Evolution Flashcards
Why would we be interested in human evolution.
High perceived capabilities- in terms of cognition, creation
We perceive our brains to be somewhat exceptional duet to spiritual cultures, abstract ideologies, technologies and memories
In reference to measuring brain size describe the difference between looking at total brain weight, brain weight as a % of body weight and the encheplaization factor.
Total brain weight- elephant, brain weight %- shrew, encephalisation factor- humans.
Describe encephalisation
brain weight/body weight to 0.60 power. Get regression line and look for the greatest deviation for humans. We see that cognitive capacity exceeds demand to run a body.
We know that one way in which our brains have changed is in overall size- how does this relate to other animals
Birds, mammals and cartilaginous fish have increased relative brain size. Exception hagfishe
Another way in which our brains have changed are in the relative regional size increases esp neocortical scaling
With the exception of lampreys all the other organisms seem to have predictable structures. they have a brainstem, cerebellum. In mammals the forebrain or telencehplaon (cerebral hemisphere) seems to have the most increase when we look across.
What can we expect when we compare utlisation of a rat brain in comparison to a human one
Olfactory cortex bigger in rats, architecture, details, cells, connectivitely, may be distinctively different rather than just relying on the gross anaotmy
Another way in which our brains have changed is through the brain architecture design (lamination, migration, segregation, mappings) esp parcellation
Parcellation may look superficially the same but there are distinctive differences
Talk me through gyrification and cortical thickness
Not drastic differences in terms of cortical thickness, we have acquired more cerebral cortex and as a result we get an increase in gyrification and folding.
What is the deal with primates?
Bigger brains (in relation to body size), more neocortex, more disticnt archictectures in the neocortex.
Give brief description of hominid evoltuion
Australopithecine Africa (only) for 2 million years, Homo Habilis 2-1.5 mya (lineage to erectus)- limited cranial volume did give rise to erecturs, homo erectus (1.5)- migrate out (asia, afirca, europe, homo sapiens, neandtrals
Summarise the evolution of grassland hypothesis and denote its criticisms
- Thought to be a driver of evolutionary change towards intelligence, but brain size increased after bipedalism suggesting that freed hands were not the trigger for cerebral expansion.
What is the modern day solution of evolution
Rapid climate changes. The variability selection hypothesis proposes that relatively rapid environmental change replaced habitat specific adaptations and favoured adaptations tat increased the ability to response and accomodate this change (such as increased intelligence and social complexity) Problem solvers survive. also the fact that we have a childhood.
Whats the deal with childhood?
Humans have huge growth after birth as well as synaptic growth. Critical period requires interaction with the environment for adequate wiring. Look at teeth for evidnce.
Describe migrations
First out of Africa 60000-2000, later spread to west Asia 45 000-35 000 and later migration to the bering strait 20 000- 15 0000
What is the deal with parcellation
As you go up in levels of mammals it does appear that you get differentiation in the brain. Stops at the old world monkeys and apes.
