Animal and plant behavior

• Behaviour can be classified into innate and learned behaviour
• Innate behaviour

  • not learned but is genetically determines response to a particular stimulus usually seen in every member of a particular species
  • occurs as a result of a specific nerve or chemical pathway laid down in the embryo. a given stimulus will produce invariably the same response (innate releaser mechanism)
  • behaviour patterns have developed and been refined over generations and their primary adaptive significance lies in their survival value to the species
  • simple nervous pathways
• Innate behaviour covers a range of responses:

  1. kineses
  2. taxes
  3. simple reflexes
  4. instinctive behaviour
• Instinctive behaviour is extremely complex and includes biological rhythms, territorial behaviour, courtship, mating, aggression, social hierarchies and social organisations
• Kinesis

  • form of response which the organism doesn't move towards or away from a stimulus
  • response is related to the intensity of the stimulus and involves a change in the rate of movement and/or change in the rate of turning of the organism
  • e.g. woodlice in a dry environment respond by rapid movements to avoid conditions
• Kinetic responses observed by the use of woodlice in a choice chamber

  • 20 woodlice placed in the center of a choice chamber
  • their rate and direction of movement are observed over 30 minutes
  • rapid movements occur when they are present in dry, light environment compared to a few movements in the dark, moist compartments
• Taxis

  • a simple response whose direction is determined by the direction of the stimulus
  • a taxic response is the movement of a whole organism towards or away from a directional stimulus
  • taxes are classified according to the directional response and nature of the stimulus
• Phototaxis

  • positive phototaxis is the movement of simple photosynthesizing organisms towards light
  • negative phototaxis is where organisms move away from the light
• Chemotaxis is the movement towards or away from a high concentration of a particular chemical substance. this enables bacteria to move towards a food source or away from toxic compounds.
• Simple reflexes

  • an automatic, rapid response to a stimulus
  • the presence of food sight or smell may also illicit a reflex response
• Instinctive behaviour

  • instinct can be described as unlearned, species-specific motor patterns
  • instinctive actions may be inborn but can be very sophisticated
  • instinctive patterns of behaviour are usually of very direct survival value to an animal involved in courtship, mating or defending territory for feeding or reproduction
  • show a high degree of stereotyping- the same pattern of behaviour when met with the same stimulus
• Importance of innate behaviour

  • invertebrates are frequently very short lived
  • instinctive behaviours allow them to survive for longer as they don't live long enough to create learned behaviours
  • vertebrates tend to live longer
  • innate beahviour in adults is an economy measure given to leave the higher areas of the brain free for other less basic functions
• Learned behaviour

  • defined as a change in behaviour caused by a learned experience
  • characteristic to the individual in a given species and depend on the experiences of that individual
  • the early environment of an organism has a pronounced effect on its later behaviour as a result of the learning process
  • the speed of learning can vary from individual to individual
  • there must be an ability to memorize and store information within the CNS
• Imprinting

  • is a simple and specialised kind of learning that occurs for a short time in very young animals of certain species
  • animal identifies with another animal or large object
  • imprinting ensures that young animals follow their parents so that the brood keeps together and avoids danger
  • allows the offspring to rapidly acquire skills possessed by parents
• Habituation

  • if a stimulus for an innate behavior is repeated many times without any positive or negative effect, the animal will stop responding o the stimulus
  • this enables the animal to ignore neutral stimuli that would have no effect on their ability to survive
  • the response to the stimulus changes
• Conditioning

  • animals learn to associate one thing with another
  • needs either a reward or punishment to reinforce the desired behaviour
  • in natural conditions a reward might be obtaining food or a mate, a punishment being attacked by another animal
• Classical conditioning (conditional reflex)

  • based on the research of Pavlov on dogs
  • involved the animals learning to produce a conditioned response to natural unconditioned stimulus but also newly acquired stimulus
  • the usual stimulus is replaced by the new stimulus
  • the animal learns to respond to both producing the same response
  • the response is unaltered but the stimulus for it is different
• Operant conditioning (trial and error learning)

  • occurs when a piece of natural trial behaviour is either rewarded or punished
  • if the animal associated the outcome of the piece of behaviour with a reward, that behaviour is likely to be repeated
  • conditioning is important in the training of animals
  • reinforcement stimuli and rewards are used to encourage and develop particular behaviour patterns by an animal
  • reinforced appropriate behaviour and eliminate inappropriate behaviour
• Continuous reinforcement

