Classification of living things| Form three topic
Classification of living things| Form three topic| study biology subject
KINGDOM PLANTAE
Is a kingdom in which all plants are grouped.
Plants: are multi-cellular eukaryotic organisms with
ability to manufacture their own food by using energy from the sun through the
process of photosynthesis.
DIVISION OF KINGDOM PLANTAE
Kingdom Plantae is made up of the following divisions:-
i) Division
bryophyta e.g. Moss plants.
ii) Division
filicinophyta or pteridophyta. E.g. Fern plants.
iii) Division
coniferophyta e.g. Pines, cypress iv) Division angiospermophyta e.g. Maize,
beans
GENERAL AND
DISTINCTIVE FEATURES OF KINGDOM PLANTAE
(i) They
are multi-cellular.
(ii) Their
cell walls made of cellulose.
(iii) They
are eukaryotic organisms.
(iv) They
have chlorophyll (v) They are autotrophs.
(vi) They
reproduce both sexually and asexually.
(vii) They
store food as starch.
(viii) Their
cells are organized into tissues, organs and organ systems.
(ix) They
show limited movement, for example opening and closing of flower petals.
(I) DIVISION
CONIFEROPHYTA (Gymnosperms)
This division is made up of the cone-bearing plants, hence
the name conifers.
The
members of this division are called conifers.
Conifers
are plants that have needle-shaped leaves and almost all green.
They include plants such as pines, spruces, cedar, red wood,
cypress and juniper.
GENERAL
CHARACTERISTICS OF DIVISION CONIFEROPHYTA
The following are the general characteristics of conifers.
(i)
They have cones.
(ii) They
neither have flowers nor fruits.
(iii) They
are wind pollinated.
(iv) They
are vascular, i.e. they have phloem and xylem tissues.
(v) Their
seeds are not enclosed in an ovary, but in cones.
(vi) They
reproduce sexually by seed.
(vii) They
do not need water for fertilization.
(viii) Their
leaves are needle-like, linear or scale-like.
(ix) They
have alternation of generation.
NB: Some
species of conifers have male and female cones on the same individual tree
while other species have plants with only male or female cones.
DISTINCTIVE
FEATURES OF DIVISION CONIFEROPHYTA
(i) Conifers
are non-flowering but seed producing plants.
(ii) They
have seed born in cones shaped structure rather than in fruits.
(iii) Their
leaves are needle- shaped and have a thick cuticle for protection and to
decrease water loss.
(iv) They
are gymnosperms which means naked- seed
(v) Their
leaves are needle-like
(vi) Their
seeds are enclosed in cones.
(vii) They
have cones. The female cones contain ovules while the male cones produce
microspores known as pollen.
THE
STRUCTURE OF PINUS
Pinus are coniferous, evergreen resinous trees which belongs to
genus Pinus
(i) Pinus
are evergreen, with needle-like leaves
(ii) Most
of pinus have thick and scaly bark, only few species have thin and flaking
bark.
(iii)Pinus
grow about 15 to 45 metres tall
(iv) Most
of pinus have female and male cones on the same trees (v) Branches of pinus arise from the same
point on the tree.
ADVANTAGES
AND DISADVANTAGES OF THE DIVISION CONIFEROPHYTA
QN: Explain the advantages and disadvantages of the division
coniferophyta
ADVANTAGES
OF CONIFERS
(i) Conifers
are source of timber.
(ii) Some
conifers are used for decoration.eg Christmas trees
(iii)Some conifers are source of wood pulp which is used to
manufacture papers.
(iv) Some
conifers are source of food. E.g. Pine leaves are used as food for some insects
(v) and
timber, as well as cedar which many people use for their homes because of its
beauty and
(vi) Some
conifers are used as medicine. E.g. Pines and cypress are rich in vitamin;
their branches cones and oils can be extracted and used as nutrient
supplements.
(vii) Conifers
are source of habitat for many birds and animals.
(viii) Some
conifers are source of firewood and charcoal.
(ix) Conifers
form a large arena for Biological research and Ecological studies.
(x) Thick
forests of conifers form green belts that modify the climate.
(xi) Some
conifers are source of useful chemical substances such as resins.
DISADVANTAGES
OF CONIFERS
(i) Conifers
have low reproduction rate since they rely on wind pollination and seed
dispersal.
(ii) Conifers
act as a habitat for dangerous animals such as snake etc.
(iii) Conifers
prevent other plants from growing as they completely shade the ground below.
