INTRODUCTION TO LIFE
SCIENCE
Concept of Life
• All living things are made of
cells. Some are unicellular and
consist of only single cell that
carries out all life processes.
• Other organisms are multicellular and are composed of
many cells which perform
specialized and specific
functions.
• IRRITABILITY is the ability of
living things to respond or
react to the factors of the
environment such as :
1. Life
2. Temperature
3. Pressure
4. Tension
5. Chemicals
6. Gravity
• Example:
a. A sunflower responds to
light by facing the sun
b. The fruit fly is attracted to
electric light and grows in
fruit media.
MRS GREN
MRS GREN
M
ovement can also refer to the
motion of a single part of an
organism. Plants show movement
when a leaf bud opens or when a
flower closes at night.
R
espiration is the conversion of
energy from carbohydrates and
fats into energy that can be used by
cells. In multi-cellular organisms,
respiration is built around the
breakdown of sugars with the use of
oxygen. This produces carbon
dioxide as a by-product.
MRS GREN
S
ensitivity refers to the way
organisms respond to their
environment. All organisms are
able to sense changes in their
environment and will respond
accordingly.
G
rowth means that living things
can become larger or increase the
number of cells in their bodies.
Growth in all animals begins
when the zygote starts to
develop.
MRS GREN
Reproduction means that living
things can produce offspring.
Excretion is the ability to clear
waste from the body.
For example, humans excrete
nitrogen when they urinate and
carbon dioxide when they
breathe out. Plants excrete
oxygen through their leaves.
MRS GREN
E
nergy and nutrients are
essential for growth, survival
and reproduction.
• Animals acquire nutrients by
eating other organisms.
• Plants use energy from the sun
to convert carbon dioxide in the
atmosphere into sugars and
their roots absorb water and
nutrients from the soil.
Activity #2
Group into 4 then form a circle.
DO: Based on your book on page 182 about
7 characteristics of life,
discuss with your group mates then choose 4 and make a
drawing on a bond paper and write why these
characteristics you’ve chosen are important?
ORIGIN OF THE FIRST LIFE
FORMS
Theories of Origin of Life
1. Special creation theory
2. Spontaneous generation theory
3. Biogenetic theory
4. Abiogenetic synthesis theory
1. Special Creation Theory
• Many people believe
that everything in this
world was created by
a Supreme Being.
• It emphasizes that the
source of all creations
is God and with him
nothing is impossible.
2. Spontaneous Generation Theory
• It is a hypothetical process by
which living organisms developed
from unplanned event.
• In 1668, Francisco Redi conducted
an experiment to see if the theory
was true.
• He put a piece of snake meat, a
fish, and a slice of veal in flasks,
covered these with muslin cloth,
and waited to see if maggots
would develop on the meat.
• He discovered that maggots grew
only when flies laid their eggs on
it.
• But Lazaro Spallanzani,
Louis Pasteur, and
John Tyndall performed
similar experiments to
prove that the
spontaneous generation
theory was wrong.
3. Biogenetic theory
• Biogenesis is a process by
which life forms produce
other life forms.
• For example, a spider lays
eggs that become another
spiders.
• According to biogenesis, life
originated from pre-existing
life.
A demonstrative
experiment, which
showed biogenesis right
down to the bacterial
level, was devised by
Louis Pasteur in 1859.
4. Abiogenetic Synthesis Theory
• Alexander Oparin and John
Haldane proposed that living
cells arose gradually from nonliving matters through a
sequence of chemical
reactions.
• According to Oparin, gases
present in the atmosphere of
primitive earth, when induced
by lightening or other sources
of energy, would react from a
simple organic compounds.
• But Louis Pasteur
finally disapproved
abiogenesis and
proved biogenesis.
Other Theories on the Origin
of Life
1. Beneath the Ice
2. Electricity
3. Panspermia (Cosmozoic Theory)
4. RNA world
5. Simple Metabolism and Reactions
6. Clay Breeding Ground
7. Submarine Hydrothermal Vents
8. Adaptation
9. Evolution
10. Biology and Society
1. Beneath the Ice
• Ice may have been
hundreds of meters
thick and was mainly due
to the sun being much
less fierce than it is
nowadays
• This theory contends
that the ice may have
protected the
compounds, allowing
them to interact and,
thereby, creating life.
2. Electricity
• It has been proven that
electricity can produce
simple sugars and amino
acids from simple
elements in the
atmosphere.
• This leads to the theory
that lightning may have
been responsible for the
origins of life, primarily
by striking through rich
volcanic clouds.
3. Panspermia (Cosmozoic Theory)
• Panspermia is the
proposal that life on
Earth began from Rocks ,
and other debris from
impacts, in the form of
highly resistant spores
(cosmozoa) such as
meteorite.
• In fact, rocks from Mars
have been found here on
Earth, and it has been
suggested that any one of
these would have brought
microbes that could have
kick-started life.
4. RNA (Ribonucleic acid) world
• This theory states that
all life sprouted from
a complex RNA world.
• RNA is known for its
role in the expression
of genes.
• To put it simple, DNA
(Deoxyribonucleic acid)
5. Simple Metabolism and Reactions
• This approach suggests that the
primordial soup simply continued to
react by itself over time, producing more
and more complex molecules, eventually
yielding life.
• The "primordial soup" idea came about
when Russian scientist Alexander Oparin
and English geneticist John Haldane each
came up with the idea independently.
• It had been theorized that life started in
the oceans
• Oparin and Haldane thought that with
the mix of gases in the atmosphere and
the energy from lightning strikes, amino
acids could spontaneously form in the
oceans. This idea is now known as
"primordial soup."
