
(LUCA- last universal common ancestor) that
existed approximately 3.6 billion years ago.
That is, if I take any two organisms on this planet right now and look at their parents and their parents parents (grandparents), etc… and
keep doing this at some point I will find that both organisms have the same great, great, great, great, etc… grandparents. We are all related.
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
AIM: How is all life united?
prokaryotes
time
eukaryotes
Phylogenetic tre
Phylo denotes tribe
genetics implies birth
A diagram showing the birth of all life and its evolutionary relatedness.
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
AIM: How is all life united?
prokaryotes
time
eukaryotes
Phylogenetic tre
Phylo denotes tribe
genetics implies birth
According to the diagram, what did we as animals evolve
Plants, Fungi and Animals
each evolved from a different
from?
type of protist.
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
AIM: How is all life united?
How do we build these trees and classify organisms (taxonomy*)?
They are built based on evolutionary relationships, which are
determined by collecting structural and molecular data.
*Taxonomy is the classification of life into groups based on evolutionary history using
structural (fossils of extinct organisms, bone structure, etc…) and molecular data (DNA,
protein sequences, etc…)
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
AIM: How is all life united?
Homologous structures – similar structure,
different functions
Structural evidence (ex. comparative anatomy)
Species with a recent common ancestor usually have similar structures. For
example, the bone structure of our arm is more similar to a bat wing than a
butterfly wing indicating that we have a more recent common ancestor with bats.
Structure can be misleading sometimes and the stronger evidence is…
Chapter 1 - Introduction: Exploring
The Scientific
Life Study of Life
AIM: How is all life united?
Molecular evidence
We can look at proteins (above) or DNA and compare them between
species. If two species have very similar DNA then they likely have a very
recent common ancestor. The more similar the more recent the common
ancestor.
*Much stronger than structural as evolution is a change in DNA over time. Different DNA can code for similar structures in certain cases.
Chapter 1 Introduction: Exploring
Life
AIM: How is all life united?
Another phylogenetic tree.
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
Using this data, how have we grouped organisms?
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
The Five Kingdoms
No nucleus or other INTERNAL
membranous organelles
ALL have Nucleus and other INTERNAL MEMBRANOUS ORGANELLES
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
The Five Kingdoms
No nucleus or other INTERNAL
membranous organelles
ALL have Nucleus and other INTERNAL MEMBRANOUS ORGANELLES
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
prokaryotes
Science is tentative!!
eukaryotes
6 kingdoms???
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
prokaryotes
eukaryotes
6 kingdoms???
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
prokaryotes
eukaryotes
3 domains
Fig 15.14B
Check out http://en.wikipedia.org/wiki/Kingdom_%28biology%29 for a history
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
Life’s three domains
Bacteria are the most diverse
4 µm
and widespread prokaryotes
and are now divided among multiple
kingdoms. Each of the rod-shaped
structures in this photo is a bacterial cell.
DOMAIN ARCHAEA
Figure 1.15
Many of the prokaryotes known
0.5 µm
as archaea live in Earth‘s
extreme environments, such as salty lakes
and boiling hot springs. Domain Archaea
includes multiple kingdoms. The photo
shows a colony composed of many cells.
Protists (multiple kingdoms)
100 µm
are unicellular eukaryotes and
their relatively simple multicellular
relatives.Pictured here is an assortment of
protists inhabiting pond water. Scientists are
currently debating how to split the protists
into several kingdoms that better represent
evolution and diversity.
Kingdom Plantae consists of
multicellula eukaryotes that carry
out photosynthesis, the conversion
of light energy to food.
Kindom Fungi is defined in part by the
nutritional mode of its members, such
as this mushroom, which absorb
nutrientsafter decomposing organic
material.
Kindom Animalia consists of
multicellular eukaryotes that
ingest other organisms.
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
Animal phyla
kingdoms
domains
Chapter 1 - Introduction: Exploring Life
AIM: How do we organize the diversity of life?
9 Major Animal Phyla
Chapter 1 - Introduction: Exploring Life
AIM: How do we organize the diversity of life?
