Transcript Kineses Taxes

Animal Behavior
Orientation behaviours:
Kineses
Taxes
Environmental Stimuli
• A slater retreating to a daytime
crevice could be responding to
the dampness, darkness or
coolness.
• Can experiment to
determine which factors
influence behaviour
2
Experiments
Choice chambers offer alternative conditions
Fair test - all others factors are kept the
same.
• Can test effect of temperature, light, humidity
3
Simple Responses - immediate surroundings
Kineses and Taxes have an immediate benefit
e.g. a slater moving into a damper place.
4
Taxes
Movement towards or away from a stimulus
Positive =
towards
Negative
= away
5
Taxes
Snails climb vertically
upwards.
Negative geotaxis
Taxes
Mosquitoes
home in on
warm flesh.
Positive thermotaxis
Taxes
Blowfly maggots
move rapidly
away from a
directional light
source.
Negative phototaxis
Positive phototaxis
Positive phototaxis = movement towards the
light e.g. many swimming algae
9
Positive Chemotaxis
eg male moths following a pheromone trail given
off by females
Negative Phototaxis
Slime Mold
The direction of the light source is
indicated by white rectangles.
e.g.
earthworms
11
Positive chemotaxis
Mosquitoes towards people along CO2 gradient
When a capillary tube filled with glucose is placed
in a medium containing E. coli, the bacteria alter
their locomotion so that they congregate near
the opening of the tube.
12
Positive rheotaxis
Movement against a current
e.g. salmon migrating upstream
13
Kinesis
• Animals have specific needs (eg food, humidity)
• No information about the location of resource?
• Undirected search
• Kinesis = random movement due to the presence
of a stimulus. The rate of activity is determined
by the intensity of the stimulus – not the
direction
14
Search methods
• Undirected search: animal moves in a more or
less straight line through unsuitable habitat.
• Directed search: when it begins to perceive
better conditions (the blue area) it slows down
and turns sharper angles to stay in the vicinity
of the improved conditions.
15
stimulus
random movements to get away
slow down as animal gets further away
16
stimulus
ALTERNATIVELY
animal moves directly away in a straight line
17
Hydrokinesis
Orthokinesis = stimulus intensity determines speed
e.g. slater’s rate of movement is inversely
proportional to the humidity
Thermokinesis
Klinokinesis = stimulus intensity
determines rate of turning
eg lice turn less often at 30° straight line. Human skin temp
is about 35° lice more likely
to linger at 35°.
35 o
30 o
Human body louse
Orthokinesis and klinokinesis movies