6. Clay Breeding Ground
• The latest theory is that clay - which is at its
most basic, a combination of minerals in the
ground - acts as a breeding laboratory for
tiny molecules and chemicals which it
'absorbs like a sponge'.
• It is suggested that clay may have served as
an area of concentrated chemical activity,
providing a breeding ground for DNA and
other components.
• The process takes billions of years, during
which the chemicals react to each other to
form proteins, DNA and, eventually, living
cells, scientists told the journal Scientific
Reports.
• Biological Engineers from Cornell
University's department for Nanoscale
Science in New York state believe that clay
'might have been the birthplace of life on
Earth'.
7. Submarine Hydrothermal Vents
• The theory suggests that life
may have begun at the
submarine hydro thermal
vents which emit the
hydrogen rich molecules.
• The rocky niches might have
gathered all the molecules
together and provided
minerals to act as a catalyst
for reactions to occur.
• These vents still constitute
chemical and thermal energy
to sustain vibrant
ecosystems.
8. Adaptation
• An adaptation is an
inherited trait that helps the
organism's ability to survive
and reproduce in its
particular environment.
• In Natural selection, genetic
trait helps some individual s
of species survive and
reproduce more successfully
than others in a particular
environment.
9. Evolution
• Evolution - “ a process of
change”
• It is a genetic make-up of a
subgroup of population of a
particular species.
• It links observations from all
elements of biology and cells
to the biosphere.
• It is simply a long -term
response to the environment
• mean a generation-togeneration change in the
proportion of different
inherited genes in a
population
10. Biology and Society
• Modern biology is changing
human’s lives. New findings
about DNA affect such fields as
medicine and agriculture.
The study of evolution is
helping health professionals
understand how disease-causing
bacteria become resistant to
antibiotic drugs.
• Environmental issues such as
water and air pollution are
changing how people think
about their relationship to the
biosphere.
Unifying Themes in the Study
of Life
1. Biological System
2. The Cellular Basis of Life
Unifying Themes in the Study of Life
1. Biological System
2. Cellular Basis of Life
a. Systems of the body
b. Ecosystem
c. Interaction of organisms
Biological System
A. Systems of the body
- is an organized group of
related parts that interact
to form a whole
EXAMPLE: Organ System
B. Ecosystem
- is a physical environment
with different species that
interact with one another
and with nonliving things.
EXAMPLE:
- organisms in the
ecosystem require a steady
supply of certain chemicals
to live.
Plants obtain most of their
necessary chemicals from
soil, water, and air.
Animals acquire most of the
chemicals they need by
eating plants or other
animals.
C. Interaction of organisms
• Organisms interact with organisms with
the same species and different species.
• Organisms use the environment to get
sunlight and oxygen for cell respiration to
get energy.
• Organisms also interact with the
environment for shelter and protection,
food and water
• Organisms camouflage with the
environment to hide from their predators.
• Plants interact with the environment to get
sunlight necessary for photosynthesis.
• Temperature and climate of the
environment may be appealing and vital for
survival of certain organisms too.
Cellular Basis of Life
The Cellular Basis of Life
•
All living things on Earth are either
unicellular or multi-cellular.
•
Most multi-cellular organisms have cells
that are specialized for different function.
Most multi-cellular organisms have
higher levels of organization.
•
•
Beginning with the cellular level, next is
tissue, wherein similar cells together
perform a specific function.
EXAMPLE:
Nerve tissue consists of many nerve cells
organized into a complex network.
•
Several types of tissue together make up
a structure called ORGAN
EXAMPLE:
The brain is an organ that consists of nerve
tissue and other types of tissues.
• Finally, several organs together
carry out a major body
function make up an Organ
system.
EXAMPLE:
The brain , spinal cord, and
nerves make up the organ
system called Nervous system.
1 Form and function
• AKA “form fits function”
EXAMPLE:
Aero-dynamic shape of a
bird’s wing
- The structure of the
bird’s bones contributes
to its ability to fly.
- Inside the bones, an
open, honeycomb-like
structure provides great
strength with little
weight.
2. Reproduction and Inheritance
• “Life begets life.”
-Organisms reproduce
their own kind
Genes (units of genetic
information) are
responsible for family
inheritance
Genes are made up of
DNA
- Inherited info in the
form of DNA enables
organisms to reproduce
their own kind.
3. Interaction with the Environment
• Each organisms interacts
continuously with its environment.
EXAMPLE:
A plant obtains water and nutrients
from the soil, carbon dioxide gas
from the air, and energy from
sunlight.
• The plants use these three “inputs”
from its environment for
photosynthesis (the process by
which plants make food).
• The plant also has an impact on its
surroundings.
EXAMPLE:
Plants release oxygen as a by-product of
photosynthesis. Other organisms as
well as plants use this oxygen for
their own survival.
4. Energy and Life
• Moving, growing,
reproducing, and other
activities of life
require organisms to
perform work.
• Work depends on a
source of energy.
• Energy is obtained in
chemical form in
sugars, fats, and other
“fuel-like” molecules in
your food.
5. Regulation
• The ability of organisms to regulate
their internal conditions.
• HOMEOSTASIS is a mechanism that
makes organisms regulates their internal
condition despite changes in their
external environment.
•
EXAMPLE:
You have a “thermostat” in your brain that
reacts whenever your body temperature
varies slightly from 37⁰C. If this internal
thermostat detects a slight rise in your
body temperature on a hot day, your
brain signals your skin to produce
sweat. SWEATING helps cool your body.
PANTING - a dog
pants on a hot
day. PANTING
causes moisture
on the large
surface of the
animal’s lungs to
evaporate, cooling
the body as a
result.