BIO 115

Human evolution

Human evolution


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Cartes-fiches 288
Langue English
Catégorie Biologie
Niveau Université
Crée / Actualisé 23.01.2021 / 24.01.2021
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How does relatedness arise?

- Kin discrimination: exists in the social amoeba -> cells know that they are related

- Familiarity: Growing up together in a social group similar to kin discrimination (good proxy)

- Green beard effect: Common ancestry is the origin of high relatedness at the cooperative trait -> strong linkage between the social gene and the green beard gene

 

Neocortex is subdivided into four lobes (ESELSBRÜCKE TOPF)

  • temporal
  • okzidental
  • parietal
  • frontal

Is high relatedness always good for cooperation?

No -> favours kin competition

i) Inelastic populations: helping one relative, indirectly harms the other by not helping them

ii) Elastic populations: extra offspring produced by cooperation can be harboured

iii) Global competition: extra offspring produced has higher prob. to colonize new patches

sensation, visual cortex, primary and secondary visual areas - WHERE?

  • Most sensory functions (vision, hearing, somatosensation) are processed in posterior regions (occipitial lobe)

  • information from retina -> Thalamus -> V1 in posterior occipitial lobe -> V2, V3 from there to V4, V5

  • V4 = Colour coding, V5 = motion perception

  • Vision involves significant processing and interpretation of raw inputs

Examples: Elastic population and global competition

Elastic population: Bacteria that cooperate through the secretion and sharing of nutrient

Global competition: High level of cooperation in within group of apes, young males leave group to compete globally with other males

Damage to V1 causes ___  while damage to secondary visual areas causes more specific ____, i.e. colour or motor blindness

V1 Damage =  total blindness; while damage to secondary visual areas causes more specific visual deficits, i.e. colour or motor blindness

Somatosensation - Where? Wie gegliedert?

  • thalamus (at the transition between brainstem and higher regions) to the primary somatosensory cortex (S1) in the posterior cortex (at the anterior end of parietal lobes)
  • topografisch gegliedert = je mehr Hirnareale einem Körperteil zugeschrieben, desto höhere somatosensorische relevanz (about one-third of all somatosensation refers to face alone (mainly lips))

Whom does selection mostly act on?

On the individual as carrier and reproductive unit of a group of linked genes

Movement and action - Where? Wie gegliedert?

  • primary motor cortex (PMC) in the frontal lobe

  • topografisch gegliedert

Definition: association areas (brain)

 

  • Cortical regions that are neither primary sensory (input) nor primary motor (output) are named association areas, they are the processing or ‘thinking’ bits of the brain
  • They include secondary sensory and motor areas and ‘high cognition’ areas
  • examples: olfaktorisch, gustatorisch, visual, somatosensory, motor, auditory
  • Humans: most of the brain is dedicated to association processes (input/output)

Example for conditional cooperation

Prisoner's dilemma from Game Theory

Conditional cooperation strategies in humans

- Iteration: allow learning and reciprocal interactions

- Tit-for-Tat: react to opponent's last move

- Win-stay-lose-shift: react to opponent and own last move

- Indirect reciprocity: when being observed people care about their image

- Generalized reciprocity: decision is based on previous positive interaction

- Costly punishment: enforcing of cooperation e.g. police

Definition: cross-modal information (McGurk-effect) - association areas brain

Information coming from different sources who disagree

- McGurk Effect suggests that our mind is highly visual - Clash between visual and auditory information, we ‘see’ the sound rather than ‘listen’ to the sound (ba ba oder da da)

 

defintion: working memory (brain)

  • the set of mental processes holding limited information in a temporarily accessible state, it is the ‘here and now’, the ‘present’ (digit memory etc.)

  • analogous to RAM memory (long-term memory is analogous to hard disk memory)

Examples: Conditional strategies outside humans

- Generalized reciprocity in rats

- Punishment in ants

- Policing in honey bees

- Conditional cooperation in paper wasps

Hippocampus and memory (Hippocampus = Seepferd) - what is his function?

