Coping with dangers

Document Sample
Coping with dangers Powered By Docstoc
					                Alford Academy

                 Higher Biology

      Unit 2: Genetics and Adaptation

             Coping with Dangers
                 Chapter 26

Name: __________________ Teacher: ________________
                        Coping With Dangers in Animals

Any action taken by an organism is part of its behaviour. For any action to occur
the organism needs receptors and effectors and feedback must be possible e.g.
An animal stops drinking water when it has had sufficient.

Instinct and Learning

    Instinct is inborn i.e. it is thought to be genetically determined.
    Learning is behaviour which is acquired due to experience.

Instinctive behaviour

An example of instinctive behaviour is avoidance behaviour. This is the behaviour
that reduces the risk of being eaten. which is demonstrated by a snail on a glass
slide. If the slide is tapped then the snail retreats into its shell.

Examples of avoidance behaviour: -
   Earthworm escapes response - withdraws rapidly into burrow when touched
   Squid dart backwards when faced with danger - squirts water through its
   Caryfish also dart backwards when faced with danger - flexes its abdomen
    very rapidly
   Snail retreats into its shell

Learned behaviour
There are 5 categories of learning. These are:

1. Habituation                                3. Imprinting
2. Associated leanring,                       4. Exploratory learning
   including ‘trial & error’ learning         5. Insight learning
   1.    Habituation

   A snail on a slide retreats into its shell if the slide is tapped. If however, the
   slide is tapped repeatedly the snail no longer responds by retreating into its
   shell since the stimulus is harmless. Unlike avoidance behaviour the snail has
   learnt to do this. This has the advantage of stopping the animal responding
   unnecessarily, which saves energy. However this behaviour is short lived
   since if the stimulus is stopped and repeated a while later the snail retreats
   into its shell again, as it may be dangerous.

Complete the following passage using the following words; unlearned, protect the
organism, repeated, harmless, learned, short-lived, avoidance behaviour,

Snail    when   tapped   retreats    into    its   shell   -   this   is   an   example   of

______________ ________________. Avoidance behaviour is _________; it

is automatic and its purpose is to          _________ ____ _________________.

If this tapping of the shell is repeated the snail eventually stops responding to

the tapping stimulus. This is an example of ____________.

Habituation is when an organism learns to ignore a harmless stimulus. For

habituation to happen the stimulus must be __________ and the stimulus must

be __________.

Habituation is an example of a __________ behaviour.

It is of an advantage to the organism because it stops it performing an escape

response to a harmless stimulus and therefore saves energy. Habituation is

_________ - ____________, after a period without the tapping stimulus the

snail if tapped will respond. If habituation was a long-term modification of the

escape response the animal would be left open to danger.

2.      Associated learning

Toad fed bee will not eat yellow/black prey in future due to danger of being stung

3.     Imprinting
     Ducklings and goslings follow the first large moving object they meet. This is a
     behavioural adaptation of survival value. It provides the means by which a
     young bird avoids danger by staying close to, and being protected by, its

4.     Exploratory Learning
     An example of exploratory learning are mice in mazes sniffing about in nooks
     and crannies trying to reach food.

5.     Insight Learning or reasoning
     This is the `highest form of learning' and depends on the animal being
     `intelligent.' Intelligence may be defined as the immediate understanding and
     response to a new situation without trial and error. How much of this
     behaviour is based on other types of learning is debatable.

                     Learning experiments and learning curves

Learning curves show a decrease in time to make a correct response e.g. a rat
going through a maze, a human typing. When each learning experiment is repeated
a few days later the individual is found to have retained some learning. (Hint for
successful studying). Learning is therefore thought to involve a long term
modification of a response. This means that in order to learn an animal must
remember a previous situation.

Ability to learn depends on intelligence. Intelligent animals can reason and solve
new problems by applying previously learned experiences.

     Now answer
      TYK questions 1-3 page 213 (old), page 233 (new)
      AYK questions 2-3 on page 219 (old), pages 240 and 241 (new)

                      Individual mechanisms of defence
There are 2 types of defense active and passive.

