General Biology Study Guide: Chapters 1, 26, 27, 28

Chapters 1, 26, 27, 28: Study Guide

Chapter 1: Introduction to Biology

This chapter introduces foundational concepts in biology, including the organization of life, scientific methodology, and the basics of evolution. Understanding these principles is essential for all subsequent topics in biology.

• Biological Hierarchy

  • Definition: The organization of living things from simplest to most complex: atom → molecule → organelle → cell → tissue → organ → organ system → organism → population → community → ecosystem → biosphere.

  • Example: A human (organism) is made up of organ systems, which are made of organs, and so on.

• Overview of Scientific Method

  • Definition: A systematic approach to inquiry involving observation, hypothesis formation, experimentation, and conclusion.

  • Key Terms: Hypothesis, variable, control, data, conclusion.

  • Example: Testing whether sunlight affects plant growth by growing plants with and without sunlight.

• Darwinian Evolution

  • Definition: The theory that species evolve over time through natural selection.

  • Darwin's Observations: Variation exists within populations; more offspring are produced than can survive; individuals with advantageous traits survive and reproduce.

  • Genetic Variation: The driving force behind evolution, caused by mutations, gene flow, and sexual reproduction.

• Mouse Video

  • Be able to answer questions about the mouse video shown in class, focusing on genetic variation and natural selection.

Chapter 26: Phylogeny and the Tree of Life

This chapter explores the diversity of life, classification systems, and evolutionary relationships among organisms. Understanding phylogeny helps biologists trace the evolutionary history of species.

• Diversity of Life

  • Known species vs. actual number of species on Earth.

  • What unifies all life? Common genetic code, cellular structure, metabolic pathways.

• Systematics

  • Definition: The scientific study of the diversity and relationships among organisms.

  • Three domains of life: Bacteria, Archaea, Eukarya.

  • Characteristics of each domain.

• Taxonomy

  • Definition: The science of naming and classifying organisms.

  • Hierarchical classification: Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.

  • Binomial nomenclature: Two-part scientific naming system (Genus species), e.g., Homo sapiens.

  • How to write correctly and who invented it (Carl Linnaeus).

• Phylogeny

  • Definition: The evolutionary history and relationships among species.

  • Based on shared characteristics and genetic information.

  • Hatch marks/branch points: Represent common ancestors in phylogenetic trees.

  • Be able to identify monophyletic, polyphyletic, and paraphyletic groups.

• Homology vs. Analogy

  • Homology: Similarity due to shared ancestry (e.g., vertebrate forelimbs).

  • Analogy: Similarity due to convergent evolution, not common ancestry (e.g., wings of birds and insects).

  • Convergent vs. divergent evolution.

• Phylogenetic Hypotheses

  • Understand what they are based on (morphological, molecular data).

Chapter 27: Bacteria and Archaea

This chapter focuses on the diversity, structure, and ecological roles of prokaryotes, including Bacteria and Archaea. Understanding their differences and significance is crucial for microbiology.

• Differences between Prokaryotic and Eukaryotic Cells

  • Prokaryotes lack a nucleus and membrane-bound organelles; eukaryotes have both.

• Bacteria vs. Archaea

  • Unique features of Archaea: Different membrane lipids, environments, and adaptations.

  • Examples of extremophiles among Archaea.

• Identifying Bacteria

  • Know prefixes (e.g., Strepto-, Staphylo-) and shapes (coccus, bacillus, spirillum).

  • Examples of beneficial, neutral, and harmful bacteria.

• Symbiosis

  • Types: Mutualism, commensalism, parasitism.

  • Examples in the human body (e.g., gut microbiota).

• Bacterial Shapes and Arrangements

  • Be able to identify or draw common shapes and arrangements.

• Bacterial Cell Structure

  • Know the purpose of cell parts: cell wall, plasma membrane, flagella, pili, nucleoid.

• Genetic Recombination

  • Transformation, transduction, conjugation.

  • How recombination increases genetic diversity.

• Energy Acquisition

  • Autotrophs vs. heterotrophs; phototrophs vs. chemotrophs.

• Pathogenic Bacteria

  • Gram-positive vs. Gram-negative bacteria.

  • Endotoxins vs. exotoxins.

  • Be familiar with diseases caused by bacteria discussed in class.

Table: Comparison of Bacteria and Archaea

Feature	Bacteria	Archaea
Cell Wall	Contains peptidoglycan	No peptidoglycan
Membrane Lipids	Ester-linked	Ether-linked
Habitat	Wide range	Often extreme environments
Pathogenicity	Many pathogenic species	Rarely pathogenic
Gene Structure	No introns (usually)	Introns present in some genes

Chapter 28: Protists

This chapter examines protists, a diverse group of mostly unicellular eukaryotes. It covers their classification, ecological roles, and evolutionary significance.

• Defining Protists

  • Protists are eukaryotes that are not plants, animals, or fungi.

  • They are polyphyletic (do not form a single clade).

  • Play roles as symbionts and parasites.

  • Examples: Plasmodium (malaria parasite), Paramecium.

• Nutritional Diversity

  • Photoautotrophs, heterotrophs, mixotrophs.

• Complexity of Protists

  • Despite being single-celled, many have complex structures and life cycles.

• Endosymbiotic Theory

  • Explains the origin of mitochondria and chloroplasts from engulfed prokaryotes.

  • Evidence: Double membranes, own DNA, similarity to certain bacteria.

• Survey of Protists

  • Four supergroups: Excavata, SAR, Archaeplastida, Unikonta.

  • Know major groups and key morphological features.

  • Understand life cycles discussed in class.

• Ecological Significance

  • Protists are important producers, decomposers, and symbionts in ecosystems.

  • Some cause diseases (e.g., malaria, sleeping sickness).