Digestion and alimentary canal

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					 Standard Grade

   Topic 3
Animal Survival
Animal Survival is divided into:
A- The need for food
B- Reproduction
C- Water and waste

    D- Responding to the
            What changes?
The environment has many places called habitats
(such as land, sea, in the air and in water).
Animals or plants live there with the conditions
they need to survive.

Organisms need to be able to detect and respond
to a stimulus or change in those surroundings.
Detecting Environmental Factors

Why? To improve their conditions (hence
survival chances) or protect themselves from harm.

Humans have many sense organs to detect stimuli

What do you think you can detect?
How does your body do it?
Lets do some experiments…..
Sense    Stimulus   Sense organ
 Sight      light      eyes
Sense    Stimulus   Sense organ
Smell   chemicals      nose

                            Above- surface
                            Left- cross-section

   Sense        Stimulus       Sense organ
Temperature   heat / cold          skin
Pain          damage               skin
Pressure      force                skin
Touch         contact              skin
     Hearing, balance

 Sense     Stimulus    Sense organ
Hearing     sound           ears
Balance   movement      part of inner
          / position         ear
            Sense                 Stimulus    Sense organ
            Taste                chemicals     tongue and

Vertical section through human tongue; a,
 a, blind lymph capillaries in the filiform
  papillæ with the underlying lymphatic
     plexus. X 45. (Teichmann, 1918.)
             Case Studies
We will look at some different species, find out
what the stimulus is, how they respond, and the
importance of it to the animal’s survival.
         Woodlouse
         Blowfly maggot
         Shore crabs
         Hedgehog
         Cockroach
         Barnacle goose
         Atlantic salmon

We will also look at how scientists find this out…
           Choice Chamber
A choice chamber is a
piece of apparatus that
lets a scientist study the
effect of differences in an
environmental factor on
the behaviour of an

Different conditions can be set up in different
sections of the chamber.
The proportion of time that the animals spend in
each area can be measured.
Hence their preferred conditions can be
   Woodlouse choice chamber
                               Woodlice move randomly.
          IN                   Those in the light respond
                               by moving quickly.

Why? This increases their
chance of moving out of
the light and into the dark.

                                  Those in the dark
Why? This behaviour               respond by moving
increases their chance of         slowly or coming to
staying in the dark.              a standstill.
Woodlouse response
 Moisture              Dark

 Moves towards         Slows & stops
 moisture              in dark places

               Importance to survival

In dry conditions they lose    When in light, easily
water through their            spotted & eaten by
permeable skin & die           predators
                            Blowfly maggot
                          The name comes from an
                          older English term for meat
                          that had eggs laid on it, which
                          was said to be fly-blown.

Their common name
is blue-bottles.
They are usually the
first insect to come in
contact with a dead
              Blowfly Fact File
 Natural life history largely unresearched

 Adults are occasional pollinators, attracted to
flowers with strong odours resembling rotting meat
 Larvae are scavengers of carrion and dung

 Rate of development is highly dependent on
temperature eg. Black blowfly egg to pupa takes 6
– 11 days, it leaves corpse, burrows into ground
and emerges as adult after 7 – 14 days…..

 If ambient temperature is known they are
used in forensic science to estimate the time of
death (rigor mortis unreliable after 72 hours).
 Used to treat badly infected wounds         Gladiator
        Blowfly reproduction

 Eggs about 1.5 mm x 0.4 mm, are yellowish or
white, look like rice balls.

 Typically lay 150-200 eggs per batch, but around
2,000 eggs during the course of her life.

 The sex ratio of blowfly eggs is usually 50:50, but
females from two species of the genus Chrysomyia
(C. rufifaces and C. albiceps) are either
arrhenogenic (laying only male offspring) or
thelygenic (laying only female offspring).
       Blowfly maggot response
                           They have no eyes
       Stimulus             yet can detect &
                            respond to light!

Moves away from light
Importance to survival
                         They hatch from eggs
Needs to stay in dark
                         laid in manure heaps and
places to obtain food,
                         in animal corpses.
moisture, shelter and
protection from
   Sense / response Questions
1. How are changes in your environment
   detected? Through your senses sending signals to the brain
2. Name 3 environmental factors that organisms
   can respond to.          Light, humidity/moisture, chemicals
3. Describe three examples of responses to
   stimuli. Woodlice stay in dark& moisture, cockroaches
             stay in dark, human response to pain etc
4. Explain the advantages of the responses which
   you described in your answer to question 2.
   Woodlice avoid predators/can breathe, cockroaches avoid
   predators, human prevent further harm/damage
5. For a named organism, explain the significance
   of a response it makes to a stimulus.
   Woodlice & cockroaches who avoid predators stay alive
   and survive
      Rhythmical behaviour
What is it?
When animals alter their behaviour in response
to a change in environmental conditions
(a trigger stimulus).

