BIOL 189A Exam #4 Study Guide

Exam #4 Study Guide For BIOL 189A, Fall 2025 (Tietjen)

Exam Format

  • Total Points: 50
    • 40 pts. selected-response questions
    • 20 pts. from new content
    • 20 pts. from previous content
    • 10 pts. free-response questions
    • 6 pts. from new content
    • 4 pts. from previous content

Chapter 11: Evolution and Natural Selection

  • What is evolution?

    • A change in the heritable characteristics of biological populations over successive generations.

  • What is adaptation?

    • Definition: A trait that enhances an organism's fitness in its environment.
    • Example: The long neck of a giraffe is an adaptation that allows it to reach leaves high in trees.

  • What is natural selection?

    • The process where organisms that are better adapted to their environment tend to survive and reproduce more than those less suited.

  • What is meant by “survival of the fittest”?

    • A phrase that describes the mechanism of natural selection where 'fittest' refers to those organisms best suited to their environment, not necessarily the strongest.

  • Can changes that occur during the lifetime of a parent be inherited by the offspring?

    • No, inherited traits are only those that are genetic and carried in the DNA.

  • How does the evolutionary story of the peppered moth an example of natural selection?

    • The population shifted in color from light to dark during the Industrial Revolution due to pollution, which made dark moths more advantageous for survival against predation.

  • What is genetic drift?

    • A mechanism of evolution that refers to random changes in allele frequencies in a population, particularly affecting smaller populations.

  • By what process do new alleles arise in a population?

    • New alleles can arise through mutations, which are changes in the DNA sequence.

  • What is the fossil record and what does it show?

    • The fossil record is a historical account of life on Earth, showing the diversity of organisms, transitions between species, and evidence of evolutionary changes over time.

  • What is the difference between homologous and analogous structures?

    • Homologous structures: Similar anatomical features that share a common ancestry (e.g., vertebrate limbs).
    • Analogous structures: Features that perform a similar function but do not share a common evolutionary origin (e.g., wings of birds and insects).

  • What is a vestigial structure?

    • Definition: A structure that has lost most or all of its original function through the course of evolution.
    • Example: The human appendix, which is reduced and has no significant role in digestion.

  • What is antibiotic resistance and how does it occur?

    • Antibiotic resistance is the ability of bacteria to survive and reproduce in the presence of antibiotics. It often occurs through mutations and selection of resistant strains due to overuse or misuse of antibiotics.

Chapter 12: Classification and Evolutionary Relationships

  • What are the three domains of life?

    • Bacteria, Archaea, and Eukarya.

  • What are the most inclusive and least inclusive categories of the Linnaean classification system?

    • Most inclusive: Domain
    • Least inclusive: Species

  • What is a scientific name and how is it written?

    • A scientific name is the formal system of naming species, using a two-part Latin name (binomial nomenclature). It is written in italics with the genus capitalized and the species lowercase (e.g., Homo sapiens).

  • What is an evolutionary tree based on?

    • An evolutionary tree is based on the genetic relationships among various species or groups, showing common ancestors and evolutionary lineages.

  • Human evolution: Homo sapiens represents the only currently living member of genus Homo – what happened to other Homo species?

    • Other species, such as Homo neanderthalensis and Homo erectus, went extinct possibly due to competition, changing environments, or other factors.
    • Is Homo sapiens currently evolving?
    • Yes, Homo sapiens continue to evolve in response to environmental pressures, disease, and other factors.

  • Why could all humans be considered “fish”?

    • All humans share a common ancestor with fish, reflecting the evolutionary transition from aquatic to terrestrial life.

  • Why does DNA provide the most accurate information for determining evolutionary relatedness?

    • DNA sequences can reveal the degree of genetic similarity between organisms, which indicates evolutionary relationships and divergence times.

  • What is an opposable thumb and with which group of organisms is it found?

    • Definition: A thumb that can be rotated and positioned opposite to the fingers, allowing for grasping. Found in primates.

  • For the evolutionary tree of all life:

    • Explain what the lines mean and how to read the diagram. Lines represent evolutionary relationships and branching points indicating common ancestors.
    • Know the identity and placement of each of the six (6) kingdoms (A-F).
    • Identify the original common ancestor of all life on Earth and where to find it on the tree.
    • Know which group was the first on Earth (with which letter and by name).
    • Identify where eukaryotes begin (between which letters).

Course Concepts from Previous Chapters

Chapter 1: Characteristics of Life

  • What are the eight (8) characteristics of all life?

