Copy of Evolution Notes

Evolution

• Concept: Change in population over time.

Mechanisms for Evolution

• Species: A group of organisms that can interbreed and produce viable offspring.

• Evolving Factor: Populations evolve, not individuals.

Evolution - Darwin

• Charles Darwin: Recognized as the father of modern evolutionary theory.

• Key Locations: Notably studied the Galapagos Islands during his voyage on the HMS Beagle.

HMS Beagle

• Expedition: Darwin's trip around the world facilitated investigation into diverse ecosystems.

Natural Selection

• Theory: Organisms with traits best suited to their environment tend to survive and reproduce.

Example of Natural Selection (Mice)

• Environmental Change: A population of mice moves to a dark area.

• Genetic Variation: Some mice are black; others are tan.

• Predation: Tan mice are more visible to birds; hence they are eaten more frequently.

• Outcome: Higher survival rates for black mice result in more black mice in the next generation.

Darwin's Finches

• Adaptation: Different finch species demonstrate varied feeding habits based on habitat:

  • Akiapola'au: forages for insects.

  • Iiwi: feeds on nectar.

  • Amakihi: nectar-feeder.

  • Maui parrotbill: searches for beetles.

  • Nihoa finch: crushes seeds with its bill.

Influences on Darwin's Theory

• Jean-Baptiste Lamarck: Introduced the idea of inheritance of acquired characteristics.

  • Example: A giraffe's neck lengthening due to stretching for heights is inherited by its offspring.

  • Organisms change due to the pressures of their environment; traits are acquired and passed down to its offspring.

Example of Natural Selection (Peppered Moths)

• Example from the Industrial Revolution showcasing how environmental changes led to shifts in moth coloration due to predation and camouflage.

Genetic Concepts in Evolution

• Genetic Variation: The differences in DNA among individuals in a population are essential for evolution.

  • Sources:

    1. Mutations in DNA.

    2. Sexual reproduction (meiosis).

Reproductive Strategies

• Sexual Reproduction: Combines DNA from two parents.

• Asexual Reproduction: Involves only one parent, leading to less genetic variation.

Advantages and Disadvantages

• Sexual Reproduction:

  • Advantages: Genetic variation.

  • Disadvantages: Requires a mate and can be time-consuming.

• Asexual Reproduction:

  • Advantages: Requires little energy and no mate.

  • Disadvantages: No genetic variation.

Evidence for Evolution

1. Fossils: Show complexity increase over time but with an incomplete record; mold or cast of organism left in rock, fossilized bone and teeth life becomes more complex over time record is incomplete.

   • Relative dating- 

     • Layers in rock bed used to date organisms

     • Deeper is older, shallow is younger

     • (tell when organisms lived in reference to other organisms older organisms show simpler body structure, while more recent organisms are more complex many fossils show strong similarities

     to existing organisms)

   • Radioisotope dating-

     • uses half-life of element to estimate age of organism (Carbon is used frequently)

   • Phylogeny-

     • description of the lines of descent of plants and animals as they lived from one to the next (how they are related)

2. Comparative Anatomy: Studies the structural similarities across different species (homologous vs analogous structures).

3. Homologous parts: modified structures among different groups of descendants

   • Vestigial Organs: Non-functional organs, e.g., vestigial toes in horses and pelvic bones in whales.

   • Analogous parts- structures in organisms that have no common origin but serve the same function

4. Comparative Embryology: Examines developmental similarities.

5. Biochemical Evidence: Analyses DNA and proteins across species.

6. Genetic Evidence: Includes mutations (mistakes in the genetic code; causes changes in populations over time) and selective breeding(humans choose plants/animals with most desirable traits and breed them to pass those traits to offspring).

7. Direct Evidence: Observations of rapid evolution in various organisms. (Rapid Evolution: Strains of bacteria becoming resistant to antibiotics Weeds and herbicides Insects and pesticide)