☰ Year plan · Science

Characteristics of living things

Week 11 · Lesson 2 General Characteristics of Living Organisms: nutrition and photosynthesis, respiration, transport, excretion, movement, growth, reproduction, sensation, adaptation · 3 lessons
3

Moving, growing and sensing

Science Prep 1 Term 1, Unit 3: pp. 64–71
GoalDescribe how living things move, grow and respond, and give examples of adaptation.
New words
stimulus · a change around a living thing that it can senseresponse · what a living thing does when it senses a stimulusadaptation · a feature that helps a living thing live in its surroundings
Explanation

People move with muscles that pull on the skeleton. Plants move much less, but they do move. The Gazania flower opens in the day, the leaves of the Mimosa fold when touched, and young sunflowers turn to follow the Sun. Single-celled animals move too. An amoeba pushes out false feet, Euglena swims with a whip-like flagellum and Paramecium moves with many tiny hairs called cilia. Living things also grow, reproduce, sense changes and adapt. A change that a living thing can sense is a stimulus, and what it does is its response. An adaptation helps it live where it does: a camel has wide feet for walking on sand, and a cactus stores water in its stem. The book leaves growth, reproduction, sensation and adaptation for you to research.

Living thingHow it moves or responds
personmuscles pull on the skeleton
Mimosaleaves fold when touched
amoebafalse feet
Euglenaa flagellum
Parameciumcilia
Worked examples
A houseplant on a windowsill leans towards the window over several days. The light is the stimulus and the leaning is the response. The plant is not walking: it is growing towards the light.
wide feetstores water
A camel can walk on soft sand because its feet are wide and flat. This is an adaptation. A cactus stores water in its thick stem, which helps it live where rain is rare.
Young sunflowers follow the Sun during the day, but this is true only for young plants. A full-grown sunflower head stays fixed. Always check the age of the plant before you make a rule.
Class activity

Watch a plant lean. Put a small pot plant near a window for a week. Draw it every day. Turn the pot round and watch what happens over the next days. If you can find a Mimosa, touch one leaf gently and watch. Then choose one of growth, reproduction, sensation or adaptation and find two facts about it to share.

Practice
1
How does an amoeba move?
2
In a plant that leans towards a window, what is the stimulus and what is the response?
3
Give one example of an adaptation.
4
Is it true that all sunflowers follow the Sun? Explain.