3 4 Describe animal behaviour and plant responses
3. 4 Describe animal behaviour and plant responses in relation to environmental factors
Organisms responses • Stimulus (cue) - change in environment that causes a response in the organism • e. g. • A receptor – any cell or group of cells that can detect change • E. g. • An effector is a cell or group of cells that respond to the change • e. g.
Environmental Stimulus Receptors Sensory nerve impulse Central nervous system Motor nerve impulse Effectors Response
Receptors • • PHOTORECEPTORS Detect visible light, infra red and UV Involve a PHOTOPIGMENT Cells can be in an ORGAN • • • SOUND RECEPTORS Mating calls or territory signals Echo location Cells are grouped into ORGANS Ears
Receptors • GRAVITY RECEPTORS • Inform animal of its position and movement • CHEMO RECEPTORS • Detect chemicals in air, food, CO 2 levels and blood hormones • Animals can produce PHEROMONES
Receptors • HEAT (THERMO) RECEPTORS • Detect changes in temperature • Within body or from touching environment • ELECTRICAL RECEPTORS • Some fish and sharks • Detect impulses emitted from organisms
Orientation Responses • Where an animal positions itself or carries out specific behaviours, when an environmental factor changes direction, duration, or intensity. • Can be – Simple e. g. taxes and kineses. – immediate movements in response to changes in factors such as light. – or complex e. g. MIGRATION or HOMING. • Help organisms avoid certain conditions and ensure survival and reproduction.
Taxis (pl. Taxes) • Movement of the whole organism towards or away from a stimulus coming from one direction. • Mainly animals and a few mobile plants e. g. Euglena swims towards light.
Taxis (pl. Taxes) • Movement towards stimulus POSITIVE • Movement away from stimulus NEGATIVE Stimulus Positive Negative temperature mosquito earthworm rise Direction determined by either body movements (klinotaxis) or by comparing stimulation of receptors on both sides of body (tropotaxis)
Examples Phototaxis Positive Negative Chemotaxis Geotaxis Thermotaxis Rheotaxis Movement of earthworms
Examples Phototaxis Positive Negative Chemotaxis Geotaxis Thermotaxis Rheotaxis Movement of body lice
Examples www. nabis. govt. nz Phototaxis Positive Negative Chemotaxis Geotaxis Thermotaxis Rheotaxis Movement of pipi when disturbed
Examples Phototaxis Positive Negative Chemotaxis Geotaxis Thermotaxis Rheotaxis Movement of a blow fly to meat
Examples Phototaxis Positive Negative Chemotaxis Geotaxis Thermotaxis Rheotaxis Movement of salmon at spawning time
Kinesis (pl. Kineses) • • • Random movement response Not related to direction of stimulus Rate determined by intensity of stimulus ORTHOKINESIS e. g. slaters move fast in bright light and slower in dim light, they move slow in high humidity (damp) and fast in low humidity (dry) • Where do they end up ?
Kinesis (pl. Kineses) KLINOKINESIS • Stimulus intensity determines rate of turning • e. g. human louse will turn frequently at high temperature 35 o. C 30 o. C • Where do they end up ?
Migration • Regular movements of large groups of animals – often annual • To find food • To breed • Long distance/risky/costly • e. g. birds, whales, eels, seals, whitebait, salmon, turtles, • Migration is under genetic control • Initiated by day length (change in season).
Activity • Biozone p 175 -176
Types of Migration • • Dispersal- one way Return migration Nomadic migration- directionless Remigration circuits- may involve more than one generation. • Migration is initiated by the activity of internal clocks, in response to environmental cues such as day length or change in temperature.
Activity • Biozone p 177 - 178 • Extension work. Pheromones p 174.
Homing & Navigation • Ability of animals to find their way home over unfamiliar territory. • e. g. homing pigeons, albatrosses, bees, limpets, frogs and toads. • Result of unusual events (e. g. storms) or movements in search of food, mates, breeding sites etc.
Navigation • Use of environmental cues for orientation examples include: – Landmarks- period of learning required before it can be used. – Magnetic fields/ compass- crystals of magnetite present in sensory system, e. g. bees, pigeons. – Sun compass- Suns position in sky changes with time of day. E. g. bees.
– Stars- complex pattern of points. Young nestling birds imprint pattern at early age. – Smells e. g. ants to get home or allow others to follow. Salmon memory of native stream. – Travel time
Summary • • Animals have sensory cells Respond to stimuli Send nerve impulses to CNS sends impulse to effector Animals change orientation (position) Simple TAXES and KINESES Complex MIGRATION and HOMING These benefit organism either by more food or better breeding
Word grid for matching pairs GEOTAXIS ORIENTATION RESPONSE ORTHOKINESIS SENSE ORGAN PHOTOTAXIS RHEOTAXIS MIGRATION STIMULUS PHEROMONES KLINOKINESIS BEHAVIOUR TROPOTAXIS CHEMO RECEPTORS STIMULUS KLINOTAXIS PHOTO RECEPTORS KINESIS TAXIS ENVIRONMENT HABITAT CNS HOMING POSITIVE THERMOTAXIS EFFECTOR
BEHAVIOUR Observable response to a stimulus STIMULUS Change in organism or environment that causes response SENSE ORGAN Organ used to detect stimuli PHOTORECEPTOR Cell or organ sensitive to light EFFECTOR Organ the responds to a message from CNS TAXIS Movement either too or away from the stimulus KINESIS Random movement of an organism to a stimulus ORIENTATION RESPONSE General movement of an animal caused by a stimulus POSITIVE THERMOTAXIS Movement towards a heat source MIGRATION Regular, annual, mass movement of a population HOMING Ability of an animal to find its way home
HOMING Ability of an animal to find its way home CNS Brain, spinal cord and nerves STIMULUS Change which causes a response PHEROMONES Chemicals to communicate between animals of same species CHEMORECEPTORS Receptors that are sensitive to chemicals KLINOTAXIS Body movements used to sense the direction of stimulus TROPOTAXIS Comparison of two or more receptors on sides of the body RHEOTAXIS Animal movement in relation to water currents GEOTAXIS Animal movement in relation to gravity PHOTOTAXIS Animal movement in relation to light intensity ORTHOKINESIS Rate of movement linked to intensity of stimulus KLINOKINESIS Stimulus intensity determines rate of turning
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