SCIENCE FORM 2 CHAPTER 1 (1.1)

CHAPTER 1

Content

1.0 Biodiversity
1.1 Diversity of organisms
1.2 Classification of organisms

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1.1 the variety of organisms

1. Living things are
called organisms.
There are many kinds
of organisms on Earth.

2. The variety of
different types
organisms on Earth is
called biodiversity

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What is biodiversity?

Biodiversity refers to wide variety of organisms on Earth

Where can we find biodiversity?

 The place where organisms live is called the
habitat.

 Biodiversity is found in various habitats such as
forests, ponds, deserts, seas and soil.

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The importance of biodiversity:

 Maintain the balance of nature
 Sources of food
 Attract tourists and so can contributes to the economy of the

country.
 Sources of medicine
 Raw material for industries
 Education

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 Restricting Exploitation of Forest Resources
 Reducing Pollution
 Stop overharvesting
 Protect habitat
 Endangered species act

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2.
BIODIVERSITY

ANIMALS PLANTS

1. There are two main groups of animals:

Animals

Vertebrates Invertebrates

Animal with Animal without
backbones backbones

B. Vertebrates

a. Smaller group compared to invertebrates.
However, we are more familiar with this group
of animals

b. Since vertebrates have backbone to support their
weight, many vertebrates are large in size

c. Examples:

 Elephants
 Eagles
 Whales
 Snakes
 Frogs
 Clown fish

Classification of vertebrates

Vertebrates

Amphibians Birds Reptiles

Fish Mammals



1.Common characteristics of fish

Body covered with slimy scales for protection
Have fins and tail to swim
Streamlined bodies to swim well
Breathe through gills
Poikilothermic (body temperature changes with the
 surrounding temperature)
Lay eggs
Carry out external fertilization (eggs are fertilized outside
 the female body)

Amphibians

1. Common characteristics of amphibians

• Body covered with moist skin
• Adults can live on land and water
• Adults breathe with lung on land and through moist

skin when in water
• Poikilothermic (body temperature changes with the

surrounding temperature)

• Lay eggs covered with jelly-like substance
• Young amphibians live in water and breathe through gills

• Carry out external fertilization (eggs are fertilized outside
the female body)

Tortoises Snake
Crocodile

1. Common characteristics of reptiles

• Body covered with hard and dry scales for protection
• Breathe with lungs
• Lay eggs with leathery shell
• Poikilothermic (body temperature changes with surrounding
temperature)

• Carry out internal fertilization (eggs are fertilized inside
the female body)

Kingfisher

Hornbill

1.Common characteristics of birds

• Body covered with feathers
• Have wings and beak
• Breathe with lungs

• Homeothermic (body temperature remains constant)

• Lay eggs with hard shells

• Carry out internal fertilization (eggs are fertilized inside the
female body)

Camel Orangutan

Tiger

Rhinoceros Elephant

1. Common characteristics of mammals

• Body covered with hair or fur
• breathe with lungs
• Homeothermic (body temperature remains constant)
• Give birth to live young
• Carry out internal fertilization (eggs are fertilized inside
the female body)

• Young mammals feed on milk from their mother’s
mammary glands

A. Invertebrates

a. More than 90% of animals are invertebrates
b. Since invertebrates have no backbone, they are

usually small in size.
c. Examples:
 Inserts such as ants, butterflies, flies, and cockroaches
 Spiders
 Crabs
 Prawns
 Worms
 Mollusks such as snails

Classification of invertebrates

Invertebrates

Without legs With leg

Without With segmented Three pairs of More than three
segmented body body legs pairs of legs

1. Without segmented body

 Without legs and without segmented bodies

2. With segmented body

 Without legs and have segmented bodies

3. With legs

 Have segmented bodies
 Have hard outer shells (exoskeleton)

Three pairs of legs

4. More than three pairs legs