          1. Active Defence Examples

           Skunk can produce a foul-smelling secretion which it squirts at it’s
           Insects defend themselves by injecting poison into their attackers
           Some caterpillars are covered with bristles
           Antelopes and ostrich flee from enemies at top speed
           Avocet can perform distraction displays - 'broken' wing
           Grass snake feigns death to avoid danger

        2. Passive Defence Examples - many animals' possess protective
           coverings which safeguard them from attacks by predators.
         Limpet shell
         Armour plating of armadillo
         Moths have markings resemble menacing eyes
         Some insects resemble leaves or twigs.

Complete the following table, using Torrance page 214-215(old), 234-235 (new).
           Protection                      Examples of animals

     Protective coverings


       Poisonous chemicals


      Patterns to blend into

        Deflection display


Now answer AYK questions 4 and 5 on page 220 (old), page 241 (new).

                       Social mechanisms for defence
By staying together as a large group many types of animal rely on the principle of
'safety in numbers' as a means of defence. The predator will find it more
difficult to capture a member of a large group rather than an individual on its
own. The members of the social group can also adopt a special formation.

   Musk Oxen of Canada adopt a special herd formation with the cows and
    calves in the centre of the herd
   Quails roost in circles with their heads to the outside - 'explode' in the
    predators face
   Baboons on the march, dominant male and the females with infants are in
    centre with the lower ranking males to the outside.

                        Coping with danger in plants
Due to their sessile nature plants cannot flee from danger, they require some
form of defence mechanisms.

Defence mechanisms found in plants

There are two main types of defence mechanisms- Structural & Chemical

1.     Structural defence mechanisms

Amongst flowering plants, a variety of structural adaptations are found to keep
herbivores at bay.

Using Torrance page 21-218 (old), 237-238 (new) complete the following
table on structural defence mechanisms.

            Plant                  Structural defence mechanism







2.     Chemical adaptations in plants (Secondary Compounds)

These are the by-products of a plant's metabolism and can act in a number of

      Chemical mimics
         Some plants make chemicals that closely resemble hormones in the
         herbivore, e.g. clover makes a substance which mimics the effect of
         oestrogen. This can affect sheep by reducing their fertility

   Poisons
       Buttercups produce a chemical that is poisonous to farm animals
       Cyanide compounds such as those produced by white clover are toxic to
       animals. When grazing damages leaves, cyanogenic compounds are
       produced rapidly.
       Hydrogen Cyanide is a highly toxic substance

Some plants produce chemicals that are unpleasant or toxic to animals: eg nicotine
& tannins
                         Ability to Tolerate Grazing

Most plants grow from meristems (growing points) well above the ground. If they
are damaged during grazing, regeneration is difficult. The meristem of grasses
are low, at ground level, and, are unlikely to be damaged even after heavy grazing.
New leaves grow quickly; therefore grasses are better able to tolerate grazing.

Many grasses possess rhizomes. These underground storage organs are capable of
asexual reproduction and help to ensure the plant’s survival

Plantains and dandelions have evolved a flat rosette habit and leaves radiate out
close to the soil and escape grazing.

Some meadow plants possess enormous powers of regeneration. Dandelions have a
small root that is capable of producing an entire plant.

Now answer TYK questions 1-3 on page 218 (old), 240 (new)

                            Coping with Dangers

                   Learning Outcome                         I can find   I can do
                                                            this in my     this
Describe what is meant by the following:
 avoidance behaviour
 habituation
 learning
Describe using named examples how an animal uses the
following strategies to protect itself:
 flight
 camouflage and warning colouration
 mimicry, death feigning and distraction displays
Describe 2 methods used by a GROUP of animals to
defend the group
List with named examples 3 structural mechanisms used
by plants for defence
Explain how the siting of meristems can improve a plant’s
tolerance of grazing
Explain the benefits to plants of having the ability to
regenerate quickly


Shared By: