1.CHARACTERISTICS & CLASSIFICATION OF LIVING ORGANISMS
Outline
1
1.1
CHARACTERISTICS
OF LIVING
ORGANISMS
2
1.2 CONCEPT
AND USE OF A
CLASSIFICATION
SYSTEM
3
1.3 FEATURES OF
ORGANISMS
4
1.4
DICHOTOMOUS
KEYS
Getting started
1.The list below contains some features of living organisms .With your partner ,discuss which of
these features are found in all living organisms
Breathing Excretion A blood system A nervous
system
Sensitivity Growth Reproduction Movement
Nutrition
Inspiration
Click to add text
2.When you have made your decisions ,write a very short description of each of the features you
have chosen .
Be ready to share your ideas
1.1 characteristics of living organisms (MRS GREN)
Movement: an action by an
organism causing a change
of position or place
Respiration: the chemical
reactions that break down
nutrient molecules in living
cells to release energy
Sensitivity: the ability to
detect and respond to
changes in the environment
Growth: a permanent
increase in size
Reproduction: the
processes that make more
of the same kind of
organism
Excretion: the removal
from organisms of toxic
materials and substances in
excess of requirements
Nutrition: the taking in of
materials for energy, growth
and development
1.2 The biological classification system
 Classification: The scientific method of dividing organisms into smaller and larger groups, on basis of their
similarities.
 Swedish botanist Carolus Linnaeus is the Father of Systematic Biology. He believed he could:
 Put every organism into a group (the science of TAXONOMY)
 Carolus Linnaeus organized taxonomy (1735).
 Give every organism a name (the science of NOMENCLATURE
 In his BINOMIAL SYSTEM, every living organism has a unique, two-part name:
 The first name is Genus, the second name is species.
 Names are written in Latin, printed in italics.
 The genus always has a capital letter, and the species always has a small letter.
 Homo sapiens
How Organisms are Classified
 There are millions of species of organisms on Earth
 Organisms share features because they originally descend from a common ancestor
• A species is defined as a group of organisms that can reproduce to produce fertile
offspring
 Originally, organisms were classified using morphology (the overall form and shape of the organism, e.g. whether
it had wings or legs) and anatomy (the detailed body structure as determined by dissection)
 DNA sequencing allowed us to classify organisms using a more scientific approach
 Cladistics is another way to classify organisms. It can use data from DNA or RNA sequences, rather than just
physical characteristics. It emphasises the evolutionary relationships between different species.
The Binomial System
• He named organisms in Latin using the binomial system where the scientific name of an
organism is made up of two parts starting with the genus (always given a capital letter) and
followed by the species (starting with a lower case letter)
• When typed binomial names are always in italics (which indicates they are Latin) e.g. Homo
sapiens.The sequence of classification is:
As an example, the complete breakdown of the classification
of lions:
kingdom - Animalia
phylum - Chordata
class - Mammalia
order - Carnivora
family -Felidae
genus - Panthera
species - leo
Workbook questions 1,2 and 3 of pages 3^4 answers
• Practice 2
• Figure 1.1 shows a plant, growing towards the light. Inside its leaves, photosynthesis is taking place.
Photosynthesis uses carbon dioxide to make glucose, and releases oxygen. Add labels to Figure 1.1. Your labels
should include short descriptions stating how the plant is showing these characteristics of living things:
• reproduction
Excretion – the plant makes oxygen as a waste
• growth
Growth – the plant makes new cells so
product of phosynthesis, and loses it from its
• sensitivity it increases in size
leaves.
• excretion
Reproduction – gametes are made in the flower, which
fuse together to produce a zygote; this is sexual
reproduction. more of the same species.)
Sensitivity – the plant senses the direction
from which light comes, and the stem and
leaves grow towards it
 Challenge
 3 Imagine that someone from another planet is visiting Earth. They see aeroplanes and birds moving through the
sky.
 Explain to the visitor why birds are alive and aeroplanes are not alive, even though they seem to share some of the
characteristics of living things
 Birds are living things because they are able to carry out all seven characteristics: they can move of their own
accord; they can reproduce; they respire; they are sensitive to changes in their environment; they grow; they
excrete; they take in nutrients.
 Aeroplanes are able to move, and they also take in ‘nutrients’, in the form of fuel. They combine oxygen with fuel
to provide energy for their movement, which is similar to respiration, and this reaction produces waste products
removed in the exhaust, which is similar to excretion. They have sensors that can detect and respond to changes in
their environment – for example, they may have lights that come on automatically when light intensity in their
surroundings falls below a particular level. However, aeroplanes do not grow, and they are not able to reproduce.
