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What is Biology?
What is Biology, you ask?
Biology is the study of life.
Living things are called organisms.
Organisms include bacteria, protists, fungi,
plants, and animals.
Viruses are not alive – they are not organisms.
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The seven characteristics of life
All life is made of cells.
All life must reproduce.
All life has heredity based on one universal
genetic code (DNA).
All life has metabolism.
All life must respond to environmental stimuli.
All life has homeostasis; it must maintain
a stable internal environment .
All life must evolve; that is, species
must change over time.
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Conservation of Mass and
Energy in Biological Systems
Mass and energy cannot be created or
destroyed but can be converted from
one form to another.
Energy is conserved as it flows through
an ecosystem.
Energy moving through an ecosystem
changes from light energy to chemical
to thermal and mechanical energy.
All organisms respond to environmental stimuli:
abiotic and biotic factors
Food web
Interdependence in Ecosystems
All life must obtain energy and has metabolism
Note units
of energy
here.
90% of energy is
not transferred
to next level.
Level
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3
2
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Organisms occupy
trophic (energy) levels
in the environment.
They use energy (90%)
for themselves and
also release heat in the
process. For these reasons, only 10% of the
energy is available to
the next higher
trophic level of the
energy pyramid.
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Animals
cannot use
light energy to make
sugar. Animals
depend on plants for
food.
Decomposer – a
consumer that
puts materials
from dead plants
and animals
back into the
soil, air, and
water
Ecology is the study of relationships
among organisms and their environment.
Ecosystem is made up of all the
communities in an area and the nonliving
things with which they interact.
When organisms rely on each other, they
are interdependent. (food chain, food web,
energy pyramids)
Biodiversity is the variety of life in an
ecosystem. (coral reefs, rain forests)
Symbiosis occurs when two or more
different species have a close relationship.
(Co-evolution)
Mutualism – both species benefit
Commensalism – one species benefit and the other is
not harmed or helped
Parasitism – one species benefits while harming the
other one.
Metabolism: the sum of all the biochemical
reactions in an organism
All organisms require energy.
1. Autotrophs get their energy from the sun.
Photoautotrophs (algae , plants) use sunlight to make
food (carbohydrates: photosynthesis)
Chemoautotrophs (usually bacteria) use chemicals
such as iron & sulfur as their energy source to make
food(carbohydrates). These organisms are the
producers of ecosystems that are in the dark(volcanic
thermals at the bottom of the ocean, caves)
2. Heterotrophs must consume food for energy
Herbivores – consume only plants
Carnivores – consume only other animals (meat)
Omnivores – consume both
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3. Decomposers – break down the complex compounds of
dead and decaying animals.

