Biology 3.3
“Plant & Animal Responses”
Tropisms
Plants grown on the ISS
• Grown in light +
zero gravity
• Grown in darkness
+ zero gravity
Plant Hormones
(for chemists)
Auxin
Cytokinins (zeatin)
Abscisic Acid
Ethylene
Gibberellins (GA3)
Nasties
Kineses
Slater – Porcellio scaber
Slater – Porcellio scaber
Hygrokinesis
Original: 1 frame/5 sec
The top half of the container is a high humidity environment. The Bottom is a low
humidity environment.
Note that animals stay in the high humidity environment.
(Original: 1 frame/60 seconds)
http://cas.bellarmine.edu/tietjen/Ec&Ev_Distance_learning/EcologyIntro/behavior
Taxes
Slater Phototaxis
• Task: Design and carry
out an experiment using
choice chambers to
demonstrate whether or
not slaters show
phototaxis.
• Consider: how MUCH of
a difference in responses
will be sufficient to be
able able state that there
is a REAL difference!
http://www.cvsd.org/university/classpage/jgriffi
Slater Phototaxis (13 Bio 2012)
• Aim: Do slaters prefer light or dark habitats?
• Hypothesis: That slaters prefer dark habitats (because this
will help them avoid desiccation)
• Results:
• Conclusions:
Slater Phototaxis (13 Bio 2011)
• Aim: Do slaters prefer light or dark habitats?
• Hypothesis: That slaters prefer dark habitats (because this
will help them avoid desiccation)
• Results:
"Do Slaters Show Phototaxis?"
Number of Slaters
Dark
Average
Light
9.0
1.9
• Conclusions: Hypothesis proved correct, slaters prefer
darker habitats. Slaters were nearly 5 times more likely to be
found in the dark. We suspect, therefore, there is a strong
preference to avoid drying out and being visible to predators.
Migration
NZ Shining Cuckoo: Breeds NZ + Chathams, migrates to Solomon Islands
Migration
Migration: the mass movement of a large number
of animals of the same species often over a large
distance.
Migration is an important response to seasonal
environmental change. In true migration animals
usually travel from one location where they breed
to another where they feed and then they move
back again.
Migration Features
–
–
–
–
–
–
–
–
–
–
–
–
Active (eg swimming), not passive dispersal (drifting in current)
Usually to feeding / breeding area
Usually two-way trip
Usually regular timing
Often long distance
Often at defined life stage
Initiated by internal clocks / timekeepers in resonse to
environmental cues (eg temp. change, daylength change)
-’s risky and costly in terms of energy – death is the ultimate
energy cost
+’s safe breeding grounds, avoid climate extremes, maintain
food supply (seasonal, food supply used up)
Eg: salmon – adults migrate up rivers to spawn
Eg: humpback whale feed at pole in summer, breed in tropics
Moving on because of food source depletion (locust) might not
count as migration.
Homing
Homing
Homing The ability of an animal
to return to home over unfamiliar
territory.
Key Features
Distances can be relatively short
(may use familiar landmarks)
Usually on a regular (eg daily,
tidal) basis
Involves navigation
Limpet ‘home scar’
Examples
Homing pigeons returning to loft
Chitons to home indentation on a
rock
Navigation
Bee Navigation
• Waggle Dance: uses solar navigation
– In vertical hive combs:
• Angle of dance to vertical indicates horizontal angle
from sun to food
• Speed, duration of waggle indicates closeness of food
(Must have a biological clock to account for the fact that
the sun moves across the sky and the angle to the food
will have changed by the time they get back to the hive).
• Round Dance: indicates food closer than 50m
– “go and look nearby and you’ll find food”
Female
Male
Monarch Navigation
• Flight patterns appear to be inherited, based
on a combination of the position of the sun
in the sky and:
• Time-compensated sun compass
– based in their antennae.
• New research shows: use the earth's
magnetic field
– Antennae protein is sensitive to violet/blue, in that
light it can function as a chemical compass
indicating alignment to magnetic field (or not).
Can’t tell N/S
Timing
Responses
Petrolisthes elongatus, half crab
Astronomical Cycles
Solar year – 365.25 days (rotations) of Earth
in one orbit (revolution) around the sun.
Lunar month – 29.5 days between full
moons
Earth day – 23 h 56min 4.09s (to rotate on
axis once)
Seasons – Caused by tilt of Earth’s axis in
conjunction with orbit around sun (23.5°)
Tidal XXXXX
Actograms
• Actogram — chart commonly used to plot
activity against time
24 hours 
Day
No Activity
Activity
Night
For the first 7-days
mice were
maintained under a
12-hour light: 12hour dark cycle, and
subsequently mice
were maintained in
constant darkness.
When the animal is
placed into constant
darkness, the period
of the free-run driven
by the endogenous
clock at around 23.5
hour cycles, is
apparent with activity
starting earlier each
day.
What is happening here?
An illustration of the effect of SCN lesions on a sample slave
rhythm. Under a 12:12 dark:light cycle, an intact nocturnal animal,
such as a rat, is active during the dark phase of the DL cycle. Almost
immediately following ablation of the SCN (SCNX), the animal's
rhythms become completely arrhythmic in the circadian time domain
My Body Temp Rhythm
Aim: to find out whether we can demonstrate
our own daily temperature variation.
Method: Hourly thermometer readings, at
rest (as much continuous data as possible)
Conclusions:
• SDP flower with short day and long night.
But if you interrupt a long night with light
then SDP don’t flower. This shows that the
long nights make them flower as short
nights (leaving the short day intact) stops
them flowering.
• LDP flower with long day and short night.
But if you interrupt a long day with
darkness then LDP still flower. This shows
that the short nights make them flower as
Social Organisation
Communication
Communication
• Essential for organisms to interact appropriately with
others of the species
• Encompasses many types of signals
– Visual: vervet monkey (shows blue testicles to indicate gender)
– Touch: slaters (communicates presence, enable clumping
behaviour)
– Sound: blackbird (squawk when cat present)
– Smell: skunk (warns predators)
• The more complex the social organisation the more
complex the signals.
– Simple: Sheep – higher pitched baa “I’ve lost my baby”…not
much other signals.
– Complex: Chimps – grooming behaviour (maintaining social
bonds)
Sexual
Dimorphism
Pheasant
m.
f.
Nyala
Terrapin
Co-Operative Behaviour
• Bees vs Hornets
(see text resource:
http://scienceblogs.com/neurophilosophy/20
07/09/19/mobs-of-honeybees-kill-hornetsby/
http://blogs.discovermagazine.com/notrocket
science/2009/07/05/mobs-of-honeybeessuffocate-hornets-to-death/)
http://www.youtube.com/watch?v=JDSf3Ksh