Because aeroplanes are not able to carry out all seven characteristics, they are not alive.
Homework
Course book question 1&2 page 7
Submission date 24.07.2023
Course book page 7 questions 1 &2 answers
1. Yaks have the scientific name Bos grunniens. Explain what this tells
us about the groups into which yaks are classified.
Yaks belong to the genus Bos and the species Bos grunniens.
2. A yakolo is the offspring of a yak and a buffalo. Yakolos are unable
to reproduce. Explain how this suggests that yaks and buffalo belong to
different species
To belong to the same species, organisms should be able to reproduce to
produce fertile offspring, but yakolos are infertile.
Dichotomous (dɪˈkɒtəməs)Keys
 Constructing & Using a Key
Keys are used to identify organisms based on a series of questions about
their features
Dichotomous means ‘branching into two’ and it leads the user through to
the name of the organism by giving two descriptions at a time and asking
them to choose
Each choice leads the user onto another two descriptions
In order to successfully navigate a key, you need to pick a single organism
to start withand follow the statements from the beginning until you find
the name
You then pick another organism and start at the beginning of the key
again,repeating until all organisms are named
Example
Parts –B-Worksheet-shows five species of mollusk
Homework
Please complete all
questions of workbook
pages 5,6,7 & 8 and
questions 3 &4 of
course book page 11
E
A
B
D
C
The biggest groups are called kingdoms. The five kingdoms are:
1.4 Kingdoms
Animal
Plant
Fungi
single-celled organisms (Protoctists)
Bacteria
The Animal kingdom
 The Animal kingdom can be further split into:
Vertebrates - animals with a backbone. These include
amphibians, mammals, reptiles, bony fish and birds.
A frog, a squirrel, a snake, clownfish.
Invertebrates - animals without a backbone. These
include molluscs, annelids, arthropods and nematodes.
 Clams, earthworm, a tarantula, Caenorhabditis
elegans.
Main features of all animals:
THEY ARE MULTICELLULAR
THEIR CELLS CONTAIN A NUCLEUS BUT
NO CELL WALLS OR CHLOROPLASTS
THEY FEED ON ORGANIC SUBSTANCES
MADE BY OTHER LIVING THINGS
Animal cells
structure
The Plant kingdom
The Plant kingdom can be
divided into:
Flowering plants produce
flowers for reproduction,
eg sunflowers and grass
plants
Non-flowering plants
reproduce using spores,
eg ferns and mosses
Main features of all plants:
they are multicellular
their cells contain a nucleus,
chloroplasts,Vacuole and cellulose cell
walls
they all feed by photosynthesis
Plant cell
structure
Main features of all fungi (e.g. moulds,
mushrooms, yeast)
Fungi
– usually multicellular
– cells have nuclei and cell walls not made from
cellulose
– do not photosynthesize but feed by
saprophytic (on dead or decaying material) or
parasitic (on live material) nutrition
Structure of
fungal
Main features of all Protoctists (e.g. Amoeba, Paramecium,
Plasmodium)
most are unicellular but some are
multicellular
all have a nucleus, some may have cell walls
and chloroplasts
meaning some protoctists
photosynthesise and some feed on organic
substances made by other living things
Main features of all Prokaryotes (bacteria, blue-green
algae)
often unicellular
cells have cell walls (not
made of cellulose)
and cytoplasm but no
nucleus or mitochondria
They have flagella
Prokaryote
cells
structure
Invertebrates
 One of the morphological characteristics used to classify invertebrates is whether they have legs or not
 All invertebrates with jointed legs are part of the phylum Arthropods
 They are classified further into the following classes.
Non-Flowering plants & Flowering Plants
 At least some parts of any plant are green, caused by the presence of the pigment chlorophyll which absorbs
energy from sunlight for the process of photosynthesis
 The plant kingdom includes organisms such as ferns and flowering plants
 Ferns:Have leaves called fronds
 Do not produce flowers but instead reproduce by spores produced on the underside of fronds.
 Flowering plants:
 Reproduce sexually by means of flowers and seeds
 Seeds are produced inside the ovary found at the base of the flower
 Can be divided into two groups – monocotyledons and dicotyledons
•
How to distinguish between monocotyledons and dicotyledons:
 1) FLOWERS
•Flowers from monocotyledons contain petals in multiples of 3
•Flowers from dicotyledons contain petals in multiples of 4 or 5
 2) LEAVES
 Leaves from monocotyledons have parallel leaf veins
•Leaves from dicotyledons have reticulated leaf veins (meaning that they are all interconnected and form a weblike network throughout the leaf)
Features of Viruses
 Viruses are not part of any classification system as they are not considered living things
 They do not carry out the seven life processes for themselves, instead they take over a host
cell’s metabolic pathways in order to make multiple copies of themselves
 Virus structure is simply genetic material (RNA or DNA) inside a protein coat
Procrastination makes easy things
hard and hard things harder.