    • 1. Cellular organization: All living things are made up of cells.
    • 2. Metabolism: All living things undergo chemical processes to maintain life.
    • 3. Homeostasis: The ability to maintain stable internal conditions.
    • 4. Growth and development: All living organisms grow and develop in predictable ways.
    • 5. Reproduction: All organisms have the ability to reproduce.
    • 6. Response to stimuli: Organisms respond to environmental stimuli.
    • 7. Adaptation through evolution: Populations evolve over time.
    • 8. DNA: All living organisms have genetic material that carries information.

  • What is the basic unit of life?

    • The cell is the basic unit of life.
Chapter 2: Properties of Water and Macromolecules

  • What type of molecule is water?

    • Water is a polar molecule, meaning it has a partial positive charge on one side and a partial negative charge on the other, leading to hydrogen bonding.

  • What type of macromolecule is glucose?

    • Glucose is a carbohydrate, specifically a monosaccharide. Its primary function is as a source of energy.

  • Why do oil and water not mix?

    • Oil is non-polar and does not have the ability to form hydrogen bonds with water, which is polar. This results in immiscibility.
Chapter 3: Cell Structure and Function

  • Cell membrane: What cells have it?

    • All cells, both prokaryotic and eukaryotic, have a cell membrane.

  • What is it made of?

    • The cell membrane is made of a phospholipid bilayer, proteins, cholesterol, and carbohydrates.

  • Define prokaryote.

    • Prokaryotes are unicellular organisms that do not have a membrane-bound nucleus or organelles; examples include bacteria and archaea.

  • What is endosymbiotic theory?

    • The endosymbiotic theory proposes that some organelles, such as mitochondria and chloroplasts, originated as free-living bacteria that were engulfed by ancestral eukaryotic cells.
Chapter 4: Metabolism and Energy Transfer

  • What is an enzyme and what is its function?

    • An enzyme is a biological catalyst that speeds up chemical reactions by lowering the activation energy.

  • Cellular respiration: during what process is the most ATP made?

    • The most ATP is produced during oxidative phosphorylation in the electron transport chain.

  • How are cellular respiration and photosynthesis reciprocal processes?

    • Cellular respiration consumes oxygen and glucose to produce carbon dioxide and water, while photosynthesis uses carbon dioxide and water to produce oxygen and glucose, reflecting the interdependence of these processes.
Chapter 6: Chromosomes and Cell Division

  • What is a chromosome?

    • A chromosome is a structure composed of DNA and proteins that organizes genetic material during cell division.

  • What are homologous chromosomes and from where do they derive in a diploid person?

    • Homologous chromosomes are pairs of chromosomes, one inherited from each parent, that contain the same genes but may have different alleles.

  • What is the purpose of mitosis?

    • Mitosis is the process of cell division that produces two genetically identical daughter cells for growth and repair.
Chapter 7: Meiosis and Genetic Variation

  • What is the purpose of meiosis?

    • Meiosis is the process that reduces the chromosome number by half, resulting in four genetically diverse gametes for sexual reproduction.

  • How are mitosis and meiosis similar to each other?

    • Both processes involve the division of a cell's nucleus and result in the distribution of genetic material to daughter cells.
Chapter 8: Inheritance Patterns

  • What is a carrier?

    • A carrier is an individual who has one copy of a recessive allele for a trait but does not express that trait phenotypically (e.g., carrier of an autosomal recessive disease).

  • How is inheritance of sex-linked disorders different from that of autosomal disorders?

    • Sex-linked disorders are typically associated with genes on the X or Y chromosomes, which can affect males (XY) and females (XX) differently, while autosomal disorders are linked to non-sex chromosomes and affect both sexes equally.

  • Be prepared to do a simple Punnett square for the results.

    • Example: Crossing a parent with purple flowers (Pp) with a parent with white flowers (pp) would yield a phenotypic ratio of 50% purple (Pp) and 50% white (pp), with genotypes reflecting the same percentages.
Chapter 9: Genes and Genetic Information

  • What is a gene?

    • A gene is a segment of DNA that contains the instructions for building a specific protein, influencing traits.

  • What type of macromolecule is DNA?

    • DNA is a nucleic acid, a type of macromolecule made of nucleotides containing genetic information.

  • What is the Central Dogma of Biology and the genetic flow of information?

    • Central Dogma: The flow of genetic information is described as DNA → RNA → Protein.

  • What is complementary base pairing?

    • Complementary base pairing refers to the specific pairing of nitrogenous bases in DNA (adenine with thymine and cytosine with guanine) that allows for the double helix structure and replication.