Lecture Notes on Evolution

Common Misconceptions about Evolution

Evolution in Games vs. Biology: Games often depict individual characters evolving, which is a misunderstanding. In biology, individuals do not evolve; populations do.
Misunderstood Terminology:
- Theory: In science, a theory is a well-substantiated explanation; not just a guess.
- Fitness: In biology, fitness refers to the ability to reproduce and pass on genes, not physical strength.
- Evolution: In casual terms, it may mean increased complexity, but in biology, evolution doesn't always mean more complexity.

Biological Evolution: Change in the inherited traits of a population over generations.
Key Point: Evolution occurs in populations, not individuals.

Gene Flow: Movement of genes between populations, often through migration.
Mutations: Changes in genetic material; can be harmful, beneficial, or neutral.
Genetic Drift: Changes in population's genetic makeup due to random events.
- Example: A lawnmower affecting a grasshopper population.
Natural Selection:
- Example: Green grasshoppers may survive better if they are camouflaged, leading to higher reproduction and greater representation of green genes in the population.

Molecular Homologies: Similarities in DNA and protein structures among organisms indicate common ancestry.
Anatomical Homologies:
- Homologous Structures: Similar structures inherited from a common ancestor (e.g., human arm and dog forelimb).
- Vestigial Structures: Structures that have lost most or all their original function (e.g., claw on chicken wings).
Developmental Homology: Similar embryonic development stages indicating shared ancestry (e.g., pharyngeal slits in vertebrates).

Provides insight into how species have changed over time.
Radiometric Dating: Determines the age of fossils by measuring radioactive decay.

Study of the distribution of species across geographical areas.
Example: Marsupials in South America and Australia have shared ancestry due to past continental connections (Pangea).

Evolution is an ongoing process as organisms continue to change across generations.
Example: Antibiotic resistance in bacteria showcases rapid evolutionary changes.

Stay curious and continue to explore the fascinating world of evolution!