Transcript iGCSE Biology Section 1 lesson 2

IGCSE BIOLOGY
SECTION 1 LESSON 2
Content
Section 1
The nature
and variety of
living
organisms
a) Characteristics of living
organisms
b) Variety of living organisms
Content
Lesson 2
b) Variety of
living
organisms
b) Variety of living organisms
1.2 describe the common features shared by organisms within the following
main groups: plants, animals, fungi, bacteria, protoctists and viruses, and for
each group describe examples and their features as follows (details of life
cycle and economic importance are not required)
Plants: These are multicellular organisms; their cells contain chloroplasts and
are able to carry out photosynthesis; their cells have cellulose cell walls; they
store carbohydrates as starch or sucrose Examples include flowering
plants, such as a cereal (for example maize), and a herbaceous legume (for
example peas or beans)
Animals: These are multicellular organisms; their cells do not contain
chloroplasts and are not able to carry out photosynthesis; they have no cell
walls; they usually have nervous coordination and are able to move from one
place to another; they often store carbohydrate as glycogen Examples
include mammals (for example humans) and insects (for example housefly
and mosquito)
Fungi: These are organisms that are not able to carry out photosynthesis;
their body is usually organised into a mycelium made from thread-like
structures called hyphae, which contain many nuclei; some examples are
single-celled; their cells have walls made of chitin; they feed by extracellular
secretion of digestive enzymes onto food material and absorption of the
organic products; this is known as saprotrophic nutrition; they may store
carbohydrate as glycogen
Examples include Mucor, which has the
typical fungal hyphal structure, and yeast, which is single-celled
Classification
Kingdom
Monera
(Prokaryotes)
Bacteria and Blue-green algae
Protoctista
Amoeba, Paramecium
Fungi
Moulds, Mushrooms, Yeast
Plants
Algae, ferns and mosses,
conifers and flowering plants
Animals
Jellyfish, worms, arthropods, molluscs,
echinoderms, fish, amphibia, reptiles,
birds and mammals.
Classification
Kingdom
Monera
(Prokaryotes)
Bacteria and Blue-green algae
Protoctista
Amoeba, Paramecium
Fungi
Moulds, Mushrooms, Yeast
Plants
Algae, ferns and mosses,
conifers and flowering plants
Animals
Jellyfish, worms, arthropods, molluscs,
echinoderms, fish, amphibia, reptiles,
birds and mammals.
Plants: These are multicellular
organisms;
their
cells
contain
chloroplasts and are able to carry out
photosynthesis; their cells have
cellulose cell walls; they store
carbohydrates as starch or sucrose
Examples include flowering plants,
such as a cereal (for example maize),
and a herbaceous legume (for
example peas or beans)
Examples of flowering plants
Examples of flowering plants
Maize – a cereal
crop
Examples of flowering plants
Maize – a cereal
crop
Pea plant – a
herbaceous
legume
Plants are multicellular
organisms in that they consist
of more than one cell.
Plants are multicellular
organisms in that they consist
of more than one cell.
Advantages to being
multicellular include:
• allows the organism to be
larger
• allows cell differentiation
(having different types of cells
with different functions)
• allows the organisms to be
more complex.
Plants are multicellular
organisms in that they consist
of more than one cell.
Multicellular organisms need
specialised organ systems to
carry out functions such as:
• photosynthesis (leaves are
organs specialised to absorb
sunlight).
• transport (roots are organs
specialised to transport water
and minerals).
• reproduction (flowers are
organs specialised to produce
male and female gametes).
Advantages to being
multicellular include:
• allows the organism to be
larger
• allows cell differentiation
(having different types of cells
with different functions)
• allows the organisms to be
more complex.
Plants are multicellular
organisms in that they consist
of more than one cell.
Multicellular organisms need
specialised organ systems to
carry out functions such as:
• photosynthesis (leaves are
organs specialised to absorb
sunlight).
• transport (roots are organs
specialised to transport water
and minerals).
