ANT214H5 Chap.7 Dietary Adaptation and Evolutionary Mismatch
Dietary Adaptation and Evolutionary Mismatch
Specify the adaptation claim
A dietary adaptation requires heritable variation, an environment that creates differential consequences, and change across generations. The trait, population and selective setting must be named.
Widespread consumption of a food does not by itself establish genetic adaptation, and a genetic association does not identify the historical pressure without population and archaeological evidence.
Behavioural and cultural adjustments may occur much faster and can alter the environment in which selection operates.
Use gene culture coevolution as a pathway
Food production and processing can create new exposures, while inherited traits may affect the costs and benefits of those practices.
Lactase persistence is a useful model because dairying practices and adult lactose digestion can be studied as interacting histories, yet the relationship varies among populations and includes cultural alternatives such as fermentation.
A good explanation traces reciprocal change rather than making culture a trigger followed by purely biological evolution.
Distinguish adaptation from acclimatisation
Genetic adaptation concerns population change across generations. Developmental plasticity shapes phenotype during development, acclimatisation changes function within a lifetime, and cultural practice changes behaviour or technology.
These responses can interact but are not interchangeable. Classifying the time scale and transmission route prevents a flexible individual response from being described as evolved and prevents a population association from being treated as destiny for each person.
Interrogate mismatch
Mismatch hypotheses propose that traits shaped in one environment encounter conditions to which they are poorly suited.
The claim needs a defined earlier environment, present exposure, mechanism and outcome. An imagined universal ancestral diet cannot supply that evidence because past diets were variable. Contemporary inequality, marketing, medication, infection and work can provide direct causes that a mismatch narrative overlooks.
Compare the hypothesis against these alternatives rather than using mismatch as a label for any modern disease.
Preserve trade-offs and variation
Adaptations can carry costs, depend on context and differ in frequency across populations. A trait that improves use of one resource may have no advantage where the resource is absent. Selection also acts on reproductive consequences, not a general goal of health.
Conclude by stating the evidence for variation, environmental relation and consequence, then identify the unresolved historical or mechanistic link. This keeps evolutionary reasoning explanatory without becoming deterministic.
Adaptation test
Use four boxes: inherited variation, environmental relation, differential consequence and generational change. If evidence is missing from one box, narrow the conclusion.
Then place developmental, acclimatory and cultural alternatives alongside the genetic account. The strongest explanation may combine time scales, but each response must retain its transmission mechanism and evidential standard.
Evolutionary conclusions should remain proportional to evidence about inheritance, history and consequence rather than the familiarity of the story.
What this chapter covers
- 01
Lactase persistence
- 02
Amylase variation
- 03
Gene culture coevolution
- 04
Evolutionary mismatch
- 05
Trade-offs and alternatives
Worked example · free
Worked example: Dietary Adaptation and Evolutionary Mismatch
- 2Classify the response as genetic, developmental, acclimatory or cultural and state its transmission route.
- 3Link inherited variation to a defined environment and differential consequence across generations.
- 3Challenge the mismatch claim with historical variation, trade-offs and direct contemporary causes.
Key terms
- Gene Culture Coevolution
- Reciprocal change in which cultural practices alter selective environments and inherited variation influences those practices.
- Lactase Persistence
- Continued lactase activity into adulthood, whose population distribution is studied alongside dairying histories.
- Evolutionary Mismatch
- A hypothesis that a trait shaped under earlier conditions produces costs in a changed environment.
- Acclimatisation
- A reversible or adjustable physiological response within an individual's lifetime.
Dietary Adaptation and Evolutionary Mismatch FAQ
Does a common dietary practice prove genetic adaptation?
No. An adaptation claim requires heritable variation, a relevant environment and evidence of differential consequence across generations. Cultural learning, technology and developmental response can also produce common practices.
What evidence makes a mismatch claim testable?
Specify the earlier environment, current exposure, trait, mechanism and population outcome, then compare alternative contemporary causes. Without those links, mismatch is a descriptive story rather than an explanatory hypothesis.
Exam move
Classify every response as genetic, developmental, acclimatory or cultural. For adaptation claims, retrieve the evidence for variation, environment, consequence and generational change.