They also break down energy into molecules that
are then returned to the environment.
 Carbon as CO2, Nitrogen,phosphorus
 Bacterias, Fungi, vultures, maggots, hyenas…
An ecosystem consists of all the
organisms living in an area, as well as the
nonliving parts of that environment.
Biotic(living)Factors
Abiotic(non-living)
Factors
Natural Changes in Ecosystems
Biotic factors – living things
Abiotic factors – nonliving things
Limiting factors – anything that limits the
ability of an organism to live in a certain
place. (space,food, temperature, shelter)
Successions – normal, gradual changes
that occur in the types of species that live
in an area. There are 2 types.
Primary succession
Ecosystems go through successions over time and will
slowly return to their original climax state if disturbed.
New soil must first be created in primary succession,
after volcanic eruptions or ice sheets scour the earth.
Secondary succession
Occurs in areas that
previously contained life
and still contain soil.
After a fire, soil remains,
and a previously
established
ecosystem can return
relatively quickly.
Natural Selection
and
Species Diversity
Evolution is the process of change over
time as a result of natural selection.
Natural selection is a mechanism for
change in populations. It occurs when
organisms with favorable variations
(DNA mutations)survive, reproduce, and
pass their variations to the next
generation. There are 3 types of natural
selection:
1. Stabilizing selection – favors average
individuals
2. Directional selection – favors one of
the extreme variations
3. Disruptive selection – individuals with
either extreme of a trait’s variation are
selected for survival.
disruptive
A population that is in genetic
equilibrium is not evolving.
Any factor that affects the genes disrupts
this equilibrium, which results in
evolution.
Mutation is a mechanism for genetic
change in the DNA.
Environmental factors such as radiation,
chemicals can cause mutations.
6 Best proofs of Evolutions
(2)
(1)
Fossil
Record
Convergent
Evolution
(3)
Comparative
Anatomy
Evidence of
Evolution
(6)
Molecular
Comparisons
(4)
(5)
Embryological
Development
Vestigial
Structures
All life must evolve
Thanks to successive mutations in their DNA, genetic drift
, natural selection and sexual reproduction, groups of
organisms (not individuals) change over time in order
to survive within changing environments. This is
Charles Darwin’s idea of evolution and survival of the
fittest. In addition long isolation of populations is
needed to create new species.
Some evidences for evolution are:
1. Fossil records show that organisms with
similar
to a
structures (homologous parts) trace back
common ancestor. Mammals, birds, reptiles
& amphibians trace back to fish, which
go back further, eventually to bacteria.
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2)Homologous structures (Divergent
evolution)
Homologous structures, body parts similar in
underlying structures but different in functions,
indicate an ancient common ancestor.
Over time (millions of years,
usually), adaptations
to new environments
cause bones (or beaks)
to change.
3)Analogous structures(Convergent
evolution)
Body parts of organisms that do not have a
common evolutionary origin but are similar in
function because they evolved in similar
medium and conditions(air, water, land). Ex:
flippers of dolphins and fins of fish, etc…
Examples of Convergence:
•
Whales and Fish
•
Marsupials and Placental Mammals
•
Counter-shading coloration and other forms of camouflage
•
Mimicry and camouflage
•
Hedgehogs and Porcupines
•
•
Cactus
Beaver and Capybara
Plants : Desert adapted Euphorbias
Vs. cactus
Euphorbia
4)Evidence
Comparative
Embryology
for Evolution - Comparative Embryology
Similarities In Embryonic Development=
Common ancestor
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5)Vestigial Structures
•
•
•
•
Mutations are always producing new body forms each generation.
Sometimes, environmental changes and mutations combine to provide
new opportunities for species.
As species evolve to fill different niches in their changing world, we
would expect their bodies to change over many generations.
Vestigial structures are body parts that are reduced in size and
function. Mutations that reduce the size of such structures are not
harmful and may actually be of a benefit to the individuals that inherit
them.
Click on one of the examples below to learn more.
Fossil whale legs Human coccyx, Snake leg spurs Reduced eyes of troglobites
Mammal male
Wings of ostriche
breasts
Home
6)Comparative Biochemistry
Comparison of Proteins & DNA
Molecular evidence of evolution.
Comparison of DNA or AA(amino acids in
proteins) sequence between different
species
– Bird & human DNA are only 60% identical
– Plant and Human DNA are only 10% identical
Comparison of Proteins(“cytochrome C”) & DNA
•
•
•
•
Even when one considers a species as distantly related to animals as a
yeast, there are still similarities to be found.
Half of the genes in a yeast are also found in humans.
Experiments have shown that mutant yeast can be fixed by inserting
the human version of a gene to replace their defective gene.
These genes have been inherited from our common ancestor, which
lived well over half a billion years ago.
Yeast
Primates
Home
7)Evolution of resistance
to
pesticides/herbicides and antibiotics in response
to selection
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8)Bio-geography/Speciation/Adaptations
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Levels of Organization
copyright cmassengale
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copyright cmassengale
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Phylogenic tree /Cladogram
Derived
Characteristics
Protists
• Unicellular Eukaryotes
• Can be autotrophic or heterotrophic
• Reproduce mostly asexually
Fungi
• Multicellular
eukaryotes
(yeast are the
only unicellular
fungi)
• Heterotrophs
• Reproduce
asexually and
sexually
Plants
• Multicelluar eukaryotes
• Autotrophs
• Reproduce sexually and
asexually
a protective
covering that
surrounds the
seed
makes seeds.
makes the plant's
food.
anchor the plant
in place and
absorb water and
other minerals
from the soil.
carries water and food
to the rest of the plant.
a protective
covering that
surrounds the
seed
makes seeds.
makes the plant's
food.
anchor the plant
in place and
absorb water and
other minerals
from the soil.
carries water and food
to the rest of the plant.
What Are the
Parts of a Flower

Most flowers have four
parts
Sepal – one of the leaflike parts that protects
a flower bud and that is
usually green
Pistil – part of a flower
that makes the eggs
that grow into seeds
Stamen – part of a
flower that makes
pollen

Flower parts
Pollen – tiny grains
that make seeds when
combined with a
flower’s egg
How Fertilization Occurs

When a pollen grain reaches a pistil, it grows a
thin tube to the ovary. Sperm from the pollen
grain combines with an egg, and a seed forms.
Fertilization –
the
combination of
sperm from a
pollen grain
with an egg to
form a seed
Where does a fruit comes from>?
Shoot Apical Meristem
Simple Tissues – consisting of one
cell type

Parenchyma – thin walled & alive at maturity; often
multifaceted.


