Where do you get the energy to ride your bike or walk up the stairs? Where
does a cheetah get the energy to run after a hare? How does a tomato plant get the
energy to make a tomato? All living things need a source of energy to live. They get
this energy from food. However, different living things get their food in different
ways. Some living things are able to make their own food. They are called producers.
Plants are living things that are producers. Plants use sunlight, water, and air to make
food. They use the energy in this food to live and grow. Other living things must find
their own food because they cannot make it. They are called consumers. Consumers
get energy by eating other living things. Some consumers, such as rabbits and cows,
eat only plants. Other consumers, such as lions and snakes, eat only animals. Still
other consumers, such as bears and raccoons, eat both plants and animals. How
Living Things Get Food A tomato plant uses sunlight, water, and air to make food. A
hare eats plants. A cheetah eats other animals. A bear eats both plants and animals.
The food chain of living things
Animals get their energy from food. Herbivores, like deer and hare, feed on
plants. Carnivores, like lions and wolves, eat meat. Omnivores, which include pigs,
bears, and humans, eat both plants and animals. In an ecosystem, all the organisms
that depend on one another in order to eat form a food chain. Plants are at the bottom
of this chain. They get their energy from the sun, which allows them to manufacture
the substances they need for their development. Most animals depend directly or
indirectly on plants. In this way, even carnivores that feed on herbivores depend on
the plants that feed their prey.
A superpredator is a carnivorous animal that is not the prey of any other
The flesh of other animals is the principal food of carnivores. For example,
snakes eat small rodents.
Herbivores are animals that eat plants. Giraffes, which eat the leaves of acacia
trees, are herbivores, as are certain rodents that eat seeds.
Plants use the energy of the sun to manufacture the nutrients they need from
the water, the carbon dioxide present in the air and the mineral elements in the soil.
Trees, flowers, cereal grains, mosses and seaweeds are examples of plants.
Decomposers feed on carcasses, excrement and plant remains. Bacteria,
microscopic fungi and certain small animals, such as earthworms, are decomposers.
In decomposing organic matter, they release mineral elements that are then used by
plants to help them develop.
Special relationships, for better or worse
Some organisms benefit from other species, without necessarily eating them.
These special relationships have different names, depending on the type of
association. Symbiosis is the association of two organisms of different species that
mutually benefit from living together and cannot survive without each other. For
example, coral is associated with algae, called zooxanthellae. It is a relationship that
is vital to both.Mutualism is a relationship of mutual aid between two organisms of
different species. In this way, the sea anemone and the clownfish protect each other,
but their association is not vital. Commensalism is an association where one species
benefits from another, without harming it or being beneficial to it. For example, the
remora is a fish that attaches itself to another organism, such as a shark, and travels
with it without disturbing it. Finally, parasitism is a harmful association, where one
species lives off another, using that species’ resources for its own benefit. Certain
flatworms, called tapeworms, parasitize the intestine of mammals.
Examples of algae
Formed from the association of an alga and a fungus, lichens live in symbiosis.
supplies them with water and mineral elements.
Examples of lichens
The dodder, a parasitic plant, has no leaves and is incapable of photosynthesis.
wound around the stalk of another plant, out of which it pumps organic matter using
The remora, a fish of the tropical seas, attaches itself to the belly of a shark
benefiting from the protection of the shark and collecting its food scraps without
harming it. This is called commensalism.
Transport in living things.(transport system in human)
In this chapter you will learn:
1. Importance of water to life
2. Processes involved in transport of material across the cell, diffusion, active
transport and osmosis.
3. Turgor and its importance in plants.
4. Transport of water and salts in plants.
5. Transpiration and factors affecting it.
6. Path of organic material in plants.
7. Open and closed circulatory system of animals and circulatory system of
an organism is called transport
Transport in unicellular organisms:
In simple and unicellular living organisms there is no need of any special
transport system.The oxygen and dissolved substances from the outside enviroment
can diffuse into the protoplasm directly.
In all living organisms’ plants and animals, physiological processes are
be kept going on for which the materials required, must be constantly transported to
and from all parts of the body right down to the individual cells. Materials are also to
be transported between the cell organism and external environment. In unicellular
and simple multicultural organisms, the distribution of materials can be adequately
brought about by diffusion and streaming movements of the cytoplasm (fig. 12.1).
Fig. 12.1 Streaming movement of cytoplasm (in Amoeba)
However, the evolution of more and more complex body structures recessitated
the development of proper transport system, and more complex the organisms are, the
more elaborate transport system they have. The complexity of transport system is
related to the size and the metabolic rate of the living organism.
