Characteristics of Living Things - Biology is Fun!€¦ · Form 3/SS+NS/ss/12-13 Characteristics of Living Things Respiration (Energy) All living organisms need energy. They get this

Biology Lesson Notes

Form 3/SS+NS/ss/12-13 Characteristics of Living Things

Characteristics of Living Things

By the end of this topic you should be able to:

identify the vital functions characteristic of all living things

recognize the cell as the basic unit of any living organism

comprehend the common features of all cells as well as the basic differences between animal and plant cells

analyze the relation between the structure and function of specialized cells

understand that cells, tissues, organs and systems represent increasing degree of organization in living organisms



The Seven Vital Functions

Living things include microbes, plants and animals. They live on the land and in the lakes, rivers, and seas.

All very different but all are alive. All can perform some common features These are the Seven Vital Functions.

Only living things have all of these features They are “tests” of being alive.

The Vital Functions are processes that all living organisms do. They tell you whether something is alive or not.



Movement

Living things move without outside help.

Non-living things move under external forces (e.g. machines, something falling).

Organisms like animals can move their whole body

(E.g. walking, running, etc.)

Organisms like plants can only move parts

of their body (E.g. opening and closing

of flower petals)



Can you match these types of movement to the pictures?

Flying Swimming

Chasing for food Migration

Venus fly-trap catching insects

Turning flower towards sun



Sensitivity (Irritability)

Living things respond to conditions around them. Organisms can identify stimuli in their surroundings and respond to them.

Green plants growing

toward sunshine Blinking when light shines

into their eyes Jumping up when stepping on a sharp pointed object

like a pin

Stimulus Organism Response



Can you match these responses to their stimuli?

The Venus fly-trap

catches insects

Roots grow into soil

Flowers close during the night

A deer runs away from a lioness

Gravitational pull

Insect touches hairs on leaves

Sun sets

Smell of predator

Roots grow down

Insect trapped

Flower closed

Fast running



Nutrition (Feeding)

All living things try to get food, and they get it in different ways

Bite with teeth (e.g. Humans and other Animals)

Suck up food with specialized suckers

(e.g. flies and other insects)

Absorb it (soak it up) through membranes/skins (e.g. Bacteria and Fungi)

Do you know of any other ways of feeding?

Amoeba engulfing food Swallowing prey whole



Some organisms can make their own food from water, CO2, nitrogen, and minerals.

Green plants

Photosynthesis is the build-up of food from Carbon dioxide and water using the Sun’s light energy.

6CO2 6H2O C6H12O6 6O2

The Equation for Photosynthesis

Carbon Dioxide

Water Chlorophyll

Light Enzymes

Glucose Oxygen



Respiration (Energy)

All living organisms need energy.

They get this energy by burning food, using a chemical process known as Respiration

Aerobic respiration uses oxygen to release energy from food.

Anaerobic respiration does not use oxygen to release energy from food.

Respiration is the burning of food (glucose) to produce energy.

C6H12O6 6O2 6CO2 6H2O 2830kJ

The Equation for Aerobic Respiration

Glucose Oxygen Enzymes Carbon Dioxide

Water Energy



The oxygen needed for aerobic respiration comes from the environment

Humans get oxygen by

breathing in air Fish get oxygen

from water

Aerobic respiration produces carbon dioxide, which is removed when we breathe out.

This exchange of gases is called gaseous exchange

There are different organs for this:

E.g. lungs in mammals, gills in fish, leaves in plants.



Growth

Non-living things become larger. E.g. Balloon grows, salt crystals grow in salty water as it evaporates

Living organisms turn some of the food into living material (bones, teeth, wood, etc.).

Living things

grow by

Becoming bigger: e.g. chick hen;

Child Adult Becoming more

complex:

e.g. Caterpillar Butterfly

Changing old parts: e.g. grasshopper sheds “skin” to make new one.

Making new parts: e.g. teeth in children.

Repairing body parts (healing injuries, replacing worn parts):

E.g. Shrubs and trees cover injuries with bark; Crabs grow new legs when old ones are lost; Human beings heal cut skin and broken

bones.



Excretion

A lot of chemical reactions take place in the body.

Chemicals are broken down to produce energy (respiration).

Chemicals are built up to form new body structures (growth).

These reactions are called Metabolism.

Waste materials are produced

These would cause illness and death if not removed.

Excretion is the process of getting rid of these waste materials.

For e.g. in animals, ammonia, which is very poisonous, is removed by first turning it to a less harmful substance and then passed out of the body as a liquid called urine.

Excretion is the removal (from the body) of waste products resulting from metabolism.



Two other processes also result in the removal of substances from the body

Can you think of other ways in which we get rid of waste materials?

Egestion the removal of undigested food from the body

Since this food has not taken part in any chemical reaction,

it is not considered as part of excretion.

Secretion the release of useful substances produced by cells or glands

into or out of the body.

E.g. tears are secreted under the eyelid.

Tears are not a harmful substance, and not a waste product.

Sweating (heat and urea)

Exhaling (CO2 and water)

Excess Water (urine)



Reproduction

All living organisms eventually die.

They avoid becoming extinct by producing copies of themselves.

Offspring have the same characteristics as parents.

Reproduction is the production of new individuals

of the same species (kind of organism)



Can you mention what different forms these organisms have in their life-cycles?

Frogs have tadpoles Dragonfly larvae spend about 3 years

in an aquatic environment Butterflies have

caterpillars

Asexual reproduction Simple microbes

(bacteria) reproduce by dividing into two sections.

Each section becomes a new living organism.

Some organisms (e.g. insects) have more than

one form in their life-cycle E.g larva and adult.

Sexual reproduction Other organisms (most animals) produce new

individuals by combining characteristics of two

parents.



Worksheet

Description of Process / Activity Vital Function

Escaping from danger

Making new leaves

Sweating

Having a snack

A plant makes and releases seeds

Oak trees develop from acorns

Laying eggs

MRS

NERG

Movement Sensitivity Reproduction Respiration Nutrition Growth Excretion



Description of Process / Activity Vital Function

Hearing a whistle

Using up energy in a race

Changing position or posture

Releasing energy from food

Getting rid of excess water as urine

A lion tearing and biting the flesh of a zebra it has caught

The breakdown of food to release energy

The change of a larva (caterpillar) into a butterfly

MRS

NERG

Movement Sensitivity Reproduction Respiration Nutrition Growth Excretion



Summary

All living things do the following things:

Respire: they break down food to obtain energy. Most organisms need oxygen for this.

Feed: food is needed for energy and for making new cells. Plants make their own food by photosynthesis but animals, fungi and most bacteria must obtain it from other living organisms.

Excrete: respiration and other chemical processes in cells produce waste products which have to be expelled.

Reproduce: all organisms eventually die. Species persist only as result of reproduction. Reproduction may be sexual or asexual.

Grow: the cells of an organism increase in number and size. The cells also become specialized and the organism increases in complexity.

Move: most organisms move, or make movements at some stage in their lives.

Respond to stimuli: living organisms are sensitive to their surroundings and respond to changes in their external and internal environment.

Documents

Characteristics of Living Things - Biology is Fun!€¦ · Form 3/SS+NS/ss/12-13 Characteristics of Living Things Respiration (Energy) All living organisms need energy. They get this