ANHB1102 Lecture Notes - Lecture 27: Evolutionary Ecology, Phenotypic Trait, Phenotypic Plasticity
25 May 2018
School
Course
Professor
Human Ecology Notes:
Introduction to Ecology and Evolution:
What is ecology?
-The relationship of organism to its environment
-Study of factors determining the numbers and distribution of organisms/organism
-The day to day workings of natural selection
Human Ecology:
-Inter-relationships between humans and their environment
-In an evolutionary context (environment as selective pressures)
-Biological Ecology: how the environment has shaped/shapes our biology
-Evolutionary Ecology: evolution of behaviour and morphology relative to environment
-Cultural Ecology: environmental shaping of socially transmitted information (e.g social
structure, political structures, economy etc)
Ecology and Adaptation:
-We are trying to survive and reproduce
-Need: food, water, shelter, mates
-What makes it hard: environment (hostile, changing), competitors (competitors have same
needs = conspecifics)
Adaptation (across generations):
-Process (verb): the process of successful interaction between an environment and a population
-Result of the process (noun): cultural or biological traits that offer an advantage in a given
environment
-Inc fitness via Natural selection
Adaptation (genetic):
-Competition: not all individuals are able to grow, survive and reproduce equally well
-Some of these differences are due to their different abilities to convert resources into biomass
and reproduction
-When a particular resource is limiting; those better able to acquire/use it will survive, grow,
reproduce more than those less able (natural selection)
Ecological processes: interface of humans with environment
Natural selection is differential replication of genotypes by different phenotypes (ie individuals) in
particular environment
Result: populations change over time in response to ecology
Acclimatisation:
-Change in organism in response to environment within a lifetime to better able them to cope with
some aspect of their environment
-Shorter term (days to weeks) responses to short-term threats to homeostasis
-Phenotypic plasticity (adaptability)
-Reversible physiological changes
-E.g skin tanning changes skin colour and reduces damage from UV
-Mechanisms are genetic adaptations that allow phenotypic change in individuals in response to
environment cue; response doesn't change genotype
-Most are species wide
-Some are population specific
Acclimation:
-Very short term (minutes to hours) response to an environmental stressor
-Adrenaline response to threat
-Male testosterone surge in response to physical confrontation
-Basis of response = genetic = subject to NS
-Usually species-wide but can also vary due to population or development
Summary: Types and Examples of Genetic Adaptation:
Example: Species-wide traits
-Upright posture, later…enlarged brain
-inc fitness
-genetic processes
-evolutionary change
-Mutation and natural selection
-Selective forces? hypothesis:
-vision (early in forest primates; depth vision reduces falls)
-bipedalism (efficiency of terrestrial movement)
-large brain (foraging complexity, social group dynamics)
Temperature Change: 150kya to present:
Human Dispersal:
Types of Adaptations
Species wide: very old
Population specific: single dispersion into various habitats genetic variation
Acclimatisation (often species wide ability): long term physiological change in individual response to
environs (days to mins)
Acclimation (can be species wide): short term physiological response (hours or mins) - fight or flight
response
Population-Specific:
-Due to population-specific environments
-More recent (after speciation)
-Skin colour variation (latitude, light)
-Post-weaning lactose tolerance (dairy husbandry)
-Genetic variations associated with phenotypic traits, so variations among populations are more
recent than homogenous traits of humans that vary from other species (derived/ancestral traits)
Last Glacial Environment (120-20 KYA):
-Exposes land
-Allowed for movement/migration
Understanding a phenotypic trait in evolutionary ecology context:
-Example of how to approach a phenotypic ‘problem’ to understand its evolution
-Each cell is a different set of ‘does trait__ fit in this cell?’
Timing of Major Changes in Humans
Changing their Environments:
-Change environment - ability to
manipulate environment in broad ways
-Making conditions better and worse for
plants to grow = agricultural revolution
Document Summary
The relationship of organism to its environment. Study of factors determining the numbers and distribution of organisms/organism. The day to day workings of natural selection. In an evolutionary context (environment as selective pressures) Biological ecology: how the environment has shaped/shapes our biology. Evolutionary ecology: evolution of behaviour and morphology relative to environment. Cultural ecology: environmental shaping of socially transmitted information (e. g social structure, political structures, economy etc) We are trying to survive and reproduce. What makes it hard: environment (hostile, changing), competitors (competitors have same needs = conspeci cs) Process (verb): the process of successful interaction between an environment and a population. Result of the process (noun): cultural or biological traits that offer an advantage in a given environment. Competition: not all individuals are able to grow, survive and reproduce equally well. Some of these differences are due to their different abilities to convert resources into biomass and reproduction.