The materials to be transported are taken close to tissues be the transport
system so that diffusion can occur efficiently into the cells. The primary function of
the transport system is to maintain a link between all cells of the body and the
external environment. It transports the nutrients to the points where they are to be
used, facilitates the elimination of metabolic wastes of each cell and transports
surplus substances to the specialized storage tissues or to out side their bodies.
Respiration In Living Organism
Respiration is the process in which food is broken down into smaller particles
along with the liberation of energy. The energy released is utilized for various
metabolic activities. In this process oxygen is inhaled inside by a living organism
when they breathe in and carbon dioxide is exhaled out.
Respiration process in humans:
In human beings, oxygen is inhaled inside the human body through nose or
mouth. Oxygen is transferred to the entire body and enters the cell. Inside the cell
food particles are broken down into smaller pieces in the presence of oxygen. During
the breakdown of food particles, energy is released in the form of ATP. This energy
released is utilized in certain metabolic activities.
C6H12O6 + 6O2 –> 6CO2 + 6H2O + ATP
Respiration process can be of two types:
It consists of two phase:
Inhalation: Air enters the body of a living organism in this process.
Exhalation: In this process, air is released outside the body of a living
Breathing rate: It can be defined as the number of times a person can breathe in
The above figure shows the respiration process. In this process, oxygen-rich air
pharynx and larynx where primary filtration of air takes place. From trachea, air is
transferred to the bronchioles in the lungs. Bronchioles are the passageways to the
Respiration in animals:
In this article we studied the respiration process and how the flow of air takes
different living organisms.
Isolation Of Living Organisms
To identify the bacterial unknowns in a mixed culture by morphological and
The identification of bacteria is a careful and systematic process that uses many
different techniques to narrow down the types of bacteria that are present in an
unknown bacterial culture. It produces benefits for many aspects of the research of
microorganisms and helps physicians correctly treat patients. Multiple tests were
performed to provide the fermentation abilities, presence of certain enzymes, and
certain biochemical reactions. Qualitative observations were made on the tests, which
were compared to unknown bacteria identification key to aid with the identification
Various steps involved in the identification of unknown bacteria are:
Isolation: The importance of this step is to isolate pure colonies of bacteria.
The streak plate is a qualitative isolation method; quadrant streaking is mostly done
to obtain pure colonies. The inoculation of the culture is made on the agar surface by
back and forth streaking with the inoculation loop over the solid agar surface. This
will make a dilution gradient across the agar plate. Upon incubation, individual
colonies will arise from the biomass.
The characteristics features of the colonies on solid agar media are then noted.
Shape : circular, irregular or rhizoid.
Size: small, medium, large( or in millimetres).
Elevation: elevated, convex, concave, umbonate/umbilicate.
Surface: Smooth, wavy, rough, granular, papillate or glistening.
Edges: entire, undulate, crenated, fimbriate or curled.
Colour: Yelow, green etc.( Note the colour of the colony).
Structure: opaque, translucent or transparent.
Degree of growth : scanty, moderate or profuse.
Nature: discrete or confluent, filiform, spreading or rhizoid.
In order to obtain the pure culture of organism, the isolated colonies are
aseptically transferred on to different nutrient agar slant tubes and incubated
overnight at 37 degree Celsius. It is then stored for future purpose.
Staining is a simple basic technique that is used to identify microorganisms.
Simple staining is used to study the morphology of all microorganisms (Fig 1). The
simple stain uses the basic dyes such as Methylene blue or basic fuschin. The strong
negative charge of the bacterial cell will strongly bind with the positive charged basic
dyes and will impart its colour to all bacteria.
Fig 1: Simple staining of cocci
to different bacteria or bacterial structures. Usually it differentiates bacteria into two
groups; gram positive and gram negative. The primary stain Crystal violet and
mordent Iodine form a strong CVI complex all bacteria. Gram positive cells due to
their thick peptidoglycan layer will retain the CVI complex even after it is subjected
to decolourization with acetone or alcohol. Hence the counter stain Safranin has no
action on gram positive cells. But in the case of gram negative, the thin peptidoglycan
layer and more lipid contents in the cell wall will easily make them susceptible to the
action of decolorizer and hence CVI complex is easily washed out and hence the
gram negative cells will the colour of counter stain Safranin. Hence after the gram
staining, the gram positive cells appear as purple and gram negative cells appear as
pink (Fig 2). The study of morphological features and staining characteristics help in
the preliminary identification of the isolate.
Gram negative enteric bacilli play an important role in the contamination of
food. Hence they are the main causative agents of intestinal infection. Gram negative
family includes Shigella, Salmonella, Proteus, Klebsiella,Escherichia,Enterobacter
etc. Usually four tests are used for differentiation of the various members of
Enterobactericeae. They are Indole test,Methyl red test, Voges proskauer test and
Citrate test; collectively known as IMViC series of reactions.
