UNIT 3. THE INTERACTION FUNCTION

WHAT TO LEARNTo learn about the interaction function.To learn about the interaction function in

plants.To learn about the interaction function in

animals:To study the receptorsTo study coordinationTo study the effectors

PROCESSES OF THE INTERACTION FUNCTION

THE PERCEPTION OF INFORMATION

PROCESSING AND COORDINATION

EXECUTION OF RESPONSES

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STIMULUS

It’s any change in the surroundings

or in the organism which can be

perceived.

RECEPTORS They perceive stimuli.

TYPES

PHOTORECEPTORS

THERMORECEPTORS

MECHANORECEPTORS

CHEMORECEPTORS

They capture light

They detect heat

They detect vibrationsThey detect substances

EFFECTORS

They carry out responses, to

produce movements,

substances, etc

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2. INTERACTION FUNCTION IN PLANTS The most frequent reactions of plants are:

TROPISMS NASTIC MOVEMENTS

CHANGES IN VITAL PROCESSES

They direct the growth towards or away

the stimulus.

Rapid movements of some parts. Reversible.

They modify their vital processes.

Ex: The shoots go to the light.

Ex:A carnivore plant close

their traps to hunt flies

Ex:Flowering in spring

3. INTERACTION FUNCTION IN ANIMALS Receptors: the sense of organs

PHOTORECEPTOR ORGANS: THE EYES

SIMPLE EYESDetect light

COMPOUND EYES: Thousand

of omatidia.

CAMARA-TYPE EYES: Clear images.

Three types

MECHANORECEPTORS ORGANS

Three types

HEARING ORGANS: Capture

Vibrations in air or water

THE LATERAL LINE: Detect vibrations

and movements in water

THE SKIN: Detect pressure

CHEMORECEPTORS ORGANS

ANTENNAE

NOSTRILS

TONGUE

To smell and taste

COORDINATION

THE NERVOUS SYSTEM

THE ENDOCRINE SYSTEM

1. Capture the signals

2. Interprete signals and give orders

3. Communicate the orders

It’s composed by neurons.

It’s composed by endocrine glands.

1.Produce substances called hormones.

The responses are short and fast

2.The hormones provoke responses

The responses are slow

and lasting

THE NERVE IMPULSE

TYPES OF NERVOUS SYSTEM

SIMPLE ANIMALS

They have a network of neurons

Ex: Cnidaria

COMPLEX ANIMALS

They have nerves and nerve centres

(Encephalon/spinal cord)

Ex: Vertebrates

Movements caused by muscles

Secretions produced by glands.

Change in the behaviour

THE EFFECTOR: THE RESPONSES

ACTIVITIES1. Complete:a) The changes in the environment which are

perceived by receptors are called:_____________b) The responses of an organism are carry out

by:_________2. Complete the sentence using these words: reversible-response-tropisms-nastic movements-

rapida) _____________ are a type of _____________ in which the

plant grows towards the stimulus or in the opposite direction. ____________ are_________ movements of some plants, and they are ____________.

3. Are they nastic movements or tropisms?a) The roots grow downwards because of gravity.b) A carnivorous plant traps an insect.c) A creeping plant twists around a tree.d)The root of a tree grows towards a water

source.e)The stem of a plant grows grows toward a

window.4. Complete the table:

ORGANS STIMULI RECEPTORSTongueLateral lineAntennaeSkinEarNoseOmatidia

5.Complete with: Nervous system or Endocrine system.

a) It produce hormones.b) It’s composed of neuronsc) It provokes slow and long-lasting responses.d) It produces rapid responses.e) It’s composed of glands.6. Imagine this situation: “A zebra sees a

lion approaching and runs off”a) What’s is the stimulus?b) Which receptor organ acts?c) What is the response?d) What are the effectors that carry out the

response?

7. Complete the text with these words: effector-receptors-stimuli-sense-coordination.Animals have a serie of __________ specialised in

capturing different types of_____________, almost all animals have____________ organs, with organs or systems to carry out the responses.

8. True or false? Correct them.a) Hormones transmit nerve impulse.b) Endocrine glands produce hormones.c) The endocrine system transmit an electric current.d) The endocrine system transmit information

through hormones.e) The nervous system transmit information as an

electric current.