lec 31- the evolution of behaviour Flashcards
what are the two types of behaviour?
innate behaviour: occurs completely the first time it is performed, no learning required, genetic component (e.g. instinct and reflexes)
learned behaviour: develops and changes in response to environmental stimuli, experimental and environmental components
do most behaviours have both innate (nature) and learned (nurture) components?
yes
what is behaviour?
a response to a stimulus mediated by the nervous system
what is a stimulus?
our senses
-external: sight, touch, smell, sound
internal: feeling hunger, fatigue, pain, sexy
what is a response?
how our body responds to certain stimuli
-fixed (innate)
-plastic (changeable)
-fight or flight
can behavioural traits vary like other traits?
yes, e.g. squirrel flight responses to stimulus
what is behavioural ecology?
study of connections between ecology, evolution, and behaviour
what are the two steps needed for behaviour to evolve via natural selection?
- there is heritable variation in the behaviour
- variation in behaviour results in a fitness differential (reproductive success changes)
(a behaviour is heritable if some of the variation is explained by variation in genes)
what did Niko Tinbergen study and what did he observe?
-he studied fixed action patterns (FAPs) in sticklebacks which are triggered by specific stimulus, always occur in the same form, cannot be changed once started, and largely innate
-he observed that the breeding male sticklebacks responded aggressively to other male breeding sticklebacks
-the aggressive response is triggered by the stimulus of seeing a red belly
- this occurs to defend territories from other breeding males which allows for the sticklebacks to have more access to females, allowing for more fertilized eggs, and thus increasing their reproductive fitness
what did Niko Tinbergen find out about the herring gull chicks?
that the red spot on a parents beak acts as a stimulus that triggers the chicks to have pecking response
why is describing innate behaviours controversial?
In adult monkeys and humans, seeing snakes, spiders, and bees causes the innate behaviour of being alarmed, while in babies they are not initially alarmed indicating that the innate behaviours for survival may actually be learned
what is the most commonly known gene that influences behaviour?
egr-1
can behaviour evolve by selection?
yes, certain behaviours can be selected for
what did the Russian experiment in 1959 on foxes do?
made them more tame over generations and domesticated
what is an animal behaviour that depends on both genes and environment?
imprinting
-e.g. imprinting in baby ducks is genetically based (hard wired) but outcome depends on environmental stimulus (who do they first see when hatched)
how do animal neurons respond to stimuli?
they respond via action potentials and calcium changes which release neurotransmitters causing the activation of the next neuron
what do neuronal proteins do?
help mediate the flow of calcium ions, affect turgor pressure of plant cells, and nerve impulses in animals
what is the origin of various proteins found in neurons?
they originate from early animals and plants
do plants have neurons?
no
what responds to stimuli in plants?
neuronal proteins
neurotransmitters and nerves evolved over many years, what was used before them in early eukaryotes?
neuronal proteins
what was the earliest animal fossil with evidence of a brain from the Cambrian period?
pikaia from china
what is the part of the brain that is responsible for speech?
Broca’s area
is the brain relatively conserved in organization throughout many species?
yes
do changes in size cause different stronger abilities in certain animals?
yes, larger olfactory bulb increases smell in dogs, larger opticbulb increases vision in birds
is brain evolution shaped by selection for ecological adaptations?
yes, relative concentration of neurons in the brain focuses on certain parts that are more important like hands and mouth for humans and head and forelimbs for moles
what is individual selection?
differential fitness of individuals causes some genotypes to outcompete others in the usual evolutionary way
what is group selection?
differential fitness of groups causes some groups to outcompete others and ultimately have higher fitness (slower to evolve because individuals in most groups also behave to favour their individual fitness)
what did Alex Taylor show?
how some crows can have abstract thoughts that let them use tools and problem solve
