Lecture 1 Flashcards
Traditional health sciences and biology: what kind of answers do they look for?
proximate answers (HOW?): mechanisms
Ecology and evolution find what kind of answers?
ultimate answers (WHY?): origin and function
Evolutionary Medicine (EM)
EM = theoretical frameworks of ecology and evolution applied to the study of health and disease
what is human ecology?
the study of humans as a mammalian species that attempts to achieve its basic biological goals while it interacts (affects and is affect by) with its ecological context
what are basic biological goals?
survival and reproduction
because these two goals lead to evolution
what is evolution and how does it occur?
A change in the genetic make up of a population between cohorts
Occurs:
- natural selection
- genetic drift
- gene flow
Natural selection
Natural selection is a process
Individuals within a species vary:
- some of that variation is linked to genetic differences
- and some of that variation is linked to differences in survival and reproduction
How does the natural selection process work?
- original population
- variation in survivorship
- surviving population of reproductively mature population
- variation in reproduction
- next generation of population
In its essence, it is a simple statement about rates of reproduction and mortality: Those individual organisms who happen to be best suited to an environment survive and reproduce most successfully, producing many similarly well-adapted descendants.
Why does the natural selection process take place?
- it is a consequence of differences among individuals in their ability to survive and reproduce in a given ecological context
What kind of traits can NS affect?
- ONLY genetically heritable traits
Heritability estimate (H) = Vg/Vp
Vg the variation in genotype
Vp the variation in phenotype
- Heritability varies from 0 to 1, with 0 representing resemblance between two individuals chosen at random
can traits associated with health and disease be linked to survival and reproduction?
Of course
so could any of these traits been favoured/disfavoured by natural selection?
YES
Some limits of NS
- NS favours reproductive success not comfort or happiness
- some “genes” (portions of genetic material) may be associated with both costs and benefits
- we compete with pathogens which have shorter life spans
- the environment in which we live is dynamic
environment = ecological context
what is ecological context?
Refers to the intricate relationships between living organisms and their physical environment, emphasizing how these interactions shape the ecosystems
what encompasses the human ecological context?
- physical environment
- socio-cultural environment
human ecology
studies how we attempt to survive and reproduce while adapting to environmental changes
investigates the relationship between environmental and biological variability between individuals
are we humans all equally exposed to all changes and challenges?
not necessarily
- prenatal exposures
- postnatal exposures
Some of these different exposures can be observed within a family, others between different families within a community, others between different regions within a country and so on
could human ecology focus ONLY on the current environment?
No
to summarise human ecology
human ecology studies humans as they attempt to achieve their biological goals within their present context understanding the constraints imposed by our evolutionary past
human ecology also studies the origin of biological variability between and within individuals and populations
the study of humans as a mammalian species that attempts to achieve its basic biological goals while it interacts with its ecological context
Genotype vs Phenotype?
- Genotype is the combination of alleles that they possess for a specific gene.
- Phenotype is the combination of their observable characteristics or traits.
- Genotype is directly inherited from its parents, phenotype is merely influenced by genotype.
- Environmental factors can also affect phenotype.
Genotype example
- eye colour
- hair colour
- height
Phenotype example
environmental factors that influence phenotype are nutrition, temperature, and stress
another is skin colour - our genes control the amount of melanin we produce, but the environment we are in influences our sun exposure therefore determining our skin colour
