Materials:
- Red solo cups
- Hole for placing the cups in the ground
Methodology:
- Insects will walk into the cup and fall into a solution.
- Consideration of whether to keep the insects alive or to kill them post-capture.
- Use of a second cup to prevent insects from crawling out.
- Possible use of cardboard to guide insects into the cup.
Future Plans:
- Test different trap designs and locations across campus.
- Initial phase: Basic trapping methods; sophistication to increase over time.
- Discussion of potential use of spectrometry for future analysis.
Natural Selection and Fitness Trade-offs
Review of previous concepts discussed in class,
Definition of fitness trade-offs and their implications in natural selection.
Mechanisms of Natural Selection
Overview of how natural selection can occur in predictable patterns:
1. Directional Selection
- Example: Ground finches on Daphne Major during a drought.
- Change in average beak depth observed.
- Selection for deeper beaks led to decreased genetic diversity as the advantageous trait became fixed.
- Fixed alleles: A frequency of 1 means all alleles are the same (e.g., only large beaks).
2. Stabilizing Selection
- Maintains average trait without changing average value, reduces variability.
- Example: Human birth weight
- Average birth weights have higher survival rates, while extremes (too large or small) face higher mortality.
3. Disruptive Selection
- Favors extreme traits while selecting against intermediate traits.
- Example: Duck bill sizes based on food sources.
- Long-tailed ducks thrive on food at the bottom; short-tailed ducks excel at surface food, while medium beak lengths are less effective.
4. Balancing Selection
- Equally advantageous alleles maintain variation in the population.
- Example: Sickle cell trait's relation with malaria resistance.
- Heterozygous individuals possess advantages that maintain both alleles in the population.
Implications of Natural Selection
Discussion on how natural selection relates to different animal adaptations and reproductive strategies.
Impact of environment on natural selection outcomes and fitness.
Ethical considerations when discussing selection traits in animals vs. humans.
Speciation and Natural Selection
Overview of sympatric speciation and how disruptive selection can lead to distinct populations.
Significance of sexual selection alongside natural selection.
Sexual Selection
Types of sexual selection:
- Intersexual Selection: Females choose males based on traits (e.g., coloration).
- Intrasexual Selection: Males compete for access to females.
Sexual dimorphism examples discussed in various species (e.g., peacocks vs. pea hens, elk, etc.).
Examples of Sexual Selection Mechanisms
Good genes hypothesis and how it relates to visual traits.
Various mating systems:
- Monogamy: One male, one female.
- Polygamy: One male with multiple females or vice versa.
- Resource defense and its influence on mating systems.
Mutation and Genetic Variation
Introduction to mutation as a source of genetic variation.
Importance of mutations in allele frequency changes leading to evolution.
Other Evolutionary Forces
Overview of other factors that lead to evolution: mutation, gene flow, genetic drift (to be covered further).
Definition and significance of gene migration (immigration vs. emigration).
Review and Upcoming Assessments
Upcoming quiz covering natural selection mechanisms and application in chosen scenarios.
Preparation for discussions on how other forces affect evolution over time (future classes will cover genetic drift).