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SARAWAK CAMPUS
SARAWAK CAMPUS
HES1610 Concepts of Biology
The unifying themes of biology:What defines living organisms?
Swinburne University of Technology
BIOLOGY
What is biology?
• Biology is the study of living things
Biology is a huge subject, encompassing many different fields
of science, examples of these are:
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• Microbiology / Immunology
• Molecular biology
• Ecology
• Genetics
• Evolution
• Physiology
• Pathology
• Zoology
• Botany
• Biochemistry
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CHARACTERISTICS THAT DEFINE
“LIFE”
Certain characteristics are common to all living organisms
(there are always exceptions in biology)
All of these are exhibited by all living organisms:
1. Growth and development
2. Organization
3. Homeostasis: regulation of metabolism and energy
production
4. Adaptation and evolution
5. Response to stimulus
6. Reproduction
7. Movement
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1. GROWTH AND DEVELOPMENT
All organisms exhibit “growth” during their
lifetime, they increase in:
Size
Structure
Functional complexity
This can involve:
Increase in cell size
Increase in cell number
Both
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1. GROWTH AND DEVELOPMENT
Some organisms:
Grow only over a specific period, after which only
“repair” occurs, not active growth. e.g. most
animals.
Others grow throughout their life. e.g. trees.
Most organisms also exhibit “development”
simultaneous with growth: a change in form
and function, e.g., from fertilized egg to
embryo to young to adult forms.
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2. ORGANISATION
Living things are organised in such a way that all
interactions and activities function
However, if the complex organisation of these
system changes the interactions no longer occur
e.g. The human brain: If a car accident shakes the human brain
up and disrupts the organisation it no longer functions normally
despite the fact that all of the original parts are present
e.g. If you take all of the components from a chloroplast and mix
them together in a test tube, photosynthesis will not occur
In both cases, there needs to be specific
organisation of the components in order for the
appropriate interactions to take place
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2. ORGANISATION
The organisation of these components is a
SYSTEM
In most cases these interaction initially take
place at a cellular level
Cells are organised into structures and structure
correlates to function
• Often analysing a biological structure can give insight into
how it works and what it does
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2. ORGANISATION
The “cell theory”: Based on the work of Schwann and
Schleiden (1838-39):
• All organisms are composed of cells
• All cells come from pre-existing cells
• Cell is the smallest organizational unit of life
Some organisms are composed of single cells
Others are composed of many of cells
Cells divide and produce other cells:
• No cells are created spontaneously from non-living matter.
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2.1 BASIC PROPERTIES OF CELLS
All cells are enclosed by an outer membrane:
Plasma membrane; this separates the inner fluid
(cytoplasm) from the cell’s environment.
All cells have the genetic material: DNA
All cells are capable of self-reproduction
All cells have specific internal structures that
carry out specific reactions and functions
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2.1 BASIC PROPERTIES OF CELLS
There are two basic types of cells:
PROKARYOTIC: those without
membrane bound nucleus and
organelles
e.g. Bacteria (simple cells)
EUKARYOTIC: those with membrane
bound organelles
e.g. Plants, animals, protists, fungi (complex cells)
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2.2 A PROKARYOTIC CELL:
A BACTERIUM
Prokaryotes contain the essentials of cells: DNA, ribosomes, plasma
membrane
It may have: cilia, flagella, cell wall, capsule
They do not contain: a nucleus, chloroplast, mitochondria,
endoplasmic reticulum, Golgi apparatus
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2.3 A EUKARYOTIC CELL:
A PLANT CELL
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2.4 A EUKARYOTIC CELL:
AN ANIMAL CELL
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2.5 SINGLE CELL ORGANISMS
The first living organisms we know of on Earth were single
celled organisms:
They formed Stromatolites, where certain prokaryotes bind thin films of
sediment together
There are still some Stromatolites living of the coast of W.A (Shark Bay)
and in Deer Cave, Gunung Mulu N.P
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2.5 SINGLE CELL ORGANISMS
Many organisms exist as a single cell:
Bacteria
Algae
Some fungi
Plankton
Amoeba
They are simple organisms, but can exists within complex
structures and have complex functions
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2.6 FURTHER ORGANIZATION IN
MULTICELLULAR ORGANISMS
Organisms can also exists as complexes of many cells,
i.e. multicellular organisms
For example:
• Us
• Plants
• Monkeys
• Fish
• Etc..etc..
