CHARACTERISTICS OF
LIVING ORGANISMS
Living and non-living organisms
What are the characteristics
these two share?
Living organisms
And what are the
characteristics these
two share?
Characteristics of living organisms
• Movement
• Respiration
• Sensitivity
• Growth
• Reproduction
• Excretion
• Nutrition
MRS GREN
Movement
An action by an
organism or part of an
organism causing a
change of position or
place
Locomotion and
Movement
Is there a difference?
Respiration
The chemical reactions in cells that break
down nutrient molecules (usually
glucose) and release energy. This energy
is used to make other chemical reactions
(metabolism).
Sensitivity
The ability to detect or
sense stimuli in the
internal or external
environment and
respond to changes in the
environment.
Growth
A permanent increase in size by
an increase in cell number or cell
size or both.
How can we measure
growth?
For example by using the
dry mass of an organism.
Various growth stages of the Emperor gum moth caterpillar (Opodiphthera eucalypti).
Sources: Encyclopædia Britannica
Reproduction
The processes that make
more of the same kind of
organism.
Excretion
Removal of waste products of
metabolism, such as toxic materials
and substances in excess of
requirements.
Excretion and
Egestion are the
same process?
Nutrition
Plants
Animals
Taking in of materials for energy, growth and development
AUTOTROPHIC
NUTRITION
HETEROTROPHIC
NUTRITION
ANOTHER FEATURE: THE CELL
CLASSIFICATION OF
ORGANISMS: WHY AND
HOW
Division of organisms into groups according to particular features.
Why?
• To more easily study organisms,
• To better protect them,
• To understand the evolutionary
relationships.
The common ancestor
Biologists try to classify organisms
according to how closely they think they are
related!
The common ancestor is a species that lived in
the past and is thought to have given rise to
several different species alive today.
How?
• Morphology and
anatomy
• DNA analyses and
proteins structure
(organisms which share a
more recent ancestors have
base sequences in DNA more
similar than those that share
distant ancestors)
Manis javanica
Species
Smallest group in which biologists classify living organisms.
“Group of organisms that can reproduce with each other to produce offspring that
can also reproduce (fertile offspring)”.
Manis crassicaudata
Manis culionensis
Manis pentadactyla
© Roger G Dolorosa
A hierarchical system
System of grouping things according to a hierarchy!
Organisms are grouped into taxa (group which forms a unit) and
these groups are given a taxonomic rank; groups of a given rank can
be aggregated to form a more inclusive group of higher rank, thus
creating a taxonomic hierarchy.
(The group becomes more and more specific, until the species level)
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Pholidota
Family
Manidae
Genus
Manis
Species
Manis javanica (Desmarest, 1822)
The binomial naming system
Genus: a group of species that share similar
features and a common ancestors
•
Binomial: Each species has a two-part name (genus + species)
•
Introduced in 1735 by Linnaeus
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Carnivora
Family
Canidae
Genus
Canis
Species
Canis lupus (Linnaeus, 1758)
This file was derived from: Eurasian wolf.JPG, CC BY-SA 4.0, https://
commons.wikimedia.org/w/index.php?curid=95523086
Dichotomous
keys
Method to identify an
organism by providing
two descriptions at a time
and asking to choose
between them. Each
choice leads to another
pair of descriptions and
this process leads to the
scientific name of the
organism.
Dichotomous key step by step
How to construct a dichotomous key
•
Look at the organisms to classify and make a list of features that clearly differ between
them.
•
Choose one of the features that can split the organisms into two groups. The groups
don’t have to be of the same size!
•
Write down the two opposites statements for the chosen feature.
•
Concentrate on the group that contains more organisms and choose another feature that
allows to split those organisms into two further groups. Keep following this process until
each group contains only one organism!
•
Go back and improve the key, by using a clear wording, check that there are two clear
alternatives and try to reduce the key to the smallest possible number of statement pairs.
Practical investigation 1
You will:
Getting started
Construct a dichotomous key
• Think about the main features of
• When you have completed your key
with athat you are looking
the work
organisms
• Make a biological drawing
and use the
to test the key.
at.
drawing to identify anpartner
organism
• Once you are happy that your key actually works you
can present it to the class
You will need:
Tip
•
•
Range of specimens of leaves
•
Paper and pencil
•
When constructing a dichotomous
key, use the most obvious features
that you can actually see!
