Characteristics of

Living Things

© H. Reidy

Characteristics of Living things

There is no simple definition of life.

In general, living things are said to have SEVEN* characteristics or features:

* Must have ALL seven, not just some, to be considered living.

© H. Reidy

Characteristics of Living things

2. Respiration

Living things need ENERGY

Respiration is the way in which things break down food to release energy. This happens in all living cells.

© H. Reidy

Characteristics of Living things

If oxygen is used in this process it is called AEROBIC RESPIRATION

If oxygen is NOT present in the process it is called ANAEROBIC RESPIRATION.

In this case, energy is released from food without the use of oxygen.

© H. Reidy

Aerobic Respiration

The equation for Aerobic Respiration is:

Food + Oxygen Carbon Dioxide

+Water

+ Energy

© H. Reidy

Characteristics of Living things

4. Growth

All living things grow

Sometimes the cells increase in size. More often, growth happens when cells divide to form extra new cells.

© H. Reidy

Characteristics of Living things

5. Reproduction

Reproduction is the formation of new individuals.

If living things did not reproduce, them they would die out (become extinct)

© H. Reidy Animals in danger of extinction

African Elephants Bengal Tiger

Gorilla

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Characteristics of Living things

6. Movement

Movement in animals usually occurs more quickly than in plants.

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Movement

It is easier to see animals walking, running, flying or swimming.

© H. Reidy

Movement

It is harder to notice movement in plants. However, roots grow and move through the soil, branches grow longer from year to year, and flower open out from buds.

© H. Reidy

Characteristics of Living things

7. Response

Living things are aware of changes in their surroundings

They are sensitive to different features (or stimuli) and react or respond to these features

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Characteristics of Living things

The sensory system in animals allows them to respond to light, sound, heat, pressure and taste

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Characteristics of Living things

3. Excretion

Excretion is the removal of waste products of chemical reactions in the body

Animals excrete waste such as CO2, salts and water.

© H. Reidy

Excretion

Plants do not excrete as much as animals. However, CO2 is excreted by leaves, especially at night.

CO2

Carbon Dioxide

© H. Reidy

Characteristics of Living things

Plants make their own food in photosynthesis.

Animals get their food by eating plants or other animals.

Nutrition is the way in which an animal or plant gets it food.

1. Nutrition

© H. Reidy The Variety of living things

Living things are arranged into 2 groups:

•The animal kingdom •The plant kingdom

Classifying animals and plants

Animals and plants can be ditinguished under the following headings:

•Movement •Method of getting food

•Whether they have cell walls

Movement

Animals move from place to place.

Plants do not move from place to place.

But, plants can move their parts.

e.g. Daisies open and close their flowers by day or by night.

© H. Reidy

Food Animals: cannot make their own food. They get food by eating plants or other animals.

Plants: make their own food in a process called photosynthesis.

Photosynthesis (Plants)

Plants(chlorophyll) + = Glucose(sugar)

Energy(sunlight) + + oxygen (gas)

carbon dioxide(gas) +

water

© H. Reidy Cell walls Animal cells: do not have a cell wall. They are only surrounded by a membrane.

Plant cells: have a strong cell wall outside the membrane. Due to this cell wall plant cells are stronger than animal cells.

NUCLEUS CELL

MEMBRANE

ANIMAL CELL PLANT CELL

NUCLEUS

VACUOLE

CELL

MEMBRANE

CELL

WALL

Differences between animals and plants

Animals Plants Move from place to place.

Do not move form place to place

Don’t make own food Make their own food

Do not carry out photosynthesis

Carry out photosynthesis

Do not have chlorophyll Have chlorophyll

Are non-green Are green

Do not have cell walls Have cell walls

Animals can be further classified:

1.Invertebrates – are animals that do not have a backbone.

97% of animals are invertebrates, e.g. jellyfish, earthworms, slugs, crabs, insects and beetles.

1.Vertebrates –are animals that have a backbone. (1 vertebra = 1 bone). They are also bigger and more complex animals, e.g. fish, frogs, snakes, birds, mice,, dogs, horses and humans.

There are so many different types (or species) of plants and animals that it is very difficult to name each one. A uselful way to identify living things is to use a key.

A simple plant key A tree that loses its leaves in winter

Single leaves Leaves divided into leaflets

Edge of leaf

Divided into ‘inlets’

Edge of leaf not

Divided into ‘inlets’

OAK BEECH

Leaflets emerge

From a central pt

Leaflets emerge in

Opposite pairs

CHESTNUT ASH

A simple animal key

1 If the animal has hair or feathers Go to 2

If the animal has no hair or feathers Go to 3

2 If there is hair or whiskers on the face or body.

Mammal

If feathers cover the body Bird

3 If the body is covered in scales Go to 4

If he body has no scales and is wet and smooth

Amphibian

4 If the animal has nostrils and lays eggs on land

Reptile

If the animal has gills + fins + lives in water

Fish