CH2 EVOLUTION & GENETICS copy

Areas of Exploration

  • Theories of Evolution and Inheritance

  • Molecular Genetics

  • Population Genetics and Evolution

  • Biotechnology and Genomics

  • Science, Culture, and Evolution

  • Chapter Author: Lana Williams (University of Central Florida)

Chapter 02: Evolution and Molecular Genetics

2.1 Theories of Evolution

  • Learning Objectives:

    • Compare pre-Darwinian perspectives with Darwinian theory of natural selection.

    • Explain Mendel’s principles of inheritance.

  • Key Concept:

    • All species evolved from different species. Although organisms appear static, evolution occurs continuously.

  • Definition of Evolution:

    • Change in heritable characteristics of biological populations over generations; serves as a unifying theory of biological sciences.

Historical Perspectives on Evolution

  • Ideas regarding species change were suggested before Darwin:

    • Plato: Immutable species concept.

    • Georges-Louis Leclerc, Comte de Buffon and Erasmus Darwin: Proposed ideas of evolutionary change in the 18th century.

    • James Hutton: Introduced uniformitarianism (geological processes shape the Earth).

    • Georges Cuvier: Advocated catastrophism to explain geological layers.

    • Charles Lyell: Popularized uniformitarianism, influencing Darwinian thought.

    • Jean-Baptiste Lamarck: Suggested inheritance of acquired characteristics.

Key Contributions to Evolutionary Theory

  • Multiple disciplines inform evolutionary theory:

    • Taxonomy: Defines and classifies organisms.

    • Biological Systematics: Studies the diversification of living forms.

    • Geology: Explains Earth’s structure and history.

    • Paleontology: Examines ancient life through fossils.

    • Evolutionary Biology: Explores processes that produce life's diversity.

    • Demography: Analyzes population dynamics.

2.2 Molecular Genetics

Learning Objectives

  • Describe eukaryotic cell organelles and their functions.

  • Explain DNA and RNA structures; mitosis and meiosis outcomes.

Cell Structure

  • Cell Types:

    • Prokaryotes: Single-celled (Bacteria, Archaea).

    • Eukaryotes: Multicellular (Animals, Plants, Fungi, Protists).

  • Key Organelles:

    • Nucleus: Command center housing DNA.

    • Ribosomes, Rough Endoplasmic Reticulum (ER): Protein synthesis.

    • Smooth ER: Lipid synthesis.

    • Golgi Body: Packages substances for transport.

    • Mitochondria: Powerhouse, ATP production.

    • Vacuoles, Lysosomes: Storage and digestion.

    • Cytoskeleton: Maintains cell shape.

DNA Structure and Function

  • Discovery: Rosalind Franklin's X-ray crystallography; Watson and Crick's model.

  • Composition:

    • Double-stranded molecule; nucleotides (A, T, C, G).

    • Function: Codes for proteins; replication for cell division.

Chromosomes and Cell Division

  • Somatic Cells: Diploid (46 chromosomes).

  • Gametes: Haploid (23 chromosomes) formed through meiosis.

  • Processes:

    • Mitosis: Produces diploid daughter cells.

    • Meiosis: Produces haploid gametes.

2.3 Population Genetics and Evolution

Learning Objectives

  • Describe mechanisms influencing population allele frequency.

  • Compare homologous and analogous traits.

  • Distinguish between allopatric and sympatric speciation.

Genetic Variation and Evolution

  • Microevolution: Change in allele frequencies over time.

  • Mechanisms of Change:

    • Natural Selection: Survival of the fittest based on favorable traits.

    • Mutation: Source of new alleles.

    • Genetic Drift: Changes due to chance events.

    • Gene Flow: Exchange of genes between populations.

Speciation

  • Allopatric Speciation: Geographic isolation leads to divergence.

  • Sympatric Speciation: New species evolve from a single ancestral species without geographic isolation.

2.4 Biotechnology and Genomics

Learning Objectives

  • Describe sequencing and cloning methods.

  • Discuss bioethical concerns of genetic testing.

Advancements in Biotechnology

  • Biotechnology involves altering genetic material for new applications.

  • Genomics studies the entire genetic makeup of organisms.

  • Gene Therapy: Experimental techniques to address genetic diseases.

2.5 Science, Culture, and Evolution

Learning Objectives

  • Compare definitions of belief, facts, hypothesis, and theory.

  • Discuss education disputes regarding evolution.

  • Address misconceptions about evolution.

Evolution in Society

  • Evolutionary theory is often mischaracterized; critics confuse scientific theory with common usage.

  • Common misconceptions recognize that evolution does not explain life's origins but rather how species change over time.

  • The debate around evolution in education has historic roots, notably the Scopes Trial (1925).

Key Terms

  • Adaptation, Gene Pool, Mitosis, Meiosis, Epigenetics, Genetic Drift, Evolution, Natural Selection, etc.

Summary

  • Biological anthropology provides insights into human evolution, relations, and behaviors. Evolution occurs through natural selection driven by genetic variations.