Study hard daily for achieving your
goals .
Workbook questions and answers pages 5 ,6,7&8
 Focus
 4. Complete the sentences, using words from the list
binomial
group
biological
healthy
reproduce
complete
living
species
fertile
genus
population
Species
An organism is a
thing. A
is a group of living organisms that can
Living
with each other to produce
offspring. Each species of organism has a two-word name. This
Fertile
system of naming is called the
system. The first of the two words in the name tells us
Binomial
the
that the species belongs to.
Genus
They both belong to the same genus, Panthera. They can produce with each other.
They have different binomials, Panthera tigris and Panthera leo. They cannot
interbreed to produce fertile offspring
The two-word name provides information about the genus and species that the organism belongs to, so scientists can
tell whether two species are related or not. The name is used by scientists all over the world, no matter what language
they speak, so all scientists can be sure they are referring to the same species
1a – Geochelone elephantopus
1b, 2b – Ophiophagus hannah
1b, 2a, 3b – Chamaeleo gracilis
Doesn’t have three pairs of legs
Has the big claws
Doesn’t have the big claws
Locust
go to 3
Crab
Centipede
1. A has a long-fin
B. Does not have a long fin
2.A. have no scales on their head
B. Has scales on their head
3.A. have multiple gill slits
B. Does not have multiple gills slits
Bannerfish
Go to 2
Goldfish
Go to 3
Shark
Trout
Course book questions 3& 4 page 11
 3 Figure 1.12 shows a sea anemone, which belongs to the animal kingdom.
 A. In the past, people used to think that sea anemones were plants. Suggest why.
Sea anemones do not obviously move. Their tentacles perhaps look like flower petals
 B. Explain how using a microscope could help you to confirm that sea anemones are animals.
You would see that their cells do not have cell walls, and never contain chloroplasts.
 4 Figure 1.13 shows part of a plant called a liverwort. Liverworts do not have roots or flowers. Suggest how you
could show that a liverwort belongs to the plant kingdom.
With a microscope, you could see that their cells would have cell walls. Some of them would also have chloroplasts
containing chlorophyll
Course book questions 5 & 6 answers page 14
 5 Staphylococcus aureus is a bacterium that is often found on human skin.
 a Name the genus to which this bacterium belongs.
Staphylococcus
 b Name the kingdom to which this bacterium belongs.
the prokaryote kingdom
 c Describe two ways in which the structure of Staphylococcus aureus differs from the structure of a plant cell.
Its cell wall is not made of cellulose. It does not have a nucleus or mitochondria. It has a circular loop of DNA. It has
plasmids
 6 Figure 1.20 shows part of a fungus. The photograph was taken with an electron microscope.
 a Name the structure labelled A.
Hypha
 b Explain how the cells in this structure differ from the cells of an organism belonging to the animal kingdom.
The cells have cell walls.
 c The structure labelled B contains spores. What is the function of this structure?
Reproduction
Homework
Please complete questions from the
course book on pages 19,21,23 & 27
Course book questions 7 -11 answers page 19 &21
 7 Name the kingdom to which mammals belong.
Animals Kingdom
 8 List two differences between amphibians and reptiles.
Amphibians have a smooth skin, but reptiles have scales. Amphibians lay eggs with no shells in water; reptiles lay
eggs with soft shells on land
 9 List (A) two external and (B) two internal features of mammals that are not found in other groups of vertebrates.
A.hair; pinnae; mammary glands
B. diaphragm; sweat glands; uterus; placenta
 10 A.List two features that are shared by myriapods and arachnids.
jointed legs; exoskeleton
 B. Describe two differences between myriapods and arachnids.
Myriapods have jointed legs on almost all segments, but arachnids have only four pairs of jointed legs. Myriapods
have one pair of antennae, but arachnids do not have antennae. Arachnids have a body divided into a cephalothorax
and abdomen, but this is not so in myriapods
 11 Fleas are insects, but they do not have wings. Suggest two features of fleas that would show that they should be
classified as insects.
Three pairs of jointed legs; one pair of antennae; body divided into head, thorax and abdomen
Course book questions 12&13 answers page 23
 12 Describe two differences between ferns and flowering plants.
Ferns do not have flowers, but flowering plants do. Ferns produce spores on the backs of their
leaves, but flowering plants do not
 13 In your local area, find two examples of monocotyledons and two examples of
dicotyledons. Explain how you were able to decide which group each plant belonged to.
