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.