• reproduction (flowers are
organs specialised to produce
male and female gametes).
Advantages to being
multicellular include:
• allows the organism to be
larger
• allows cell differentiation
(having different types of cells
with different functions)
• allows the organisms to be
more complex.
Plants are autotrophs – this
means that they are able to
produce their own food using
sunlight energy =
PHOTOSYNTHESIS
Examples of flowering plants
Maize – a cereal
crop
Maize is also known as corn
(corn on the cob). It is a cereal
crop
Examples of flowering plants
Maize – a cereal
crop
Maize is also known as corn
(corn on the cob). It is a cereal
crop
Cereal crop – a grass
such as wheat, oats, or
corn, the starchy
grains of which are
used as food
Examples of flowering plants
Maize – a cereal
crop
Maize is also known as corn
(corn on the cob). It is a cereal
crop that originated in South
America, but is now grown
around the world.
Different varieties of maize
yield cornmeal, cornflour,
sweetcorn and popcorn.
Examples of flowering plants
Maize – a cereal
crop
Maize is also known as corn
(corn on the cob). It is a cereal
crop that originated in South
America, but is now grown
around the world.
Different varieties of maize
yield cornmeal, cornflour,
sweetcorn and popcorn.
Photosynthesis in maize is a
little different to other plants.
Maize is known as a C4 plant
because the pathway is
different but more effective.
Examples of flowering plants
Peas belong to a group of
plants known as legumes.
Pea plant – a
herbaceous
legume
Examples of flowering plants
Peas belong to a group of
plants known as legumes.
Many legumes, including peas
contain symbiotic bacteria
Pea plant – a
herbaceous
legume
Examples of flowering plants
Peas belong to a group of
plants known as legumes.
Many legumes, including peas
contain symbiotic bacteria
Symbiotic bacteria
– bacteria living
with other
organisms to mutual
benefit
Pea plant – a
herbaceous
legume
Examples of flowering plants
Peas belong to a group of
plants known as legumes.
Many legumes, including peas
contain symbiotic bacteria.
These bacteria live in root
nodules and have the ability
to fix atmospheric nitrogen.
Pea plant – a
herbaceous
legume
Examples of flowering plants
Peas belong to a group of
plants known as legumes.
Many legumes, including peas
contain symbiotic bacteria.
These bacteria live in root
nodules and have the ability
to fix atmospheric nitrogen.
en.wikiperdia.org
Pea plant – a
herbaceous
legume
Animals:
These are multicellular
organisms; their cells do not contain
chloroplasts and are not able to carry
out photosynthesis; they have no cell
walls; they usually have nervous
coordination and are able to move from
one place to another; they often store
carbohydrate as glycogen.
Examples include mammals (for
example humans) and insects (for
example housefly and mosquito)
Examples of animals
Examples of animals
Mammals
eg. humans
Examples of animals
Mammals
eg. humans
Insects
eg. housefly and
mosquito
Examples of animals
Mammals
eg. humans
Animals are
multicellular
organisms in that
they consist of more
than one cell.
Insects
eg. housefly and
mosquito
Examples of animals
Mammals
eg. humans
Animals are
multicellular
organisms in that
they consist of more
than one cell.
Animals are
heterotrophs – they
cannot manufacture
their own food, but
have to consume
ready-made organic
molecules
Insects
eg. housefly and
mosquito
Animal cells differ from
plant cells in that they do
not have chloroplasts (so
cannot photosynthesise) and
do not have cellulose cell
walls.
Animal cells differ from
plant cells in that they do
not have chloroplasts (so
cannot photosynthesise) and
do not have cellulose cell
walls.
Animals usually have organs
and organ systems. The
nervous system is an
example of an organ system,
and enables communication
between cells.
Animals usually have organs
and organ systems. The
nervous system is an
example of an organ system,
and enables communication
between cells.
Animals usually have organs
and organ systems. The
nervous system is an
example of an organ system,
and enables communication
between cells.