The veins on the leaves – monocots have parallel veins, but dicots have a network of veins;
The flowers – monocots have flowers with parts in multiples of three, but dicots have flowers
with parts in multiples of four or five
 14 Figure 1.45 shows a virus. With reference to the diagram, and your own knowledge,
discuss whether or not viruses can be considered to be living organisms.
The diagram shows that the virus is not made of cells. All living organisms are made of cells.
Viruses are unable to carry out any of the characteristics of living organisms on their own – they
do not show movement, growth, excretion, respiration, sensitivity or nutrition. However, they
can reproduce, and some scientists consider that this justifies classification as a living organism.
But they can only do this inside a living cell, which suggests that they cannot be considered to be
alive themselves.
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1 Which characteristic is not shown by all living organisms?
A. excretion
B. movement
C. photosynthesis
D. respiration
2 Which feature is found in all vertebrates and all arthropods?
A. a backbone
B. an exoskeleton
C. antennae
D. cells without cell walls
3 The binomial of the okapi is Okapia johnstoni. What genus does the okapi belong to?
A animals
B johnstoni
C mammals
D Okapia walls
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4 Which are features of monocotyledons?
A. flower parts in multiples of four or five, one cotyledon in seeds
B. one cotyledon in seeds, vascular bundles in a ring
C. vascular bundles in a ring, network of veins in leaf
D. parallel veins in leaf, flower parts in multiples of three
5 What two features do all viruses possess?
A. cell membrane, cell wall
B. cytoplasm, nucleus
C. genetic material, protein coat
D .ribosomes, plasmids
B
D
A
E
C
 b i Explain the meaning of the term species.
a group of organisms that can reproduce /to produce fertile offspring
 ii Biologists give each species a two-word Latin name. What is the term used to describe this naming system?
Binomial
 7.The table shows features of three animals.
A. Name the major group that all of these animals belong to.
Arthropods
B. Each animal is classified into a smaller group within this major group
P-Archinids Q-Insects R-Myriapods
C. List two features, other than those shown in the table, that animal Q has, which are not shared with animals
P and R.
Two pairs of wings body divided into head, thorax and abdomen
• 8 Three species of tree have the following Latin names:
• Carpodiptera africana
• Commiphora africana
• Commiphora angolensis
 A.Which two species do biologists consider to be the most closely related? Explain your answer.
Commiphora africana and Commiphora angolensis ,because they belong to the same genus
 B. Commiphora africana is a dicotyledon. State two features that it shares with all other dicotyledons, but not with
monocotyledons.
• net of veins in leaves
• flower parts in multiples of four or five
• vascular bundles in stem arranged in a ring
• main roots with side roots
• seeds with two cotyledons
 9.All living organisms are classified into five kingdoms. These include the plant, animal and fungus kingdoms.
 A.Name the other two kingdoms.
prokaryote and protoctist
 B. Describe two ways in which the cells of fungi differ from those of plants
cells with cell walls not made of cellulose ; do not have chloroplasts
 B. Describe two ways in which the cells of fungi differ from those of plants.
cells with cell walls not made of cellulose ; do not have chloroplasts
 C. The diagram below shows a virus.
• i Name parts X and Y.
X genetic material (accept DNA or RNA) Y protein coat
• ii Explain why viruses are not generally classified into any of the five
kingdoms.
Only organisms are classified into kingdoms
• viruses are not considered to be organisms because they cannot carry
out the characteristics of living things and are not made of cell
Workbook questions and answers page
i)It is larger.
2)Label lines are straight.
3)Label lines always touch the part they are labelling.
4)There is no shading.
5)The lines are continuous, not broken which means they are clearer
Anus
Tail
Mouth
Head
It has cells that do not have cell walls. It has cells that do not have chloroplasts. Some learners may also
mention that it has cells that do not have large vacuoles containing cell sap. It is able to move its body from
place to place
Fungi have cells with cell walls not made of cellulose. They do not have chlorophyll and do not
feed by photosynthesis. They are made of hyphae. They feed by digesting waste organic material
and absorbing it
A – amphibian
B – mammal
C – bird
D – fish; E – mamma
They have mammary glands; the young develop in a uterus, attached by a placenta; they have different types of teeth; they have
a pinna; they have sweat glands; they have a diaphragm.
Reptile
They have several pairs of jointed legs; they have an exoskeleton.
They have cells with walls made of cellulose
Their cells contain chlorophyll
They feed by photosynthesis
Ferns do not produce flowers
They reproduce by producing spores on the underside of their fronds