GRE PSYCH (Ethology)
Terms
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- ethology
- study of animal behaviours, especially innate behaviours that occur in a natural habitat
- Charles Darwin
- made concept of evolytion scientifically plausible in asserting that natural selection was at its core. His ideas about evolution have been applied to and tested in ethology.
- Konrad Lorenz
- founder of ethology as a distinct research area. Best known for his work with "imprinting", "animal aggression", "releasing stimuli", and "fixed action patterns"
- imprinting
- in certain species (most often birds) the young attach to or imprint on the first moving object they see after birth. This attachment is most commonly displayed by a "following response". Lorenz also found that imprinting was subject to a sensitive learning period, after which imprinting would not occur.
- animal aggression
- Lorenz's theory of instinct fueled the fire for ethology's great debate over innate behaviour. Drawing from Darwin's ideas, Lorenz argued that certain kinds of aggression were necessary for the survival of species. Argued that aggressive behaviour is instinctual rather than learned and that even human intraspecies aggression can be explained through survival needs.
- releasing stimuli
- aka releasers or sign stimuli. Releasing stimuli in one individual of a species elicits an automatic, instinctual chain of behaviours from another individual in the same species. Lorenz called these "fixed action patterns". Lorenz's work with this was later continued by Tinbergen.
- fixed action patterns
- instinctual, complex chains of behaviours triggered by releasing stimuli. Have 4 defining characteristics: they are uniform patterns, they are performed by most members, they are more complex than simple reflexes, and they cannot be interrupted once started.
- Nikolaas Tinbergen
- one of the founders of modern ethology. Best known for his use of mofels in naturalistic settings. Continued Lorenz's work with releasing stimuli. Most famous experiments involved stickleback fish and herring gull chicks.
- stickleback fish
- In the spring, develop red coloration on bellies and fight each other. Tinbergen hypothesized that the red belly acted as a releasing stimulus for the attacks. Built various models of stickleback fish and the red-bellied models, no matter how crude, were attacked.
- herring gull chicks
- When hungry, peck at end of their parents' bills, which have a red spot at the tip. Parent then regurgitates the food for them. Tinbergen hypothesized that red spot on the bill signals the pecking. Chicks pecked more at a red-tipped model bill than at a plain model bill. The greater the contrast between the bill and the red spot, the more vigorously they pecked, even when the contrast was so strong as to be unnatural.
- supernormal sign stimulus
- artificial stimulus that exaggerates the naturally occurring sign stimulus or releaser. More effective than the natural releaser at eliciting fixed action patterns.
- Karl von Frisch
- major figure in study of animal behaviour. Famously discovered that honeybees communicate through a dance they perform. Also studied the senses in fish.
- Walter Cannon
- coined term "fight or flight". Also coined the the term and proposed the idea of "homeostasis"
- fight or flight
- change of an animal's internal state in an emergency situation that triggers the animal to choose fight or flight in response
- homeostasis
- regulation of the body to maintain equilibrium
- genes
- basic unit of heredity. Composed of DNA molecules and are organized in chromosomes. Nucleus of human cells contains 23 pairs. Chromosomes in cells act as carriers for genes, and therefore for heredity.
- gamete
- sperm or ovum in humans
- haploid
- in human gametes, 23 single chromosomes
- diploid
- all human cells other than gametes contain 23 pairs of chromosomes
- zygote
- fertilized egg. Where 2 separate sets (one from each parent) of 23 chromosomes come together. Diploid because it contains 23 pairs of chromosomes
- genotype
- total of all genetic material that an offspring receives (23 pairs or 46 total chromosomes).
- dominant genes
- always beat out recessive genes
- recessive genes
- not manifested unless it is paired with another recessive gene
- alleles
- pairing up of possible dominant and recessive gene variations for each characteristic. The 2 genes that make up an allele occupt the same place on the chromosome.
- phenotype
- external characteristics. Phenotypic expression is partially determined by heredity or genotype, but can also be influenced by the environment.
- natural selection
- determines which animals survive and reproduce. Individuals best suited to the environment are most likely to survive, and they will pass on their genes. Explains the evolution or genetic development of species over time.
- genetic drift
- particular genotypes are selected out or eliminated from a population over time due to natural selection
- fitness
- ability to reproduce and pass on genes.
- inclusive fitness
- Animals will be invested in the survival of not only their own genes but also the genes of their kin. Favored over individual fitness.
- kin slection
- Sruvival of the genes of an animal's kin. Creates inclusive fitness. Explains why parents protect their young and why individual animals may put themselves at risk to warn their siblings of a predator.
- instinctual behaviours
- aka innate behaviours. Present in all normal members of a species. Stereotypic in form throughout members of a species, even when performed for the first time. Independent of learning or experience. There is an interaction between instinct and learning.
- altruism
- behaviour that solely benefits another. Truly altruistic behaviours are those toward non-kin. Most likely, these behaviours are similar to a group mentality. Individuals will help others if the benefit outweighs the cost or if they expect to be repaid somehow.
- biological clocks
- internal rhythms that keep an animal in sync with the environment.
- circadian rhythms
- endogenous rhythms that revolve around a 24-hour time period
- courting
- behaviours that precede sexual acts that lead to reproduction. Attracts a mate and isolates a mate of the same species.
- displacement activities
- aka irrelevant behaviours. Behaviours that seem out of place, and illogical, and have no particular survival function.
- estrus
- period in which a female of the species is sexually receptive
- inbreeding
- breeding within the same family. Evolutionary controls prevent this. e.g. facial markings of swans are similar for members of the same family and swans usually choose mates with diff markings
- mimicry
- evolved form of deception. e.g. harmless species of snakes mimic coloration of poisonous ones to escape predation
- instinctual drift
- when an animal replaces a trained or forced response with a natural or instinctive response.
- pheromones
- chemicals that act as messengers between animals. The exchange of pheromones is thought to be the most primitive form of communication between animals. Can transmit such states as fear or sexual receptiveness.
- reproductive isolating mechanisms
- serve to prevent interbreeding between 2 different, but closely related and possibly genetically compatible, species.
- behavioural isolation
- reproductive isolating mechanism in which courtship or display behaviours of a particular species allows an individual to identify a mate within its own species
- geographic isolation
- reproductive isolating mechanism in which different species breed in different areas to prevent confusion or genetic mixing.
- mechanical isolation
- reproductive isolating mechanism in which different species have incompatible genital structures.
- isolation by season
- reproductive isolating mechanism in which potentially compatible species mate during diff seasons
- sensitive/critical periods in learning
- times when a developing animal is particularly vulnerable to the effects of learning (or to the lack of such learning). e.g. learning of songs in species of birds, imprinting
- sexual dimorphism
- structural differences between the sexes. Has arisen through both natural and sexual selections
- sexual selection
- according to Darwin, is a form of natural selection. However, it is not necessarily the fittest that win out but rather those with the greatest chance of being chosen as a mate (usually the best fighters, the best courters, and the most attractive individuals).
- selective breeding
- contrived breeding. Mates are intentionally paired to increase the chances of producing offspring with particular traits.