Through co-ordination of
the nervous and muscular
systems animals are able to
physically move from one
place to another.
Feeding – animals store
carbohydrates as
glycogen
Feeding – animals store
carbohydrates as
glycogen
Mosquitoes have tubular
mouthparts that are adapted
for piercing the skin and
sucking blood from the skin
capillaries
Feeding – animals store
carbohydrates as
glycogen
Mosquitoes have tubular
mouthparts that are adapted
for piercing the skin and
sucking blood from the skin
capillaries
Fungi: These are organisms that are not able to
carry out photosynthesis; their body is usually
organised into a mycelium made from thread-like
structures called hyphae, which contain many
nuclei; some examples are single-celled; their
cells have walls made of chitin; they feed by
extracellular secretion of digestive enzymes onto
food material and absorption of the organic
products; this is known as saprotrophic nutrition;
they may store carbohydrate as glycogen.
Examples include Mucor, which has the typical
fungal hyphal structure, and yeast, which is
single-celled
Examples of fungi
Examples of fungi
Mucor
(bread
mold)
en.wikiperdia.org
Yeast
Toadstools
sciencedaily.com
Examples of fungi
en.wikiperdia.org
Sporangia – pin-like
structures that project
upwards from the
mycelium. They contain
the spores (the
reproductive cells)
Hyphae – thread-like
branching structures
which make up the main
body (or mycelium) of a
multicellular fungus.
Fungi do not have
chlorophyll, so are unable to
photosynthesise.
Fungi do not have
chlorophyll, so are unable to
photosynthesise.
Most fungi are saprotrophs
– they live on dead organic
matter.
Fungi do not have
chlorophyll, so are unable to
photosynthesise.
Most fungi are saprotrophs
– they live on dead organic
matter.
en.wikiperdia.org
The hyphae secrete
enzymes into the organic
material (eg. bread) and
digest it to liquid products.
The digested products are
then absorbed back into the
hyphae and used for
respiration or growth.
Summary - comparisons
Summary - comparisons
Plants
Example
Cell type
Cell structure
Nutrition
Other
features
Animals
Fungi
Summary - comparisons
Plants
Example
Cell type
Cell structure
Nutrition
Other
features
Animals
Fungi
Summary - comparisons
Plants
Animals
Fungi
Multicellular
Multicellular
Multicellular,
unicellular
Example
Cell type
Cell structure
Nutrition
Other
features
Summary - comparisons
Plants
Animals
Fungi
Cell type
Multicellular
Multicellular
Multicellular,
unicellular
Cell structure
Cellulose cell wall,
contain
chloroplasts
No chloroplasts or
cell walls
Thread-like
hyphae that
contain nuclei
Example
Nutrition
Other
features
Summary - comparisons
Plants
Animals
Fungi
Cell type
Multicellular
Multicellular
Multicellular,
unicellular
Cell structure
Cellulose cell wall,
contain
chloroplasts
No chloroplasts or
cell walls
Thread-like
hyphae that
contain nuclei
Nutrition
Autotrophs – make
food by
photosynthesis
Heterotrophs –
consume readymade food
Saprotrophs –
feed on dead
organic matter
Example
Other
features
Summary - comparisons
Plants
Animals
Fungi
Cell type
Multicellular
Multicellular
Multicellular,
unicellular
Cell structure
Cellulose cell wall,
contain
chloroplasts
No chloroplasts or
cell walls
Thread-like
hyphae that
contain nuclei
Nutrition
Autotrophs – make
food by
photosynthesis
Heterotrophs –
consume readymade food
Saprotrophs –
feed on dead
organic matter
Other
features
Store
carbohydrates as
starch
Store
carbohydrates as
glycogen
Store
carbohydrates as
glycogen
Example
End of Section 1 Lesson 2
In this lesson we have covered:
• Outline of the plant kingdom
• Outline of the animal kingdom
• Outline of the fungi kingdom