3.3 plants and animals

• Adaptive advantage

  Any trait that results in an organism having a greater chance of surviving to an age where it can reproduce.
• Biological clock

  An endogenous timing system an organism uses to synchronise its activities with the environment and keep track of time.
• Endogenous

  A stimulus originating within the organism itself, e.g. hormonal changes, is this.
• Endogenous rhythm

  A rhythm that continues even in the absence of any external cues.
• Entrainment

  The synchronisation of an endogenous rhythm with an external cycle or cue such as light and dark.
• Hypothalamus

  A region in the brain that is the location of the biological clock in mammals.
• Period

  Length of time/duration
• Physiology

  Chemical or physical functions in an organism.
• Pineal gland

  A tiny organ in the brain that is the location of the biological clock in birds, reptiles, and amphibians.
• Suprachiasmatic nucleus (SCN)

  A group of cells in the hypothalamus, just behind the eyes, responsible for the biological clock.
• Zeitgeber

  An exogenous cue that synchronises/entrains an organism's endogenous rhythms to the rhythms of the environment, e.g. the Sun or the light-dark cycle.
• Behaviour

  An organism's interactive response to its environment.
• Gene

  Section of DNA that codes for a protein and trait of an organism.
• Habituation

  A short term learned behaviour where the organism learns not to respond to a harmless stimulus.
• Behaviour

  An organism's interactive response to its environment.
• Gene

  Section of DNA that codes for a protein and trait of an organism.
• Habituation

  A short term learned behaviour where the organism learns not to respond to a harmless stimulus.
• Imprinting

  A rapid learning process by which a newborn or very young animal establishes a behaviour pattern of recognition and attraction towards other animals of its own kind. The tendency of young animals to follow the first moving thing they see.
• Innate behaviour

  Any genetically determined behaviour (not learned behaviour).
• Learned behaviour

  A behaviour based on experience, or passed on from one individual to another by imitation.
• Motor (efferent) neurons

  Neurons that send nerve impulses from the central nervous system (CNS) to effector organs.
• Nerve impulse

  Electrical signals transmitted through neurons so that the central nervous system can sense the environment (through receptors) and produce a response (through efferent organs).
• Pheromone

  A chemical that an animal produces which changes the behavior of another animal of the same species.
• Physiology

  Chemical or physical functions in an organism.
• Receptor

  A structure that detects stimuli and sends a signal to another part(s) of the organism.
• Sensory (afferent) neurons

  Neurons that send nerve impulses from receptors to the central nervous system (CNS).
• Stimulus

  A change in an organism's environment to which it can respond.
• Territory

  A defined area, used by an animal for a specific purpose, delineated in some way (e.g. by scent) and defended against individuals of the same species.
• Abiotic factor

  Physical or non-living factor such as light, temperature, and humidity.
• Homing

  The ability of an organism to return 'home' across unfamiliar territory.
• Innate behaviour

  Any genetically determined behaviour (not learned behaviour).
• Kinesis

  A non-directional animal orientation response in which the speed or movement or rate of turning is proportional to stimulus intensity.
• Learned behaviour

  A behaviour based on experience, or passed on from one individual to another by imitation.
• Negative response

  Response away from the stimulus
• Pheromone

  A chemical that an animal produces which changes the behavior of another animal of the same species.
• Positive response

  Response towards the stimulus
• Stimulus

  A change in an organism's environment to which it can respond.
• Taxis

  Animal orientation and movement in response to a directional stimulus.
• Navigation

  The process of using environmental cues to find a desired location or stay on a desired course.
• Adaptive advantage


  Any trait that results in an organism having a greater chance of surviving to an age where it can reproduce.