KINGDOM PLANTAE BIOLOGY CLASSIFICATION NOTES

KINGDOM PLANTAE PART 2

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:-

1. Division bryophyta e.g. Moss plants.
2. Division filicinophyta or pteridophyta. E.g. Fern plants.
3. Division coniferophyta e.g. Pines, cypress
4. Division angiospermophyta e.g. Maize, beans

GENERAL AND DISTINCTIVE FEATURES OF KINGDOM PLANTAE

• They are multi-cellular.
• Their cell walls made of cellulose.
• They are eukaryotic organisms.
• They have chlorophyll
• They are autotrophs.
• They reproduce both sexually and asexually.
• They store food as starch.
• Their cells are organized into tissues, organs and organ systems.
• They​ show limited movement, for example opening and closing of flower petals.

(I) DIVISION CONIFEROPHYTA (Gymnosperms)

• This division was formerly known as Gymnosperms( Gymno meaning naked and sperma meaning seed) therefore plant that contain naked seed.
• 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 are 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.

• They have cones.
• They neither have flowers nor fruits.
• They are wind pollinated.
• They are vascular, i.e. they have phloem and xylem tissues.
• Their seeds are not enclosed in an ovary, but in cones.
• They reproduce sexually by seed.
• They do not need water for fertilization.
• Their leaves are needle-like, linear or scale-like.
• 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.

FIGURE OF MALE CONE

FIGURE OF FEMALE CONE

DISTINCTIVE FEATURES OF DIVISION CONIFEROPHYTA

• Conifers are non-flowering but seed producing plants.
• They have seed born in cones shaped structure rather than in fruits.
• Their leaves are needle- shaped and have a thick cuticle for protection and to decrease water They are gymnosperms which means naked- seed
• Their leaves are needle-like
• Their seeds are enclosed in cones.
• 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
• Pinus are evergreen, with needle-like leaves
• Most of pinus have thick and scaly bark, only few species have thin and flaking bark.
• Pinus grow about 15 to 45 metres tall
• Most of pinus have female and male cones on the same trees
• Branches of pinus arise from the same point on the tree.

ADVANTAGES AND DISADVANTAGES OF THE DIVISION CONIFEROPHYTA

ADVANTAGES OF CONIFERS

1. Conifers are source of timber.
2. Some conifers are used for decoration.eg Christmas trees
3. Some conifers are source of wood pulp which is used to manufacture papers.
4. Some conifers are source of food. E.g. Pine leaves are used as food for some insects
5. and timber, as well as cedar which many people use for their homes because of its beauty and
6. 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.
7. Conifers are source of habitat for many birds and animals.
8. Some conifers are source of firewood and charcoal.
9. Conifers form a large arena for Biological research and Ecological studies.
10. Thick forests of conifers form green belts that modify the climate.
11. Some conifers are source of useful chemical substances such as resins.

DISADVANTAGES OF CONIFERS

1. Conifers have low reproduction rate since they rely on wind pollination and seed dispersal.
2. Conifers act as a habitat for dangerous animals such as snake etc.
3. Conifers prevent other plants from growing as they completely shade the ground below.
4. 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.
P​lants which are found in division angiospermophyta are called angiosperms

ANGIOSPERMS

These are flower and seed bearing vascular plants.

GENERAL FEATURES OF ANGIOSPERMS

• They bear flowers which are reproductive structures.
• They produce seeds enclosed in an ovary.
• They have well developed vascular system for transporting water and dissolved substances.
• They have alternation of generation

DISTINCTIVE FEATURES OF ANGIOSPERMS

• They bear flowers which are reproductive structures.
• They bear seeds enclosed in an ovary.
• They have endosperm produced after fertilization to nourish the embryo.
• Their haploid gametophyte is confined inside the ovary or anther of the flower.
• They have double fertilization

D​ouble 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:

• Class Monocotyledonae
• Class Dicotyledonae

CLASS MONOCOTYLEDONAE

This consists of plants whose seed are made up of only one cotyledon.
M​embers of class monocotyledonae are called monocots Example of monocots

• M​aize plant
• G​rasses
• P​alm trees
• S​ugarcanes

DISTINCTIVE FEATURES OF CLASS MONOCOTYLEDONAE

• Monocots have one cotyledon
• Monocots have narrow leaves with parallel venation. (iii)Monocots have fibrous root systems.
• Floral parts are in 3, or multiple of 3.
• Monocots have no cambium hence there is no secondary growth. (vi)Monocots have scattered vascular bundles in their stems.

DIAGRAM OF MONOCOT LEAF 

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
• Peas
• Sunflowers
• Hibiscus

DISTINCTIVE FEATURES OF CLASS DICOTYLEDONAE

• Dicots have two cotyledons
• Dicots have broad leaves with net-like venation. (iii)Dicots have tap root system
• Floral parts are in 4 or 5 or multiple of 4 or 5.
• Dicots have vascular cambium which brings about secondary growth. (vi)Vascular bundles in dicot stem are arranged in a ring form.

DIAGRAM OF DICOT LEAF

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

Example Maize plants

1. Have seeds with two cotyledon  
2. Have leaves with parallel venation
3. Have fibrous root system
4. Have long and narrow leaves
5. Have no cambium
6. Vascular bundles in stem are scattered
7. Floral parts are in 3, or multiple of 3.

DICOTS

Example Bean plants

1. Have seeds with two cotyledons
2. Have leaves with net-like venation
3. Have tap root system
4. Have short and broad leaves
5. Have cambium
6. Vascular bundles in stem are arranged in a ring
7. Floral parts are in 4 or 5 or multiple of 4 or 5.

ADVANTAGES AND DISADVANTAGES OF DIVISION ANGIOSPERMOPHYTA
ADVANTAGES OF ANGIOSPERMS

• Angiosperms are source of food to other living organisms such as human being.
• Angiosperms provide different varieties of wood for furniture, paper and building materials.
• Some angiosperms are used to make medicine.
• Angiosperms are source of oxygen which is used for cellular respiration.
• Angiosperms are source of raw materials for textile industry. E.g. cotton (vi)Angiosperms are used to modify climate.
• Angiosperms provide a wide range of habitats for different species of organisms.

DISADVANTAGES OF ANGIOSPERMS

• 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.
• Some angiosperms are drugs that can be abused when taken. E.g. Marijuana, cocaine, tobacco, caffeine.
• 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

• Both are seed producing plants
• Both have true roots, stems and leaves
• Both have vascular bundles

DIFFERENCES BETWEEN DIVISION CONIFEROPHYTA AND DIVISION ANGIOSPERMOPHYTA


ANGIOSPERMS

1. They produce fruits that contain seeds
2. They are flowering plants  
3. Their seeds are enclosed in an ovary
4. Their reproductive structures are flowers

GYMNOSPERM

1. They produce cones that contain seeds
2. They are non-flowering plants
3. Their seeds are enclosed in cones
4. Their reproductive structures are cones

ECONOMIC IMPORTANCE OF KINGDOM PLANTAE

1. Plants give out oxygen which is used for cellular respiration.
2. Plants are source of fuel to man e.g. Charcoal and firewood
3. Plants are source of food to man and herbivorous animals,
4. Some plants are used to make medicine. E.g. quinine, moarobaini etc
5. Plants provide shade and good habitat for wildlife and birds.
6. Plants beautify and decorate the environment
7. Leguminous plants add nitrate nutrients in the soil.
8. Some plants provide raw materials used in textile industries
9. Some plants are source of timber.
10. Some plants are drugs that can be abused when taken. E.g. Marijuana, cocaine, tobacco, caffeine.
11. Some plants are poisonous when eaten they cause death to human and other animals.
12. E.g. Some cassavas have cyanide acid that inhibits cellular respiration.