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SS1: BIOLOGY - 1ST TERM

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  1. Introduction to Biology | Week 1
    6 Topics
    |
    1 Quiz
  2. Recognizing Living Things | Week 2
    3 Topics
    |
    1 Quiz
  3. Organisation of Life | Week 3
    3 Topics
  4. Classification of Living Organisms | Week 4
    7 Topics
    |
    1 Quiz
  5. Kingdom Prokaryotae / Monera & Kingdom Protista | Week 5
    3 Topics
    |
    3 Quizzes
  6. Kingdom Fungi & Kingdom Plantae | Week 6
    9 Topics
    |
    2 Quizzes
  7. Kingdom Animalia I | Week 7
    6 Topics
    |
    1 Quiz
  8. Kingdom Animalia II | Week 8
    5 Topics
    |
    1 Quiz
  9. The Cell | Week 9
    3 Topics
    |
    1 Quiz
  10. The Cell Structure and Functions | Week 10
    4 Topics
    |
    1 Quiz
  11. The Cell and its Environment | Week 11
    4 Topics
    |
    1 Quiz
  12. Nutrition in Plants | Week 12
    4 Topics
    |
    1 Quiz



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Characteristics of Spermatophyte:

1. They are multi-cellular, seed-producing plants including most trees, shrubs, and herbaceous plants.

2. They are vascular plants and have well-developed vascular tissues.

3. They have true roots, leaves and stems.

4. They reproduce sexually and do not need water for reproduction.

5. They are mainly terrestrial green plants.

6. The seed plants are divided into gymnosperms and angiosperms.

Classification of Spermatophyte:

Spermatophytes can be divided into two main classes. These are

i. Gymnosperm
ii. Angiosperm

Class Gymnospermae:

Gymnosperms
Conifers are Gymnosperms; Vascular plants that possess “exposed” seeds.

1. Gymnosperms have a well-differentiated plant body and vascular tissues.

2. They are seed-bearing plants that do not produce flowers.

3. They have true roots, stems and leaves.

4. The seeds grow exposed on a cone, not enclosed within a fruit. Hence, the term “Gymnosperm”, which is derived from the Greek word, gymno = naked and Sperma = seed, which means naked seed.

5. They bear no fruits.

6. They show alternation of generation with the sporophyte as the gymnosperm plant or dominant generation while the gametophyte is severely reduced.

7. Examples are

i. Palm-like Cycads
ii. Gingkoes – (fan-like leaves)
iii. Gnetophytes (scale-like leaves)
iv. Conifers e.g. pines (needle-like leaves e.g Whistling pine), firs, spruces.

cycad
Cycad.
Gingkoes
Gingko.
Welwitschia
Welwitschia (Class Gnetophyte.)
conifers
Conifer plant.

Class Angiospermae (Flowering Plants):

angiosperms
Angiosperms.

Characteristics:

1. They have true roots, stems and leaves hence they are said to have a well-differentiated body.

2. They produce seeds which are enclosed by fruits.

3. Fruits develop from the ovaries of flowers.

4. They have a well-developed vascular system.

5. Sporophytes are dominant with the gametophyte (flower) severely reduced.

6. Angiosperms are grouped into monocotyledons and dicotyledons.

7. Examples include. oil palm tree, maize plant, mango tree etc.

flowering plant
Structure of a flowering plant.

Difference between Gymnosperm and Angiosperm:

Gymnosperm:Angiosperm:
They do not bear flowers.They are flowering plants.
Seeds are naked.Seeds are enclosed.
Seed borne on cones.Seeds develop from ovules.

Sub-Classes of Flowering Plants:

Flowering plants are divided into two subclasses;

i. Monocotyledonae
ii. Dicotyledonae

Monocotyledons are flowering plants with only one cotyledon in their seeds. Most monocots have long narrow leaves e.g. grasses, cereals, palms, and coconut.

monocot maize
Maize Plant – Monocot.

Dicotyledons are flowering plants with two cotyledons in their seeds. Their leaves are usually broad with their leaf veins forming a branching network e.g. mango, orange, waterleaf, cowpea, groundnut, Neem tree.

Water leaf plant
Waterleaf plant – Dicot plant.

Difference between Monocotyledons & Dicotyledons:

S/nMonocots:Dicots:
1.EmbryoThey possess only one cotyledon
in their seeds.

Screenshot 2022 07 27 at 22.58.01
They possess two cotyledons
in their seeds.

Screenshot 2022 07 27 at 22.57.54
2.RootsThey have a fibrous root system.

Screenshot 2022 07 27 at 23.46.00
They have a tap root system.

Screenshot 2022 07 27 at 23.45.52
3. FlowersFloral parts are arranged in threes
and multiples of threes.

Screenshot 2022 07 27 at 23.07.04
Floral parts are arranged in
fours and fives.

Screenshot 2022 07 27 at 23.07.10
4.LeavesTheir leaves have parallel venation.

dicot
Their leaves have net venation.

dicot2
5. Secondary
Growth
They do not undergo secondary growth.They undergo secondary growth.
6.GerminationThey exhibit hypogeal germination.
i.e. the cotyledon is returned below the soil.

hypogeal e1659021582379

They exhibit epigeal germination. i.e.
the cotyledons shoot out to the soil surface.

epigeal e1659021488567
7. Stem
Structure
Vascular bundles are scattered.

monocot stem
Vascular bundles of stem are
arranged in rings.

dictot stem

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