Recording data
1. Make a large drawing of one of the organism and label the drawing!
2. State the features of your organism that help you to identify which group it belongs to
3. State the group that your organism belongs to
Five kingdoms
The largest group into which living organisms are classified
• Animals
• Fungi
• Plants
• Protoctista or Protista
• Prokariotes
Animals
•
Cells have a nucleus, but no
cell walls or chloroplasts
•
Feed on organic substances
made by other organisms
Organic substances: substances
whose molecules contain
carbon. In biology organic
compounds are the one made
by living things
Cellulose: a carbohydrate
that forms long fibres and
makes up the cell wall of
plants
Chlorophyll: a green
pigment that absorbs
energy from light. This
energy is used to combine
Carbon dioxide with
water to make glucose
Plants
•
Cells have a nucleus, cell
walls (cellulose) and
chloroplasts (Chlorophyll)
•
Autotrophic (Photosynthesis)
•
May have roots, stems,
leaves and flowers
•
They are adapted to remain
in one place
Decomposers:
organisms yay break
down organic
substances outside their
bodies, releasing
nutrients from them
that other organisms
can use
Spores: small groups of
cells surrounded by a
protective wall used in
reproduction
Fungus
•
Have nuclei
•
Usually multicellular, but can be
unicellular
•
Have cell walls (Chitin)
•
Do not have chlorophyll
•
Saprophytic or parasitic nutrition
•
Most fungi are decomposers
•
The main body of most fungi are
made of hyphae (long threads
made of many cells joined end to
end)
•
They reproduce through spores
Protoctist
•
Multicellular or unicellular
•
Cells have a nucleus
•
Cells may have or not a cell
wall and chloroplasts
•
Autotrophic or
Heterotrophic
Plasmids: small
extrachromosomal
DNA molecule. Often
carry genes that benefit
the survival of the
organism (e.g.
antibiotic resistance)
Prokaryote
•
Subdivided in Bacteria and Archaea
•
Unicellular, but can form colonies
•
Have no nucleus
•
Circular loop of DNA, free in the
cytoplasm
•
Often have plasmids
•
Have cell walls, not made of
cellulose, but of peptidoglycan
•
Have no mitochondria
•
Some can carry out photosynthesis
Groups within the animal kingdom: Phyla
Vertebrates
Arthropods
Vertebrates: five classes
Have a rod running along the length of
the body to support them
•
Fish
•
Reptiles
•
Birds
•
Amphibians
•
Mammals
Class: Reptile
Insects
Crustaceans
Arachnids
Myriapods
Class: Insects
• 3 pairs of jointed legs!
• 2 pairs of wings
• Breathe trough tracheae
• Body divided into head, thorax and
abdomen
• 1 pair of antennae
Class: Arachnids
• 4 pairs of jointed legs!
• No antennae
• Body divided into 2 parts:
abdomen and cephalothorax
Class: Crustaceans
• More than 4 pairs of jointed
legs!
• Two pairs of antennae
Class: Myriapods
• Body consists of many similar
segments
• Each segment has jointed legs
• One pair of antennae
Activity 1.4
This file was derived from: Eurasian wolf.JPG, CC BY-SA 4.0, https://
commons.wikimedia.org/w/index.php?curid=95523086
Manis pentadactyla
Classifying plants: Four phyla
Algae
Bryophyte
(Mosses)
(Pteridophyte)
Ferns
Flowering
plants
Pteridophyte: Ferns
• Plants with roots,
stems and leaves
(fronds)
• Have leaves (fronds)
• Do not produce flowers
• Reproduce by spores
Flowering plants
• Plants with roots, stems and leaves
• Reproduce using flowers and seeds
• Seeds are produced inside the ovary, in
the flower.
Two main groups of flowering plants
Monocotyledons
Plants with one
cotyledon (seed leave)
Dicotyledons
Plants with two
cotyledons (seed leaves)
Dicots Vs. Monocots
•
Seeds with two cotyledons
•
Have main root with side roots
•
Leaves with veins
•
Flower parts in multiple of four or five
•
Vascular bundles in the stem arranged in a ring
•
Seeds with one cotyledons
•
Roots grow out directly from stem and then branch
•
Leaves with parallel veins
•
Flower parts in multiple of three
•
Vascular bundles in the stem arranged randomly
Viruses
•
•
Don’t show the seven characteristics
of living organisms.
•
They need a host cell to replicate and
infect other cells. The host cell is killed.
They are made of:
•
•
Piece of DNA or RNA
A protein coat