BES108D Final Exam Study Guide: Evolution, Diversity, and Plant Biology

Final Exam Study Guide: BES108D

Overview

This study guide summarizes the main topics and chapters relevant to the BES108D final exam, as outlined by Dr. Benazir Alam. The exam covers chapters related to evolution, the origin of species, phylogeny, prokaryotic diversity, seed plant evolution, and ecology. Students are advised to review chapters holistically, focusing on conceptual connections.

Chapters Covered

• Ch. 22: Descent with Modification: A Darwinian View of Life

• Ch. 23: The Evolution of Populations

• Ch. 24: The Origin of Species

• Ch. 26: Phylogeny and the Tree of Life

• Ch. 27: Bacteria and Archaea

• Ch. 30: Plant Diversity II: The Evolution of Seed Plants

• Ch. 52: An Introduction to Ecology and the Biosphere

• Ch. 54: Community Ecology

Key Topics from Chapter 30: Plant Diversity II – The Evolution of Seed Plants

Spores vs Seeds

Seed plants evolved from ancestors that reproduced via spores. Understanding the differences between spores and seeds is crucial for grasping plant reproductive strategies.

• Spore: A single-celled reproductive unit capable of developing into a new organism without fusion with another cell. Common in ferns and mosses.

• Seed: A multicellular structure containing an embryo, a food supply, and a protective coat. Found in gymnosperms and angiosperms.

• Key Differences:

  • Seeds provide greater protection and nourishment to the developing embryo.

  • Seeds can remain dormant until conditions are favorable for germination.

  • Spores are generally less resistant to harsh environmental conditions.

Feature	Spore	Seed
Structure	Single cell	Multicellular (embryo, food, coat)
Protection	Minimal	High (seed coat)
Dispersal	Wind, water	Wind, animals, water
Dormancy	Short-term	Long-term
Examples	Ferns, mosses	Gymnosperms, angiosperms

Pollination Mechanisms

Pollination is the transfer of pollen from the male anther to the female stigma in angiosperms. Mechanisms vary and are adapted to maximize reproductive success.

• Wind Pollination: Pollen is carried by air currents; common in grasses and some trees.

• Animal Pollination: Insects, birds, and mammals transfer pollen as they feed on nectar or pollen.

• Water Pollination: Rare; pollen floats on water to reach other plants.

• Self-Pollination: Pollen from the same flower fertilizes the ovule; reduces genetic diversity.

• Cross-Pollination: Pollen from one plant fertilizes another; increases genetic diversity.

Reproductive Structures of Angiosperms

Angiosperms (flowering plants) have specialized reproductive organs that facilitate pollination and seed formation.

• Flower: The reproductive structure; contains male and female organs.

• Stamen: Male organ; consists of anther (produces pollen) and filament.

• Carpel (Pistil): Female organ; consists of stigma (receives pollen), style, and ovary (contains ovules).

• Ovule: Develops into a seed after fertilization.

• Fruit: Mature ovary that protects seeds and aids in dispersal.

Plant-Derived Medicines

Many angiosperms produce compounds used in medicine. These secondary metabolites have diverse biological activities.

• Alkaloids: e.g., morphine from Papaver somniferum (poppy), used as painkillers.

• Glycosides: e.g., digoxin from Digitalis (foxglove), used for heart conditions.

• Terpenoids: e.g., taxol from Taxus brevifolia (Pacific yew), used in cancer treatment.

• Phenolics: e.g., salicylic acid from willow bark, precursor to aspirin.

Example: The discovery of quinine from the bark of Cinchona trees revolutionized malaria treatment.

Holistic Study Advice for Chapters 23, 24, 26, and 52

These chapters cover population evolution, speciation, phylogenetic relationships, and ecological principles. Students should focus on understanding how evolutionary processes shape biodiversity and how organisms interact within ecosystems.

• Population Evolution: Mechanisms such as natural selection, genetic drift, and gene flow.

• Speciation: Processes leading to the formation of new species; reproductive isolation.

• Phylogeny: Evolutionary relationships depicted in tree diagrams; classification systems.

• Ecology: Interactions between organisms and their environment; levels of ecological organization.

Additional info: Students should integrate concepts across these chapters, such as how speciation affects community structure and how phylogenetic trees inform our understanding of evolutionary history.

Review Chapters 22 and 27

These chapters were covered in previous midterms. Ensure thorough review of:

• Ch. 22: Darwinian evolution, evidence for evolution, and mechanisms of natural selection.

• Ch. 27: Diversity, structure, and function of bacteria and archaea; their ecological roles.

Summary Table: Key Concepts Across Chapters

Chapter	Main Concept	Key Terms
22	Evolution by natural selection	Adaptation, fitness, descent with modification
23	Population genetics	Gene pool, allele frequency, Hardy-Weinberg
24	Speciation	Reproductive isolation, hybrid, allopatric/sympatric
26	Phylogeny	Cladistics, monophyletic, paraphyletic
27	Bacteria & Archaea	Prokaryote, extremophile, nitrogen fixation
30	Seed plant evolution	Gymnosperm, angiosperm, pollination
52	Ecology	Biosphere, ecosystem, biotic/abiotic
54	Community ecology	Competition, predation, symbiosis

Equations and Formulas

• Hardy-Weinberg Equation:

• $p^2 + 2pq + q^2 = 1$

• Population Growth (Exponential):

• $\frac{dN}{dt} = rN$

• Population Growth (Logistic):

• $\frac{dN}{dt} = rN \left(1 - \frac{N}{K}\right)$

Additional info: This guide expands on brief syllabus points to provide context and examples for exam preparation. Students should refer to lecture notes and textbook chapters for detailed explanations and diagrams.