Collenchyma – thick walled & alive at maturity
Sclerenchyma – thick walled and dead at maturity



Sclerids or stone cells – cells as long as they are wide
Fibers – cells longer than they are wide
Epidermis – alive at maturity


Trichomes – “pubescence” or hairs on epidermis
Root Hairs – tubular extensions of epidermal cells
Stoma position
Gas exchange
Oxygen
Roots – function and
structure
 Hold plant in position
 Absorb water and minerals
from the soil
 Specialised cells to increase
surface area for water intake
Root hair cells
(x150)
Water is Polar
Hydrogen
_
Hydroge
+
• In each water molecule, the oxygen atom
attracts more than its "fair share" of electrons
• The oxygen end “acts” negative
• The hydrogen end “acts” positive
• Causes the water to be POLAR
• However, Water is neutral (equal number of eOxygen
and p+) --- Zero Net Charge
++
Hydrogen Bonds Exist
Between Water Molecules
• Formed between a highly
Electronegative oxygen atom of
polar water molecule and a
Hydrogen atom of an other water
molecule.
• One hydrogen bond is weak , but
many hydrogen bonds are strong
Oxygen
Hydrogen
Oxygen
Hydrogen
Properties of Water
• Cohesion(surface tension-surface film, water transport
In plants)
• Adhesion(water transport in plant)
• High Specific Heat(resist Temp change)
• High Heat of Vaporization(cools
transpiration)
• Less Dense as a Solid(ice
body during
floats, insulates)
• Green house gas for the Earth
All life has metabolism
Sunlight is the ultimate energy for life on Earth.
Photo-synthesis is carried
out in the Chloroplast of producers
such as algae, phytoplankton, plants.
All life has metabolism
Cellular Respiration (in Mitochondria)
Through respiration, cells release the chemical
energy stored in foods created by photosynthesis.
6O2 + C6H12O6
6CO2 + 6H2O + 36 ATP
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Comparison of
Photosynthesis and Cellular Respiration
Photosynthesis video
6CO2 + 6H2O → C6H12O6 + 6O2
Cellular Respiration
P + ADP + C6H12O6 + 6O2
video
→ 6CO2 + 6H2O + ATP
Human anatomy
The BRAIN
Cerebral Cortex - The outermost layer of gray
matter making up the superficial aspect of the
cerebrum.
Cerebral Cortex
Cerebral
Cortex
http://www.bioon.com/book/biology/whole/image/1/1-6.tif.jpg
The Cerebellum
–helps coordinate
voluntary
movement and
balance
The Limbic System
• Hypothalamus, pituitary,
amygdala, and hippocampus
all deal with basic drives,
emotions, and memory
• Hippocampus  Memory
processing
• Amygdala  Aggression
(fight) and fear (flight)
• Hypothalamus  Hunger,
thirst, body temperature,
pleasure; regulates pituitary
gland (hormones)
Brain parts
The Limbic System
 Hypothalamus
 neural structure lying
below (hypo) the
thalamus; directs several
maintenance activities
 eating
 drinking
 body temperature
 helps govern the
endocrine system via the
pituitary gland
 linked to emotion
 (show video)
The lobes of the cerebral hemispheres
Planning, decision
making speech
Sensory
Auditory
Vision
The Cerebral Cortex
•
•
•
•
Frontal (Forehead to top)  Motor Cortex
Parietal (Top to rear)  Sensory Cortex
Occipital (Back)  Visual Cortex
Temporal (Above ears)  Auditory Cortex
A. Primary Motor Cortex/ Precentral Gyrus
B. Broca’s Area
C. Orbitofrontal Cortex
Cortical Regions
D. Primary Olfactory Cortex (Deep)
E. Primary Auditory Cortex
A.
F. Wernike’s Area
K.
I.
G. Primary Visual Cortex
B.
H. Visual
Association Area
H.
G.
I. Primary Gustatory Cortex
J. Somatosensory
Association Cortex
K. Primary Somatosensory
Cortex/ Postcentral Gyrus
J.
C.
D.
E.
F.
http://williamcalvin.com/BrainForAllSeasons/img/bonoboLH-humanLH-viaTWD.gif
The Heart and the circulatory system

The right and left sides of
the heart are separated
by a septum, or wall.

The septum prevents the
mixing of oxygen rich and
oxygen poor blood.
The Heart

On each side of the septum
are two chambers.

The upper chamber
(receives blood) is the
atrium.