Movement In Living Things
Movement is one of the characteristics of all living beings.
Animals move in search of food, shelter, water, and many other purposes.
Learn about the different types of movement in animals such as:
Also learn about the skeletal system in animals, which helps in support and
movement of animals.
All living organisms show movement in different ways. Though plants are
Learn about the movement in plants:
Coordination And Regulation In Living Organisms
All the living organisms (plants and animals) respond and react to changes in
the environment around them. The changes in the environment to which the
organisms respond and react are called stimuli (singular of stimuli is stimulus). The
living organisms show response to stimuli such as light, heat, cold, sound, smell,
taste, touch, pressure, pain, water, and force of gravity, etc.
The response of organisms to a stimulus is usually in the form of some
movement of their body part. For example, if a man touches a very hot utensil
accidentally, he quickly pulls his hand away from the hot utensil. Here, heat is the
stimulus and the man reacts by moving his hand away from the hot utensil. Similarly,
when the sun is bright, we close our eyes. In this case, light is the stimulus and we
reacting by closing the eyes.
Both, plants and animals react (or respond) to various stimuli around them. But
the method of reacting to stimuli is not similar in plants and animals. They react to
stimuli in different ways. For example, plants bend towards light but animals do not
bend towards light. The animal Amoeba reacts to the presence of food by moving
towards the food particle.
Similarly, Amoebae tend to aggregate (collect together) in moderately warm
water which is their reaction to the stimulus called heat. Amoeba and other protozoal
react to the mechanical obstacles by avoiding them. We find that the Amoeba (which
is an animal) can react to different stimuli in different ways.
The animals can react to stimuli in many different ways because they have a
nervous system and an endocrine system involving hormones. The plants, however,
react to stimuli in a very limited way. This is because the plants do not have a
nervous system like the animals have. The plants use only the hormones for
producing reaction to external stimuli.
From all the above examples we conclude that when a stimulus acts on our
body, then we react (or 1 respond) in a manner which is in the best interest of our
body. The reaction (or response) which we give to the stimulus involves many organs
of our body.
It is, therefore, necessary that all the concerned organs should work with one
another in a systematic manner so as to produce the required reaction. In other words,
the various organs should co-operate with one another to provide proper reaction to
The working together of the various organs of an organism in a systematic
manner so as to produce a proper response to the stimulus is called coordination. We
will now discuss the control and coordination in plants, animals and human beings,
one by one. Let us start with control and coordination in plants.
Control and Coordination in Plants:
The plants do not have a nervous system and sense organs like eyes, ears, or
nose, etc., like the animals, but they can still sense things. The plants can sense the
presence of stimuli like light, gravity, chemicals, water, and touch, etc., and respond
to them. The plants can sense things like light, gravity, chemicals, water, and touch,
etc., by the action of hormones in them.
The stimuli like light, gravity, chemicals, water, and touch, etc., are called
environmental changes. So, we can also say that the plants coordinate their behaviour
against environmental changes by using hormones. The hormones in plants do not act
the same way as in animals.
The hormones in plants coordinate their behaviour by affecting the growth of a
plant. And the effect on growth of the plant can result in the movement of a part of
the plant like shoot (stem) or root, etc.
Animals use both nervous system and hormones for coordination of their
activities. Plants have no nervous system, so plants use only hormones for
coordination. Thus, the reaction (or response) of plants to different stimuli like light,
gravity, chemical substances, water, and touch etc., is due to the effect of hormones.
Control And Coordination In Living Organisms – Ii : Brief And Long Answers
The movement of curvature of plants in the direction of stimuli is known as tropism.
Phototropism : When illuminated by a unidirectional light, the response of
agrowing plant by bending towards that light is called phototropism.
and absorption, as a response to the gravitational force is called geotropism.
Chemotropism : The movement of a plant or its part as a response to certain
chemicals is called chemotropism. For example, germination of pollen grains and
development of pollen tubes as a response to the chemicals secreted by the surface of
The response by some plants to the external stimuli without any directional
movement of growth or curvature towards that external stimuli is called nastic
The leaves of Mimosa (touch-me-not) are sensitive to touch. They droop when
All insectivorous plants bend down or curl up when touched by insects.
A sunflower plant bends towards the sun.
Of the above examples, (i) and (ii) are examples of thigmonastic response and
(iii) is an example of photonastic response.
Distinguish between tropic movement and nastic movement.
flowering and germination in plants.
Plants are (i) Long-day plant and (ii) Short-day plant on the basis of the
duration of light received by them.
Day natural plants do not respond to photoperiodism.
