Biology Chapter on Gene Pool and Speciation

Study Notes

Refers to the complete set of alleles present within a population
A larger and more diverse gene pool has a greater variety of genes and alleles, leading to increased genetic diversity

Environmental selection pressures, genetic drift, gene flow, and mutations play a significant role in changing allele frequencies in a population’s gene pool.
Mutations are the source of new alleles

Individuals are considered different species when they can no longer interbreed to produce viable and fertile offspring
Allopatric and sympatric speciation are two types of speciation

Involves the formation of a new species due to a geographical barrier, such as a mountain range or a river
Geographic separation prevents gene flow
Different selection pressures exist in different environments, resulting in the accumulation of variations
Eventually, enough differences accumulate that the separated populations become distinct species

Occurs when new species evolve within the same geographical area, without a physical barrier
Individuals within the population may develop unique adaptations to specific resources or ecological niches
Over time, these variations lead to reproductive isolation

Fossils can be dated using relative and absolute dating methods
Relative dating uses stratigraphy, the study of the relative positions of rock layers. Lower layers are older than upper layers.
The law of faunal succession states that fossils closer to the surface are younger than those found below them.
Absolute dating uses methods like radiometric dating to determine the exact age of a fossil.
Conditions that increase the likelihood of fossilisation include:
- rapid burial by sediment, protecting the remains from scavengers and decomposition
- hard exoskeletons provide better preservation
- protection from weathering elements like wind, sunlight, and water
- constant humidity and cold temperatures slow down decomposition

Structural morphology, comparing homologous and vestigial structures, provides evidence for relatedness between species.
Molecular homology relies on DNA and amino acid sequences to establish evolutionary relationships
Whole genome sequencing is used to determine the degree of similarity between genomes of different species

Phylogenetic trees are diagrams that illustrate the evolutionary relationships between different species.
Individuals sharing the most recent common ancestor are considered more closely related.

Fossil and DNA evidence, including mtDNA and whole genomes, are used to trace the migration patterns of modern human populations around the world
The migration of Aboriginal and Torres Strait Islander populations is particularly significant
Regional genetic variation in Australia reflects long-term adaptation to specific landscapes

Connections to Country and Place are evident in cultural practices deeply intertwined with landscapes
Dreamtime stories, cultural practices, and land management techniques illustrate the enduring link between Aboriginal and Torres Strait Islander peoples and their ancestral lands