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2.6. FURTHER ORGANIZATION IN
MULTICELLULAR ORGANISMS
Cells with similar functions and structures are organized
into a TISSUE
• e.g. Muscle, epidermis.
Various tissues, each with different structure/ functions:
organized together form an ORGAN which has a specific
function
• e.g. Epithelial tissue, muscle tissues together form the
heart,
• e.g. Epidermal cells, mesophyll cells and vascular
tissue form the leaf
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2.6 FURTHER ORGANIZATION IN
MULTICELLULAR ORGANISMS
In many animals, many organs + tissues together form a
coordinated SYSTEM, with a major function
• e.g. Cardiovascular, digestive systems
Many systems interact to form an ORGANISM: e.g.
• Humans: cardiovascular, respiratory, nervous,
digestive reproductive, immune systems
• Plants: circulatory, reproductive
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2.7 ANIMAL TISSUES AND
SYSTEMS
Epithelial tissue: makes up
human skin and lining of other
body organs
Circulatory system: circulates
blood around the body
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2.8 PLANT TISSUES AND SYSTEMS
Chloroplast Leaf cells
Mesophyll tissue
Leaf: organ
Tree: an
organism
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2.9 FURTHER HEIRCHY IN THE
BIOLOGICAL WORLD
All organisms that can reproduce between themselves, but are
reproductively isolated from others, form a SPECIES
All organisms of a certain species, living within a certain
geographic area, form a POPULATION
The various populations within a certain geographic area
together form a COMMUNITY
The communities, (living organism) and their non-living
environment (water, temperature, light, food, minerals),
together form an ECOSYSTEM
The components of an ecosystem are interdependent for energy
exchanges: form food chains / food webs
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Species in your household:
• Yourself and your family members, dogs, lawn grass, ferns, the
caterpillar on the plants, the snails in the garden, trees
Populations on your street:
• Humans (200); dogs (5); grass plants (5 million) etc.
Your street community:
• The human population + the cat population + the dogs + the grass
plants + the ferns of the one type + the caterpillars + the snails
Your street ecosystem:
• The community + the cars + soil + air + fallen leaves + dog poo +
caterpillars + snails
2.9 FURTHER HEIRCHY IN THE
BIOLOGICAL WORLD
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2.10 A GRASSLANDS/SAVANNA
ECOSYSTEM
Grasslands with scattered trees, herbivores and carnivores +
abiotic (environmental) factors: fire, wind, rain
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2.11 A RAINFOREST ECOSYSTEM
Tall trees + climbing vines + shorter plants + animals living on the
fruits and leaves of these + the abiotic (environmental) factors:
rainfall, sunlight, organic matter
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2.12 AQUATIC ECOSYSTEM
Marine, freshwater (river, lakes), aquarium, mangrove, etc…
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3. HOMEOSTASIS
All organisms carry out a number of chemical reactions, to
obtain the energy required for nutrition, growth and
development, and repair.
Reactions that break up larger molecules into smaller ones and
release their stored energy: CATABOLISM
• e.g. Glucose CO2 + H2O ( + energy)
Reactions that synthesize large molecules from smaller ones
and store energy into these: ANABOLISM
• e.g. Glucose molecules (+ energy) starch or glycogen
Sum of anabolic and catabolic reactions: METABOLISM.