1. Porifera
2. Cnidaria
3. Platyhelminthes
4. Nematoda
5. Annelida
6. Mollusca
7. Arthropoda
8. Echinodermata
9. Chordata
9 Major Phyla
(under animalia)
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
King Phillip Came Over For Grape Soda
(mnemonic)
Kingdom, phylum, class, order, family, genus, species
Most inclusive
Least inclusive
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
Least inclusive
Species Genus Family
Order
Class
Phylum
Kingdom
Domain
Ursus
americanus
(American
black bear)
Ursus
Ursidae
• Classifying life
Carnivora
Mammalia
Chordata
Animalia
Figure 1.14
Eukarya
Most inclusive
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
I.
Human classification
1. Domain - Eukarya
2. Kingom Animalia
3. Phylum Chordata
a) Gill pouches some time in development
b) A tail at some time during development
c) A stiff notochord
d) Thickened set of nerves down the back
4. Subphylum Vertebrata
5. Class Mammalia
a) Hair
b) Nurse young
6. Order Primata
a) Grasping fingers and toes
b) Eyes in the front of the head
c) Large brain
d) Fingernails
7. Family Hominidae
a) Primates that walk erect with straight-knee bipedalism
b) We are the only living member of this family
c) Many ancestral forms
8. Genus Homo
a) HUGE brains
9. Species: Homo sapiens
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
Modern day species
Branch points are speciation events
Ancestoral species
Phylogenetic Tree
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
Chimpanzees are most closely related to old
world monkeys, Orangutans or New world
monkeys? Explain.
Orangutans as their most recent common ancestor was 16 million years ago (Ma). The other two
species are 25 and 40 Ma.
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
Why is Proconsui not up with the other species
on the tree?
Remember that moving upward is time. This species went extinct.
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
QUESTION
After working for months in the lab you finally have the information you need to build a
simple phylogenetic tree showing the relationship of six species (A, B, C, D, E, and F).
You determined that the DNA sequence of A was most similar to that of C and E, and
that the DNA sequence of B was most similar to F. After closer examination, however,
you determined that the DNA sequence of C was slightly more similar to A than to E.
Species D had a DNA sequence with equal similarity to all the other organisms. Draw a
phylogenetic tree showing the evolutionary relationship of these six species.
Chapter 1 Introduction: Exploring
Life
AIM: How do we organize
the diversity of life?
Chapter 1 Introduction: Exploring
Life
AIM: How do we organize
the diversity of life?
http://evolution.berkeley.edu/evosite/evo101/IIAFamilytree.shtml
Chapter 1 - Introduction: Exploring Life
NEW AIM: What is Science?
What is
Science
Science is something that you do. It is a verb. It’s the process we use to try and know
something. It is the only way to try to know something.
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
How do we do
science
?
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
You need to simply make observations.
This is easier said than done in most cases. For
example, yes, if you want to know how many
bottles are recycled per day in school you can
just count them at the end of the day. A simple
observation.
However, if you want to know how a certain
protein binds to DNA and turns on a gene you
obviously can’t just look at it.
Making observations is one of the most difficult
parts of science!!
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
You need to simply make observations.
Hypothetical Observation:
You observe that over the past year you have not
gotten sick. Not a single cold, which is very
uncommon for you.
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
You need to simply make observations.
Hypothetical Observation:
You observe that over the past year you have not
gotten sick. Not a single cold, which is very
uncommon for you.
This should lead to a question…why have I not
gotten sick this year?
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
You need to simply make observations.
Hypothetical Observation:
You observe that over the past year you have not
gotten sick. Not a single cold, which is very
uncommon for you.
This should lead to a question…why have I not
gotten sick this year?
Perhaps it is that new tea I have been drinking
made by heating the leaves of two plants,
Camellia japonica and Lobelia chinensis in water
at 100 degrees C for two minutes. …
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
You need to simply make observations.
Hypothetical Observation:
You observe that over the past year you have not
gotten sick. Not a single cold, which is very
uncommon for you.
This should lead to a question…why have I not
gotten sick this year?
Perhaps it is that new tea I have been drinking
made by heating the leaves of two plants,
Camellia japonica and Lobelia chinensis in water
at 100 degrees C for two minutes. …
If the leaf extract is medicinal in nature then I
should be able to give it to other people and they
should also become ill less often...