Main features:
  It is regular
  It is triggered by an external stimulus
  It possesses an internal component which
 causes it to persist even in the absence of the
 trigger stimulus (biological clock)
            You got rhythm?
Why have it?
Allows organism to exploit regular events in the
environment and increases its survival chances.

Rhythmical behaviour can occur:
 Daily (occurs once every 24 hours, or at the
     same times of day)
 Monthly
 Annual / Seasonal (daylength, temperature)
 Tidal (occurs at each turn of the tide, each
     complete cycle takes 12.5 hours)
      Daily rhythms- examples
 Sun’s position & movement during the day

 Night/day (active during day- diurnal,
at night-nocturnal)

 Movement of leaves/flowers during constant light

 Insects emerge from pupae at a particular time of
 In internal organs and cells, the release
of enzymes & hormones vary during the day

Watch Planet earth sequences-
Ice world- penguins, Deep oceans- Blue whale
        Rhythmical Behaviour
                                    Shore crabs

                              You may have met
                              them on the beach in
                              rock pools…

                             Read workbook p94, 95

1. Write a note on how the crab’s activity is
   related to the movement of the tide.
2. Identify the trigger stimulus.
3. Explain what happens to the crabs’ pattern of
   activity when placed in constant laboratory
                 Shore crabs
Rhythmical behaviour

High activity at high tide

   Trigger stimulus

Importance to survival
Food available at high
tide (small seashore
animals). This is when
they become very active
and feed
                            Name used from 1450’s,
                            derived from the middle
                            English word 'heyghoge'.
                            Other folk names include
                            ‘urchin’, 'hedgepig' and
There are 16 species,
native to parts of
Europe, Asia and Africa.
They have changed little
over 15 million years and
have adapted to a
nocturnal, insectivorous
way of life.
             Hedgehog fact file
 Pest control-     …but by eating         They also
a hedgehog         them it can take in      feed on
eats up to 200g    chemical insecticides    snails, frogs,
insects a night!   and may poison itself    toads,
                                            snakes, bird
 …but they eagerly                         eggs, carrion,
eat foods that are                          mushrooms,
high in fat and sugar                       grass roots,
instead of low-fat,                         berries,
protein-rich insects.                       melons,
They are also lactose-                      watermelons,
intolerant.                                 earthworms
                                            after rain!
 Eating these foods can lead to obesity,
a fatty, damaged liver and heart disease.
 Can become pests where they have been
introduced by man eg. North Uist and Benbecula as
they have no natural predators & eat bird’s eggs.
 Predators in forest: birds (esp owl), ferrets
Smaller long-eared hedgehog predators:
foxes, wolves, mongooses
 Lifespan 4 – 7 years in the wild (record 16)

 Communicate with grunts, snuffles and some
species use loud squeals
 Defence: rolls into a tight ball,
causing all of the spines to point
 Desert hedgehogs run away, or attack intruder by
ramming it with its spines, ball last resort!
   Hedgehog              Sleep for a large portion
                         of the daytime either
Rhythmical behaviour     under cover of bush or
      pattern            grass or rock or in a hole
                         in the ground, generally
     Hibernation         dig out dens for shelter.
  Trigger stimulus
 Decreasing daylength
 and temperature

Importance to survival

Conserves energy
when food is in short    All wild species have the
supply (over winter)     ability to hibernate…
                   Common household roaches
                   A. German cockroach,
                   B. American cockroach,
                   C. Australian cockroach,
                   D&E. Oriental cockroach
                   (♀ & ♂)

                   Largest is C which grows
                   up to 9cm long, 30g weight.