Creating/assessing lasting memories is one of the roles of the hippocampus (not the cortex)

Tragedy of the commons

overexploitation of the common resource yields a short-time benefit compared to long-term collapse of the system -> could be us with how the world is looking climate change etc.

Classification of pathogens

- Viruses

- Bacteria

- Protists (eukaryotic single-celled organisms)

- Macroparasites

Clive wearing - lost his two hippocampi - what happened?

- Working memory and awareness remain intact but no new episodic memories are formed (kein Langzeitgedächtnis mehr)

- His reality is a constantly moving window of 10-30 seconds of awareness

Obligate vs opportunistic pathogens

Obligate: relieson host for replication and transmission (survival in the environment possible)

Opportunistic: replicate in environmental habitats, but can infect hosts

Theory of Constructive memory (brain - clive wearing case)

- memory is ‘imagined’ or recreated every time it is recalled

Transmission routes of pathgens

- Environmentally acquried (food, water, other objects)

- Vector transmitted (mosquitoes, ticks, flies)

- Horizontal transmission (blood, STDs, aerosols)

- Vertical transmission (mother-to-offspring)

- Nosocomial transmission (hospital acquired)

What is etiology?

Study of the causes and origins of diseases

central executive - where in the brain is it and what is its function?

  • concept representing the highest-level association area in the brain
  • Most functions associated with CE are located in the prefrontal cortex

What is epidemiology?

Study of the distribution and determinants of health-related events within populations

ventromedial syndroms - what does Damage to prefrontal areas cause?

  • Damage to prefrontal areas cause deficits in cognitive control
  • patients exhibit inappropriate behaviour (‘antisocial’, ‘selfish’, ‘immature’)

Endemic

local outbreak

Epidemic

more widespread, larger outbreaks

Pandemic

affects a large fraction of the worldwide population

prefrontal area of the brain - what is it known for? name one specific are in prefrontal medial cortex?

  • known as the "self area", damage can cause personality change or disorders as loss of ego
  • one specific region is: theory of mind (medial präfrontal kortex) - thinking about myself or others

Distribution of human infectious diseases

Not all diseases are everywhere

There are more diseases in the tropics than in the temperate zone

Diseases have limited distribution ranges, only few are worldwide

theory of mind (brain - prefrontal medial cortex) - theory is questioned

true?

- true: For example, ‘ToM’ is everywhere in the brain, ToM areas’ perform other, more general functions too

What are the three types and levels of globalization (pathogens)

- Infectious agents specific to humans are highly globalized

- Zoonotic dieseases have to lowest level of globalization

- Multi-host infectious agents have intermediate level of globalization

- > the shallower the slope the more globalized

Disease and migration patterns

Migration patterns correlated with presence of fewer but more widespread pathogens

What is special about human cognition?

  • what made human brain so large and human cognition so special is its intimate relationship with a special type of information: cultural information (evidence: early dependence of hominins on cultural information)

  • No longer: learning

Origin of diseases

- domestication -> close interaction between humans and animals -> increased probability for diseases to hop from animals to humans (humans share many diseases with domesticated animals)

- agriculture -> higher population densities -> larger groups -> closer interactoins -> increased transmission opportunities -> crowd epidemic diseases

 

Hominins, culture and human cognition - what was important for the evolution of human cognition?
(gene-culture co-evolution)

  • dependence on cultural artefacts were part of the hominin lifestyle before our brains were large

  • large brain, language, etc. started to evolve

The ultimate cognitive function of brains is the _____

acquisition of cultural information (missing topic in neuroscience)

Hunter-gatherer vs. temperate zone agricultural societies

hunter-gatherer: exposure to local pathogens -> diverse set of pathogens -> wild animal reservoirs -> many potential vectors present

temperate zone agricultural societies: exposure to domesticated animals -> fewer pathogens -> higher population density -> croweded epidemic disease -> fewer vectors -> more global spread of pathogens

Temperate vs. tropical disesase

 

large amount of diseases from the old world

Temperate: acute; crowded epidemic disease; dies or recovers within weeks; long-lasting immunity; large proportion from domesticated animals

Tropical: transmitted by insect vectors: animal reservoirs more frequent; few are acute, lasting for months even years