The lower chamber (pumps
blood out of heart) is the
ventricle.
Pathway of Blood

Deoxygenated blood passes
from the right atrium into the
right ventricle and then goes
to the lungs.

From the lungs, blood
moves back toward the
heart into the left atrium to
the left ventricle and then
passes into the aorta to go
to the rest of the body
Immune response 1
1)The First Line of Defense
skin, stomach acid, mucus
2) The Second Line of Defense
White blood cells
3)The Third Line of Defense
~Antibodies~
Immune response( 3rd line of defense)
Acquired Immunity
1)Active immunity: Antidodies are made by the body
a)Natural : Because of memory T cells and Memory B cells, we are protected
from getting sick twicw from the same disease
b) Artificial : Men made vaccin made from dead organism , triggers a secondary
immune response and create Memory B and T cell for soecific desease.
2)Passive immunity: Antidodies are made by an other individual and
are “ bored” or “imported” by the host.
1a) Natural :When a new born baby is breast fed, the colostrum in the milk
contains antibodies and memory cells from the mother
b) Artificial : Serum made for deease such as yellow and dingue fever are
made of antibodies taken from animals or previously sickk individuals . This
serum are good only for a couple of month.
All organisms are made of cells
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All organisms are made of cells
Cells are the building blocks of life.
All cells come from pre-existing cells.
Viruses (in red here) are not
made of cells; they are not alive.
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The cell theory states that



all living things are made up of cells;
basic units of structure and function in
living things are cells
that new cells can only be produced
from living, existing cells.
Cell membrane
Separates the living from non-living environment.
Made of protein
and lipid
On design mode double click on table
Cellular organelles: Description and Function
ORGANELLE LOCATION
DESCRIPTION
FUNCTION
cell wall
plant, not animal
*outer layer
*rigid, strong, stiff
*made of cellulose
*support (grow tall)
*protection
*allows H2O, O2, CO2 to pass into
and out of cell
cell membrane
both plant/animal
*plant - inside cell wall
*animal - outer layer;
cholesterol
*selectively permeable
*support
*protection
*controls movement of materials
in/out of cell
*barrier between cell and its
environment
*maintains homeostasis
nucleus
both plant/animal
*large, oval
*controls cell activities
nuclear
membrane
both plant/animal
*surrounds nucleus
*selectively permeable
*Controls movement of materials
in/out of nucleus
cytoplasm
both plant/animal
*clear, thick, jellylike
*supports /protects cell organelles
material and organelles
found inside cell
membrane
endoplasmic
reticulum (E.R)
both plant/animal
*network of tubes or
membranes
*carries materials through cell
/rough ER contains ribosomes
ribosome
both plant/animal
*small bodies free or
attached to E.R.
*produces proteins
mitochondrion
both plant/animal
*bean-shaped with
inner membranes
*breaks down sugar molecules into
energy
vacuole
plant - few/large
animal - small
*fluid-filled sacs
*store food, water, waste (plants
need to store large amounts of food)
lysosome
plant *small, round, with a
uncommon
membrane
animal - common
*breaks down larger food molecules
into smaller molecules
*digests old cell parts
chloroplast
plant, not animal
*green, oval usually
containing chlorophyll
(green pigment)
*uses energy from sun to make food
for the plant (photosynthesis
Golgi bodies
both plant/animal
Network of membrane
Process protein and waste products
Nucleolus
both plant/animal Inside the Nucleus
Chromosome
both plant/animal
Inside the Nucleus
Centrioles
both plant/animal
In Cytoplasm
Controls production of ribosomes
Contains DNA
Attach chromosome during cell
division
Cell membrane
A cell must be able to obtain food and get rid
of wastes through its cell membrane
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Diffusion
The movement of particles from a region of high
concentration to a region of low concentration.
Click here for video
Examples: perfume in air, smoke in air, sugar in water,
oxygen through cell membranes
Passive transport: Osmosis
Diffusion of water from an area of high
concentration of water molecules to
one of low concentration across a
partially permeable membrane.
Partially permeable means only some things can
pass, not everything: usually small molecules with
no charge, like H2O, CO2, & O2.
“High” water concentration means that there are a
lot of water molecules per same unit of volume.
“Low” water concentration means that
there is a lot of something dissolved in
the water, so fewer molecules of water.
video
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Active transport:
Diffusion(against the concentration gradient) of any molecules
from an area of low concentration of that molecule to one
of higher concentration across a partially permeable
membrane using ATP as a source of energy.
Ions pump such as sodium and Hydrogen .
Endo, exo-cytosis and phagocytosis when a cell absorbs
or excretes.
Video1:Phagocytocys
Video2: Active
transport
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