(iv) Wood
products from conifers are soft and easily attacked by terminates.
(II) DIVISION
ANGIOSPERMOPHYTA
This division includes all flowering plants such as mango
trees, hibiscus flowers, maize, beans etc.
Plants
which are found in division angiospermophyta are called angiosperms
ANGIOSPERMS
These are flower and
seed bearing vascular plants.
GENERAL FEATURES
OF ANGIOSPERMS
(i) They
bear flowers which are reproductive structures.
(ii) They
produce seeds enclosed in an ovary.
(iii)They have well
developed vascular system for transporting water and dissolved substances.
(iv) They have alternation of generation
DISTINCTIVE
FEATURES OF ANGIOSPERMS
(i) They
bear flowers which are reproductive structures.
(ii) They
bear seeds enclosed in an ovary.
(iii)They have endosperm produced after fertilization to
nourish the embryo.
(iv) Their
haploid gametophyte is confined inside the ovary or anther of the flower.
(v) They
have double fertilization
Double fertilization is the process
whereby one sperm fertilizes the egg cell to form the diploid zygote, while the
other sperm fertilizes the central polar cell to form triploid endosperm.
CLASSES OF
THE DIVISION ANGIOSPERMOPHYTA AND THEIR DISTINCTIVE FEATURES
Division Angiosperms is divided into two classes,
namely:
(i) Class
Monocotyledonae
(ii) Class
Dicotyledonae
CLASS
MONOCOTYLEDONAE
This consists of plants whose seed are made up of only one
cotyledon.
Members of class monocotyledonae are
called monocots
Example
of monocots
Maize
plant
Grasses
Palm
trees
Sugarcanes
DISTINCTIVE
FEATURES OF CLASS MONOCOTYLEDONAE
(i) Monocots
have one cotyledon
(ii) Monocots
have narrow leaves with parallel venation.
(iii)Monocots have fibrous root systems.
(iv) Floral
parts are in 3, or multiple of 3.
(v) Monocots
have no cambium hence there is no secondary growth.
(vi) Monocots
have scattered vascular bundles in their stems.
DIAGRAM OF
MONOCOT STEM AS SEEN UNDER A LIGHT MICROSCOPE
DIAGRAM OF
MONOCOT ROOT AS SEEN UNDER A LIGHT MICROSCOPE
CLASS
DICOTYLEDONAE
This consists of plants whose seeds are made up of two cotyledons.
Members of class dicotyledonae are called dicots Example of dicots
- Bean plants
- Groundnuts
- Sunflower
- Hibiscus
DISTINCTIVE
FEATURES OF CLASS DICOTYLEDONAE
(i) Dicots
have two cotyledons
(ii) Dicots
have broad leaves with net-like venation.
(iii)Dicots have tap root system
(iv) Floral
parts are in 4 or 5 or multiple of 4 or 5.
(v) Dicots
have vascular cambium which brings about secondary growth.
(vi) Vascular bundles in dicot stem are arranged in a ring form.
DIAGRAM OF DICOT STEM AS SEEN UNDER A LIGHT MICROSCOPE
DIFFERENCES
BETWEEN MONOCOTS AND DICOTS
MONOCOTS DICOTS
E.g. Maize plants E.g.
Bean plants
(i) Have
seeds with two cotyledon Have
seeds with two cotyledons
(ii) Have
leaves with parallel venation Have
leaves with net-like venation
(iii)Have fibrous root system Have
tap root system
(iv) Have long
and narrow leaves Have short and broad leaves
(v) Have
no cambium Have cambium
(vi)
Vascular
bundles in stem are scattered Vascular bundles in stem are
arranged in a ring
(vii)Floral parts are in 3, or
multiple of 3. Floral parts are in 4
or 5 or multiple of 4 or 5.
ADVANTAGES
AND DISADVANTAGES OF DIVISION ANGIOSPERMOPHYTA
QN: Explain advantages and disadvantages of division
angiospermophyta
ADVANTAGES
OF ANGIOSPERMS
(i) Angiosperms
are source of food to other living organisms such as human being.
(ii) Angiosperms
provide different varieties of wood for furniture, paper and building
materials.
(iii)Some angiosperms are used to make medicine.
(iv) Angiosperms
are source of oxygen which is used for cellular respiration. (v) Angiosperms
are source of raw materials for textile industry. E.g. cotton (vi) Angiosperms are used to modify climate.
(vii) Angiosperms provide a wide range of
habitats for different species of organisms.