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
You need to simply make observations.
Controlled Experiment
An experiment is simply a way of making more
observations to see if your hypothesis is
supported or refuted.
Design the experiment…
Make sure you indicate the independent variable,
dependent variable, control group, experimental
group, the variables you will try to control, etc…
Chapter 1 - Introduction: Exploring Life
AIM: How is all life united?
Things to keep in mind:
1. A hypothesis is NOT and IF/THEN. It is a statement that answers your question like: The plants
getting fertilizer will grow taller. NOT if the plants get fertilizer then they will grow taller.
2. The independent variable is the one you alter (it starts with the letter “I” = “I alter”. It is not fertilizer,
it is the AMOUNT OF fertilizer. – goes on x axis of graph
3. The dependent variable is what you measure…height, mass, color, etc… - goes on y axis of
graph
4. Make sure you use a placebo (sugar pill) if you are treating HUMAN subject only.
5. Always maximize sample size, use a control group for comparison if necessary, and the
experiment must be repeatable to be VALID.
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
There are two possible outcomes of your new
observations obtained by doing the controlled
experiment:
Let’s say you observe that 68% of the
people receiving the extract got sick
fewer times than the control group over
the first year of the study…what does
this tell you?
This is of course known as the
scientific method.
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
A Case Study in Scientific Inquiry: Investigating
Mimicry in Snake Populations
• In mimicry
– A harmless species resembles a harmful
species
Flower fly
(non-stinging)
Honeybee (stinging)
Figure 1.26
• In this case study
– Mimicry in king snakes is examined
– The hypothesis predicts that predators in non–coral
snake areas will attack king snakes more frequently
than will predators that live where coral snakes are
present
Scarlet king snake
Key
Range of scarlet king snake
Range of eastern coral snake
North
Carolina
South
Carolina
Eastern coral snake
Figure 1.27
Scarlet king snake
Field Experiments with Artificial Snakes
• To test this mimicry hypothesis
– Researchers made hundreds of artificial snakes, an
experimental group resembling king snakes and a
control group of plain brown snakes
(a) Artificial king snake
Figure 1.28
(b) Brown artificial snake that has been attacked
• After a given period of time
– The researchers collected data that fit a key
prediction
Key
Key
% of attacks on artificial king snakes
% of attacks on brown artificial snakes
Field site with artificial snakes
17%
In areas where coral snakes
were absent, most attacks
were on artificial king snakes
83%
X
X
X
North
X
Carolina
XX
South
X
Carolina X
X
XX
XXX
16%
84%
Figure 1.29
In areas where coral
snakes were present,
most attacks were on
artificial brown snakes
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
Tentative and Fallible
The findings of science are based on observation, but the observations
could be misleading. For example, the Earth appears to be flat…
Likewise, people thought Newton’s law of gravity was correct, but Einstein
came along and revised it. This type of thing happens all the time.
In addition, it was originally thought that water was HO. All of the
observations pointed to HO at the time…
The more reliable observations you make, the closer one gets to knowing
the truth…
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
What do scientists do with their findings?
They publish them in scientific journals like Science, Nature, Cell, EMBO, PLOS One, etc…
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
We are always doing science!
Because you are always making observations, predictions, etc… When you
walk down the hall you are collected data (visual data with your eyes,
auditory data with your ears, etc…). With this data you generate questions
and make predictions.
For example, you observe someone running at you.
Hypothesis: The person will run into me.
Prediction: If I do not move then I will get hit.
Experiment: Stay put.
Results: The person hit me supporting my hypothesis.
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
Theory
1. Very broad in nature (describe many, many different phenomenon).
2. Supported by enormous numbers of observations
3. Examples:
Theory of Evolution
Cell Theory
Law
1. Very concise in nature (describes a very specific phenomenon).
2. Supported by enormous numbers of observations
3. Examples:
Law of Gravity
Laws of thermodynamics
Laws of motion
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
GOD
and
Science
Chapter 1 - Introduction: Exploring Life
AIM: What is Science?
So is this class really about
science
?
Chapter 1 - Introduction: Exploring Life
Overview
Eleven themes that
unify biology
Table 1.1