evolution Flashcards
why do we study non-human animals?
- there are similarities of brain structure and function across species
- allows study of phylogeny (evolution) of the brain
- understand particular behavioural adaptations
what does Hippocampal lesions in rats show?
- impairs conditioning to contextual cues in animals
what has Hippocampal damage in rats acted as a model for in humans?
- the effects of hippocampal damage in rats = the base model for humans with amnesia (which has occurred due to hippocampal damage)
why are the rat studies essential?
- essential in telling us which neuronal systems are key
what has been found in both birds and mammals in relation to the hippocampus?
hippocampal volume found to be relatively enlarged in food storing species
what are the characteristics of an organism according to Darwinian Theory?
- characteristics of an organism have specific functions
- these functions are selected for if these functions allow organism to survive and reproduce more successfully
what idea is Darwinian Theory consistent with?
- common ancestry
what are Homonids?
- human like apes evolved from primates
- have grasping hands for climbing
- forward facing eyes for stereoscopic depth perception
what do present day hominids include?
- chimpanzees
- gorillas
- orangutangs
- humans
define endemic
species that are not found elsewhere
what are the mechanisms of natural selection?
- genetic drift
- the environment
- speciation
what can have selective advantages?
- mutations
define functionalism
- belief that characteristics of living organisms perform useful functions
- in order to understand the physiological (why animal has something) basis of behaviour, we have to understand what the behaviours accomplish
explain how functionalism and natural selection go hand in hand
- functionalism = the idea that the best way to understand a behaviour or a physiological structure is to understand how the behaviour is a useful function for organism
- natural selection = the process where inherited traits that are a selective advantage to organism become more frequent in a population
define mutation
random, rare change to genetic information
this can be passed to offspring
provides genetic variability
define selective advantage
a characteristic of an organism that increases chance of organism producing more offspring
define evolution
a gradual change in structure and physiology (function of organism behaviour) of species
generally producing more complex organisms as a result of natural selection
provide an example of natural selection
- grey squirrels
- these can digest acorns, red squirrels cannot
- grey squirrels carries a virus that is more deadly to red squirrels
- red squirrels breed less under pressure
- the decline in red squirrels can be understood in terms of the number of selective advantages that grey squirrels have
how is human evolution evidenced?
- fossil records
what were the earliest mammals?
- small nocturnal predators that fed on insects
where did the first hominids (humanlike apes) appear?
- Africa
- appeared in drier woodlands, the savanna, grasslands
when did the first hominid leave Africa?
- 1.7 million years ago
what does DNA analysis of chimps, gorillas, organutans and humans show?
- there is very little difference between species
- humans and chimps share almost 99% of DNA
how is human brain evolution marked?
- differences in hominid brain size
- brain size also links to body size
what is the encephalization quotient?
- a measure of relative brain size
- is often used to convey how small or large a species brain is compared to other species of similar body size
why do humans have a slower maturation process (‘neoteny’)?
- to allow brain development
- birth canal limits the size of the head
- development of head is supported by prenatal care
how has social development supported the evolution of large brains?
- supported evolution of larger brains
- brain reaches adult size (1400 grams) at adolescence
- neoteny allows more time for growth
- this is important factor in development of large brains
what else has been supported by social factors?
evolution of cognitive domains (skills)
what did neoteny most likely drive?
- development of social skills to co-ordinate child care
