Introduction to Evolutionary Biology

Focus on chapters sixteen to eighteen of the coursework material.
Chapters are brief and cover important evolutionary concepts.
Emphasis on content rather than length; students should grasp key ideas from text.

Students encouraged to send specific email inquiries regarding textbook material.
Avoid vague questions; instead, specify what concepts or information are unclear.
Inquiries sent close to deadlines may not receive timely responses; proactive communication is recommended.

Four primary agents of evolution discussed, with an honorary mention of a fifth:
1. Natural Selection
2. Mutation
3. Gene Flow
4. Genetic Drift
5. Non-random Mating (honorary): more relevant from the second generation onwards.
Key Point: Non-random mating influences the allele frequency indirectly by modifying genotype frequencies in the first generation.

Definition of Inbreeding: Mating between genetically similar individuals, often relatives.
Consequences of Inbreeding:
- Increased homozygosity.
- Decreased heterozygosity.
- More frequent expression of deleterious traits, particularly recessive alleles.
Fitness implications: Homozygous recessive individuals may show lower fitness (e.g., increased mortality, diseases).
Inbreeding Depression: A decline in biological fitness due to inbreeding as illustrated in various species.

A practical example from European bird populations where hatching failures correlate significantly with increased inbreeding coefficients.
Statistical Relationship: As inbreeding in birds increased, the rate of embryo (egg) failures also increased, creating an accelerated curve demonstrating inbreeding depression.

Inbreeding: Tends to occur more frequently in isolated populations and can lead to negative fitness consequences.
Outbreeding: While beneficial for increasing genetic diversity, extreme outbreeding can disrupt adapted gene complexes resulting in lower survival (known as outbreeding depression).

Genetic Rescue Concept: Bringing new genetic material into an inbred population to improve fitness (via hybridization).
Examples of genetic rescue efforts in Florida panthers:
- Initial populations shrank to about 20-25 individuals leading to noticeable genetic defects and poor survival.
- Introduction of Texas panthers to enhance genetic diversity resulted in rebound of the population.

Historical population ranges for Florida Panthers significantly reduced due to urbanization and habitat fragmentation.
Genetic analysis showed low genetic variability leading to various health issues (e.g., heart defects, poor fertility rates).
Outcome: Successful genetic rescue increased population size from 20 individuals significantly through reproductive success influenced by hybrid vigor.

Hybrid Vigor (Heterosis): Hybrid offspring show greater fitness than their parent populations.
Genetic Variability: A critical component for population resilience against disease and environmental changes.
Demographic Response: Positive changes in population structure and fitness thanks to the introduction of genetically diverse individuals.

Genetic rescue techniques used in conservation biology; understanding genetic variability's role in preventing extinction is crucial.
Use of model organisms to study genetic dynamics

Long duration (decades) and significant financial investment required for successful implementation and monitoring.
Difficulty in attributing population growth solely to genetic intermissions versus environmental factors.

The necessity for continuous research and evolving strategies in wildlife conservation emphasizes the importance of genetic principles in maintaining biodiversity.
Discussions on inbreeding and genetic rescue indicate profound implications for species survival leading graduate students to consider the genetic complexities of conservation efforts.