Lecture 3 Flashcards
What is epigenome
Set of chemical marks in an individual’s genome that affects in gene expression. This set of marks is heritable but can be modified by environmental exposures.
What are epigenetic factors
- non coding RNA
- histone modifications
- histone variants
- chromatin remodelling factors
- DNA methylation
Why is the epigenome necessary for development
- cell differentiation
- tissue differentiation
- life history events
What potential adaptive advantage could the epigenome provide
- allows for changes in expression of the otherwise static genome to respond to environmental conditions
epigenetic changes are associated with _____
environmental stressors
- changes are reversible
What is life history theory
- postulates that Ontogeny has been shaped by natural selection
- organisms are expected to follow resource allocation patterns across their lifespan that result in an optimization of their Overall Biological Fitness
What is ontogeny
development from the moment of conception
What is overall fitness
individual fitness + inclusive fitness
What is individual fitness
Offspring produced by self
What is inclusive fitness
positive? effect on the fitness of relatives
What is the formula to calculate trait would have positive selective value
- Hamilton
- rb> c
c - reproductive cost to self
b- reproductive benefit to recipient
r- coefficient of relatedness
How do individuals maximize fitness
by optimizing resource allocation throughout life span
What is the principle of allocation
at any given life stage resources used for one purpose cannot be used for another
How does natural selection relate to principle of allocation
ns expected to favour evolution of optimal allocation patterns
What do we need to allocate energy to
- growth
- maintenance
- reproduction
What are the human life stages
- prenatal
- childhood
- adolescence
- reproductive life
- post-reproductive life: menopause and andropause
What is senescence
- end of childbearing to death
Why are most nonsocial mammals weaned into independence while humans are dependent post weaning
- early human diet is particular… digestive system matures slowly but energetic demands are substantial
Why is human childhood particular
- relatively small body size
- comparatively slow and steady rate of growth
- dependent feeding
- Higher RMRs than any other mammalian species
- large expensive fast growing brain
- motor and cognitive immaturity
- adrenarche (shared with chimps) and mid-growth spurt (unique to humans)
What differentiates humans from apes
in humans delays in
- eruption of first permanent molar
- menarche
- first birth
- shorter birth intervals
- can rear multiple offspring simultaneously
What do short IBIs in humans provide
reproductive advantage over other apes because we can produce and rear 2 offspring through infancy in time it takes chimps or orangutans to produce and rear one offspring