AP Bio Evolution Notes Pt.1

AP Biology Notes: Evolutionary Biology

Topic: Introduction to Evolutionary Biology

Key Concepts

1. Definition: Evolution is the change in the genetic composition of a population over time, leading to diversity and unity of life.

2. Central Theme: Evolution unifies biology by explaining patterns of similarity and diversity.

3. Core Principle: All species descend from a common ancestor.

4. Example of Evolution: Green sea slug acquiring photosynthesis genes through horizontal gene transfer from algae.

Topic: Evidence for Evolution

Key Concepts

1. Fossil Record:

   • Shows progression of life forms over millions of years.

   • Examples: Evolution of humans and horses.

2. Comparative Anatomy and Embryology:

   • Homologous Structures: Similar structures (e.g., human arms, bird wings) derived from common ancestors.

   • Vestigial Structures: Residual parts (e.g., whale hind leg bones) with no current function.

   • Embryology: Shared developmental traits, like gill slits in vertebrate embryos, reflect common ancestry.

3. Biogeography:

   • Distribution of species corresponds with tectonic plate movements.

   • Examples: Marsupials in Australia, Galápagos finches.

4. Molecular Biology:

   • Universal genetic code and DNA structure.

   • Similar DNA sequences indicate shared ancestry.

   • Gene duplications facilitate new protein functions.

5. Direct Observations:

   • Real-time examples: Antibiotic resistance in bacteria, pesticide resistance in plants.

Topic: Mechanisms of Evolution

Key Concepts

1. Natural Selection:

   • Definition: Differential survival and reproduction based on advantageous traits.

   • Principles:

     • Traits are inherited.

     • Overproduction of offspring leads to competition.

     • Variations exist among individuals.

   • Example: Long-necked tortoises in the Galápagos outcompete short-necked ones in food-scarce environments.

2. Genetic Variation:

   • Sources: Mutations and sexual reproduction.

   • Mutations can be neutral, beneficial, or harmful.

3. Adaptation:

   • Traits increasing survival and reproduction.

   • Examples: Cheetah speed, snow leopard fur.

Topic: Processes and Patterns

Key Concepts

1. Divergent Evolution:

   • Common ancestor, species evolve in different directions.

   • Example: Limb structures in humans, birds, and whales.

2. Convergent Evolution:

   • Unrelated species evolve similar traits due to similar pressures.

   • Example: Wings in bats and insects.

3. Speciation:

   • Allopatric: Geographic separation leads to genetic divergence.

   • Sympatric: Speciation within the same habitat via mechanisms like polyploidy.

   • Adaptive Radiation: Rapid evolution of species from a common ancestor.

   • Example: Hawaiian honeycreepers.

Topic: Misconceptions about Evolution

Key Concepts

1. Evolution is not goal-directed:

   • Traits evolve based on environmental pressures, not towards perfection.

2. Humans are still evolving:

   • Examples include resistance to diseases and dietary adaptations.

3. Theory of Evolution is robust:

   • Supported by extensive evidence across disciplines.

Topic: Human Evolution and Ongoing Processes

Key Concepts

1. Examples of Current Evolution:

   • Bacteria evolving drug resistance.

   • Animal adaptations to climate change.

2. Connection to Modern Research:

   • Genomic studies reveal evolutionary trends.

Topic: Connection to AP Biology Curriculum

Key Learning Objectives

1. Big Idea 1: Evolution drives unity and diversity of life.

2. Practices:

   • Analyze data supporting evolution (e.g., fossil records, DNA sequences).

   • Design experiments to investigate evolutionary processes.

3. Enduring Understandings:

   • Speciation and extinction are ongoing.

   • Genetic variation and environmental change drive evolution.