SECONDARY ONEINTEGRATED SCIENCE

Unit 2Looking at living things

2.3 Diversity of living things

Dec-2010

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REVISION

Do you remember what did we do in the last lesson? Observation of living things

External features Behaviours

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THE WIDE VARIETY OF LIVING THINGS

How many kinds of living things can you find in this picture of showing a corner of a park?

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THE WIDE VARIETY OF LIVING THINGS

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OK!Let me count how many living things!

5…10…

There are at least 10 living things just at a corner of a park!

Oh! I can’t imagine how Oh! I can’t imagine how many kinds of living many kinds of living things in the world!things in the world!

THE WIDE VARIETY OF LIVING THINGS

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Let me tell you the answer.

Scientists estimate that Scientists estimate that there are 4 million to 12 there are 4 million to 12

million kinds of living million kinds of living things on Earth. things on Earth.

THE WIDE VARIETY OF LIVING THINGS

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WOW! However, I have a question.

Why is the total number Why is the total number of kinds of living things on of kinds of living things on

Earth only an estimate?Earth only an estimate?

THE WIDE VARIETY OF LIVING THINGS

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It is because some living It is because some living things cannot be seen things cannot be seen

directly and some of them directly and some of them live in the deep sea or live in the deep sea or hide themselves from hide themselves from human. So the exact human. So the exact

number remains unknown.number remains unknown.

THE WIDE VARIETY OF LIVING THINGS

These living things differ in:

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size

body forms body structure

THE WIDE VARIETY OF LIVING THINGS

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LIVING THINGS AND THEIR HABITATS

Natural environment where living things live

http://www.youtube.com/watch?v=zNTHVLxPP54

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Can you point out the habitats

mentioned in the video?

LIVING THINGS AND THEIR HABITATS

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BehavioursBody

features

help living things to adapt to their habitats

IN THE FOREST

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some plants climb on tree trunks

reach for more sunlight

IN THE GRASSLAND

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antelopes run fast

escape from predators

IN THE DESERT

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cacti store a lot of water

survive in dry environment

IN THE FRESHWATER STREAM

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webbed feetfrogs have webbed feet

swim in water

IN THE OCEAN

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dolphins have a streamlined body

swim with little water resistance

IN THE POLAR REGION

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seals have a thick layer

of fat under skin

keep warm in coldenvironment

WHAT ELSE?

Hong Kong Wetland Park http://www.wetlandpark.com/en/biodiversity/

hab_fm.asp

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ROLE PLAY

3 students Imagine you are a specified living thing and

follow the instructions below. Do the suitable action (e.g. move slowly/ voice) Say the special feature(s) you have Choose the most favourable habitat for you to live Explain your choice

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1. CAMEL

(A) Grassland (B) Desert (C) Polar region

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2. PENGUIN

(A) Polar region (B) Rainforest (C) River

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3. SHEEP

(A) Ocean (B) Polar region (C) Grassland

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>

RECALLING YOUR MEMORY

Worksheet of 2.2 Observing Living Things Question of finding differences between two

tortoises Answers included

Size Weight Pattern Colour Etc.

Those differences are called variations23

VARIATIONS

The differences among the individuals of the same kind of living things

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VARIATIONS Continuous

Have a range of intermediate between two extremes.

E.g. Height

Discontinuous Have no intermediates. Either have the characteristic or don’t. E.g. Blood type

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CLASSROOM ACTIVITY 2.4

Variations within humans Can you roll your tongue? Do you have free or attached earlobes? Can you bend your thumb back? Measure your hand-span in cm. Draw a bar chart to show the distribution.

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WHAT SHOULD WE LEARN FROM VARIATIONS?

Not bad or good Everyone has his/ her own characteristics Respect and accept each other

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SUMMARY

Scientist estimate (估計 ) 4 millions to 12 millions kinds of living things on Earth

They are different in size, body form and body structure

There are many habitats (生境 ) in the world where living things are living in Desert (沙漠 ) Ocean ( 海洋 ) Forest ( 森林 ) Polar region (極地 ) Etc.

Living things adapt (適應 ) the habitats by their body features and behaviours

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SUMMARY

Variations (差異 ) exist among the individuals of the same kind of living things.

Continuous variations ( 連續差異 ) Height Weight

Discontinuous variations ( 不連續差異 ) Skin colour Blood type

We should respect (尊重 ) and accept (接納 ) everyone.

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