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Classification of living things| Form three topic

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

 




DIAGRAM OF DICOT ROOT 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



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