                   They are mainly nocturnal
                   and run away from light.
Men in Black       Exception is Oriental (D&E)
 chapter 26        which is attracted to light.
            Cockroach fact file
 In buildings they often die on their backs as they
cannot grab hold of something with their legs and turn
 Could be one of the few species to survive a nuclear
blast as they bury themselves underground and…

 Radiation lethal dose is 90K – 105K rems for
German cockroach, 800 rems for a human (16 life)
 Can survive 1 – 4 weeks without a head- breathe
through spiracles in body, don’t control it with their
brain, don’t need blood like a human and…
 Survive on very little food- up to a month without
any! Can eat the glue from the back of stamps
 If you have a shellfish allergy, you are likely
to be allergic to eating cockroaches
 Predators      Lifespan              Reproduction
only a few      development from       German
including       egg to adult takes     cockroach
birds, bats,    3-4 months. Adults     carries an egg
house           live up to a year      capsule
centipede,                             containing
wasps, small                           around 40 eggs.
animals                                In favourable
                                       conditions 1
                                       female may
                                       produce 300-
                                       400 offspring

 Other cockroach species have 100 eggs in a sac,
only need to be inpregnated once to be able to lay
eggs for rest of lifespan- up to 1 million offspring

Rhythmical behaviour

     Night activity

  Trigger stimulus

Importance to survival

Less chance of being
caught by predators
when feeding at night
             Annual rhythms
More about courtship and hibernation…

Read workbook p97.
Watch Biovideo 63 Sexual reproduction in animals,
‘internal fertilisation’

Use both sources of information to write notes on:
1. 3 features they have in common to be true rhythmical
   behaviours. Regular, trigger stimulus to start
                  if no trigger-continues at expected time
2. The environmental trigger stimulus that brings about
   courtship in the great crested grebe and the red deer.
   Daylength (grebe- increasing, red deer-decreasing)
3. The environmental trigger for hedgehog hibernation.
   Decreasing daylength and temperature
4. The survival value of all these behaviours.
    Increased chance of reproducing, and offspring surviving.
    Hedgehog- Energy conservation when little food available
            Biological clock
These rhythms can all operate independently of
external conditions even if all the stimuli have
been removed. This shows that organisms have
an internal biological clock.

The biological clock is
adjustable and can be triggered
by external stimuli.

We will look at the biological clock and
some circadian rhythms in humans…

The word circadian comes from
circa diem (Latin) "about a day".
           Circadian rhythms
                    The circadian "clock" in
                    humans is located mainly in
                    the hypothalamus (brain)
                         The circadian rhythms
                         determine human sleeping
                         patterns and…

there are patterns of brain wave activity, hormone
production, cell regeneration, and other biological
activities linked to this 24-hour cycle.

Factors outside the body, especially bright light,
help to set the internal clock to the day cycle or
time schedule appropriate to where the person is.
Human circadian rhythms




           Rhythm Problems
In a person with a circadian rhythm sleep
disorder, the body is unable to maintain its
normal rhythm.
The natural sleep schedule changes so that
the person is out of phase with day and night.

We can all be affected by:

 Shifting into or out of British summer time
 Travelling across time zones (jet lag)
 Shift work that involves late evening or
     Plant Circadian rhythms
Regulate metabolic activities such as
photosynthesis, moving leaves and flowering.
They run on an approximately 24 hour period.

The internal biological clock enables the
organism to anticipate the needs of the day
in good time to prepare for them.

Eg. Open flowers at night if you are
bat-pollinated, during the day if you
are bird- or bee-pollinated.
Grandidier’s Baobab
tree, and Madagascar
fruit bat (Eiodolon
which pollinates them
at night-time.
         Biorhythm questions
1. What is meant by a trigger stimulus?
2. Describe three examples of rhythmical
   behaviour. For each one identify the trigger
3. Describe what is meant by a ‘biological clock’
4. Describe the type of advantage gained from
   most rhythmical behaviours.
5. Explain why the midge larvae in a pond tend to
   change into flying adults at nearly the same
   time on the same day.
   What is the advantage for the midges?
     Planet earth sequence, Forests- insects
            Annual rhythms
We will look at 2 animals that migrate and consider
the advantages of this type of behaviour to them:

    Barnacle                   Atlantic
     goose                     salmon
      Watch Incredible journeys - Osprey
             Barnacle geese
    Vital Statistics        Branta leucopsis
Eggs: 4-5
Incubation: 24-25 days
Fledging: 40-45 days
Maximum lifespan: 18 years
Length: 58-70cm
Wingspan: 132-145cm
Weight: 1300-2200g
Eat leaves, roots, stems,seeds
UK breeding: 1,000 birds
UK wintering: 60,000 birds
Flies in packs and long lines,
with a noisy chorus of barking
or yapping sounds
             Where are they?
In winter, Islay holds 70 % of the
world's Greenland barnacle geese
(37,000) and 40% of the Greenland
white-fronted goose population