  • every response is reinforced
  • is continuous reinforcement is used acquisition of the behaviour will occur faster
  • extinction of the learned habiour will also occur faster upon termination of continuous reinforcement
• Exploratory learning

  • involves storing information that may be useful at a later date
  • animals spend a long time with their parents have many opportunities for this learning
  • enables animals to survive at a time long after the learning occurs
• Insight learning

  • highest form of learning
  • involves animals using several past experiences and synthesising them in order to solve a problem
  • involves thought and reasoning
• Extended parental care

  • in primates few offspring are produced and parental care occurs over a relatively long time period
  • long period provides opportunity for learning e.g. hunting skills, communication, social interaction
• Innate behaviour summary

  • inherited
  • not changed by environment
  • inflexible
  • similar in all members of species or breed
• Learned behaviour

  • not inherited
  • changed by environment
  • quickly adapts to new circumstances
  • differs between individuals of a particular species
• Endogenous rhythms are controlled internally and have nervous and hormonal components
• Exogenous rhythms are controlled by external environmental factors e.g. photo-periods and lunar cycles
• Territorial behavior

  • animals defend their territory by displays e.g. threat displays and postures
  • carnivores scent mark the boundary of their territories
  • weaker individuals may be pushed to outer regions of the habitat or have no territory at all which jeopardizes their reproductive success
• Courtship and mating

  1. rising levels of reproductive hormone and the maturation of gonads
  2. coloration changes by the development of a red belly in male sticklebacks
  3. increase in size of parts of the body
  4. mating calls
  5. postural displays
  6. use of chemical sex attractants
• Importance of courtship behavior

  • recognize members of their own species
  • recognize opposite gender
  • identify a mate who is capable of breeding
  • form a pair bond that will lead to successful mating and raising of offspring
  • synchronize mating so that it takes places when there is maximum probability of the sperm and egg meeting
• Pheromones are secreted and released by organisms of small amounts of chemical substances leading to specific physiological or behavioral responses in other members of the same species
• Role of pheromones

  • function as natural sex attractants
  • e.g. civetone in the civet cat and muscone from musk deer
  • secreted from anal glands and used commercially in perfumes
  • mares and cows secrete pheromones on heat
• Bombykol

  • pheromone released by reversible glands at the tip of the abdomen in adult female silk moths
  • olfactory receptors on the antenna of male moths detect the presence of the pheromone molecules in great dilutions
  • males make a rheotactic response by flying upwind until they reach the female
• Courtship and conflict

  • may tighten the pair bond between the mating pair and the synchronization of gonad development so that gametes mature at the same time
  • certain spider species conflict between male and female only diminishes for the act of copulation which culminates in the female killing the male
• Courtship and mating behavior of three spined stickleback

  • result of complex interplay of motivational stimuli linked to endogenous and exogenous rhythms
  • leads to changes of secondary sexual characteristics and territorial behavior
  • male builds a nest
  • if suitable a female appears he performs a series of zig zag dance, if the female responds he leads her to inspect the nest and the whole courtship ritual is composed
• Altruism is a form of social behavior where one organism puts itself either at risk or personal disadvantage for the good of other individual members of the species
• Altruism mechanisms

  1. kin selection
  2. reciprocal altruism
• Kin selection

  • eusocial insect colonies with sterile females acting as workers to assist their mother in the production of additional offspring
  • changes in gene frequency across generations that are driven by interactions between related individuals
• Hamilton's rule

  • rB > C
  • r= the genetic relatedness of the recipient to acting individual
  • B= the additional reproductive benefit gained by the recipient of the altruistic act
  • C= the reproductive cost to the individual of performing the act
• Eusocial insects

  • used to describe social systems with three characteristics

  1. overlap in generations between parent and their offspring
  2. cooperative brood care
  3. specialized castes of non-reproductive individuals
• Social insects

  • display presumed kin selected traits
  • r is abnormally high between worker sisters in a colony due to haplodiploidy
  • Hamilton's rule is presumed to be satisfied because the benefits in fitness for the workers are to exceed the cost of lost reproductive opportunity