DISADVANTAGES
OF ANGIOSPERMS
(i) Some
angiosperms are poisonous when eaten they cause death to human and other
animals. E.g. Some cassavas have cyanide
acid that inhibits cellular respiration.
(ii) Some
angiosperms are drugs that can be abused when taken. E.g. Marijuana, cocaine, tobacco, caffeine.
(iii) Some
angiosperms are bad weeds, they reduce crop yields. E.g. Cuscuta kilimanjari is
parasitic to coffee plantations.
SIMILARITIES
OF DIVISION CONIFEROPHYTA AND DIVISION
ANGIOSPERMOPHYTA
(i) Both
are seed producing plants
(ii) Both
have true roots, stems and leaves
(iii)Both have vascular bundles
DIFFERENCES
BETWEEN DIVISION CONIFEROPHYTA AND DIVISION
ANGIOSPERMOPHYTA
ANGIOSPERMS
GYMNOSPERM
(i) They
produce fruits that contain seeds They
produce cones that contain seeds
(ii) They
are flowering plants They are
non-flowering plants
(iii)Their seeds are enclosed in an ovary Their seeds are enclosed in cones
(iv) Their
reproductive structures are flowers Their
reproductive structures are cones ECONOMIC IMPORTANTCE OF KINGDOM PLANTAE
(i) Plants
give out oxygen which is used for cellular respiration.
(ii) Plants
are source of fuel to man e.g. Charcoal and firewood
(iii) Plants
are source of food to man and herbivorous animals,
(iv) Some
plants are used to make medicine. E.g. quinine, moarobaini etc (v) Plants
provide shade and good habitat for wildlife and birds.
(vi) Plants
beautify and decorate the environment
(vii) Leguminous
plants add nitrate nutrients in the soil.
(viii)
Some plants provide raw materials used in
textile industries (ix) Some plants are source of timber.
(x) Some
plants are drugs that can be abused when taken. E.g. Marijuana, cocaine, tobacco, caffeine.
(xi) Some
plants are poisonous when eaten they cause death to human and other animals.
E.g. Some cassavas have cyanide acid
that inhibits cellular respiration.
REVISION
QUESTION
1. Choose
the correct answer from the choices given
(i) Absence of flowers and fruits is a characteristics
of_____________
A. Monocots
B. Dicots
C. Conifers
D. Vascular
plants
(ii) One of the following is a similarity between Gymnosperms and
Angiosperms
A. They
reproduce sexually by seeds
B. They
are wind pollinated
C. They
have cones
D. They
have seeds with cotyledons
(iii)Plants are said to be vascular if___________
A. They
contain phloem
B. They
contain cambium
C. They
contain xylem
D. They
contain xylem and phloem
(iv) In flowering plants, seeds are enclosed in___________
A. Ovules
B. Ovaries
C. Fruits
D. cones
(v) An example of the most important drug extracted from the
angiosperms is_____
A. Penicillin
B. Magnesium
C. Quinine
D. All
the above
2. State
whether each of the following statements is true or false
(i) Most
coniferous tree(evergreen plants) have needle leaves throughout the whole
year___
(ii) Conifers
are seedless plants_____________
(iii) Angiosperms
are not flowering plants_____________
(iv) Cones
produce a sweet scent during winter______________
(v) Monocots
have fibrous root system_______________
(vi) Dicots
have seeds with only one cotyledon____________
(vii) The
phloem in both dicots and monocots functions as a conductor of organic
nutrients from one part of the plant to another____________
(viii) Angiosperms
do not provide food for man or animal____________
(ix) Monocots
stem vascular bundles is in a ring-form
(x) All
dicots and monocots are flowering plants_____________
(xi) In
most dicots, their roots develop from the lower end of the embryo at the
radical______
3. Explain
the general and distinctive features of the division coniferophyta.
4. Describe
the structure of Pinus.
5. What
is the advantage of conifers having needle-like leaves?
6. How
useful is division Coniferophyta to human beings?
7. Explain
the general and distinctive features of the division Angiospermophyta 8. (a)
Give three similarities of division Coniferophyta and division Angiospermophyta
(b) How is division coniferophyta different from division Angiospermophyta?
9.
What are the characteristic differences between
monocots and dicots?
10. (a)
Draw well labeled diagrams of monocots and dicot stems as seen under a light
microscope.
(b) How different is the arrangement of vascular bundles in
monocot and dicot stems?
11. State
the economic importance of division Angiospermophyt
