Form 2 note's: Science Form 2 Biodiversity

SCIENCE - FORM 2

Biodiversity

VARIETY OF LIVING THINGS AND THEIR CLASSIFICATION

1. The living thngs found on Earth are humans, animals and plants.

2. A living thing is known as an organism.

3. Animals and plants have various shapes, sizes and habitats.

4. The differences that exist between the same species of living things are called variations.
Habitat of living things

1. A habitat is the neutral place where a living thing lives.

2. Different animals and plants live in different habitats.

Classification of animals based on common characteristics
1. Animals can be classified based on common characteristics.

2. Examples of classification of animals based on their habitats and their breating organs are shown
on the next page.

Classification of plants based on common characteristics
1. Plants are also classified based on their common characteristics.

2. Examples of the classification of plants based on habitat, type of stem, and method of reproduction
are shown on the next page.

Constructing a system of classification
1. A dichotomus key of identification is used to classify organism.

2. Pairs of opposite characteristics are used in the identification key.

3. At each instance, a pair of opposite characteristics are used.

4. The identification key is constructed following two ways to identify the following animals.

(a) Chart form

(b) Using statements

1. With wings ................................................. see ( 2 )
Without wings ............................................ see ( 3 )
2. Segmented body ........................................ Bee
      Unsegmented body .................................... see ( 4 )
3. With legs .................................................... Cat
   No legs ....................................................... see ( 5 )
4. With feathers .............................................. Eagle
No feathers ................................................. Bat
5. Has hard shell ............................................. Garden snail
No shell ...................................................... Snake
System of classification of animals

Animals can be classified into two groups :
(a) Invertebrates ( animals without back-bones )
(b) Vertebrates ( animals with backbones )
Invertebrates
1. Invertebrates are animals which do not have backbones.

2. Invertebrates make up the most number of animals in the world.

3. Most invertebrates live in the water.

4. Some invertebrates have a hard external skeleton for protection like the crab and the beetle.

5. Some invertebrates have soft bodies using their body fluids for support olike the earthworms and
leeches.

6. Generally, invertebrates can be classified into two groups, that is
(a) with jointed legs (b) without jointed legs

Vertebrates

1. Vertebrates are animals with backbones.

2. Warm-blooded vertebrates ( homoiothermic ) have fixed body temperatures, cold-blooded
vertebrates ( poikilothermic ) have body temperatures that change according to the temperature of
their surroundings.

3. Vertebrates can be divided into five main groups, which are fish, amphibians, reptiles, birds and
mammals as shown below :

Unusual characteristics of some mammals

1. Bats - have wings and fly like birds

2. Whales and dolphins - live in water like fish.

3. Anteaters - lay eggs, have dry scales on their bodies like reptiles.

4. Platypus - lay eggs and have beaks like ducks

5. Porcupines - the body is covered with spines for protection
System of classification of plants

1. Plants can be classified into two main groups, i.e. flowering plants and non-flowering plants.

2. Flowering plants are divided into dicotyledons and monocotyledons.

Flowering plants
1. This type of plant produces flowers, seeds and fruits. The flowers normally become fruits.

2. This type of plant produces flowers for reproduction.

3. Flowering plants can be divided into dicotyledons and monocotyledons.

4. Examples of dicotyledons are rubber trees, durian trees, hibiscus plants and rambutan trees.

5. Characteristics of a dicotyledons are shown below.

6. Examples of monocotyledons are paddy plant, maize plant, grass and oil palm.

7. Characteristics of monocotyledons are shown below.

Non-flowering plants

1. Non-flowering plants do not produce flowers, fruits and seeds.

2. These plants reproduce by spores or binary fission.

3. Non-flowering plants are divided into four groups, i.e. :
(a) algae (c) fungus
(b) moss (d) ferns