WE WILL STUDY SOME KEY METABOLIC REACTIONS LATER
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3.1 HOMEOSTASIS:
REGULATION OF METABOLISM
All metabolic reactions must be regulated tightly, to
maintain a constant internal environment in cells
WHY IS HOMEOSTASIS ESSENTIAL?
So the cells can obtain the required nutrients, carry out
various biochemical reactions at appropriate rates, not get
overheated and not build up any waste products
HOW IS SUCH REGULATION ACHIEVED?
Through the action of ENZYMES:
Through self-regulation of some reactions by FEEDBACK
MECHANISMS:
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3.2 ENZYMES
Specialized proteins
Biological catalysts: regulate the rates of
biochemical reactions
Carry out specific reactions, efficiently, in specific
cells, under certain conditions, generally in a step-
wise manner, each step being regulated
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We will visit these later.
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3.3 FEEDBACK REGULATION
The product of the reaction itself regulates the rate of its
own synthesis, by various mechanisms.
Negative feedback: Most common
The product inhibits (some part of) the reaction
(or the reaction chain)
i.e. When this product exceeds a certain
threshold the reaction shuts down
e.g. When you are hot, your hypothalamus tells
your glands to produce sweat to cool down, once
your body reaches the correct temperature you
stop sweating
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3.3 FEEDBACK REGULATION
Positive feedback: Less common
The product activates (some part of) the reaction
(or the reaction chain)
i.e. This leads to more production of itself
e.g. When you have a cut and start bleeding,
your platelet will accumulate at the site of the tear
and a clot will form, thus stopping the bleeding
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3.3 FEEDBACK REGULATION
MECHANISMS
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3.3 EXAMPLES OF HOMEOSTASIS
Regulation of blood glucose: Glucose obtained through food,
then delivered by blood to all cells.
• Too much glucose circulating, it gets stored in liver
• Too little glucose circulating the stored materials converted/broken
down to glucose, or sugar replenished by eating
Regulation of body temperature. Control centre:
hypothalamus in the brain.
• Increase in body temp: blood vessels dilated, sweating increased:
sweat evaporates, skin cooled.
• Drop in temp: sweat glands shut, blood vessels narrowed. Blood
sent to deeper parts of body: reduced heat loss.
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3.3 HOMEOSTASIS
The amount of blood
circulated to the ears is
adjusted according to the
external temp and thus
the heat loss from the
animal.
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4. ADAPTATION AND EVOLUTION
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4. ADAPTATION AND EVOLUTION
Adaptation: Inherited traits that help survival and
reproduction of an organism in a particular
environment
Evolution: Change in the genetic composition
of a population over generations
Passing on the traits and mutations that were utilized
for adaptation, as well as mutations that occurred
randomly and survived
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4. ADAPTATION AND EVOLUTION
In nature, every advantage increases an animal's chances
of survival, and therefore its chances of reproducing
This simple fact has caused animal species to evolve a
number of special adaptations that help them survive in
their particular environments
Many adaptations revolve around food, as this is essential
for survival:
• Finding food
• Eating food
• Preventing them from becoming food - camouflage
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4. ADAPTATION AND EVOLUTION
Adaptations can be:
Physical, physiological, behavioural,
For feeding, or withstanding adverse conditions, or
self-protection etc
e.g. Fur of polar bears, streamlined bodies of fish/birds,
light bones of birds, legs of kangaroos, camouflage of
some animals, changes in human anatomy
The ability of a population to adapt and
evolve is essential for its survival over
generations
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Wings create airfoils:
• Changes in air current that produce lift
4. ADAPTATION AND EVOLUTION
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The upright human
body: supported by
backbone + rib
cage+ skull
The joints allow
flexibility and precise
manipulations
ADAPTATION AND
EVOLUTION
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Why humans walk on 2 legs?