Plants respond to photoperiodic stimulus by a 531omplimenta pigment present
in them called phytochrome.
Coordination in animals.
All multicellular organisms, except porifera, have well-developed nervous
Hydra and other cnidarians possess nerve cells which form a nerve net in the
In invertebrates, the nerve net condenses into nerve mass called ‘ganglion’.
Higher organisms possess sensory organs (receptors) related to light, hearing, taste,
touch and smell.
Receptors receive the stimulus and pass on the message to the brain through
The brain transmits information to the effector organ (generally muscles and
glands) through motor neuron.
The brain acts as the center for the analysis of information.
Motor neurons stimulate the muscles of the organ to respond.
Hormones also play an important role in control and coordination in animals.
In vertebrates there is a successive development of nervous system.
The nervous system of human beings is highly developed.
Hormones secreted by endocrine glands control various biochemical and
mechanical activities carried out in the organisms. This is chemical control.
Write an explanatory note on human brain.
Human brain is the main coordinating center for all the activities of the human
It is protected by a bony box in the skull called cranium and three membranes
There is a fluid called cerebrospinal fluid in the space between these
Cerebrospinal fluid acts as a cushion and protects the brain from mechanical
The brain is divided into three regions : (i) fore-brain (ii) mid-brain and (iii)
Fore-Brain consists of cerebrum and olfactory lobes.
Cerebrum is the most complex and 533omplimenta part of the brain.
It consists of two cerebral hemispheres.
It has sensory area to receive impulse from the sense organs and motor area to
send impulse to muscles and effector organs.
Cerebrum has four regions having different centers of activity : (i) frontal lobe
(ii) parietal lobe (iii) temporal lobe (iv) occipital lobe.
The frontal lobe possesses centres for voluntary muscular activities.
Temporal lobe possesses the centres for auditory and olfactory reception.
Occipital lobe possesses the centres for visual reception.
Mid-Brain is a part of the brain stem and possesses the regions for visual
reception, auditory reception and touch.
Hind-Brain consists of cerebellum, pons and medulla oblongata.
Cerebellum is situated on the posterior side of the fore-brain and it controls the
rhythmic movement of muscles, body balance and posture.
Pons connects various parts of the central nervous system and cerebellum by
the transverse bands of nerves.
Pons takes part in the regulation of respiration and helps in the movement of
head as per audio-visual perception in coordination with medulla oblongata and
Medulla oblongata possesses the centres to regulate heartbeats, breathing,
blood-pressure, sneezing, coughing, vomiting, swallowing, hiccups, etc.
Spinal cord is a cylindrical structure.
It is the posterior extension of of medulla oblongata.
The vertebral column and meninges protect the spinal cord.
There are 31 pairs of spinal nerves arising from the spinal cord.
These nerves connect various organs of the body to the brain.
They help in the conduction of impulses from brain to organs and from organs
They also perform reflex action.
An unconscious and involuntary response of effectors to the stimulus is called
Due to reflex action we suddenly withdraw our leg when we step on a very hot
or pricking object.
Similarly, our response towards very hot or very cold water is sudden and
The reflex action is performed by the spinal cord when the brain is busy or at
In reflex action, a message from the receptors is relayed by sensory nerves to
Autonomous nervous system.
organs located in the body cavity without the awareness of brain is called
This system controls heart, blood vessels, glands, uterus and coelomic organs.
Autonomous nervous system is of two types: (i) sympathetic (ii)
The involuntary actions of the body are controlled and regulated by the
coordination of these two systems.
The effects of sympathetic and parasympathetic nervous systems are
complimentory and contradictory.
For example: If the sympathetic system increases the heartbeats abnormally,
the parasympathetic system decreases it and brings it back to normal.
Characteristics of hormones.
They are specific chemical messengers.
Generally the origin and the target area of hormones are different.
They are directly poured into the blood (from the gland) and carried by blood
The effect of a hormone is either rapid or slow (i.e. it may increase or decrease
the speed of some process). For example, acetylcholine increases the speed of the
conduction of impulses whereas decreases (slows down) the effect of sex hormones.
Endocrine glands. Endocrine glands play an important role in coordination (in
These are ductless glands and secrete hormones which are specific chemical
The main endocrine glands are hypothalamus, pituitary,, pineal, thyroid,
parathyroid, pancreas, adrenal, testis and ovary.
Pituitary gland is called the master gland as it regulates the secretion of
hormones by other endocrine glands.
The function of the pituitary gland is controlled by the secretion of
How is brain protected ? The brain is surrounded by cranium, a bony box in the
skull and three membranes called meninges. In the space between these membranes
there is a fluid called cerebrospinal fluid. This fluid protects the brain against
mechanical shocks. Thus brain is protected.