BSC2010-evolution-7-2024

Overview of Life Forms

• Organisms are classified into three domains:

  • Archaea

  • Bacteria

  • Eukaryota

    • Includes Metazoa (animals), Excavata, Amoebozoa, SAR, Archaeplastida, and Fungi

Evolution Introduction

• Richard Dawkins, author of The Selfish Gene, presents concepts in his illustrated work The Genetic Book of the Dead.

Course Schedule for BSC 2010 (Fall 2024)

• Oct 30: Introduction to Evolution

• Nov 1: Natural Selection

• Nov 4: Sexual Selection

• Nov 6: Processes of Evolution I

• Nov 8: Processes of Evolution II

• Nov 11: Veteran's Day: No Class

• Nov 13: Genome Evolution

• Nov 15: Phylogenetics

• Nov 18: Macroevolution 1: Origin of Species

• Nov 20: Macroevolution 2: Speciation and Extinction

• Nov 22: Human Evolution

• Nov 25-29: Thanksgiving Break - No Class

• Dec 2: Origins and Early Diversity of Life

Phylogenetics Study

• Outline Topics:

  • Describing relationships among species

  • Types of data used:

    • Fossil data

    • Morphological data

    • Molecular data

  • Techniques:

    • Radiocarbon dating

  • Phylogenetics:

    • Reconstructing phylogenetic trees

    • Principle of parsimony

  • Classification and Taxonomy:

    • Binomial nomenclature

    • Hierarchical classification system

Constructing the Tree of Life

• Three Means of Determining Relationships:

  1. Fossil Record

  2. Morphological Data

  3. Molecular Data

Fossil Record Analysis

• Fossil Characteristics:

  • Preserved parts or impressions of organisms

  • Generally hard parts like bones and teeth

• Significance:

  • Inform species diversity, speciation, and extinction

  • The fossil record is often biased and incomplete

  • Challenges exist in preservation, especially of soft tissues.

Dating Rocks and Fossils

• Methods of Dating:

  • Sedimentary strata show relative ages.

  • Absolute Ages:

    • Determined by radiometric dating

    • Involves decay of isotopes (parent to daughter) at constant rates

• Half-lives:

  • Each isotope has a known half-life.

Morphological Data and Analysis

• Traits Comparison:

  • Homologies vs Analogous traits

  • Use fossil record and geographical patterns for insights

• Example:

  • Anteaters, both placental and marsupial mammals.

Molecular Data

• DNA Sequences Comparison:

  • Similar sequences suggest closer relations

  • Molecular results may contradict morphological and fossil data comparisons.

Phylogenetic Trees

• Relationships depicted using trees

  • Trees represent hypotheses about evolutionary relationships

  • Base on differences in traits/DNA

Applications of Phylogenetics

• Uses:

  • Understand relationships among taxa

  • Examine biogeography and trait evolution

• Applications:

  • Conservation (e.g., testing products)

  • Agriculture (analyzing cultivars)

  • Forensics (DNA fingerprinting)

  • Medical research (e.g., tracing anthrax strains)

Understanding Taxonomy

• Classification Hierarchy:

  • Kingdom, Phylum, Class, Order, Family, Genus, Species

• Example:

  • Human Taxonomy:

    • Kingdom: Animalia

    • Phylum: Chordata

    • Class: Mammalia

    • Order: Primates

    • Family: Hominidae

    • Genus: Homo

    • Species: H. sapiens

Binomial Nomenclature

• Format:

  • Genus species

  • Rules: Capitalize the genus; italicize or underline the full name.

Principle of Parsimony

• Definition:

  • Simplest hypothesis explaining patterns (trees) chosen.

  • Focuses on minimizing shared derived characters.

Challenges in Phylogenetics

• Common Issues:

  • Data limitations and disagreements with fossil interpretations.

  • Problems of horizontal gene transfer and trait reversals in data interpretation.

Summary of Biological Classification

• Karl Linnaeus' Contribution:

  • Established classification based on morphological traits.

  • Introduced binomial nomenclature and hierarchical systems.

• Evolutionary Relationships:

  • Study of systematics integrates taxonomy and phylogenetics.