ADAPTATION AND EVOLUTION
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http://ngm.nationalgeographic.com/2006/07/bipedal-body/video-interactive
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Over 6 million years: brain size increased, jaws shortened and flattened,
skeletal modifications, changes in food, upright walking, development of
language, learning, social systems
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ADAPTATION AND EVOLUTION
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ADAPTATION AND EVOLUTION
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EVOLUTION OF THE GALAPAGOS FINCHES
ACCORDING TO FOOD SOURCE
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CAMOUFLAGE
A gecko/lizard resembles dry
leaves
Batesian mimicry: When in danger, the larva of hawkmoth (an insect) resembles a snake!46
A praying mantis
A green vine
snake
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CAN YOU RECOGNIZE THIS??
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5. RESPONSE TO STIMULUS AND
ENVIRONMENT
All organisms respond to stimuli
Stimulus: physical or chemical change, in the internal or external
environment of an individual. e.g. Changes in intensity or direction of light
Sound
Smell
Pressure
Gravity
Touch
Changes in amount/ composition of soil, water, air
The nature of response may vary
• e.g. Simple cells may move towards / away from light, plant shoots
grow towards light, roots grow towards gravity, some plants (touch-me-
not, Venus flytrap) respond to touch, animals respond to sounds, smell.
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5.1 PHOTOTROPISM:
RESPONSE TO LIGHT
Shoots grow towards light, roots grow away from it
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5.2 GRAVITROPISM:
RESPONSE TO GRAVITY
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Roots grow towards gravity,
shoots grow away from it
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5.3 THIGMOTROPISM:
RESPONSE TO TOUCH
Touch-me-not:
Touching causes rapid
loss or water from the
base of leaves: they
close (loss of K+,
followed by loss of
water).
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5.4 PHOTOPERIODISM
Response to season
A physiological response to the relative
lengths of night and day
Some plants flower during summer, others
during spring or autumn, some trees shed
there leaves in autumn so they have no
leaves in winter
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5.5 ANIMALS RESPOND TO
STIMULI TOO
What do bears do in winter? Why?
What happens to our pupils (eye) when the
light is bright?
What do dogs do when they get hot?
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6. REPRODUCTION AND HEREDITY
The ability of a species to reproduce, i.e., to produce offspring
like itself, is key to its survival
Genetic information in cells is contained in the form of DNA,
which has the ability to make identical copies of itself
DNA is thus passed on from parent cells to daughter cells, and
from parents to offspring
DNA stores the genetic information in the form of instructions on
how to make proteins, proteins carry out various biochemical
reactions in the body and are also structural components of cells.
MORE LATER: IN GENETICS
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DOES THIS MEAN THE GENETIC
MATERIAL IS STATIC?
Genetic variability between individuals is created
by different mechanisms:
Collectively called MUTATIONS
Mutations lead to a change in the sequence of
DNA, this causes changes in the instructions for
making proteins and thus cell’s functions
The changes are inherited by the next
generations of cells and thus organisms
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7. MOVEMENT
All living organisms move, or are
capable of movement.
Movement by:
Flagella, cilia, pseudopodia, legs, wings,
fins, etc.
Movement may or may not be obvious.
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7. MOVEMENT
Sometimes movement is restricted to early
developmental stages
• e.g. Larvae, adults are fixed to a support (e.g. corals,
sponges), but still may have cilia/ flagella that beat in the
water and gather food
Plants do not appear to move, however,
• Their leaves move towards light
• Some plants also turn their flowers towards the sun;
• Others show obvious movement in response to certain
stimuli (e.g. certain insectivorous plants).
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MOVEMENT: VENUS FLY-TRAP
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IN SUMMARY
The living world, no matter how diverse, still
has some unifying characteristics which are
shared by all:
GOHARRM
Growth, organisation, homeostasis, adaptation,
response to stimulus, reproduction, movement
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IN SUMMARY
Now apply this information to the following
situations to work out if these are living
organisms or not
Are viruses living or nonliving?
Are seeds living or non-living?
Are salt or sugar crystals growing in a saturated solution
living or nonliving?
Are we living?
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