The RSPB bought the land at the
head of Loch Gruinart in 1984.
This area holds one of the main
barnacle goose roost sites and some
of the most important feeding areas
for barnacle geese and white-fronted
geese. Many in Solway firth too,

They are seen in UK between October & March.
           Barnacle goose

Rhythmical behaviour

   Trigger stimulus
 Increasing daylength

Importance to survival
 Breed in Iceland to
 escape predators,
 migrate to Scotland
 in winter for food
      Workbook- Barnacle goose
   Read workbook p96 and collect sheet G2 migration

1. What are the environmental conditions that
   affect the lives of Barnacle geese in the two
   places it inhabits?
2. Identify the trigger stimulus
3. Why does migratory behaviour increase the
   survival chances of the Barnacle geese?         Canadian goose
                                                   in the Atlantic

                                   Then read workbook
                                   p105 and answer the
             Atlantic salmon
    Vital Statistics      Salmo salar
 Live up to 8 years
 Average weight 3.6 –5.5kg
Develop bright hues around
spawning times
 Females lay up to 20,000
eggs in October-November
 Flesh often orange-red         Record catch- 38kg
 Eat smaller fishes,
crustaceans, and insects.
 They are found in both
fresh and salt water in the
colder regions of the
northern hemisphere.
             Salmon migration
Adults migrate hundreds or thousands of miles
from the sea into cold fresh water in late spring or
early summer.

They swim upriver (up to 4 miles per
day) to spawn in exactly the same
places as the generation before.
During the migrations and nest-building activity
that precede mating, neither the females nor the
males consume food.
Migration routes- Atlantic salmon

 The salmon fishing industry is one of the major industries of the states along the
 American Pacific coast, providing 60,000 jobs and more than $1 billion in income
 per year for the region
 However, some experts have raised concerns about hatchery-raised salmon
 because they compete with wild salmon for food and are more vulnerable to
 predators than are wild salmon.
 In addition, hatchery salmon usually have less genetic diversity than wild salmon,
            Salmon life cycle
The eggs hatch in 2 weeks to
6 months, depending on the
species and the water

Salmon develop from alevins to
fry and emerge from the gravel.
Eventually turn bright silver
(smolts) and descend to sea.

When they are fully grown and reach
sexual maturity, the salmon begin
the migration back to fresh water to
Atlantic salmon
      Rhythmical behaviour

          Trigger stimulus
        Increasing daylength

      Importance to survival
       Breed in Scotland,
       migrate to Atlantic
       coast of Greenland for
       rich feeding grounds
   Workbook- Atlantic salmon
Read workbook p96 and collect sheet G2 migration

1. What are the environmental
   conditions that trigger
   migratory behaviour in the
   young salmon in the fresh
   water river?
2. What triggers migratory
   behaviour in the adult salmon
   in the seas and oceans?
                                   Then read
3. Why does migratory behaviour
                                   workbook p104
   increase the survival chances
                                   and answer the
   of the Atlantic salmon?
                     Summary questions
  1. Why is it important that animals respond to
     changes in their environment?
The conditions an animal chooses are usually the best for its survival
  2. Why do blowfly maggots move away from the light?
By staying in dark places they are more likely to obtain food & protection
  3. Explain the why the response of woodlice to
     environmental stimuli increases their chances of
They move to where it is damp where they can breathe easier
  4. What is rhythmical behaviour?
Behaviour of animal in response to regular changes in the environment
  5. What is meant by a trigger stimulus?
An environmental condition or change that sets off a behavioural
  6. Give an example of rhythmical behaviour shown by
     hedgehogs, what is the trigger stimulus?
Decreasing day length and temperature
   Bird migration                   Wordsearches-
                                    reproduction, water
   workbook p102
   Bird migration
   PS data and Q                    Crossword- reproduction

                          Project on rhythmical
                          behaviour- ask to see S3
                          March 2006 powerpoint
                          presentation for ideas & book
Suggested weblinks:
Bird Migration- why they do it and how
Salmon fact file and link to conservation organisation at
Major conservation issues in pacific north-west USA. msn encyclo.
         Textbook Torrance, SG Biology, p121

Look at the table which gives examples for
various rhythmical behaviours including tidal
(green flatworm, fiddler crab)

Draw up a table with the headings:
type / animal / description of rhythmical behaviour /
external trigger stimulus / significance

  Type      Animal                   Significance

Copy it and add in the ones we have studied in
this topic to summarise the behaviours.