Development and life history Flashcards
What is meant by “life-history”?
Life history is the different stages an individual goes through from birth to death.
It makes predictions about how these phases appear based on how long they take to become independent and social and function in society.
Describe a primates lifespan?
Primates are very long-lived, their body size and lifespan is correlated where larger bodied animals live longer.
Monkeys live 15-30 years.
Great apes live up to 50 years.
Humans can live up to 120 years.
Why do female primates live longer than males?
Because males have riskier lives; such as extreme male-male competition for access to fertile females and a lot disperse out and need to fight their way into a new group and climb the ranks of resources.
How does primate socialisation change through a primates life-history?
Can see modification of behaviour in different individuals depending on who they interact with and see changes with age. These differences occur as individuals learn as a product of interactions with others.
A large brain allows multiple complex relationships. Larger group sizes tends to be correlated with large group size.
Their is a lengthy period of dependence. Infants watch mothers and learn from them through observation, social learning e.g chimps cracking nuts.
Heavy reliance on learning. Infants are born unable to do anything so their is long period of observation before being able to do it themselves. If an infant loses their parent early in life this can have a serious impact on survival.
What is meant by altricial and precocial?
Altricial = underdeveloped brain at birth (humans have the most underdeveloped brain and most helpless animal)
Precocial = well-developed brain size. Animals are able to walk at birth.
What is the human infant challenge?
Because humans are bipedal, the shape of our pelvis has changed leading in a narrow birth canal. With this and the humans large brain their is an obstructional dilemma.
To get around this humans are born early and their skull plates un-fused.
The female body when pregnant also releases a relaxin hormone to make the pelvis more flexible.
Human females also need an obligate midwife.
What is an alternative view to why humans are born early (Dunsworth et al., 2012)?
“not about being bipedal, why we’re born
early is actually about energy - theres a point
in pregnancy where the energy taken to grow the
baby it would suck so much energy from mum
she would no longer be healthy - tipping point
= go into labour”
Why do apes have an easier parturition than humans?
apes have a lot more space in canal than
humans… however some monkey species do
have similar makeup to humans… but don’t
struggle at birth
Is a primates birth assisted and how can a birth effect social rank?
It’s generally unassisted except in marmosets and humans. New infant draw the attention of others. So if a low ranking female has a baby she is allowed into the central group moving up the social hierarchy.
Because infant primates have a lot to learn. What adaptations have developed to ensure this critical learning period to take place?
Single births allow for more attention to go on the developing baby.
Infants are born with grasping hands and carried 24/7 so they have a continuous opportunity to learn through observation and experience.
