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Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Characteristics of Living Things
By the end of this topic you should be able to:
identify the vital functions characteristic of all living things
recognize the cell as the basic unit of any living organism
comprehend the common features of all cells as well as the basic differences between animal and plant cells
analyze the relation between the structure and function of specialized cells
understand that cells, tissues, organs and systems represent increasing degree of organization in living organisms
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
The Seven Vital Functions
Living things include microbes, plants and animals. They live on the land and in the lakes, rivers, and seas.
All very different but all are alive. All can perform some common features These are the Seven Vital Functions.
Only living things have all of these features They are “tests” of being alive.
The Vital Functions are processes that all living organisms do. They tell you whether something is alive or not.
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Movement
Living things move without outside help.
Non-living things move under external forces (e.g. machines, something falling).
Organisms like animals can move their whole body
(E.g. walking, running, etc.)
Organisms like plants can only move parts
of their body (E.g. opening and closing
of flower petals)
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Can you match these types of movement to the pictures?
Flying Swimming
Chasing for food Migration
Venus fly-trap catching insects
Turning flower towards sun
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Sensitivity (Irritability)
Living things respond to conditions around them. Organisms can identify stimuli in their surroundings and respond to them.
Green plants growing
toward sunshine Blinking when light shines
into their eyes Jumping up when stepping on a sharp pointed object
like a pin
Stimulus Organism Response
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Can you match these responses to their stimuli?
The Venus fly-trap
catches insects
Roots grow into soil
Flowers close during the night
A deer runs away from a lioness
Gravitational pull
Insect touches hairs on leaves
Sun sets
Smell of predator
Roots grow down
Insect trapped
Flower closed
Fast running
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Nutrition (Feeding)
All living things try to get food, and they get it in different ways
Bite with teeth (e.g. Humans and other Animals)
Suck up food with specialized suckers
(e.g. flies and other insects)
Absorb it (soak it up) through membranes/skins (e.g. Bacteria and Fungi)
Do you know of any other ways of feeding?
Amoeba engulfing food Swallowing prey whole
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Some organisms can make their own food from water, CO2, nitrogen, and minerals.
Green plants
Photosynthesis is the build-up of food from Carbon dioxide and water using the Sun’s light energy.
6CO2 6H2O C6H12O6 6O2
The Equation for Photosynthesis
Carbon Dioxide
Water Chlorophyll
Light Enzymes
Glucose Oxygen
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Respiration (Energy)
All living organisms need energy.
They get this energy by burning food, using a chemical process known as Respiration
Aerobic respiration uses oxygen to release energy from food.
Anaerobic respiration does not use oxygen to release energy from food.
Respiration is the burning of food (glucose) to produce energy.
C6H12O6 6O2 6CO2 6H2O 2830kJ
The Equation for Aerobic Respiration
Glucose Oxygen Enzymes Carbon Dioxide
Water Energy
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
The oxygen needed for aerobic respiration comes from the environment
Humans get oxygen by
breathing in air Fish get oxygen
from water
Aerobic respiration produces carbon dioxide, which is removed when we breathe out.
This exchange of gases is called gaseous exchange
There are different organs for this:
E.g. lungs in mammals, gills in fish, leaves in plants.
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Growth
Non-living things become larger. E.g. Balloon grows, salt crystals grow in salty water as it evaporates
Living organisms turn some of the food into living material (bones, teeth, wood, etc.).
Living things
grow by
Becoming bigger: e.g. chick hen;
Child Adult Becoming more
complex:
e.g. Caterpillar Butterfly
Changing old parts: e.g. grasshopper sheds “skin” to make new one.
Making new parts: e.g. teeth in children.
Repairing body parts (healing injuries, replacing worn parts):
E.g. Shrubs and trees cover injuries with bark; Crabs grow new legs when old ones are lost; Human beings heal cut skin and broken
bones.
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Excretion
A lot of chemical reactions take place in the body.
Chemicals are broken down to produce energy (respiration).
Chemicals are built up to form new body structures (growth).
These reactions are called Metabolism.
Waste materials are produced
These would cause illness and death if not removed.
Excretion is the process of getting rid of these waste materials.
For e.g. in animals, ammonia, which is very poisonous, is removed by first turning it to a less harmful substance and then passed out of the body as a liquid called urine.
Excretion is the removal (from the body) of waste products resulting from metabolism.
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Two other processes also result in the removal of substances from the body
Can you think of other ways in which we get rid of waste materials?
Egestion the removal of undigested food from the body
Since this food has not taken part in any chemical reaction,
it is not considered as part of excretion.
Secretion the release of useful substances produced by cells or glands
into or out of the body.
E.g. tears are secreted under the eyelid.
Tears are not a harmful substance, and not a waste product.
Sweating (heat and urea)
Exhaling (CO2 and water)
Excess Water (urine)
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Reproduction
All living organisms eventually die.
They avoid becoming extinct by producing copies of themselves.
Offspring have the same characteristics as parents.
Reproduction is the production of new individuals
of the same species (kind of organism)
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Can you mention what different forms these organisms have in their life-cycles?
Frogs have tadpoles Dragonfly larvae spend about 3 years
in an aquatic environment Butterflies have
caterpillars
Asexual reproduction Simple microbes
(bacteria) reproduce by dividing into two sections.
Each section becomes a new living organism.
Some organisms (e.g. insects) have more than
one form in their life-cycle E.g larva and adult.
Sexual reproduction Other organisms (most animals) produce new
individuals by combining characteristics of two
parents.
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Worksheet
Description of Process / Activity Vital Function
Escaping from danger
Making new leaves
Sweating
Having a snack
A plant makes and releases seeds
Oak trees develop from acorns
Laying eggs
MRS
NERG
Movement Sensitivity Reproduction Respiration Nutrition Growth Excretion
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Description of Process / Activity Vital Function
Hearing a whistle
Using up energy in a race
Changing position or posture
Releasing energy from food
Getting rid of excess water as urine
A lion tearing and biting the flesh of a zebra it has caught
The breakdown of food to release energy
The change of a larva (caterpillar) into a butterfly
MRS
NERG
Movement Sensitivity Reproduction Respiration Nutrition Growth Excretion
Biology Lesson Notes
Form 3/SS+NS/ss/12-13 Characteristics of Living Things
Summary
All living things do the following things:
Respire: they break down food to obtain energy. Most organisms need oxygen for this.
Feed: food is needed for energy and for making new cells. Plants make their own food by photosynthesis but animals, fungi and most bacteria must obtain it from other living organisms.
Excrete: respiration and other chemical processes in cells produce waste products which have to be expelled.
Reproduce: all organisms eventually die. Species persist only as result of reproduction. Reproduction may be sexual or asexual.
Grow: the cells of an organism increase in number and size. The cells also become specialized and the organism increases in complexity.
Move: most organisms move, or make movements at some stage in their lives.
Respond to stimuli: living organisms are sensitive to their surroundings and respond to changes in their external and internal environment.
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