Human Evolution (one)
Ally Network
Both coordinators are part of the UWA Ally Network, supporting diversity, equity, and sexual and gender diversity.
They are accredited mental health first aiders.
Acknowledgment of Country
Acknowledgment of Whadjuk people as traditional custodians.
Understanding Evolution
Understanding evolution requires information, evidence, data, and facts, not faith.
It's crucial in human biology to explain antibiotic resistance, horticultural practices, body shapes in human populations, Sherpa adaptation to high altitudes, and lactose tolerance.
Definition of Evolution
Evolution means change over time, specifically inherited biological change in a population over generations.
Charles Darwin called it descent with modification.
Evolution is a genetic change in a population over generations; populations evolve, not individuals.
Peppered Moth Example
Demonstrates evolution with a shift in moth populations from predominantly light to dark due to industrialization and pollution.
Aspects of Studying Evolution
Fact: Establishing that evolution occurred with evidence.
Course: Determining the pathway and timeline of evolutionary changes.
Mechanism: Understanding the driving forces behind evolutionary change, such as natural selection.
Natural Selection
Darwin and Wallace proposed natural selection as a mechanism for evolutionary change.
Darwin observed potential fertility, limited resources, and variation among organisms.
Inference: Struggle for existence, differential survival and reproduction based on advantageous traits.
Evolutionary change is caused by differential survival and reproduction among organisms differing in hereditary traits.
Moth Example Revisited
Increased Pollution led to increased predation on light-colored moths, increasing the survival rate of dark-colored moths.
Pollution reduction is now reversing this trend.
Darwin's Challenges
Time: Initial estimates of Earth's age were too short for Darwin's theory.
Heredity: Lack of understanding of how traits are inherited and how variation arises.
Terminology
Gene: A region on a chromosome that codes for a trait.
Allele: A variation of a gene; individuals have two alleles for each gene.
Genotype: The specific combination of alleles an individual has.
Phenotype: The observable characteristics resulting from the interaction of genotype and environment; natural selection acts on the phenotype.
Darwinian Fitness
Survival and reproduction.
Reproductive success is key.
Types of Selection
Natural, Artificial, and Sexual Selection.
Stabilizing, Directional, and Disruptive Selection.
Selection Pressures: Biotic and Abiotic factors that influence survival and reproduction.
Competition
Interspecific: Competition between different species for resources.
Intraspecific: Competition within a species for resources, such as mates.
Types of Selection in Detail
Stabilizing Selection: Selects against extremes, maintaining the mean value.
Directional Selection: Shifts the mean value over time by selecting against one end of the spectrum.
Disruptive Selection: Selects against the mean value, potentially leading to two distinct populations.
Sexual Selection
Traits that enhance mating success are favored, leading to distinct body types and behaviors.
Examples are plumage on male ducks and peacocks or antlers on male deer.
Involves power to conquer and the power to charm.
Speciation
A population becomes separated. Natural selection acts differently on the two sub populations and over time, those populations can become so different, such that when that barrier goes away, if they cannot interbreed, then they are classed as two species.
Scale of Evolution
Microevolution: Small-scale changes in genetic frequencies within a population from one generation to the next.
Macroevolution: Large-scale genetic changes over millennia, leading to new species.
Theories of Evolutionary Change
Gradualism: Slow, incremental changes over time.
Punctuated Equilibrium: Long periods of stasis interrupted by sudden, rapid changes.
Evolutionary Forces
Mutation, gene flow (migration and reproduction), and random genetic drift. These will be covered in detail in 1.102.